AU - Barbosa JA, Rebello MA
TI - Prostaglandin A1 inhibits replication of Mayaro virus in Aedes albopictus cells.
SO - Brazilian Journal of Medical & Biological Research 1995 Jan;28(1):27-30
AB - Prostaglandin A1 (PGA1) reduced Mayaro virus replication in Aedes albopictus (mosquito) cells in culture. The highest nontoxic dose of PGA1, 7.5 microM, decreased virus production by 90%. In Mayaro virus-infected cells, PGA1 inhibited virus-specific protein synthesis. However, in mock-infected cells the presence of PGA1 stimulated the synthesis of several proteins with molecular masses of 70, 57 and 23 kDa, respectively. The data obtained from this study show that PGA1 plays a role in the metabolic regulation of Aedes albopictus cells, blocking the synthesis of Mayaro virus and inducing the synthesis of cellular polypeptides.

AU - Motta MC, Fournier MV, Carvalho MG
TI - Serum concentration and increased temperature alter Mayaro virus RNA and protein synthesis in Aedes albopictus (mosquito)-infected cells.
SO - Brazilian Journal of Medical & Biological Research 1995 Jan;28(1):18-26
AB - We have previously shown the inhibition of Mayaro virus multiplication in Aedes albopictus-infected cells maintained at a supraoptimal temperature for growth (37 degrees C) and a stimulation of virus production in response to high serum concentrations in the incubation medium. In the present study, we addressed the question of how the effect of continuous heat stress and high serum concentration soon after infection interfere with virus macromolecule synthesis. Cells maintained at 28 degrees C in the presence of 2% serum synthesized a viral genomic RNA of 12 kb and a subgenomic RNA of 5.2 kb 6 h postinfection. Analysis of the protein profile showed the presence of the viral nucleocapsid protein of 34 kDa (P34). However, if infected cells were maintained at 37 degrees C, a smear starting immediately below the 5.2-kb RNA was noticed and the viral P34 was not detected by SDS-PAGE. Addition of 10% serum to the growth medium of infected cells maintained at 37 degrees C results in a viral RNA profile and protein synthesis similar to those observed in cultures kept at 28 degrees C, i.e., the smear was not observed and the P34 protein was detected. The results suggest that the inhibition of virus multiplication by temperature may be related to the inhibition of viral nonstructural protein synthesis early during infection. The presence of high serum levels in the incubation medium protects macromolecule synthesis against heat stress.

AU - Coppenhaver DH, Singh IP, Sarzotti M, Levy HB, Baron S
TI - Treatment of intracranial alphavirus infections in mice by a combination of specific antibodies and an interferon inducer.
SO - Am. J. Trop. Med. Hyg. 1995 Jan;52(1):34-40
AB - Finding an effective treatment for viral infections that cause encephalitis remains an important problem. A model of human alphavirus infections, Semliki Forest virus, causes lethal encephalitis in weanling mice. Mice are viremic within 24 hr of an intraperitoneal challenge with the equivalent of three 75% lethal doses of Semliki Forest virus. Virus reaches the brain by 48 hr, and mortality results in all mice in 5-7 days. Introduction of virus intracranially accelerates the course of the infection. Neither anti-Semliki Forest virus hyperimmune serum nor the potent interferon inducer poly I:CLC given intraperitoneally are protective when used therapeutically after an intracranial virus infection, but a combination of 1,000 U hyperimmune serum and 80 micrograms/mouse of poly I:CLC results in a 50% survival rate. This combination treatment of intracranial Semliki Forest virus infection eliminates detectable viremia and reduces virus load in the brain over the course of the infection. These data show that when combined, specific antibody and an interferon inducer can interact synergistically to protect mice from alphavirus infections of the central nervous system even when given after the virus is replicating in the target organ.

AU - McGill PE
TI - Viral infections: alpha-viral arthropathy. [Review]
SO - Baillieres Clinical Rheumatology 1995 Feb;9(1):145-50
AB - Six different mosquito-borne viruses (Chikungunya, O'nyong-nyong, Mayaro, Ross River, Sindbis and Barmah Forest) have been associated with arthritis in humans. These viruses are prevalent in the tropics and subtropics and they produce similar symptoms, consisting of fever, joint pains and rash. The symptoms are usually of short duration, around 1 week; complete recovery is the rule apart from exceptional cases of Chik infection. Precise diagnosis requires a serological service which is not available in many parts of the tropics these days. Treatment is symptomatic and there is no vaccine currently available. With an increasing number of visitors to the tropics being exposed to potential infection and with rapid air transport it is possible that visitors may return home during the viraemic incubation stage, infect the local mosquito populations and then develop clinical disease. [References: 31] virus.

AU - Ben-Nathan D, Maestroni GJ, Lustig S, Conti A
TI - Protective effects of melatonin in mice infected with encephalitis viruses.
SO - Arch. Virol. 1995;140(2):223-30
AB - We examined the effect of the pineal neurohormone melatonin (MLT) on protection from viral encephalitis. The antiviral activity of MLT was evaluated in normal mice inoculated with Semliki Forest virus (SFV) and in stressed mice injected with the attenuated non-invasive West Nile virus (WN-25). Administration of MLT (s.c.) daily from 3 days before through 10 days after virus inoculation reduced viremia and significantly postponed the onset of disease and death by 7 to 10 days. Moreover, MLT injection reduced mortality of SFV (10 PFU) inoculated mice from 100% to 44%. In mice inoculated with high dose of SFV (100 PFU), MLT postponed death and reduced mortality by 20%. In all of the surviving mice anti-SFV antibodies were detected 22 days after virus inoculation. Infection of mice stressed by either isolation or dexamethasone injection with WN-25 induced mortality of 75% and 50% respectively, which was reduced by MLT administration to 31% and 25%, respectively. The efficiency of MLT in protecting from lethal viral infections warrants further investigations on its mechanisms of action.

AU - Mokhtarian F, Shi Y, Zhu PF, Grob D
TI - Immune responses, and autoimmune outcome, during virus infection of the central nervous system.
SO - Cellular Immunology 1994 aug;157(1):195-210
AB - A combined role of a virus infection of the central nervous system (CNS) and an autoimmune response to myelin basic protein (MBP), an autoantigen of the CNS, is suggested in the pathogenesis of multiple sclerosis (MS). SJL mice are highly susceptible while B6 mice are less susceptible to the induction of experimental autoimmune encephalomyelitis (EAE), the autoimmune model of MS. Peripheral inoculation of Semliki forest virus (SFV) into SJL and B6 mice resulted in: (1) Higher viral titers, more severe clinical disease, and hence a stronger nonspecific and SFV-specific lymphoproliferation, and production of IFN-gamma and TNF/LT was observed by splenocytes (SPL) of B6 than by those of SJL mice, on Day 7 postinfection. (2) Following viral clearance, however, proliferation to SFV, and to MBP, and the production of IFN-gamma and TNF/LT by SPL of SFV-infected SJL mice were significantly higher, while the production of TGF-beta was significantly lower than by those of B6 mice. In conclusion, the immune responses to SFV, and to MBP, which were triggered by SFV infection were significantly higher and more prolonged in the SPL of SJL mice, the EAE-susceptible mice, than by those of B6 mice after the infection was cleared.

AU - Preece NE, Amor S, Baker D, Gadian DG, O'Neill JK, Urenjak J
TI - Experimental encephalomyelitis modulates inositol and taurine in the spinal cord of Biozzi mice.
SO - Magnetic Resonance in Medicine 1994 Dec;32(6):692-7
AB - In this high resolution magnetic resonance spectroscopic study of experimental allergic encephalomyelitis (EAE) and Semliki Forest virus (SFV) infection of the Biozzi AB/H mouse, marked increases in the initially low levels of N-trimethyl compounds in the spinal cord were observed during probable demyelinating episodes. There was also a pronounced and reproducible modulation of the levels of taurine and myo-inositol during acute and again during chronic relapsing EAE. The ratio of N-acetyl-aspartate to creatine in the spinal cord of mice infected with the mutant M9 strain of SFV decreased to approximately 70% of that seen in normal mice.

AU - Uemura Y, Yang YH, Heldebrant CM, Takechi K, Yokoyama K
TI - Inactivation and elimination of viruses during preparation of human intravenous immunoglobulin.
SO - Vox Sanguinis 1994;67(3):246-54
AB - We report here the results of our evaluation of virus inactivation during the manufacturing steps of two intravenous immunoglobulin (IGIV) preparations. Virus inactivation and/or removal by processing steps, such as ethanol fractionation and polyethylene glycol precipitation, and deliberate virucidal steps, such as solvent/detergent treatment and pasteurization, were tested on a variety of human pathogenic and experimental model viruses, including human immunodeficiency, Hepatitis C, Mumps, Vaccinia, Chikungunya, Vesicular Stomatitis, Sindbis, and ECHO viruses. All viruses were successfully inactivated and/or eliminated by the processing steps studied. In some cases, however, multiple steps were required. We conclude that the incorporation of steps deliberately designed to inactivate or remove viruses during the production of IGIV provides an extra measure of viral safety.

AU - Guy JS, Barnes HJ, Smith LG
TI - Experimental infection of young broiler chickens with eastern equine encephalitis virus and Highlands J virus.
SO - Avian Diseases 1994 Jul-Sep;38(3):572-82
AB - Two-week-old broiler chickens were experimentally infected with either eastern equine encephalitis (EEE) virus or Highland J (HJ) virus. Mortality rates were 24/30 (80%) in EEE-virus-inoculated chickens and 2/30 (7%) in HJ-virus-inoculated chickens. Chickens inoculated with EEE virus exhibited severe depression and somnolence on days 1-6 postexposure (PE), with 17/30 birds dying during this period. After day 6 PE, EEE-virus-inoculated chickens exhibited abdominal distention, depression, and growth retardation, and an additional seven chickens died. Pathologic changes in EE-virus-inoculated chickens dying on days 1-6 PE consisted of multifocal necrosis in the heart and liver, as well as lymphoid depletion and necrosis in the thymus, spleen, and bursa of Fabricius. Ascites, pericardial effusion, and right ventricular dilatation of the heart were the predominant lesions in chickens dying after day 6 PE. No clinical signs were observed in sham-inoculated controls or in most HJ-virus-inoculated chickens. Ascites, pericardial effusion, and multifocal myocardial necrosis were observed in 2/30 HJ-virus-inoculated chickens that died or were euthanatized after development of clinical signs. These findings indicate that both EEE virus and HJ virus are pathogenic for young chickens.

AU - Guy JS, Barnes HJ, Ficken MD, Smith LG, Emory WH, Wages DP
TI - Decreased egg production in turkeys experimentally infected with eastern equine encephalitis virus or Highlands J virus.
SO - Avian Diseases 1994 Jul-Sep;38(3):563-71
AB - Turkey breeder hens were experimentally infected with strains of eastern equine encephalitis (EEE) virus or Highlands J (HJ) virus previously isolated from turkey hens experiencing decreased egg production. Depression and inappetance were observed on day 1 postexposure (PE) in hens inoculated with either EEE virus or HJ virus, and egg production fell in each virus-inoculated group from approximately 75% to less than 20% within 2-3 days PE. Egg production remained depressed (less than 20%) for 15 days in EEE-virus-inoculated hens and for 7 days in HJ-virus-inoculated hens. EEE virus and HJ virus were recovered from various tissues on days 1-5 PE, and virus was detected in eggs laid on days 2-5 PE. The findings of this study confirm that EEE virus and HJ virus are potential causes of decreased egg production in turkey breeder hens.

AU - Yu S, Aaskov JG
TI - Development of a candidate vaccine against Ross River virus infection.
SO - Vaccine 1994 Sep;12(12):1118-24
AB - Ross River virus is a mosquito-borne alphavirus which causes several thousand cases of arthritis (epidemic polyarthritis) each year. In this study, binary ethylenimine (BEI) was used to destroy the infectivity of this virus without abolishing the antigenicity or immunogenicity of the virion. Mice immunized intramuscularly with BEI-inactivated virus, with or without Alhydrogel adjuvant, produced antibody which neutralized Ross River virus in vitro, and the mice also failed to develop viraemia when challenged intravenously with live virus. Serum neutralization and in vivo protection were greatest when BEI-inactivated virus was administered without adjuvant.

AU - Khalili-Shirazi A, Gregson N, Webb HE
TI - A study of brain gangliosides and other glycolipids after infection with Semliki Forest virus.
SO - Biochemical Society Transactions 1994 May;22(2):87S

AU - Griffin DE, Levine B, Tyor WR, Tucker PC, Hardwick JM
TI - Age-dependent susceptibility to fatal encephalitis: alphavirus infection of neurons. [Review]
SO - Arch. Virol. - Supplementum 1994;9:31-9
AB - Sindbis virus encephalitis in mice provides a model for studying age-dependent susceptibility to acute viral encephalitis. The AR339 strain of SV causes fatal encephalitis in newborn mice, but weanling mice recover uneventfully. Increased virulence for older mice is associated with a single amino acid change from Gln to His at position 55 of the E2 glycoprotein. Weanling mice with normal immune systems clear infectious virus from neurons through an antibody-mediated mechanism. This does not happen in newborn mice because the infected neurons die soon after they are infected. Death in immature neurons, as well as most other mammalian cells infected with Sindbis virus, occurs by induction of apoptosis. This can be prevented by cellular expression of bcl-2, an inhibitor of apoptosis, which is expressed by mature neurons in culture. We conclude that mature neurons are resistant to induction of apoptosis after infection with SV through expression of cellular inhibitors of apoptosis. This provides the opportunity for antibody to clear virus by a noncytolytic mechanism. [References: 22]

AU - Eleazer TH, Hill JE
TI - Highlands J virus-associated mortality in chukar partridges.
SO - Journal of Veterinary Diagnostic Investigation 1994 Jan;6(1):98-9

AU - Muller U, Steinhoff U, Reis LF, Hemmi S, Pavlovic J, Zinkernagel RM, Aguet M
TI - Functional role of type I and type II interferons in antiviral defense.
SO - Science 1994 Jun 24;264(5167):1918-21
AB - Mice lacking the known subunit of the type I interferon (IFN) receptor were completely unresponsive to type I IFNs, suggesting that this receptor chain is essential for type I IFN-mediated signal transduction. These mice showed no overt anomalies but were unable to cope with viral infections, despite otherwise normal immune responses. Comparison of mice lacking either type I or type II IFN receptors showed that, at least in response to some viruses, both IFN systems are essential for antiviral defense and are functionally nonredundant.

AU - Anonymous
TI - Ross River virus infection.
SO - Weekly Epidemiological Record 1994 Apr 1;69(13):98-9

AU - Griffin DE, Levine B, Ubol S, Hardwick JM
TI - The effects of alphavirus infection on neurons. [Review]
SO - Annals of Neurology 1994;35 Suppl:S23-7
AB - Sindbis virus is an alphavirus that causes encephalitis in mice. The primary target cells for central nervous system infection are neurons. The outcome of neuronal infection is dependent on the age of the mouse at the time of infection (maturity of the neuron) and the strain of virus used for infection (virulence of the virus). Sindbis virus causes neuronal death by inducing apoptosis. As neurons mature, they become resistant to virus-induced apoptosis, resulting in a persistent infection. Host production of antibody to a viral surface glycoprotein acts to downregulate virus replication in the infected neurons by a noncytolytic mechanism and clears infectious virus from the central nervous system. Specific genetic changes in the virus result in more virulent strains that cause severe disease and sometimes death in mature animals. These same genetic alterations also confer the ability to overcome the resistance of neurons to induction of cell death. Therefore, mature neurons infected with virulent viruses do not recover from infection even in the presence of an adequate immune response. [References: 27]

AU - Levine B, Hardwick JM, Griffin DE
TI - Persistence of alphaviruses in vertebrate hosts. [Review]
SO - Trends in Microbiology 1994 Jan;2(1):25-8
AB - Alphaviruses are a group of arthropod-borne, positive-strand RNA viruses that cause acute encephalitis or arthritis. These viruses were previously thought to cause only acute infections in vertebrates, but recent evidence suggests that host immunological and tissue-specific factors may act together to promote the persistence of alphavirus genomes in vivo. [References: 34]

AU - Glasgow GM, Killen HM, Liljestrom P, Sheahan BJ, Atkins GJ
TI - A single amino acid change in the E2 spike protein of a virulent strain of Semliki Forest virus attenuates pathogenicity.
SO - J. Gen. Virol. 1994 Mar;75 ( Pt 3):663-8
AB - The virulent strain SFV4 of Semliki Forest virus (SFV), produced from the infectious clone pSP6-SFV4, is lethal after intranasal (i.n.) infection of adult mice and for pregnant mice after intraperitoneal (i.p.) infection. In contrast, the A7 strain of SFV is avirulent when given i.n. to adult mice, but induces fetal death in pregnant mice after i.p. infection. The nucleotide and deduced amino acid sequences of part of the core and all of the envelope region of A7-SFV were determined and compared to those of SFV4. A7 differed from SFV4 at 80 nucleotides (nt) in the coding sequence, 15 of which were associated with amino acid differences and seven of which (two in the E2 protein and five in E1) were non-conservative. The 3' non-coding sequence of A7 was longer (415 nt) than that of SFV4 (263 nt) and a divergent sequence of 181 nt was present adjacent to the end of the E1 coding region. The effects on virulence of two mutations in the E2 gene of SFV4, resulting in the non-conservative amino acid substitutions present in A7, were analysed. One mutation (mut 8729 a/c) resulted in only slight attenuation, whereas the other (mut 8902 a/g) resulted in avirulence for pregnant mice. However, mut 8902 a/g was lethal for the majority of developing fetuses after i.p. infection of the mother.

AU - Wesselingh SL, Levine B, Fox RJ, Choi S, Griffin DE
TI - Intracerebral cytokine mRNA expression during fatal and nonfatal alphavirus encephalitis suggests a predominant type 2 T cell response.
SO - Journal of Immunology 1994 Feb 1;152(3):1289-97
AB - Sindbis virus (SV) causes an acute encephalomyelitis in mice. A T cell-dependent inflammatory response is first detected 3 days after infection and includes T cells, B cells, and macrophages. The cytokines produced locally by intrinsic cells of the brain in response to infection and by infiltrating mononuclear cells and their contributions to outcome of infection have not been identified. Semiquantitative reverse transcriptase-PCR was used to evaluate the expression of mRNAs for IL-1 beta, IL-2, IL-4, IL-6, IL-10, TNF-alpha, leukemia inhibitory factor (LIF), and TGF-beta in the brain during fatal and nonfatal SV encephalitis of immunocompetent BALB/cJ and immunodeficient scid/CB17 mice. IL-1 beta and IL-6 mRNAs were detected in uninfected mice before infection and were up-regulated within 24 h. TGF-beta mRNA was also constitutively expressed in uninfected mice. LIF mRNA was occasionally detected in uninfected mice but increased in amounts only in BALB/cJ not scid mice after infection. TNF-alpha, IL-4, and IL-10 mRNAs were not found in uninfected mice but were induced within 24 h and continued to rise through 7 days after infection with substantially higher levels in BALB/cJ than scid mice. These data suggest that intrinsic brain cells produce IL-1, IL-4, IL-6, IL-10, LIF, and TGF-beta mRNAs in response to viral infection. IFN-gamma and IL-2 mRNAs were detected only in BALB/cJ mice and not until 3 days after infection with the initiation of inflammation. IL-4 and IL-10 mRNAs were more persistent and more easily detectable than IL-2 and IFN-gamma mRNAs. These data suggest a predominant type 2 cytokine response in the brain during SV encephalitis. BALB/cJ mice infected with a neurovirulent strain of SV (NSV), had 100% mortality, whereas NSV-infected scid mice developed persistent nonfatal infection. Inflammation was more intense in NSV-infected mice, however, no substantial differences in cytokine mRNA levels were detected when compared with mice with nonfatal SV infection suggesting that the cytokines measured do not in and of themselves lead to fatal central nervous system disease.

AU - Vene S, Franzen C, Niklasson B
TI - Development of specific antibody patterns and clinical symptoms following Ockelbo virus infection.
SO - Arch. Virol. 1994;134(1-2):61-71
AB - Sixteen patients with symptoms typical for Ockelbo disease (rash, arthralgia, fever) were enrolled in a 2 1/2 year study, during which clinical symptoms were recorded and ELISA was employed to study specific IgM, IgG and IgG subclass development. Initially, all patients presented with rash and arthralgia, and five patients still suffered from joint symptoms at the end of the study period. Ockelbo virus specific IgM was detected during the first week post onset in 6 patients and in 15 patients by day 14. One patient failed to develop specific IgM and was later diagnosed with a human parvovirus B19 infection. All patients were IgM-negative 2 1/2 years post onset. Seroconversions or significant titer rises for specific total IgG were seen in 15 patients. IgG titers generally peaked within one year but in two patients maximum titers were seen 2 1/2 years post onset. Development of IgG1 followed that of total IgG, while IgG3, after an initial increase in all Ockelbo disease patients, remained at peak levels for one year in four patients, three of whom still had detectable IgG3 at the end of the study period. Ockelbo virus specific IgG2 or IgG4 was not detected in any of the patients.

AU - Roehrig JT
TI - Immunogens of encephalitis viruses.
SO - Veterinary Microbiology 1993 Nov;37(3-4):273-84
AB - The equine encephalitis viruses are members of the genus Alphavirus, in the family Togaviridae. Three main virus serogroups represented by western (WEE), eastern (EEE) and Venezuelan equine encephalitis (VEE) viruses cause epizootic and enzootic infection of horses throughout the western hemisphere. All equine encephalitis viruses are transmitted through the bite of an infected mosquito. The first equine encephalitis virus vaccines were produced by virus inactivation. Problems with inadequate inactivation, which may have caused a major epidemic/epizootic of VEE in central America and Texas in the 1970s, led to the development of a live attenuated VEE virus vaccine (TC-83) derived by cell culture passage. Inactivated vaccines are still used to prevent equine infections with WEE and EEE viruses. Alphaviruses are small single stranded, positive sense RNA viruses. The 12000 nucleotide genome is enclosed in an icosahedral nucleocapsid composed of multiple copies of the capsid (C) protein. The virion is enveloped. The membrane is modified by the insertion of heterodimers of two glycoproteins: E1 and E2. Monoclonal antibody analysis of the surface glycoproteins have provided a detailed understanding of important protective antigens. Recent studies comparing gene sequences from virulent and avirulent VEE viruses have begun to delineate mechanisms of alphavirus attenuation.

AU - Rebello MC, Fonseca ME, Marinho JO, Rebello MA
TI - Interferon action on Mayaro virus replication.
SO - Acta Virologica 1993 aug;37(4):223-31
AB - Treatment of TC7 cells with interferon (IFN) drastically reduced the yield of infectious Mayaro virus under experimental conditions that virus attachment and penetration into the cells were not affected. In IFN-treated cells, synthesis of Mayaro virus proteins was inhibited and cellular protein synthesis was restored. This phenomenon is dependent on IFN concentration and multiplicity of infection. Electron microscopy of these cells revealed normal and anomalous viral particles inside cytoplasmic vacuoles. This suggests that IFN also interferes with Mayaro virus morphogenesis and inhibits the release of virions from cells.

AU - Lundstrom JO, Vene S, Saluzzo JF, Niklasson B
TI - Antigenic comparison of Ockelbo virus isolates from Sweden and Russia with Sindbis virus isolates from Europe, Africa, and australia: further evidence for variation among alphaviruses.
SO - Am. J. Trop. Med. Hyg. 1993 Nov;49(5):531-7
AB - The plaque-reduction neutralization test (PRNT) was used to compare 15 isolates of Ockelbo virus from Sweden, one isolate of Ockelbo virus from Russia, the Egyptian prototype Sindbis virus, and Sindbis-like viruses from Slovakia, South Africa, Cameroon, and australia. Strains from northern Europe (Sweden and Russia) were indistinguishable by PRNT. We observed some antigenic variation between isolates of Sindbis virus from Europe, Africa, and australia. An australian strain (C-377) was shown to be distinct from prototype Sindbis virus, and the Acrocephalus strain from Slovakia was shown to be identical to prototype Sindbis virus. All other strains, including Ockelbo virus isolates, were shown to be subtypes of prototype Sindbis virus.

AU - Subak-Sharpe I, Dyson H, Fazakerley J
TI - In vivo depletion of CD8+ T cells prevents lesions of demyelination in Semliki Forest virus infection.
SO - J. Virol. 1993 Dec;67(12):7629-33
AB - Following intraperitoneal infection of BALB/c mice with the A7(74) strain of Semliki Forest virus, the virus spreads to the central nervous system (CNS) and initiates an acute inflammatory reaction which includes lesions of primary demyelination. This demyelination is dependent upon activated T lymphocytes. To determine whether CD4+ or CD8+ T cells are involved in the pathogenesis of the demyelination, we have investigated the course of infection in animals treated with monoclonal anti-CD4 or anti-CD8 antibodies. In the normal course of infection, virus was detectable in the brain by infectivity assay and in situ hybridization for up to 14 days. Antiviral immunoglobulin M (IgM) and all subclasses of IgG were produced. From day 10 to 21 postinfection lesions of inflammatory demyelination were present, most notably in the cerebellum and corpus callosum but also in other white matter tracts. Administration of anti-CD4 antibodies removed CD4+ cells from the spleen, prevented production of antiviral IgG, increased virus titers in the brain, and increased demyelination. Administration of anti-CD8 antibodies depleted CD8+ cells from the spleen and did not affect antiviral IgG synthesis or spread of brain virus but reduced CNS inflammatory responses and virtually abolished lesions of demyelination. Administration of both antibodies depleted both T-cell subsets from the spleen, prevented IgG antibody production, increased brain virus, and abrogated both CNS inflammation and lesions of demyelination. In conclusion, the CNS demyelination induced by Semliki Forest virus can be prevented by in vivo depletion of CD8+ T lymphocytes.

AU - Wages DP, Ficken MD, Guy JS, Cummings TS, Jennings SR
TI - Egg-production drop in turkeys associated with alphaviruses: eastern equine encephalitis virus and Highlands J virus.
SO - Avian Diseases 1993 Oct-Dec;37(4):1163-6
AB - Alphaviruses were isolated from tracheas of turkey breeders in two North Carolina flocks experiencing a severe drop in egg production. Highlands J virus was isolated from one of the breeder flocks, in which production decreased by as much as 72.6% in selected houses over a 48-to-96-hour period. Eastern equine encephalitis virus was isolated from the second breeder flock, which experienced an egg-production drop of 44.5%. Clinical signs in both flocks were similar, with inactivity and the egg-production drop being the only clinical signs observed. Eggs from affected breeders were small and white, and a few were soft-shelled. Sera collected from the flocks 2 to 3 weeks after production began dropping confirmed the presence of antibodies to the viruses recovered. In the first flock, egg production failed to return to above 50%, although heat stress may have played a role in production recovery. The second flock was taken out of production and recycled.

AU - Mudge P
TI - Update on Ross River fever. [Review]
SO - australian Family Physician 1993 Oct;22(10):1792-3
AB - Ross River fever, or epidemic arthritis, is caused by the Ross River virus and usually mild and short-lived although persisting joint symptoms can develop. This article reviews the cause, diagnosis and treatment of this sometimes debilitating disease. [References: 6]

AU - Michael MA, Cottam HB, Smee DF, Robins RK, Kini GD
TI - Alkylpurines as immunopotentiating agents. Synthesis and antiviral activity of certain alkylguanines.
SO - Journal of Medicinal Chemistry 1993 Oct 29;36(22):3431-6
AB - Several simple 8-substituted 9-alkyl- and 7,8-disubstituted 9-alkylguanine derivatives were synthesized as potential antiviral agents. These were tested for antiviral protection against a lethal Semliki Forest virus (SFV) infection in mice, and their antiviral properties were evaluated from a structure-activity standpoint. In this model system, 9-alkylguanines with the alkyl chain consisting of four to six carbons were found to be the most active. Substitution of the 8-position of the purine ring did not enhance activity, with the exception of the 7-alkyl-8-oxo substituent. These data were found to support the hypothesis that guanines need not contain an intact carbohydrate moiety in order to exhibit antiviral activity by virtue of immune potentiation. Hence, phosphorylation of guanosine analogs that exhibit antiviral activity by a similar mechanism does not play a significant role.

AU - Tyor WR, Griffin DE
TI - Virus specificity and isotype expression of intraparenchymal antibody-secreting cells during Sindbis virus encephalitis in mice.
SO - Journal of Neuroimmunology 1993 Oct;48(1):37-44
AB - To study the generation of specific antibody responses within the central nervous system (CNS), we have utilized a murine model of acute viral encephalitis. When Sindbis virus (SV) is injected intracerebrally into weanling mice it causes an acute non-fatal encephalitis and recovery is primarily dependent on the development of antiviral antibody. We used a modified enzyme-linked immunoassay to determine the number of antibody-secreting cells (ASC) specific for SV and their Ig isotype in brain, spleen and cervical lymph nodes over the course of the acute encephalitis. The numbers of SV-specific ASC peak early in spleen and lymph nodes and then begin to increase in brain, suggesting that initial stimulation of B cells occurs primarily in peripheral lymphoid tissue followed by B cell entry into the circulation and appearance in the brain. The pattern for each individual isotype was similar with peak numbers of SV-specific cells present in the spleen 5-7 days after infection, while numbers in the brain continue to rise through day 20 when most ASC were secreting IgG2a or IgA SV-specific antibody. The data suggest therefore that most isotype switching from IgM to IgG and IgA occurs in peripheral lymphoid tissue. An exception to this pattern is IgG1, where numbers of ASC producing IgG1 do not show a peak in spleen and continue to rise in brain through the course of acute encephalitis. The data also indicate that early in infection a large proportion of ASC in the brain are not specific for SV and demonstrate that recruitment of ASC into the CNS is non-specific.(ABSTRACT TRUNCATED AT 250 WORDS)

AU - Penna JE, Irving LG
TI - Evidence for meningitis in Ross River virus infection [letter].
SO - Medical Journal of australia 1993 Oct 4;159(7):492-3

AU - Levine B, Griffin DE
TI - Molecular analysis of neurovirulent strains of Sindbis virus that evolve during persistent infection of scid mice.
SO - J. Virol. 1993 Nov;67(11):6872-5
AB - To understand the role of tissue-specific adaptation and antibody-induced selectional pressures in the evolution of neurovirulent viruses, we analyzed three strains of Sindbis virus isolated from the brains of persistently infected scid mice and four strains of Sindbis virus isolated from the brains of scid mice with viral reactivation following immune serum treatment. For each viral isolate, we tested neurovirulence in weanling BALB/c mice and sequenced regions of the E2 and E1 envelope glycoprotein genes that are known to contain important determinants of Sindbis virus neurovirulence. One strain isolated from a persistently infected scid mouse and two strains isolated from scid mice with viral reactivation were neurovirulent, resulting in mortality in 80 to 100% of weanling BALB/c mice. All three neurovirulent strains contained an A-->U change at nucleotide 8795, which predicts a Gln-->His substitution at E2 amino acid position 55. No nucleotide changes were detected in the other sequenced regions of the E2 and E1 envelope glycoprotein genes or in the avirulent isolates. Our findings indicate that tissue-specific adaptations, rather than antibody-induced selectional pressures, are a critical determinant of the evolution of neurovirulent strains of Sindbis virus and provide evidence that E2 His-55 is an important neuroadaptive mutation that confers neurovirulence properties on Sindbis virus. AU - Ficken MD, Wages DP, Guy JS, Quinn JA, Emory WH
TI - High mortality of domestic turkeys associated with Highlands J virus and eastern equine encephalitis virus infections.
SO - Avian Diseases 1993 Apr-Jun;37(2):585-90
AB - High mortality occurred in two flocks of commercial turkey hens placed in southern North Carolina in fall 1991. Daily mortality peaked at 3.19% in Flock 1 and 3.79% in Flock 2. Clinical signs included restlessness, somnolence, vocalization, and acute death. Gross lesions included atrophy of the bursa of Fabricius, thymus, and spleen, and watery intestinal contents. Microscopic changes included moderate to marked lymphocyte necrosis and depletion in the bursa, thymus, and spleen, widely scattered necrosis of pancreatic acinar cells, and mild villous atrophy and fusion in the jejunum and ileum with cuboidal to low columnar epithelial cells covering the villous tips. In Flock 1, at 27 days of age, reovirus and picornavirus particles were detected in the feces. One week later, togavirus-like particles were observed in fecal contents, and two of seven serum samples showed seroconversion to Highlands J virus. Eleven days later, five of six serum samples were positive for antibodies against Highlands J virus, with a fourfold increase in the geometric mean titer. In Flock 2, seroconversion to eastern equine encephalitis virus was observed in four of 10 serum samples 11 days after the onset of clinical signs. Based on the above observations, it is suspected that these alphaviruses were the cause of the clinical syndrome.

AU - Guy JS, Ficken MD, Barnes HJ, Wages DP, Smith LG
TI - Experimental infection of young turkeys with eastern equine encephalitis virus and highlands J virus.
SO - Avian Diseases 1993 Apr-Jun;37(2):389-95
AB - Depression, somnolence, and increased mortality were observed in 2-week-old turkeys inoculated intramuscularly with either eastern equine encephalitis (EEE) virus or Highlands J (HJ) virus. Mortality rates in EEE virus- and HJ virus-inoculated turkeys were 7/30 (23%) and 9/30 (27%), respectively; no sham-inoculated controls died. Both EEE virus- and HJ virus-inoculated turkeys developed viremia that lasted 2 days; peak mean titers were 5.5 and 3.2 log10 plaque-forming units per ml of blood, respectively. Pathologic changes in both EEE virus- and HJ virus-inoculated turkeys consisted primarily of multifocal necrosis in the heart, kidney, and pancreas, and lymphoid necrosis and depletion in the thymus, spleen, and bursa of Fabricius. The findings indicate that EEE virus and HJ virus are pathogenic for young turkeys.

AU - de Andrade AF, Carvalho M da G
TI - Metabolic and morphological changes in A. albopictus cells infected with Mayaro virus under heat-shock conditions.
SO - Arch. Virol. 1993;131(1-2):101-14
AB - We addressed the question how temperature elevation inhibits Mayaro virus replication in Aedes albopictus infected cells. The morphology and macromolecular changes induced by temperature, infection and high serum concentration were investigated in these cells. Cells incubated with 2 and 10% serum at 28 degrees C disclosed an intense vacuolization and inhibition of [35S]methionine incorporation in a time-dependent manner. 34 and 50 kDa viral structural proteins were detected 24 h after infection. In contrast, an inhibition of viral proteins synthesis occurred when infected cells were kept at 37 degrees C (heat-shock conditions). Total cellular RNA was isolated from mock and infected cells incubated at 28 or 37 degrees C. Northern blot analysis with a Mayaro genomic probe coding for viral structural proteins showed a decrease in the amount of viral 26S RNA in stressed cells when compared to those kept at 28 degrees C. Taken together, these results suggest that the inhibition of viral proteins synthesis in response to temperature elevation is associated with a decrease in the amount of subgenomic 26S RNA.

AU - Li XD, Qiu FX, Yang H, Rao YN, Calisher CH
TI - Isolation of Getah virus from mosquitos collected on Hainan Island, China, and results of a serosurvey.
SO - Southeast Asian Journal of Tropical Medicine & Public Health 1992 Dec;23(4):730-4
AB - An isolate of Getah virus was obtained from Culex mosquitos collected in Mao'an Village, Baoting County, Hainan Province, China, in 1964. The virus (strain M-1) replicated in laboratory-bred Aedes aegypti and Cx. fatigans (= quinquefasciatus), and was transmitted by laboratory-bred Ae. albopictus to healthy newborn albino mice. Skeletal muscles of newborn albino mice experimentally infected with the virus showed degeneration, atrophy, necrosis, and inflammatory changes of muscle fibers. Antibody prevalence in humans and animals ranged from 10.3% by neutralization tests of samples from healthy people in 1979 to 26.4% by CF tests of samples from people with febrile illnesses in 1982. The high prevalence of antibody in pigs, horses, and goats (17.6% to 37.5%) indicated that infection with Getah or a closely related virus is relatively common in domestic animals.

AU - Gu HX, Artsob H, Lin YZ, Wang DM, Zhao BY, Long QZ
TI - Arboviruses as aetiological agents of encephalitis in the People's Republic of China.
SO - Trans. R. Soc. Trop. Med. Hyg. 1992 Mar-Apr;86(2):198-201
AB - A serological study was undertaken to determine the role of arboviruses as etiological agents of encephalitis in the People's Republic of China (PRC). Paired sera were collected during mosquito seasons in 1988-1990 from 614 patients with possible viral encephalitis in 15 regions of PRC and tested for haemagglutination inhibiting antibodies to selected arboviruses. Seroconversions were documented to alphavirus and flavivirus antigens in 13.0 and 18.7% of patients respectively in most of the study areas. No California group seroconversion was detected. The age of alphavirus seroconvertors ranged from 2 months to 32 years and of flavivirus seroconvertors from 6 months to 50 years, with higher numbers in males. Serious central nervous system manifestations were seen more commonly in flavivirus seroconvertors. This study affirms the importance of flavivirus as causative agents of encephalitis in PRC and provides evidence that one or more alphaviruses are causing symptomatic infections with neurological involvement in PRC.

AU - Grosfeld H, Lustig S, Gozes Y, Velan B, Cohen S, Leitner M, Lachmi B, Katz D, Olshevski U, Shafferman A
TI - Divergent envelope E2 alphavirus sequences spanning amino acids 297 to 352 induce in mice virus-specific protective immunity and antibodies with complement-mediated cytolytic activity.
SO - J. Virol. 1992 Feb;66(2):1084-90
AB - We have proposed a general algorithm for identification of potential immunoprotective domains (cassettes) on the envelope E2 polypeptide of alphaviruses (H. Grosfeld, B. Velan, M. Leitner, S. Cohen, S. Lustig, B.E. Lachmi, and A. Shafferman, J. Virol. 63:3416-3422, 1989). To assess the generality of our approach, we compared analogous E2 cassettes from Sindbis virus (SIN) and Semliki Forest virus (SFV), two alphaviruses which are philogenetically very remote. The antigenically distinct SFV E2 and SIN E2 cassettes exhibit comparable immunological characteristics. Most significantly, the SIN E2 LMN cassette cluster (E2 amino acids 297 to 352 fused to beta-galactosidase), like the analogous SFV E2 LMN cassettes, elicited high titers of antivirus antibodies in mice and proved to be highly effective in protection against lethal challenge. Mice immunized with SIN E2 LMN were completely protected against intracerebral challenge of 10 to 100 50% lethal doses of different neurovirulent SIN strains. Anti-SIN LMN antibodies, like anti-SFV LMN antibodies, lacked in vitro neutralizing activity, yet both exerted protection against homologous challenge upon transfer to mice. The two antibody preparations exhibited virus-specific complement-mediated cytolysis of cells infected with the homologous but not heterologous virus. These results suggest a possible mechanism for virus-specific E2 LMN-induced protection and demonstrate the generality of our methodology for deciphering immunogenic and protective domains in alphavirus systems. Results suggest also that the E2 LMN sequence of any given alphavirus should be considered as a component of a synthetic vaccine against that specific virus.

AU - Anonymous
TI - Barmah Forest virus [editorial].
SO - Lancet 1991 Apr 20;337(8747):948-9

AU - Asai T, Shibata I, Uruno K
TI - Susceptibility of pregnant hamster, guinea pig, and rabbit to the transplacental infection of Getah virus.
SO - Journal of Veterinary Medical Science 1991 Dec;53(6):1109-11

AU - Kamada M, Kumanomido T, Wada R, Fukunaga Y, Imagawa H, Sugiura T
TI - Intranasal infection of Getah virus in experimental horses.
SO - Journal of Veterinary Medical Science 1991 Oct;53(5):855-8
AB - Aerosol transmission in equine Getah virus (GV) infection was examined by intranasal inoculation with 10(3.0) to 10(7.0) TCID50 of the MI-110 strain in 7 experimental horses. The establishment of intranasal infection of GV was confirmed in all these horses by detecting serum neutralizing antibody against the MI-110 strain. Horses inoculated with more than 10(4.0) TCID50 of the virus manifested mild pyrexia, eruptions, serous nasal discharge, lymphopenia or monocytosis. Viremia ranging from 10(1.0) to 10(3.5) TCID50/0.2 ml occurred in horses inoculated with 10(5.0) TCID50, or more. Virus recovery from the nasal cavity was observed only in horses inoculated with 10(7.0) TCID50, and the viral titers recorded were 10(3.0) TICD50/ml or less. From these results, it is assumed that GV disseminated from the nasal cavity of naturally infected horses, except for intranasal infection with a lot of the virus, is probably very low in titer. So it seems to be rare that GV in natural cycles is spread from horse to horse by aerosol transmission.

AU - Kamada M, Wada R, Kumanomido T, Imagawa H, Sugiura T, Fukunaga Y
TI - Effect of viral inoculum size on appearance of clinical signs in equine Getah virus infection.
SO - Journal of Veterinary Medical Science 1991 Oct;53(5):803-6
AB - A study was performed to examine the effect of viral inoculum size on the appearance of clinical signs in equine Getah virus (GV) infection by intramuscular inoculation with 10(1.3) to 10(6.3) TCID50 of the MI-110 strain in 6 experimental horses. When inoculated with more than 10(3.3) TCID50 of the virus, every horse developed pyrexia, edema in the hind legs, serous nasal discharge, lymphopenia and viremia in the relatively early stage of disease. On the other hand, enlargement of the submandibular lymph node was observed only in horses inoculated with 10(5.3) and 10(6.3) TCID50 of the virus, while typical eruptions were developed in every horse inoculated with 10(4.3) TCID50 or less. These results demonstrated that the appearance of clinical signs in equine GV infection was dependent on viral inoculum size. Besides, it was assumed to be rare chance that eruptions and enlargement of the submandibular lymph node were developed simultaneously in a horse.

AU - Levine B, Hardwick JM, Trapp BD, Crawford TO, Bollinger RC, Griffin DE
TI - Antibody-mediated clearance of alphavirus infection from neurons.
SO - Science 1991 Nov 8;254(5033):856-60
AB - Humoral immunity is important for protection against viral infection and neutralization of extracellular virus, but clearance of virus from infected tissues is thought to be mediated solely by cellular immunity. However, in a SCID mouse model of persistent alphavirus encephalomyelitis, adoptive transfer of hyperimmune serum resulted in clearance of infectious virus and viral RNA from the nervous system, whereas adoptive transfer of sensitized T lymphocytes had no effect on viral replication. Three monoclonal antibodies to two different epitopes on the E2 envelope glycoprotein mediated viral clearance. Treatment of alphavirus-infected primary cultured rat neurons with these monoclonal antibodies to E2 resulted in decreased viral protein synthesis, followed by gradual termination of mature infectious virion production. Thus, antibody can mediate clearance of alphavirus infection from neurons by restricting viral gene expression.

AU - Ubol S, Griffin DE
TI - Identification of a putative alphavirus receptor on mouse neural cells.
SO - J. Virol. 1991 Dec;65(12):6913-21
AB - Alphaviruses replicate in a wide variety of cells in vitro. The prototype alphavirus, Sindbis virus, causes an age-dependent encephalitis in mice and serves as an important model system for the study of alphavirus neurovirulence. To begin to understand the role of cellular virus receptors in the pathogenesis of Sindbis virus infection, we developed an anti-idiotypic antibody made in rabbits against a neutralizing monoclonal antibody specific for the E2 surface glycoprotein. The anti-idiotypic antibody (anti-Id 209) bound to N18 mouse neuroblastoma cells and inhibited adsorption of 35S-labeled virus by 50%. Binding of anti-Id 209 was inhibited by pretreatment of N18 cells with various proteases but not with neuraminidase or phospholipase, while virus binding was inhibited by pretreatment with phospholipase as well as protease. Anti-Id 209 precipitated proteins of 110 and 74 kDa from N18 cells intrinsically labeled with [35S]methionine. N18 cells grow with two phenotypes in culture, and immunoprecipitation of 125I-surface-labeled cells showed that the 74-kDa protein was present on loosely adherent cells growing in aggregates, while the 110-kDa protein was present in smaller amounts on firmly adherent cells growing as a monolayer. Analysis of brain cells from newborn mice by flow cytometry showed that all cells expressed the receptor protein at birth, but by 4 days after birth half of the cells had ceased receptor expression. A survey of other cell lines showed the protein to be present on murine fibroblastic and other rodent neuroblastoma cell lines but rarely on human neural or nonneural cell lines. These studies suggest that one of the receptors for Sindbis virus on mouse neural cells is a protein that is regulated during development of the nervous system. Developmental down-regulation of receptor protein expression may contribute to the age-dependent nature of susceptibility of mice to fatal alphavirus encephalitis.

AU - Shibata I, Hatano Y, Nishimura M, Suzuki G, Inaba Y
TI - Isolation of Getah virus from dead fetuses extracted from a naturally infected sow in Japan.
SO - Veterinary Microbiology 1991 May;27(3-4):385-91
AB - Three viruses producing a cytopathic effect in cell culture were isolated from dead fetuses extracted from a naturally infected sow, and were found to be serologically identical by neutralization tests. One of the viruses was cloned and named the Sakura strain. The Sakura strain was identified as Getah virus by cross-neutralization tests.

AU - Pinto AJ, Morahan PS, Brinton M, Stewart D, Gavin E
TI - Comparative therapeutic efficacy of recombinant interferons-alpha, -beta, and -gamma against alphatogavirus, bunyavirus, flavivirus, and herpesvirus infections.
SO - Journal of Interferon Research 1990 Jun;10(3):293-8
AB - Recombinant (r) preparations of interferons (IFN)-alpha, -beta, and -gamma were shown to protect mice against experimental virus infections with herpes simplex virus type 2 (HSV-2), and with three RNA-containing viruses from different families: Banzi, a flavivirus; Semliki Forest virus (SFV), an alphatogavirus; and Caraparu, a bunyavirus. The antiviral effects of the three different types of IFN were different with each virus. HSV-2 was the most sensitive virus, followed by SFV. Against Banzi virus, IFN-gamma was only effective when given both before and after infection. Against Caraparu virus, only IFN-gamma had a significant effect. These results suggest that IFN therapy might be valuable in human infections with these viruses, but that the correct choice of IFN and dose regimen is likely to be important.

AU - Truyen U, Kaaden OR
TI - Studies on the role of linear epitopes in neutralization of alphaviruses.
SO - Zentralblatt Fur Veterinarmedizin - Reihe B 1990 Mar;37(2):118-24
AB - By using three synthetic peptides (16-19 amino acids in length) representing different regions of glycoproteins E1 (peptide 3) and E2 (peptides 1 and 2) of Sindbis and Semliki Forest virus and isolated glycoprotein fractions of both viruses in reduced and non-reduced form, the role of linear epitopes for the neutralization was investigated. The reaction patterns of sera induced by immunization with these antigens indicate that conformational epitopes do play the major role in neutralization of alphaviruses. Furthermore, no cross-neutralization of these alphaviruses classified in different antigenic complexes within this genus was found.

AU - Olaleye OD, Omilabu SA, Baba SS
TI - Growth of Igbo-Ora virus in some tissue cultures.
SO - Acta Virologica 1990 aug;34(4):367-71
AB - VERO, MRC5, MDCK, and MA104 cells were tested for their ability to support the growth of Igbo-Ora virus. In VERO and MRC5 cell cultures the virus replicated to high titres causing apparent cytopathic effects (CPE) (cell rounding and complete lysis) and formation of complement fixing antigens. The virus grew to lower infectious titre in MDCK and MA104 cell cultures in which CPE was limited to cell rounding only.

AU - Uryvaev LV, Parasiuk NA, Ionova KS, Mikheeva TG, Zlobin AIu, Skvortsova TM, Mel'nikova EE, Glushchenko OP, L'vov DK
TI - [Monoclonal antibodies to the Karelian fever virus. The characteristics of their biological properties]. [RUSSIAN]
SO - Voprosy Virusologii 1990 Jul-aug;35(4):322-6
AB - Biological properties of 6 variants of monoclonal antibodies (MAb) to Karelian fever virus, a member of the alpha-virus serocomplex Sindbis-WEE, produced by the available hybridomas. The productivity of hybridomas of the "Karel" series in tissue culture and in cultivation as ascitic fluid was evaluated. Among the antibodies analysed, all were specific to envelope proteins, of them 2 were against protein E2 and four against protein E1. Comparison of MCA biologic activity (neutralizing, antihemagglutinating activities, participation in immunofluorescence, EIA, and immune blotting) allows one to distinguish four different hybridomas among them producing specific antibodies differing in their properties.

AU - Mezencio JM, de Souza W, Fonseca ME, Rebello MA
TI - Ultrastructural study of Mayaro virus replication in BHK-21 cells.
SO - Arch. Virol. 1990;114(3-4):229-35
AB - The replication of Mayaro virus in BHK-21 cells was studied by electron microscopy. The infected cells show an intense vacuolization and proliferation of membranous structures. At 5 h post-infection, precursor virus particles were seen in the cytoplasm of infected cells. Later, mature virus particles were found outside the cells and budding from the plasma membrane. Enveloped virus particles were also observed inside the vesicles and budding across their membrane. The release of virus particles into the extracellular space by exocytosis was also observed. In a later stage of the infection, inclusion bodies were sometimes present in the cytoplasm of infected cells. We conclude that in BHK-21 cells, budding from the plasma membrane is the main process of Mayaro virus maturation, and in this kind of cell replication differs significantly from that observed in Aedes albopictus cells.

AU - Hiruma M, Ide S, Hohdatsu T, Yamagishi H, Tanaka Y, Fujisaki Y
TI - Polymyositis in mice experimentally inoculated with Getah virus.
SO - Nippon Juigaku Zasshi - Japanese Journal of Veterinary Science 1990 aug;52(4):767-72
AB - Mice inoculated intracerebrally with parent, large-plaque (LP) and small-plaque (SP) strains of Kanagawa strain of Getah virus showed clinically recumbency and paralysis. The LP strain caused recumbency more rapidly and killed mice more early after inoculation than the parent and SP strains. Microscopically, skeletal muscles of the whole body were involved showing degenerative or inflammatory changes. In mice inoculated with the parent or SP strains, there were degeneration and necrosis of the muscle fibers with inflammatory cell infiltration and regenerative reaction. The lesions were particularly conspicuous in muscles of the hind legs. In mice inoculated with the LP strain, most of the muscle fibers revealed degeneration and necrosis, but reactive changes were poor. In addition, the periosteum and muscular connective tissue were thickened with karyorrhexis. Electron microscopically, virus particles were recognized mainly in cisternae of sarcoplasmic reticulum in skeletal muscle fibers of mice inoculated with the LP strain, while they were rare in those of animals injected with the parent and SP strains. From these finding, it was suggested that Kanagawa strain of Getah virus has the virulence to skeletal muscles of mice.

AU - Hohdatsu T, Takahasi N, Ide S, Yamagishi H, Saito H, Fujisaki Y, Koyama H
TI - The relation between pathogenicity and plaque size of Getah virus Kanagawa strain in suckling mice.
SO - Nippon Juigaku Zasshi - Japanese Journal of Veterinary Science 1990 Jun;52(3):519-26
AB - The relation among biological properties, particularly pathogenicity for suckling mice, and plaque size was studied in four virus strains: Getah virus strain Kanagawa; two strains obtained by plaque cloning of the Kanagawa strain, Getah Kanagawa SP (G-K-SP) strain which forms small plaques (SP) only and strain G-K-LP which forms large plaques (LP) only; and strain Haruna which forms SP only. There were no marked differences among the four strains in serological properties, growth curves and sensitivity to pH, trypsin and temperature. Strain G-K-LP showed higher pathogenicity for suckling mice than strain G-K-SP. However, the pathogenicity of strain Haruna, which forms SP only, was as high as that of strain G-K-LP. Some of the clones in SP of strain Kanagawa kill all mice in 5 to 6 days after inoculation while the others required 9 to 11 days or longer before causing death. The present study showed that the pathogenicity of Getah viruses shortly after being isolated from the field, such as the Kanagawa strain, is different between large and small plaques, and even among small plaques, at least in suckling mice, and that the pathogenicity has no relation to plaque size.

AU - Phillips DA, Murray JR, Aaskov JG, Wiemers MA
TI - Clinical and subclinical Barmah Forest virus infection in Queensland.
SO - Medical Journal of australia 1990 May 7;152(9):463-6
AB - Barmah Forest virus is a mosquito-borne agent (alphavirus) reported to cause both clinical and subclinical infections in New South Wales. This report describes 29 cases of clinical Barmah Forest virus infection diagnosed between July 1988 and March 1989 (21 from Queensland, six from New South Wales and two from Victoria) and provides evidence of extensive subclinical infection with this virus (0.23% of the population per annum) throughout Queensland. It also includes a description of the first isolation of Barmah Forest virus from a patient. Data obtained in the course of the study suggest that Barmah Forest virus infections may not be diagnosed correctly in many instances because of the similarity of the symptoms of this disease to those of epidemic polyarthritis and the small number of laboratories providing the necessary serological services.

AU - Scott TW, Lorenz LH, Weaver SC
TI - Susceptibility of Aedes albopictus to infection with eastern equine encephalomyelitis virus.
SO - Journal of the American Mosquito Control Association 1990 Jun;6(2):274-8
AB - We examined susceptibility of a strain of Aedes albopictus from Houston, Texas to experimental infection with eastern equine encephalomyelitis (EEE) virus. After 15 days of extrinsic incubation, all Ae. albopictus examined by the cell culture assay and fluorescent antibody staining were infected but only 57% (4/7) of the mosquitoes that refed transmitted virus by bite. Data supported the concept of a salivary gland infection barrier to EEE virus in Ae. albopictus and the conclusion that virus replicates in fat body following dissemination from the midgut and prior to infection of salivary glands. Assay of adult progeny from females that fed on viremic chicks and fluorescent antibody studies of infected females failed to provide evidence that EEE virus is transmitted vertically by Ae. albopictus.

AU - Lahesmaa-Rantala R, Stahlberg TH, Granfors K, Kuusisto P, Toivanen A
TI - Serological cross-reactions against Yersinia enterocolitica in patients infected with other arthritis-associated microbes.
SO - Clinical & Experimental Rheumatology 1990 Jan-Feb;8(1):5-9
AB - In order to investigate arthritis-triggering, serologically cross-reactive antigens, sera from patients infected with arthritis-associated microbes, Salmonellae, Chlamydia trachomatis, and Sindbis-like alphavirus, were reacted against SDS-PAGE separated and immunoblotted Yersinia enterocolitica 0:3 antigens. These sera reacted with Yersinia to the same extent as did the control sera taken from patients with streptococcal, staphylococcal and Bordetella pertussis infections or from healthy blood donors. Moreover, the various sera produced different reactivity patterns, directed against several different antigens. Although sera from test subjects, as well as from controls including healthy individuals, recognized some Yersinia antigens, these patterns differed markedly from those recognized by sera taken from patients with Yersinia infection. Significantly, analysis of the reactivities against the different molecular weight antigen components of Yersinia revealed no dominant band or pattern which could thus have been defined as arthritis-associated.

AU - Dropulic B, Masters CL
TI - Entry of neurotropic arboviruses into the central nervous system: an in vitro study using mouse brain endothelium.
SO - Journal of Infectious Diseases 1990 Apr;161(4):685-91
AB - Arbovirus infection of cerebral microvascular endothelial cells was investigated in an in vitro mouse brain endothelial (MBE) cell model. Alphaviruses replicated to a greater extent than did flaviviruses, indicating that viremia may be important in neuroinvasion. Also, some viruses (e.g., Semliki Forest virus) replicated to high titers while others (e.g., Murray Valley encephalitis virus) did not. Viruses that replicated to high titers showed luminal polarity of virus release, indicating that infection of the endothelium may be important in both maintenance of viremia and neuroinvasion; viruses that did not so replicate showed abluminal polarity of release, indicating that virus is actively transported across the endothelial monolayer, another mechanism for neuroinvasion. Infection of MBE cells with highly and less-neuroinvasive strains achieved similar results, indicating that the endothelium does not discriminate between neuroinvasive strains. However, the cerebral microvascular endothelium may be important in discriminating between viruses that invade the brain parenchyma and those that do not: neuron-tropic Ross River virus T48 replicated to higher titers than did ependymal-tropic Ross River virus NB5092. Thus, viruses probably use multiple cellular mechanisms to invade the central nervous system across the cerebral microvascular endothelium.

AU - Calisher CH, Karabatsos N, Foster JP, Pallansch M, Roehrig JT
TI - Identification of an antigenic subtype of eastern equine encephalitis virus isolated from a human.
SO - Journal of Clinical Microbiology 1990 Feb;28(2):373-4
AB - Eastern equine encephalitis (EEE) virus was isolated from the cerebrospinal fluid of a 6-year-old male who had clinically diagnosed aseptic meningitis and subsequently died. Several standard serologic tests that use polyclonal antibody and indirect immunofluorescence and hemagglutination inhibition tests that use monoclonal antibody provided evidence that the isolate was an antigenic subtype of prototype North American EEE virus. We believe that this is the first evidence of an antigenic subtype of EEE virus.

AU - Mathews JH, Roehrig JT
TI - Specificity of the murine T helper cell immune response to various alphaviruses.
SO - J. Gen. Virol. 1989 Nov;70 ( Pt 11):2877-86
AB - We investigated the specificity of the T helper (Th) cell immune response to three alphaviruses: Venezuelan equine encephalomyelitis (VEE), eastern equine encephalitis (EEE) and western equine encephalitis (WEE). Single cell suspensions were prepared from spleens of virus-primed C3H mice, and T lymphocyte populations were enriched by nylon wool chromatography. T cells were incubated in vitro with irradiated, syngeneic splenic stimulator cells previously exposed to purified virus. Cellular proliferation was measured by [3H]thymidine uptake 5 days post-stimulation. The predominant proliferating cell type secreted interleukin-2 and was of the Th cell phenotype Thy-1+, Lyt-1+,2-, L3T4+. Stimulation of VEE, EEE and WEE virus-primed Th cells with homologous and heterologous virus resulted primarily in a proliferative response specific for the immunizing virus. The corresponding antibody response, as measured by ELISA using purified virus as antigen, was also specific for the immunizing virus. The magnitude of the blastogenic response of VEE TC-83 virus-primed lymphocytes to a battery of VEE subtype viruses was remarkably similar to schemes of antigenic classification. The results indicate that the dominant Th cell epitopes on these alphaviruses represent regions largely virus-specific and lead to a virus-specific B cell response which does not change over time after primary inoculations of mice with VEE and WEE viruses and multiple inoculations of mice with EEE virus.

AU - Greiser-Wilke I, Moenning V, Kaaden OR, Figueiredo LT
TI - Most alphaviruses share a conserved epitopic region on their nucleocapsid protein.
SO - J. Gen. Virol. 1989 Mar;70 ( Pt 3):743-8
AB - Fourteen hybridoma cell lines secreting antibodies against the Semliki Forest virus nucleocapsid protein were established and employed for identification of conserved epitopes among 27 alphavirus types and subtypes. Using an antibody capture test, the antibodies were found to cross-react to variable degree with alphaviruses belonging to the Semliki Forest, western encephalitis and eastern encephalitis complexes, as well as Middelburg and Ndumu. None of the antibodies reacted with either Venezuelan equine encephalitis or Barmah Forest virus. Due to their reactivity with Fort Morgan, Y62-33, Whataroa and chikungunya, the monoclonal antibodies were divided into six reactive types. Competition assays showed that the epitopes for all the types were either identical or clustered on a single domain of the nucleocapsid protein.

AU - Smirnov IuA, Kapitulets SP, Tsilinskii IaIa, Esenaliev RO, Morev PG, Oraevskii AA, Nikogosian DN
TI - [Inactivation of alpha VEE virus using a high intensity laser with UV-radiation]. [RUSSIAN]
SO - Biofizika 1989 Jul-aug;34(4):570-3
AB - Inactivation of VEE virus with laser UV impulses of nano- and picosecond duration was investigated. It has been shown that in both cases there is a decrease of the inactivation cross-section with the rise of irradiation intensity. It points to the fact that the major lethal photoproduct in VEE is formed by a single-quantum mechanism.

AU - Walton TE, Jochim MM, Barber TL, Thompson LH
TI - Cross-protective immunity between equine encephalomyelitis viruses in equids.
SO - American Journal of Veterinary Research 1989 Sep;50(9):1442-6
AB - Eighteen equids were inoculated with eastern equine encephalomyelitis (EEE) and 18 equids with western equine encephalomyelitis (WEE) viruses to produce EEE virus- and WEE virus-immunized equids. Twelve surviving EEE virus-seropositive equids, 15 surviving WEE virus-seropositive equids, and 10 nonimmunized, seronegative equids (controls) were subsequently inoculated with an equine pathogenic (epizootic) strain of Venezuelan equine encephalomyelitis (VEE) virus to determine cross-protective immunity. Challenge infection produced 90% mortality in control (nonimmunized) equids, and 40% mortality in WEE virus-seropositive equids; all EEE virus-seropositive equids survived. Postchallenge exposure VEE viremia levels in EEE virus- or WEE virus-seropositive equids were lower than those in the 10 nonimmunized VEE virus-inoculated control equids. Plaque-neutralizing antibody responses to VEE virus in the EEE virus- and WEE virus-seropositive equids were similar in time of onset and titer to the antibody responses of nonimmunized equids. Neutralizing antibody to the third equine encephalomyelitis virus (either EEE virus or WEE virus) was detectable in 19 of 27 equids after inoculation with the challenge virus, VEE. Demonstration of cross-protective immunity between EEE or WEE virus and VEE virus in equids confirmed field observations made during the VEE epizootic in Texas in 1971.

AU - Meek AD, Faragher SG, Weir RC, Dalgarno L
TI - Genetic and phenotypic studies on Ross River virus variants of enhanced virulence selected during mouse passage.
SO - Virology 1989 Oct;172(2):399-407
AB - We have passaged Ross River virus (RRV) in mice to generate variants with increased mouse virulence and attempted to relate changes in virulence to genome sequence changes. RRV NBO (zero passage in mice) is a plaque-purified clone of the mouse-avirulent strain RRV NB5092, and is of low virulence for day-old mice. During RRV NBO replication in infant mice, its virulence for day-old mice increased markedly with time. By 7 days postinfection the LD50 value of harvested virus (passage level one) was congruent to 10(4)-fold less than that of the parental virus. No further decrease in LD50 followed 10 serial passages in infant mice. However, 10th passage level virus showed increased clinical effects in week-old mice by comparison with virus from passage levels one and two. The growth kinetics of RRV variants in mice suggested that the rate and extent of RRV replication in the brain tissue determined the enhanced mouse virulence of serially passaged virus. Seven out of eight independently passaged, 10th passage level variants had changes in the E2 gene leading to one or two amino acid substitutions. The changes were at residues 212, 232, 234, 251, 341, 27 and 172, and 72 and 134 in these variants; all changes except two were nonconservative. Residues 212, 234, and 251 form part of a neutralization determinant in RRV. Changes in epitope b2 (which includes amino acids 246, 248, and 251) alter the kinetics of RRV entry into cells (P. Kerr, R. C. Weir, and L. Dalgarno, unpublished data). First and second passage level virus of enhanced virulence was unchanged in E2 or E1 gene sequences from RRV NBO. However, 1st, 2nd, and 10th passage level virus induced higher levels of virus-specific RNA synthesis than did RRV NBO in cultured BHK cells. We propose a model for the mechanism of virulence enhancement on passaging RRV NBO in mice.

AU - Vrati S, Fernon CA, Dalgarno L, Weir RC
TI - Location of a major antigenic site involved in Ross River virus neutralization.
SO - Virology 1988 Feb;162(2):346-53
AB - The location of a major antigenic domain involved in the neutralization of an alphavirus, Ross River virus, has been defined in terms of its position in the amino acid sequence of the E2 glycoprotein. The domain encompasses three topographically close epitopes which were identified using three E2-specific neutralizing monoclonal antibodies in competitive binding assays. Nucleotide sequencing of the structural protein genes of monoclonal antibody-selected antigenic variants showed that for each variant there was a single nucleotide change in the E2 gene leading to a nonconservative amino acid substitution in E2. Changes were at positions 216, 234, and 246-251 in the amino acid sequence. The epitopes are in a region of E2 which, though not strongly conserved as to sequence among Ross River virus, Semliki Forest virus, and Sindbis virus, is conserved in its hydropathy profile among the three alphaviruses. The epitopes lie between two asparagine-linked glycosylation sites (residues 200 and 262) in E2. They are conserved as to position between the mouse virulent T48 strain and the mouse avirulent NB5092 strain.

AU - Weaver SC, Scott TW, Lorenz LH, Lerdthusnee K, Romoser WS
TI - Togavirus-associated pathologic changes in the midgut of a natural mosquito vector.
SO - J. Virol. 1988 Jun;62(6):2083-90
AB - Arthropod-borne viruses were not previously believed to cause discernible pathologic changes in their natural mosquito vectors. We report cytopathologic lesions in the midgut of the mosquito, Culiseta melanura, 2 to 5 days after oral infection with eastern equine encephalomyelitis virus. Sloughing of densely staining, heavily infected epithelial cells into the midgut lumen was observed by light and transmission electron microscopy, along with degeneration of cells within the epithelium. Pathological changes in midgut epithelial cells sometimes included loss of brush border and basal lamina integrity. Disruption of the midgut basal lamina could result in bypassing of barriers to virus dissemination within the mosquito and allow rapid transmission to occur. Alternatively, luminal sloughing of heavily infected midgut epithelial cells may serve to modulate mosquito infections. These findings challenge previous beliefs regarding the benign nature of arbovirus-invertebrate host relationships.

AU - Lvov DK, Vladimirtseva EA, Butenko AM, Karabatsos N, Trent DW, Calisher CH
TI - Identity of Karelian fever and Ockelbo viruses determined by serum dilution-plaque reduction neutralization tests and oligonucleotide mapping.
SO - Am. J. Trop. Med. Hyg. 1988 Dec;39(6):607-10
AB - The causative agents of Ockelbo disease in Sweden, Pogosta disease in Finland, and Karelian fever in the USSR have been attributed to alphaviruses (family Togaviridae) related to Sindbis virus. We compared prototypes Sindbis, Ockelbo, and Karelian fever viruses by neutralization tests. We also analyzed oligonucleotide fingerprint maps of prototypes Ockelbo and Karelian fever viruses and a strain of Sindbis virus from Czechoslovakia. The results indicate that Ockelbo and Karelian fever viruses are essentially identical and suggest that Ockelbo disease, Pogosta disease, and Karelian fever are synonyms for the same disease.

AU - Karabatsos N, Lewis AL, Calisher CH, Hunt AR, Roehrig JT
TI - Identification of Highlands J virus from a Florida horse [published erratum appears in Am J Trop Med Hyg 1989 Mar;40(3):228].
SO - Am. J. Trop. Med. Hyg. 1988 Dec;39(6):603-6
AB - A virus, strain 64A-1519, isolated from the brain of a horse dying of encephalitis in Florida in 1964, was identified as western equine encephalomyelitis (WEE) virus. Recently, we used polyclonal and monoclonal immune reagents to identify this isolate by comparing it to 2 strains of WEE virus and to Highlands J (HJ) virus in hemagglutination-inhibition, immunofluorescent antibody, and plaque-reduction neutralization tests. These tests demonstrate that strain 64A-1519 is a strain of HJ virus distinct from WEE virus.

AU - Scott TW, Olson JG, All BP 3d, Gibbs EP
TI - Detection of eastern equine encephalomyelitis virus antigen in equine brain tissue by enzyme-linked immunosorbent assay.
SO - American Journal of Veterinary Research 1988 Oct;49(10):1716-8
AB - Sensitivity and specificity of an antigen-capture ELISA vs virus isolation in cell culture were evaluated for the detection of eastern equine encephalomyelitis (EEE) virus in the brain tissue of naturally infected equids. Brain specimens from 16 equids with neurologic disease were examined by ELISA and by inoculation onto baby hamster kidney cell cultures. Of 10 brain samples from which virus was isolated in the cell culture bioassay, all were correctly identified as containing EEE virus antigen by ELISA. None of the remaining 6 specimens, without detectable infectious EEE virus, contained detectable antigen. Sensitivity and specificity of the ELISA were 100% with no false-positive or false-negative results. The antigen-capture ELISA was a rapid, sensitive, specific, and simple alternative to a traditional bioassay for the detection of EEE virus.

AU - Kumanomido T, Kamada M, Wada R, Kenemaru T, Sugiura T, Akiyama Y
TI - Pathogenicity for horses of original Sagiyama virus, a member of the Getah virus group.
SO - Veterinary Microbiology 1988 aug;17(4):367-73
AB - Sagiyama virus is a member of the Getah virus group. Its pathogenicity for horses was examined. All the horses infected with the original 4 strains of Sagiyama virus (M6/Mag 33, Mag 121, Mag 132 and Mag 258) developed pyrexia ranging from 39.0 to 40.0 degrees C. Other clinical signs, characterized by eruptions, edema in the hind legs, enlargement of the submandibular lymph node and mild leukopenia, were also manifested. Viremia occurred 1-4 days post-inoculation (p.i.). Virus was recovered from spleen, liver, lung and various lymph nodes of a horse autopsied on Day 4 p.i. The maximum titer of virus (10(6.0) TCID50 g-1) was detected in the inguinal lymph node. Seroconversion was demonstrated in all the infected horses on Day 5 p.i. These clinical signs and virological findings were similar to those of horses infected naturally. The results indicate that Sagiyama virus has pathogenicity for horses and is similar to that of Getah virus.

AU - Berezina LK, Chizhov NP, L'vov DK
TI - [Chemoprophylaxis and chemotherapy of arbo- and arenavirus infections]. [Review] [RUSSIAN]
SO - Voprosy Virusologii 1988 May-Jun;33(3):268-75

AU - Kumanomido T, Wada R, Kanemaru T, Kamada M, Hirasawa K, Akiyama Y
TI - Clinical and virological observations on swine experimentally infected with Getah virus.
SO - Veterinary Microbiology 1988 Mar;16(3):295-301
AB - The pathogenicity of Getah virus for swine was examined. All 8 pigs (4 adults and 4 piglets) inoculated with Strains MIP-99 and MI-110 developed pyrexia ranging from 39.4 to 40.7 degrees C and anorexia. Mild depression and diarrhea were observed in 2 of the 4 piglets. These clinical signs were transient. Viremia occurred 1-2 days post-inoculation (p.i.) and the maximum titer was 10(3.0) TCID50 0.1 ml-1. The virus was recovered from a piglet autopsied on Day 3 p.i. from spleen and various lymph nodes. The maximum titer of virus (10(3.75) TCID50 0.1 g-1) was detected in the inguinal lymph node. Seroconversion was demonstrated in all the pigs on Day 6 p.i. These results suggest that Getah virus is mildly pathogenic for swine, which may play a role as an amplifying host in nature.

AU - Kumanomido T, Wada R, Kanemaru T, Kamada M, Akiyama Y, Matumoto M
TI - Transplacental infection in mice inoculated with Getah virus.
SO - Veterinary Microbiology 1988 Feb;16(2):129-36
AB - Transplacental transmission was demonstrated in pregnant mice subcutaneously inoculated with Getah virus. Viremia was shown in the infected dams, and high-titered virus was detected in the placenta and later in the fetus, suggesting virus invasion of the fetus through hematogenous infection of the placenta. High-titered virus was shown in the fetal brain and muscle and in the brain of the young dying soon after birth. Intrauterine infection resulted in a reduction of the litter size, number of young born alive and survival rate to 1 week of age. These results were further corroborated by necropsy performed several days after virus inoculation. The stage of gestation at the time of virus inoculation greatly influenced these results. Dams inoculated at 12 days of gestation delivered all dead babies, whereas virus inoculation at 5 days of gestation had no effect on the number of young born alive. The dams inoculated at 8 days of gestation had reduced litter sizes and those inoculated at 16 days of gestation produced slightly fewer live babies. Gestational stage at the time of virus inoculation also influenced viral growth in fetuses and placentas. The infection rate was low in dams inoculated at 5 days of gestation, high in dams inoculated at 8 or 16 days of gestation and 100% in dams inoculated at 12 days of gestation. High-titered virus was shown in placentas and fetuses of the dams inoculated at 8, 12 or 16 days of gestation. These results suggest that Getah virus may readily cross the placental barrier through hematogenous infection of the placenta in mice.

AU - Fleming JO
TI - Viral neurovirulence. [Review]
SO - Laboratory Investigation 1988 May;58(5):481-3

AU - Katz JB, Hanson SK
TI - Encephalomyelitis vaccines: a Vero-derived cell culture alternative to primary duck embryonic cell cultures [letter].
SO - Vaccine 1988 Feb;6(1):6

AU - Faragher SG, Meek AD, Rice CM, Dalgarno L
TI - Genome sequences of a mouse-avirulent and a mouse-virulent strain of Ross River virus.
SO - Virology 1988 Apr;163(2):509-26
AB - The nucleotide sequence of the genomic RNA of a mouse-avirulent strain of Ross River virus, RRV NB5092 (isolated in 1969), has been determined and the corresponding sequence for the prototype mouse-virulent strain, RRV T48 (isolated in 1959), has been completed. The RRV NB5092 genome is approximately 11,674 nucleotides in length, compared with 11,853 nucleotides for RRV T48. RRV NB5092 and RRV T48 have the same genome organization. For both viruses an untranslated region of 80 nucleotides at the 5' end of the genome is followed by a 7440-nucleotide open reading frame which is interrupted after 5586 nucleotides by a single opal termination codon. By homology with other alphaviruses, the 5586-nucleotide open reading frame encodes the nonstructural proteins nsP1, nsP2, and nsP3; a fourth nonstructural protein, nsP4, is produced by read-through of the opal codon. The RRV nonstructural proteins show strong homology with the corresponding proteins of Sindbis virus and Semliki Forest virus in terms of size, net charge, and hydropathy characteristics. However, homology is not uniform between or within the proteins; nsP1, nsP2, and nsP4 contain extended domains which are highly conserved between alphaviruses, while the C-terminal region of nsP3 shows little conservation in sequence or length between alphaviruses. An untranslated "junction" region of 44 nucleotides (for RRV NB5092) or 47 nucleotides (for RRV T48) separates the nonstructural and structural protein coding regions. The structural proteins (capsid-E3-E2-6K-E1) are translated from an open reading frame of 3762 nucleotides which is followed by a 3'-untranslated region of approximately 348 nucleotides (for RRV NB5092) or 524 nucleotides (for RRV T48). Excluding deletions and insertions, the genomes of RRV NB5092 and RRV T48 differ at 284 nucleotides, representing a sequence divergence of 2.38%. Sequence deletions or insertions were found only in the noncoding regions and include a 173-nucleotide deletion in the 3'-untranslated region of RRV NB5092, compared with RRV T48. In the coding regions, most of the nucleotide differences are silent; there are 36 amino acid differences in the nonstructural proteins and 12 in the structural proteins. The distribution of amino acid differences between the two RRV strains correlates with the location of domains which are poorly conserved in sequence between alphaviruses. The possible role of amino acid differences in envelope glycoproteins E1 and E2 in determining the different antigenic and biological properties of RRV NB5092 and RRV T48 is discussed.

AU - Boughton CR, Hawkes RA, Naim HM
TI - Illness caused by a Barmah Forest-like virus in New South Wales.
SO - Medical Journal of australia 1988 Feb 1;148(3):146-7
AB - Barmah Forest virus, a recently-discovered arbovirus which belongs to the alphavirus genus of the family Togaviridae, has been shown to cause infections in humans in New South Wales. The present report documents three patients in whom Barmah Forest viral infection appears to have resulted in illness. Barmah Forest virus or a closely-related alphavirus may, as are several other alphaviruses, be pathogenic.

AU - Carvalho MG, Rebello MA, Mezencio JM
TI - Effect of high temperature on Aedes albopictus cells infected with Mayaro virus.
SO - Brazilian Journal of Medical & Biological Research 1987;20(6):857-60
AB - The multiplication of Mayaro virus in Aedes albopictus cells was drastically inhibited after incubation at 37 degrees C. The effect of short-term exposure of infected cells to high temperatures (heat shock) produced a preferential translation of the heat shock messengers when compared to the viral mRNAs. When cells were shifted back to 28 degrees C (the optimum growth temperature for Aedes albopictus cells), preferential translation of viral mRNA occurred. Although the infected cells were programmed for preferential translation of viral messengers, the thermal treatment was able to shift the translational machinery towards synthesis of heat shock proteins.

AU - Scrimgeour EM, Aaskov JG, Matz LR
TI - Ross River virus arthritis in Papua New Guinea.
SO - Trans. R. Soc. Trop. Med. Hyg. 1987;81(5):833-4
AB - In 1975 it was reported that antibodies to Ross River virus (RRV) were present in the sera of many population groups in Papua New Guinea. We describe here 3 cases of polyarthritis that occurred in Port Moresby, the capital of Papua New Guinea, during 1980-81 and in which the diagnosis of RRV infection was confirmed by serological tests, and 3 other cases in which serological tests suggested RRV infection but were not diagnostic. A possible case of fatal RRV encephalitis is also reported.

AU - Liu TH, Chen WF
TI - Susceptibility of mammalian cell cultures to infection with arbo-togaviruses.
SO - Chung-Hua Min Kuo Wei Sheng Wu Chi Mien i Hsueh Tsa Chih - Chinese Journal of Microbiology & Immunology 1987 Nov;20(4):349-55
AB - Six alphaviruses and four flaviviruses were inoculated intracerebrally into 1 to 3 days old suckling mice. All mice developed CNS diseases and died 2-5 days post-infection. It appeared that alphaviruses were more virulent than flaviviruses since they brought death to the injected mice earlier than the flaviviruses. The susceptibilities of nine different culture cells to those viruses were also investigated using plaque assay. BHK-21 cells produced clearer plaques and were more sensitive than other cells. Plaque reduction tests using antibodies against various viruses revealed no cross-reactions between alphavirus and flavivirus. However, minor cross-reactions were found within groups. The results of this study suggest that BHK-21 cells can be used for the large scale screening of viruses in domestic animal specimens and for detecting serum neutralizing antibodies against arboviruses.

AU - Carter IW, Fraser JR, Cloonan MJ
TI - Specific IgA antibody response in Ross River virus infection.
SO - Immunology & Cell Biology 1987 Dec;65 ( Pt 6):511-3
AB - Sera were collected over a period of several years from the onset of initial symptoms from 77 patients with Ross River virus infection. When tested for virus-specific IgA antibodies, using an enzyme-linked immunosorbent assay (ELISA) based on antibody class capture, 245 out of 704 sera were antibody-positive. Although Ross River virus IgA antibodies were present in the serum of all patients soon after onset of symptoms, the IgA response was relatively short-lived in comparison with specific IgM antibodies. The results suggested that the detection of high levels of Ross River virus IgA antibodies was of potential value in differentiating between recent and past infection, especially in those patients with persisting IgM antibodies.

AU - Kawamura H, Yago K, Narita M, Imada T, Nishimori T, Haritani M
TI - A fatal case in newborn piglets with Getah virus infection: pathogenicity of the isolate.
SO - Nippon Juigaku Zasshi - Japanese Journal of Veterinary Science 1987 Dec;49(6):1003-7

AU - Journeaux SF, Brown WG, Aaskov JG
TI - Prolonged infection of human synovial cells with Ross River virus.
SO - J. Gen. Virol. 1987 Dec;68 ( Pt 12):3165-9
AB - Primary cultures of human synovial cells shed infectious virus for 14 to 35 days following infection with isolates of Ross River virus which had been passaged in the C6/36 line of Aedes albopictus mosquito cells. No frank cytopathic effect was seen in infected synovial cells and they continued to replicate for the duration of the experiments.

AU - Clark GG, Dein FJ, Crabbs CL, Carpenter JW, Watts DM
TI - Antibody response of sandhill and whooping cranes to an eastern equine encephalitis virus vaccine.
SO - Journal of Wildlife Diseases 1987 Oct;23(4):539-44
AB - As a possible strategy to protect whooping cranes (Grus americana) from fatal eastern equine encephalitis (EEE) viral infection, studies were conducted to determine the immune response of this species and sandhill cranes (Grus canadensis) to a formalin-inactivated EEE viral vaccine. Viral-specific neutralizing antibody was elicited in both species after intramuscular (IM) vaccination. Subcutaneous and intravenous routes of vaccination failed to elicit detectable antibody in sandhill cranes. Among the IM vaccinated cranes, the immune response was characterized by nondetectable or low antibody titers that waned rapidly following primary exposure to the vaccine. However, one or more booster doses consistently elicited detectable antibody and/or increased antibody titers in the whooping cranes. In contrast, cranes with pre-existing EEE viral antibody, apparently induced by natural infection, exhibited a rapid increase and sustained high-antibody titers. Even though EEE virus vaccine induced neutralizing antibody and produced no adverse side effects, further studies will be required to determine the protective efficacy of the antibody.

AU - Kay BH, Pollitt CC, Fanning ID, Hall RA
TI - The experimental infection of horses with Murray Valley encephalitis and Ross River viruses.
SO - australian Veterinary Journal 1987 Feb;64(2):52-5
AB - Eleven weanling horses were inoculated with Murray Valley encephalitis and Ross River viruses either by intravenous injection or by the bite of Culex annulirostris or Aedes vigilax mosquitoes infected orally. Five of the 11 horses circulated trace amounts of MVE virus for 1 to 5d and they infected 7/408 Cx annulirostris which subsequently fed on them. Haemagglutination-inhibiting antibody persisted at detectable levels for the 24-week observation period. With Ross River virus, only one of 11 horses inoculated developed a viraemia detectable by inoculation of suckling mice but 5 horses contained virus sufficient to infect 41/383 Cx annulirostris that fed on them 3 to 4 days after inoculation. On primary inoculation with Ross River virus, only 2 horses developed HI antibody but late responses occurred in 3 horses following probable naturally acquired re-infections. With both viruses, most horses remained normal, some developed mild pyrexia and transient clinical signs. This paper, therefore, indicates that horses are unlikely to be efficient amplifiers of either MVE or RR viruses and does little to incriminate them as important pathogens.

AU - Calisher CH, Fremount HN, Vesely WL, el-Kafrawi AO, Mahmud MI
TI - Relevance of detection of immunoglobulin M antibody response in birds used for arbovirus surveillance.
SO - Journal of Clinical Microbiology 1986 Nov;24(5):770-4
AB - Young chickens were inoculated with 5,000 PFU of eastern equine encephalitis (EEE) virus and bled at intervals thereafter for determinations of hemagglutination-inhibiting (HI), neutralizing (N), immunoglobulin M (IgM), and IgG antibodies. HI, N, and IgM antibodies were first detected 4 days after infection, and IgG was detected 7 days after infection. All four antibodies persisted through day 90 after infection. HI, N, and IgM antibody titers remained elevated and were not cross-reactive with the related alphavirus western equine encephalitis (WEE) virus. IgG antibody titers also remained high, but heterologous reactivity to WEE virus increased with time after infection. Serum samples from sentinel chickens and wild birds infected in nature with EEE, WEE, or St. Louis encephalitis virus and submitted to this laboratory from state and local health departments were tested for IgM antibody by using anti-chicken IgM for capture and for IgG antibodies to the EEE and WEE viruses. There was essentially complete correlation between HI, N, and either IgM (indicating recent infections) or IgG (indicating more remote infections) antibody. We conclude that the IgM antibody capture enzyme immunoassay can be used as a specific and sensitive assay to replace the routinely used HI test for detecting antibody in sentinel chickens and in young, wild birds used for arbovirus surveillance. The test is rapid and relatively inexpensive and can be performed in essentially all adequately supplied laboratories.

AU - Knoroz MIu, Davydova AA, Eremian LK, Barinskii IF
TI - [Virus-specific antibodies in persons inoculated with a bivaccine against eastern and western equine encephalomyelitis]. [RUSSIAN]
SO - Voprosy Virusologii 1986 May-Jun;31(3):353-4

AU - Van der Waals FW, Asher DM, Goudsmit J, Pomeroy KL, Karabatsos N, Gajdusek DC
TI - Post-encephalitic epilepsy and arbovirus infections in an isolated rainforest area of central Liberia.
SO - Tropical & Geographical Medicine 1986 Sep;38(3):203-8
AB - Among a population of 4.436 Bassa, Kpelle and Mano people in the Gbawein and Wroughbarh Clan region of Grand Bassa Country, Liberia, 123 cases of epilepsy could be documented. In 38% of these cases infections involving the central nervous system precipitated the onset of seizures. Sera from 67 epilepsy patients, 50 direct healthy relatives and 22 geographically matched controls were tested for antibodies to 16 arboviruses of the Togaviridae and Bunyaviridae known to occur in Africa. Antibodies to arboviruses were found in 16.5% of the epilepsy patients, 36% of the mostly older family members, and in 22% of the controls. Males and females were equally affected as were the different clans and language groups. Although meningoencephalitis with sequelae, like seizures, are known to result from arbovirus infections, no evidence for a correlation between epilepsy in this are of Central Liberia and previous arbovirus infection could be established.

AU - Vrati S, Faragher SG, Weir RC, Dalgarno L
TI - Ross River virus mutant with a deletion in the E2 gene: properties of the virion, virus-specific macromolecule synthesis, and attenuation of virulence for mice.
SO - Virology 1986 Jun;151(2):222-32
AB - A mutant of RRV T48 the prototype strain of Ross River virus has been isolated with a 21-nucleotide deletion in the gene coding for the envelope glycoprotein E2. Direct sequencing of the 26 S subgenomic RNA, together with HaeIII and TaqI restriction digest analysis of cDNA to RNAs from cells infected with the mutant virus (RRV dE2) and with RRV T48, were consistent with the deletion being the only major alteration in the mutant genome. The E2 protein of RRV dE2 virions had a higher electrophoretic mobility than that of RRV T48 E2 protein. Neither RRV dE2 nor RRV T48 virions contained more than trace amounts of E3, the small envelope glycoprotein found in Semliki Forest virus. RRV dE2 generated small plaques on Vero cell monolayers; plaque formation was not temperature-sensitive between 32 and 41 degrees. By comparison with RRV T48 the infectivity of RRV dE2 virions was thermolabile at 50 degrees. In BHK cells RRV dE2 grew with similar kinetics to RRV T48. Rates of synthesis of 26 S RNA and 49 S RNA were higher in cells infected with RRV dE2 than in cells infected with RRV T48. Virus-specific protein synthesis and shut-down of host protein synthesis occurred 2-3 hr earlier in RRV dE2-infected cells than in cells infected with RRV T48. Minor differences between the two viruses were observed in the profiles of virus-specific proteins generated in infected cells. In day-old mice RRV dE2 induced less severe symptoms of hind leg paralysis than did RRV T48. A small increase in LD50 and average survival time was observed in RRV dE2-infected mice by comparison with RRV T48 infected mice. Peak titers reached by RRV dE2 in the hind leg muscle, brain, and blood of day-old mice were 3-4 log units less than the titers reached during infection with RRV T48. In week-old mice the differences in virulence between the two strains were magnified: RRV dE2 induced no detectable symptoms even when injected at high doses (8 X 10(6) PFU) whereas the LD50 and average survival time for RRV T48 were unchanged from those in day-old mice. Peak RRV dE2 titers in hind leg muscle, brain, and blood, respectively, were 2, 5, and 5 log units less than the corresponding titers for RRV T48. Peak muscle titers reached by RRV dE2 were similar (approximately 10(8) PFU/g tissue) in day-old mice where lethality was high and in week-old mice where the virus was avirulent.(ABSTRACT TRUNCATED AT 400 WORDS)

AU - Calisher CH, Berardi VP, Muth DJ, Buff EE
TI - Specificity of immunoglobulin M and G antibody responses in humans infected with eastern and western equine encephalitis viruses: application to rapid serodiagnosis.
SO - Journal of Clinical Microbiology 1986 Feb;23(2):369-72
AB - Paired sera from 20 humans with eastern equine encephalitis (EEE) virus infections and from 17 humans with western equine encephalitis (WEE) virus infections, all with previously demonstrated fourfold or greater rises or falls in hemagglutination-inhibiting, complement-fixing, or neutralizing antibody titers, were tested for immunoglobulin M (IgM) and IgG antibodies by an enzyme immunoassay. All individuals with EEE and 14 of 17 individuals with WEE had IgM antibody, some as early as 1 day after onset. Two of the three persons with WEE who did not develop IgM antibody died. IgM antibody declined but persisted for at least 3 months after the onset of illness in one individual each with EEE and WEE. IgG antibody was not detected until the middle of week 2 after onset. The sensitivity of the IgM antibody capture enzyme immunoassay described and the specificity, as shown by the absence of heterologous alphavirus reactivity, indicate that this is the test of choice for the rapid diagnosis of human infections caused by EEE and WEE viruses.

AU - Calisher CH, el-Kafrawi AO, Al-Deen Mahmud MI, Travassos da Rosa AP, Bartz CR, Brummer-Korvenkontio M, Haksohusodo S, Suharyono W
TI - Complex-specific immunoglobulin M antibody patterns in humans infected with alphaviruses.
SO - Journal of Clinical Microbiology 1986 Jan;23(1):155-9
AB - Sera from humans with serologically confirmed eastern equine encephalitis, western equine encephalitis, Pogosta (Ockelbo), Mayaro, Ross River, and chikungunya virus infections were tested by immunoglobulin M (IgM) antibody capture enzyme immunoassay. Diagnostically useful IgM antibody titers were detected, and selected sera with high IgM antibody titers were tested for IgM antibody with nine heterologous alphaviruses. The results provide evidence for the complex specificity of IgM antibody and indicate the usefulness of this test in both individual cases and epidemic situations.

AU - Crooks AJ, Lee JM, Stephenson JR
TI - The purification of alphavirus virions and subviral particles using ultrafiltration and gel exclusion chromatography.
SO - Analytical Biochemistry 1986 Feb 1;152(2):295-303
AB - Conventional methods of virus purification using ultracentrifugation frequently result in distorted particles with low levels of biological activity, and are thus unsuitable for preparing samples for high-resolution techniques such as neutron scattering, X-ray scattering in solution, and X-ray crystallography. Moreover, in the event of an instrument failure, ultracentrifugation can also pose a significant hazard when preparing pathogenic viruses or subunits derived from them. By employing exclusively ultrafiltration and gel exclusion chromatography, a method has been developed to prepare highly purified, intact alphavirus particles retaining high levels of biological activity. These procedures have also been adapted to prepare aggregates of viral envelope protein with a defined immunogenic content.

AU - Liprandi F, Gomez B, Walder R
TI - Replication of alphaviruses in cultures of donkey monocytes.
SO - Arch. Virol. 1986;87(3-4):163-71
AB - Representative strains of Venezuelan equine encephalitis virus (VEEV) and Eastern equine encephalitis virus (EEEV) were compared for their ability to grow in cultures of unstimulated leucocytes and monocytes derived from donkey peripheral blood. Replication of epizootic and vaccine strains of VEEV, but not of enzootic strains was observed in this system. Only a minority of monocytes supported virus replication as detected by immunofluorescence, electron microscopy and infectious center assays. EEEV did not appear to replicate in this cell system although virus attached to and was internalized by monocytes.

AU - Mullbacher A, Marshall ID, Ferris P
TI - Classification of Barmah Forest virus as an alphavirus using cytotoxic T cell assays.
SO - J. Gen. Virol. 1986 Feb;67 ( Pt 2):295-9
AB - Barmah Forest virus, an arbovirus, does not cross-react convincingly with alpha-, flavi- or bunyavirus immune sera. Secondary cytotoxic T cells generated in vitro immune to a number of alphaviruses cross-lyse Barmah Forest virus-infected target cells. Flavivirus (West Nile and Kunjin)- and Bunyamwera virus-immune Tc cells lyse homologous virus-infected target cells, but not alphavirus-infected targets. Using cytotoxic T cell assays Barmah Forest virus can be classified as an alphavirus.

AU - Zhirnov OP, Ovcharenko AV, Mel'nikova EE, Gaidamovich SIa, Bukrinskaia AG
TI - [Antiviral activity of proteinase inhibitors in cultured cells infected with alpha-viruses]. [RUSSIAN]
SO - Molekuliarnaia Genetika, Mikrobiologia, i Virusologa 1985 Dec;(12):30-6
AB - The ability of synthetic inhibitors of trypsin-like (TLCK) and chymotrypsin-like (TPCK) proteinases and natural antiproteinase oligopeptides of animal (aprotinin) and microbial (enzistatin) origin to suppress multicycle replication of different alpha viruses (Semliki, Sindbis, Venezuelan equine encephalomyelitis viruses) in cultured cells was studied. Antiviral activity was found to be induced by TPCK and aprotinin (Gordox). These compounds were shown to reduce virus yield 100-fold and to prevent the involvement of cells into infection process. The mechanisms of antiviral activity and chemotherapeutic possibilities of antiproteinase compounds are discussed.

AU - Aaskov JG, Ross PV, Harper JJ, Donaldson MD
TI - Isolation of Ross River virus from epidemic polyarthritis patients in australia.
SO - australian Journal of Experimental Biology & Medical Science 1985 Oct;63 ( Pt 5):587-97
AB - Ross River virus was isolated from two out of four seronegative serum samples obtained from epidemic polyarthritis patients in australia. Virus isolated from each patient was found to be phenotypically diverse. These isolations suggest that previous failure to isolate virus from epidemic polyarthritis patients in this country may have been due to failure to obtain material (serum) from patients early enough in the course of the disease and to the use of relatively insensitive isolation techniques.

AU - Carter IW, Smythe LD, Fraser JR, Stallman ND, Cloonan MJ
TI - Detection of Ross River virus immunoglobulin M antibodies by enzyme-linked immunosorbent assay using antibody class capture and comparison with other methods.
SO - Pathology 1985 Jul;17(3):503-8
AB - An enzyme-linked immunosorbent assay based on antibody class capture was developed for the detection of Ross River virus-specific immunoglobulin M antibodies (RRV IgM). The assay was specific, reproducible and precise. When compared with conventional tests for the detection of RRV IgM, such as hemagglutination inhibition following sucrose density gradient centrifugation and indirect enzyme-linked immunosorbent assay, the class capture assay was more sensitive. In 186 sera which were collected from 39 patients with RRV infection over a period of 1-4 yr from onset of initial symptoms, RRV IgM persisted for at least 1-2 yr. Sera were tested both at a single dilution from which the results were expressed as a binding index and in a dilution series in which they were expressed as an antibody titre. Binding index values gave better discrimination between sera collected during acute and later phases of the disease and may be of greater value than antibody titres in the diagnosis of RRV infection.

AU - L'vov DK, Skvortsova TM, Gromashevskii VL, Berezina LK, Iakovlev VI
TI - [Isolation of the causative agent of Karelian fever from Aedes sp. mosquitoes]. [RUSSIAN]
SO - Voprosy Virusologii 1985 May-Jun;30(3):311-3
AB - The results of isolation of an Alphavirus strain from Aedes sp. mosquitoes collected in the focus of Karelian fever are presented. According to the results of serological studies, the isolated strain LEIV-9298 Karelia belongs to the antigenic complex Sindbis-Western equine encephalomyelitis. The appurtenance of the isolated agent to the Alphavirus genus has been confirmed by electron microscopic examinations. A rise of antibody titres to LEIV-9298 Karelia virus in paired sera of subjects with a history of Karelian fever allows it to be considered the causative agent of this disease.

AU - Sentsui H, Kono Y
TI - Reappearance of Getah virus infection among horses in Japan.
SO - Nippon Juigaku Zasshi - Japanese Journal of Veterinary Science 1985 Apr;47(2):333-5

AU - Chizhov NP, Luk'ianova RI
TI - [Model of experimental Pixuna infection in white mice]. [RUSSIAN]
SO - Voprosy Virusologii 1985 Mar-Apr;30(2):214-5
AB - The results of the development of a nonfatal model of experimental infection induced by Pixuna alpha-virus and suitable for the evaluation of the effectiveness of antiviral drugs are described. The asymptomatic infection induced in white mice by intranasal inoculation of Pixuna virus is characterized by intensive virus multiplication in the brain and spleen of the animals. In these organs virus reproduction is observed early after infection and amplification of the agent reaches maximum titres within 72 h postinfection. With this model, the main criterion of the effectiveness of antiviral drugs would be their effect on virus reproduction in the spleen and brain.

AU - Solianik RG, Anosova GV, Fedorov IuV
TI - [Effect of immunosuppressants on the enhanced sensitivity of white mice to the eastern equine encephalitis virus]. [RUSSIAN]
SO - Virologie 1985 Jan-Mar;36(1):41-6
AB - EEE virus infection could be induced in white mice whose natural resistance to this virus had been reduced by immunosuppressive drugs such as: Adreson, Cyclophosphan and hydrocortisone.

AU - Griffiths BB, McClain O
TI - Immunological response of chickens to eastern equine encephalomyelitis virus.
SO - Research in Veterinary Science 1985 Jan;38(1):65-8
AB - The dominant immunoglobulin against eastern equine encephalomyelitis (EEE) virus and its duration and the longevity of the EEE virus haemagglutination inhibition (HI) antibodies were determined in sentinel and 125 immunised and hyperimmunised domestic chickens by enzyme-linked immunosorbent assay and the HI test respectively. The chickens ranged in age from 10 weeks to 18 months, were of varied pedigrees and from different countries. Results show that the HI antibody (IgG) is short-lived. It peaks and disappears within 30 days. The secondary response is dominated by the IgM immunoglobulin which is relatively long-lasting. These results are contrary to classical expectations and were observed in all the chickens studied. If these observations are found to be characteristic of birds generally, the present standard method of EEE virus seroepidemiological surveillance must be modified to be effective.

AU - Aaskov JG, Hadding U, Bitter-Suermann D
TI - Interaction of Ross River virus with the complement system.
SO - J. Gen. Virol. 1985 Jan;66 ( Pt 1):121-9
AB - In the absence of virus-specific antibody, Ross River virus failed to activate either the classical or alternative complement pathways. Instead, it inhibited the cleavage of C3 via both pathways. The virus did not appear to act by disrupting C3bBb complexes or by preventing cleavage of factor B by factor D. Instead Ross River virus was found to interfere with the actual cleavage of C3 by activated factor B (C3bBb) of the alternative pathway and C4b2a of the classical pathway.

AU - Mathews JH, Roehrig JT
TI - Determination of the protective epitopes on the glycoproteins of Venezuelan equine encephalomyelitis virus by passive transfer of monoclonal antibodies.
SO - Journal of Immunology 1982 Dec;129(6):2763-7
AB - We have previously characterized seven unique antigenic epitopes on the two envelope glycoproteins of the Venezuelan equine encephalomyelitis (VEE) virus vaccine strain, TC-83, by using monoclonal antibodies. The in vitro function of virus neutralization was primarily associated with one epitope on the gp56 (gp56c). To determine which epitopes were important in protecting animals from VEE infection, purified monoclonal antibodies were inoculated i.v. into 3-wk-old Swiss mice. Twenty-four hours later these animals were challenged i.p. with 100 IPLD50 of virulent VEE virus (Trinidad donkey). High-avidity anti-gp56c, anti-gp50b, anti-gp50c, and anti-gp50d monoclonal antibodies protected animals from virus challenge. Rabbit antisera to the gp56 and the gp50 glycoproteins were also effective in protecting mice from challenge with virulent VEE virus. Less antibody was needed to protect animals if the antibody was directed against the critical neutralization site. Less avid antibodies to the gp56c and gp50b epitopes demonstrated little or no protection in vivo. Protection, therefore, appeared to be a function of the passive antibody's specificity, avidity, and ability to bind to virion antigenic determinants topologically proximal to the critical neutralization site.

AU - Peiris JS, Porterfield JS
TI - Antibody-dependent plaque enhancement: its antigenic specificity in relation to Togaviridae.
SO - J. Gen. Virol. 1982 Feb;58(Pt 2):291-6
AB - The antigenic specificity of antibody-dependent plaque enhancement (ADPE) on the macrophage cell line P388D1 has been investigated using viruses in the flavivirus and alphavirus genera. Whereas ADPE detected group-specific antigenic determinants in the flaviviruses, narrower specificity (type and subgroup) was seen with alphaviruses. ADPE titres correlated well with haemagglutination inhibition titres.

AU - Niklasson B, Espmark A, LeDuc JW, Gargan TP, Ennis WA, Tesh RB, Main AJ Jr
TI - Association of a Sindbis-like virus with Ockelbo disease in Sweden.
SO - Am. J. Trop. Med. Hyg. 1984 Nov;33(6):1212-7
AB - An alphavirus isolated from Culiseta mosquitoes has been associated with Ockelbo disease, an exanthema arthralgia syndrome occurring in Sweden. The isolate was made from mosquitoes collected in Edsbyn (central Sweden), an area with considerable Ockelbo disease morbidity. This isolate proved to be indistinguishable from Sindbis virus by complement-fixation and hemagglutination-inhibition tests, and was antigenically related to Sindbis in plaque reduction neutralization tests. Patients with Ockelbo disease developed neutralizing antibodies to the virus in their convalescent sera, suggesting that it is the etiologic agent of the disease.

AU - Scott TW, Burrage TG
TI - Rapid infection of salivary glands in Culiseta melanura with eastern equine encephalitis virus: an electron microscopic study.
SO - Am. J. Trop. Med. Hyg. 1984 Sep;33(5):961-4
AB - Transmission electron microscopy was used to determine if eastern equine encephalitis (EEE) virus infects and replicates in the salivary glands of Culiseta melanura after 3 days of extrinsic incubation (EI). The Cs. melanura studied were from a colony strain, were orally infected, and had EI periods of 55-69 hours. Both naked nucleocapsids and enveloped virions were present in aggregates, suggestive of viral replication, within salivary gland acinar cells. Nucleocapsids were present in the cytoplasm below the plasma membrane that lined apical cavities. Enveloped virions occurred in the salivary matrix within apical cavities. Some nucleocapsids appeared to be budding through the plasma membrane around apical cavities and maturing into infectious virions. These results suggest that Cs. melanura is capable of biological transmission of EEE virus after less than or equal to 3 days of EI.

AU - Scott TW, Hildreth SW, Beaty BJ
TI - The distribution and development of eastern equine encephalitis virus in its enzootic mosquito vector, Culiseta melanura.
SO - Am. J. Trop. Med. Hyg. 1984 Mar;33(2):300-10
AB - The timing and sequence of eastern equine encephalitis (EEE) virus replication was studied in the organs from a colony strain of orally infected Culiseta melanura. Three methods of virus assay were used: fluorescent antibody (FA) staining of dissected organs; virus titration in cell culture of whole mosquitoes, dissected organs, hemolymph, and egg rafts; and transmission electron microscopy (TEM) of infected hindguts. EEE virus replicated rapidly in Cs. melanura, first in the posterior midgut, after which it disseminated into the hemocoel where hemolymph transported virus to other organs causing a systemic infection that eventually involved all organs examined, except ovarioles. No initial decrease in virus titer of whole mosquitoes or dissected organs was observed when mosquitoes were collected at daily intervals. Muscle tissue contained the greatest amount of specific fluorescence and the largest aggregates of virus that were visible by TEM. Dissemination of virus occurred rapidly, in some mosquitoes after less than or equal to 17 hours of extrinsic incubation (EI). All infected mosquitoes had disseminated infections after 3 days of EI. Maximum amounts of virus were obtained from whole mosquitoes on the 7th day of EI. FA staining of hindguts was determined to be a rapid and reliable method for detection of EEE virus dissemination and replication in Cs. melanura.

AU - Rosen L
TI - [Transovarial transmission of arboviruses by mosquitoes (author's transl)]. [French]
SO - Medecine Tropicale 1981 Jan-Feb;41(1):23-9
AB - An important aspect of the epidemiology of arboviruses is the manner in which the viruses are maintained during winter, dry season, or other adverse environmental periods when their arthropod hosts are inactive. One possibility is that the viruses survive in arthropods. In the case of mosquito-borne viruses, it is probable that such viruses could be maintained in this manner only if they were transmitted from one insect generation to the next by transovarial transmission. Such transmission was reported in 1905 by Marchoux and Simond for yellow fever virus in Aedes aegypti. Other workers were unable to confirm this observation and, until very recently, it was believed to be in error. Interest in transovarial transmission of viruses by mosquitoes was reawakened with the recovery of La Crosse virus from field-collected larvae of Aedes triseriatus in 1972. Among bunyaviruses, transovarial transmission has been observed mainly among the California serogroup viruses in Aedes mosquitoes. Among flaviviruses, transovarial transmission has been demonstrated experimentally for the viruses of principal interest to man, namely, yellow fever, dengue, japanese encephalitis, and St-Louis encephalitis. Thus far, the only field evidence of transovarial transmission of flaviviruses is the isolation of yellow fever virus from Aedes furcifei/taylori males captured in nature in 1977. At present there is not conclusive evidence that transovarial transmission of alphaviruses occurs in mosquitoes. Among rhabdoviruses, transovarial transmission of vesicular stomatitis virus has been demonstrated experimentally at a relatively high rate in phlebotominae flies. Many factors are known to affect the experimental transovarial transmission of viruses. The significance of such transmission in nature can only be assessed by field studies.

AU - Fauran P, Donaldson M, Harper J, Oseni RA, Aaskov JG
TI - Characterization of Ross River viruses isolated from patients with polyarthritis in New Caledonia and Wallis and Futuna Islands.
SO - Am. J. Trop. Med. Hyg. 1984 Nov;33(6):1228-31
AB - Viruses isolated during 1979 and 1980 from patients with polyarthritis in New Caledonia and Wallis and Futuna Islands have been found to be more closely related to Ross River virus than any other regional Alphavirus. On the basis of virulence in suckling mice the majority of these isolates were found to be more closely related to the NB5092 strain of Ross River virus than to the prototype T48 strain.

AU - Tsilinskii IaIa, Prianichnikova LV, Karpova EF, Shablinskaia LM
TI - [Effect of the method of passage on the biological properties of attenuated alphavirus strains]. [RUSSIAN]
SO - Voprosy Virusologii 1984 May-Jun;29(3):294-301
AB - Experiments with attenuated clones of Venezuelan equine encephalomyelitis virus and Eastern equine encephalomyelitis virus were carried out to study the regularities in changes of biological properties of virus in "undiluted" passages and in passages by subcultivation of small doses. In the latter case the biological activity of the virus remained at the initial low level but in "undiluted" passages it increased, due to accumulation in the population of clones with altered plaque phenotype and increased reproductive potential. In a number of cases this virus had a higher level of residual virulence than the original one. The evidence that the main source of virus variability in the "undiluted" passages lies, in genetic interaction in which defective virus takes part, is presented. Mixed infection with participation of defective interfering particles and the genetic interaction occurring in it are considered to be the mechanism which is conducive to restoration of biological activity of alphaviruses.

AU - Karmysheva VIa, Ovsiannikova NV, Malenko GV, Pogodina VV
TI - [Comparative study of glial cells infected with alpha-, flavi- and picornaviruses]. [RUSSIAN]
SO - Vestnik Akademii Meditsinskikh Nauk SSSR 1984;(1):40-5

AU - Galabov AS, Velichkova E, Karparov A, Sidzhakova D, Danchev D, Chakova N
TI - Antiviral activity of tetrahydro-2(1H)-pyrimidinones and related compounds.
SO - Arzneimittel-Forschung 1984;34(1):9-14
AB - 24 derivatives of tetrahydro-2(1H)-pyrimidinone and related compounds were tested in vitro for antiviral activity against representatives of six viral taxonomic groups. The screening was carried out by a two-stage procedure including the agar-diffusion plaque-inhibition test and the one-step growth cycle setup. A distinct activity of three mono- and bis-morpholinomethyl derivatives of tetrahydro-2(1H)-pyrimidinone (THP), 1,3-bis(piperidinomethyl)-THP, the 1-morpholinomethyl derivative of tetrahydro-2(1H)-pyrimidinethione (THPT) and the related N,N'-bis(morpholinomethyl)-urea against the fowl plague virus was established. In the one-step growth cycle setup these compounds inhibited 87.5-99.6% of the infectious virus yield. Two of the compounds, namely 1-morpholinomethyl derivatives of THP and THPT manifested a strong inhibitory effect on the reproduction of Semliki Forest virus as well, exceeding 99.9% in the one-step growth cycle test. A borderline effect was observed in some derivatives against vaccinia virus and Newcastle disease virus. The structure-activity relationship of this group of compounds is discussed.

AU - Glazebrook R
TI - Ross River virus.
SO - australian Nurses Journal 1984 Feb;13(7):37-9

AU - Milner AR, Marshall ID, Mullbacher A
TI - Effect of pregnancy on stimulation of alphavirus immunity in mice.
SO - J. Virol. 1984 Apr;50(1):73-6
AB - The state of pregnancy was associated with a marked enhancement of both proliferative and cytotoxic T cell antiviral immune responses after infection of mice with avirulent Semliki Forest virus. Strong responses were obtained from the spleen and the para-aortic lymph nodes that drain the uterus. This immune enhancement seemed to be in response to the increased antigenic challenge that originated from infected placental and fetal tissue and was released during the process of abortion. Immune enhancement was not observed in pregnant mice similarly infected with Ross River virus, which also established an intrauterine infection but does not cause abortion.

AU - Tsilinskii IaIa, Karpova EF
TI - [Variability of attenuated alphavirus strains in virion aggregate infection]. [RUSSIAN]
SO - Voprosy Virusologii 1983 Sep-Oct;28(5):601-7
AB - A natural process of infection with multiploid virions was stimulated and the genetic effects occurring in this infection were studied in experiments with homogeneous attenuated strain of Venezuelan equine encephalomyelitis virus producing the smallest plaques. The process of infection with multiploid virions was reproduced by infecting the cells with artificially obtained aggregates. Under these conditions, small- and large-plaque virus was produced which in some cases had a higher virulence than the parental strain. A possible mechanism of this phenomenon and its practical implications for the evaluation of the properties of attenuated alphavirus strains is discussed.

AU - Solianik RG, Karpova EF, Tsilinskii IaIa, Tymchishin PN
TI - [Molecular biology characteristics of an attenuated mutant of the Eastern equine encephalomyelitis virus]. [RUSSIAN]
SO - Voprosy Virusologii 1983 Jul-aug;28(4):50-3
AB - The main molecular biology parameters of an attenuated mutant DMS-20/6 of eastern equine encephalomyelitis virus derived by treatment with dimethylsulphate of the wild type virus (strain No. 627) were determined. The sedimentation coefficient of sucrose density gradient purified and concentrated virus was 280 S, the buoyant density of virions in sucrose density gradient was 1.19 g/cm3. The DMS-20/6 virion had 3 proteins with molecular weights of 56, 50, and 34 kilodaltons, and the size of virions by negative staining was 58-77 nm.

AU - Darwish MA, Hoogstraal H, Roberts TJ, Ahmed IP, Omar F
TI - A sero-epidemiological survey for certain arboviruses (Togaviridae) in Pakistan.
SO - Trans. R. Soc. Trop. Med. Hyg. 1983;77(4):442-5
AB - Complement-fixation test reactions to eight viruses of the family Togaviridae were studied in 372 serum samples (157 rodents, 172 domestic animals, 43 humans) from Pakistan. Antibodies to each tested virus were detected. The highest over-all prevalence rates were for West Nile (WN) (7.8%), Japanese encephalitis (JE) (3.2%) and Zika (ZIKA) (2.4%) viruses, followed by Sindbis (SIN), Chikungunya (CHIK), Uganda S (UGS) and Royal Farm (RF) viruses (1.6 to 1.3%). One human serum (male, age 58 years) reacted with Dengue-1 (DEN) virus antigen (titre 1:32). Antibodies to each virus except RF were detected in human sera; antibodies to RF virus were detected only in rodent and domestic animal sera. The roles of rodents in the epidemiology of WN, JE and ZIKA viruses should be investigated. At least six of these eight viruses cause fevers in humans (fevers of unknown origin comprise about one third of the febrile episodes recorded in Pakistan).

AU - Fraser JR, Ratnamohan VM, Dowling JP, Becker GJ, Varigos GA
TI - The exanthem of Ross River virus infection: histology, location of virus antigen and nature of inflammatory infiltrate.
SO - Journal of Clinical Pathology 1983 Nov;36(11):1256-63
AB - The exanthem of epidemic polyarthritis, a disease caused by Ross River (RR) virus, was examined three days after onset of the common erythematous and the rare purpuric forms of the eruption. The dermis showed a light perivascular infiltrate of mononuclear cells in both, with extravasation of erythrocytes in the latter. No immunoglobulins (IgM, IgG, IgA) or complement components (Clq, C3) were detected. Most of the infiltrating cells were T lymphocytes of the T suppressor-cytotoxic class. Their perivascular location, the scarcity of other lymphocytes or phagocytes, and rapid resolution of the rash indicated that the T lymphocytes were responsible for cytotoxic destruction of virus-infected cells. A few monocyte-macrophage cells were identified in the perivascular infiltrate. RR virus antigen was found in the basal epidermal and eccrine duct epithelial cells of both types of lesion and in the perivascular zone of the erythematous lesion, but appeared to have been eliminated from this region in the purpuric lesion. It is suggested that secondary effects of the T-cytotoxic reaction on nearby capillaries are responsible for erythema, oedema and purpura in the exanthem.

AU - Jahrling PB, Hesse RA, Anderson AO, Gangemi JD
TI - Opsonization of alphaviruses in hamsters.
SO - J. Med. Virol. 1983;12(1):1-16
AB - Immune elimination of alphaviruses in immunized hamsters appears to involve formation of virus/antibody aggregates which are subsequently cleared from the circulation by cells of the reticuloendothelial system (RES). Virulent strains of Venezuelan (VEE) and Western equine encephalitis (WEE) viruses which were cleared slowly from the circulation of nonimmune hamsters, were cleared rapidly when inoculated into the blood of immunized hamsters. Likewise, when these viruses were mixed with specific hamster immune serum prior to inoculation, they were efficiently cleared from the circulation of nonimmune hamsters. Virus, mixed with specific immune serum, or inoculated into immunized hamsters, formed virus/antibody aggregates, as demonstrated by density gradient centrifugation, filtration through polycarbonate membranes, precipitation with Staphylococcus protein A, and electron microscopy. Cleared virus was concentrated primarily in liver and spleen, as confirmed by autoradiography. Immune clearance of virulent VEE was demonstrable within 5 to 6 days following immunization of hamsters with live attenuated VEE vaccine, strain TC-83. In these hamsters, a close association was established between formation of virus/antibody aggregates, rapid clearance, and survival of challenged hamsters. Adsorption of virus to hamster macrophages in culture was enhanced by immune serum in the presence of complement. These results are compatible with the hypothesis that immune clearance of virus in the intact hamster involves a complement-dependent interaction of virus/antibody complexes with cells which possess Fc and complement receptors. The clearance of immune complexes by the RES serves to amplify the protective effect of neutralizing antibody alone.

AU - Eisner RJ, Nusbaum SR
TI - Encephalitis vaccination of pheasants: a question of efficacy.
SO - Journal of the American Veterinary Medical Association 1983 aug 1;183(3):280-1

AU - Mullbacher A, Ashman RB, Blanden RV
TI - Induction of T cell hyporesponsiveness to Bebaru in mice, and abnormalities in the immune responses of progeny of hyporesponsive males.
SO - australian Journal of Experimental Biology & Medical Science 1983 Apr;61 (Pt 2):187-91
AB - Non-specific hyporesponsiveness of cytotoxic T cells to alphaviruses and alloantigens was induced in male mice by multiple, large injections, starting at birth, of gamma-inactivated alphavirus, stock-grown in outbred mouse brains. Offspring of matings between 2 out of 17 treated males and normal females also exhibited significant non-specific hyporesponsiveness (in comparison with normal control mice), without prior exposure to gamma-inactivated alphavirus stock.

AU - Tsilinskii IaIa, Karpova EF
TI - [Genetic function of the multiploid virions of alphaviruses]. [RUSSIAN]
SO - Voprosy Virusologii 1983 Jan-Feb;28(1):74-7
AB - The natural process of infection with multiploid virions of alphaviruses was modeled by inoculation of cells with artificially obtained aggregates. After infection with the aggregates the progeny of attenuated clones of Venezuelan equine encephalomyelitis virus was found to have some new properties. The virus produced larger plaques and had higher reproduction activity. In some cases, changes in the electrophoretic mobility of virion structural proteins was observed, especially a decrease in the molecular weight of the most conservative of them, C-protein. These properties were retained in passages of the virus in cell cultures. The observed phenomenon is associated with genetic interaction between defective virus genomes getting into cells as the aggregate component. Formation of multiploid virions and infection with these particles are considered as the process providing for retention of the biological properties of the virus under conditions of accumulation of DI-particles in the population.

AU - Halstead SB
TI - Immune enhancement of viral infection. [Review]
SO - Progress in Allergy 1982;31:301-64

AU - Wolcott JA, Wust CJ, Brown A
TI - Immunization with one alphavirus cross-primes cellular and humoral immune responses to a second alphavirus.
SO - Journal of Immunology 1982 Sep;129(3):1267-71

AU - Roehrig JT, Gorski D, Schlesinger MJ
TI - Properties of monoclonal antibodies directed against the glycoproteins of Sindbis virus.
SO - J. Gen. Virol. 1982 Apr;59(Pt 2):421-5
AB - Four monoclonal antibodies that react with