Topic:Alphavirus
Alphaviruses are a group of viruses transmitted primarily by mosquitoes and are known to cause disease in horses and humans. In equine populations, alphaviruses such as Eastern Equine Encephalitis Virus (EEEV), Western Equine Encephalitis Virus (WEEV), and Venezuelan Equine Encephalitis Virus (VEEV) are of particular concern due to their ability to cause severe neurological disease. Infection in horses can lead to symptoms ranging from fever and lethargy to more severe signs such as ataxia, paralysis, and encephalitis, often resulting in high mortality rates. Understanding the transmission dynamics, pathogenesis, and immune response in horses is crucial for developing effective prevention and control strategies. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, clinical presentation, diagnosis, and management of alphavirus infections in horses, as well as advancements in vaccine development and vector control methods.
Molecular evidence for the origin of the widespread Venezuelan equine encephalitis epizootic of 1969 to 1972. Venezuelan equine encephalitis (VEE) virus is a mosquito-borne pathogen that has caused encephalitis in equine species and humans during sporadic outbreaks in the western hemisphere. The last, and most widespread, VEE outbreak occurred in South America, Central America, Mexico and the U.S.A. (Texas) during 1969 to 1972. We have cloned and sequenced the genome of a virulent VEE subtype I-AB virus, strain 71-180, isolated in Texas in 1971. Thirty-four nucleotide differences were detected between the genome of 71-180 virus and that of the subtype I-AB Trinidad donkey (TRD) virus isolated during t...
Phylogenetic analysis of alphaviruses in the Venezuelan equine encephalitis complex and identification of the source of epizootic viruses. We studied the evolution of alphaviruses in the Venezuelan equine encephalitis (VEE) complex using phylogenetic analysis of RNA nucleotide sequences from limited portions of the nsP4, E1, and 3' untranslated genome regions of representative strains. The VEE complex constituted a monophyletic group of viruses (descended from a common ancestor); some serologic VEE varieties such as subtype III formed monophyletic groups while subtype I did not. Subtype II Everglades and variety ID enzootic viruses formed a monophyletic group which also included all epizootic variety IAB and IC VEE isolates. Ever...
Trajectory analysis of winds and eastern equine encephalitis in USA, 1980-5. Backward trajectories of winds were determined to identify possible sources of eastern equine encephalitis virus associated with isolation of virus from mosquitoes or birds or outbreaks in horses between 1980 and 1985 in Maryland, New Jersey, New York and Michigan, USA. The results of the trajectory analyses suggested that eastern equine encephalitis virus could have been carried by infected mosquitoes on surface winds at temperatures 13 degrees C or higher from North Carolina north-eastwards along the Atlantic Coast to Maryland and New Jersey and thence to upstate New York and from western Ke...
[Antibodies against Venezuelan equine encephalitis in the human population of the Mara district of the state of Zulia, Venezuela]. Antibodies against Venezuelan Equine Encephalitis Virus (VEEV) were studied in the human population of Mara District, Zulia State, Venezuela. Two hundred thirty nine blood samples were taken from the towns of San Rafael de Mara, Santa Cruz de Mara, La Sierrita-4 Bocas, Carrasquero, Isla de San Carlos e Isla de Toas, during june, july and september, 1988. Donors samples were classified by age, sex and serological titres. Eighty nine were less than 15 years old (37.2%) and 150, over 15 years old (62.7%). From the 239 samples, 224 were negative (93.7%) and 15 positive (6.3%). Our results indicate...
The full-length nucleotide sequences of the virulent Trinidad donkey strain of Venezuelan equine encephalitis virus and its attenuated vaccine derivative, strain TC-83. Nucleotide sequence analysis of cDNA clones covering the entire genomes of Trinidad donkey (TRD) Venezuelan equine encephalitis (VEE) virus and its vaccine derivative, TC-83, has revealed 11 differences between the genomes of TC-83 virus and its parent. One nucleotide substitution and a single nucleotide deletion occurred in the 5'- and 3'-noncoding regions of the TC-83 genome, respectively. The deduced amino acid sequences of the nonstructural polypeptides of the two viruses differed only in a conservative Ser(TRD) to Thr(TC-83) substitution in nonstructural protein (nsP) three at amino acid ...
Arboviruses recovered from sentinel livestock in northern Australia. Over 700 arboviruses were recovered between 1981 and 1987 from the blood of sentinel livestock near Darwin. Twenty-three isolates were made from sheep, goats, swamp buffalo (Bubalus bubalis) and horses, and the remainder were from cattle. The isolates have been typed as 27 separate viruses belonging to the bluetongue, epizootic haemorrhagic disease, Palyam, Simbu, bovine ephemeral fever, Tibrogargan and alphavirus groups. Ten of these viruses have not been isolated elsewhere in Australia and four have been isolated only in Darwin. Considerable annual variations in virus activity and in the dur...
Nucleotide sequence of the 26 S mRNA of the virulent Trinidad donkey strain of Venezuelan equine encephalitis virus and deduced sequence of the encoded structural proteins. A cDNA clone containing all of the 26 S mRNA coding region of the RNA genome of Venezuelan equine encephalitis (VEE) virus, virulent strain Trinidad donkey (TRD), has been constructed and sequenced. The nucleotide and deduced amino acid sequences of the 26 S RNA of VEE virus conform to the general organization of the alphavirus subgenomic mRNA. Excluding the poly(A) tail, the VEE 26 S RNA is 3913 nucleotides long with a protein coding region of 3762 nucleotides. Codon usage in the translated region is nonrandom and correlates well with that reported for Sindbis (SIN), Semliki Forest (SF), and ...
Properties of monoclonal antibodies against glycoproteins of western equine encephalitis virus. To analyze the biological activities of the alphavirus glycoproteins, eight different monoclonal antibodies against the two glycoproteins of western equine encephalitis virus were isolated. Five of the eight monoclonal antibodies were shown to be specific for E1 and three for E2 protein by an enzyme-linked immunosorbent assay and by radioimmunoprecipitation. Three of the five anti-E1 and all of the anti-E2 monoclonal antibodies inhibited hemagglutination by purified virions. One anti-E1 and two anti-E2 monoclonal antibodies possessed high virus-neutralizing activity.
Ross River virus activity along the south coast of New South Wales. The sera of 468 blood donors and 63 domestic animals, collected from the south coast of New South Wales, were tested for the presence of antibodies to Ross River virus. Antibodies were detected in 7% of human sera, 25% of cow sera and 65% of horse sera. Using the blood donors as 'human sentinels', seroconversions were demonstrated in two donors from the Nowra-Kiama region and from a patient in the same area; none of the three had been outside of the study area during the period of seroconversion or at the time of infection. Of the 15 seropositive horses, 6 (40%) had lived continuously since bi...
An epidemic of Getah virus infection among racehorses: isolation of the virus. During the autumn of 1978 a disease characterised by fever and occasionally by exanthema and/or oedema of the limbs was seen in approximately 13 per cent of horses in a training stable in the Kanto district of Japan. A virus was isolated by the intracerebral inoculation of one-day-old mice from blood and nasal swabs taken from naturally and experimentally infected horses. The virus was subsequently passaged in two monkey kidney cell lines in which it produced complete cytopathic changes. Infected horses developed neutralising, complement fixing and haemagglutinin inhibiting antibodies to the v...
Survey on antibody to Getah virus in horses in Japan. A seroepidemiological survey was performed on antibody against Getah virus in horses in Japan by the complement fixation test. The positive rate was 35 and 53% in two areas where an outbreak of the infectious disease was reported, whereas it was in a range of 3.3 to 24.2% in other areas, except in certain prefectures of the Kyushu district where a high positive rate was observed. In the Hokkaido district, the northernmost part of Japan, no reactors were found in horses under 6 years old, unlike in any other district. It was also suggested that Getah virus infection might have already been prev...
Radioimmunoassay for quantitation of antibodies to alphaviruses with staphylococcal protein A. A radioimmunoassay (RIA) procedure is described for measuring antibodies to alphaviruses in human and other mammalian sera. The test employed protein Abearing Staphylococcus aureus as a solid-phase immunoadsorbent for (3)H-labeled viruses complexed with immunoglobulin G. Using antibodies produced in humans and guinea pigs, the RIA procedure clearly differentiated among antibodies to Venezuelan, western, and eastern equine encephalomyelitis viruses. Sensitivity of the RIA depended on the concentrations of labeled viruses employed. The dilution of serum that effected binding of 50% of the (3)H-l...
Study of homologous and heterologous antibody response in California horses vaccinated with attenuated Venezuelan equine encephalomyelitis vaccine (strain TC-83). Of 359 horses vaccinated with attenuated Venezuelan equine encephalomyelitis (VEE) vaccine (strain TC-83), 87% developed hemagglutination-inhibition (HI) antibodies to VEE virus within 1 month. Blood from a subsample of 101 of the 359 horses was obtained over a 1-year period. Within 1 month after vaccination, 84% of the 101 horses had developed VEE HI antibodies, 87% had developed VEE-neutralizing (Nt) antibodies, and 78% had developed VEE complement-fixing (CF) antibodies. One year after vaccination, 58% of the horses had VEE HI antibodies and 73% had VEE Nt antibodies. The percentage of hors...
Occurrence and distribution of western equine encephalomyelitis in Florida. Research and surveillance programs relating to the occurrence and distribution of western equine encephalomyelitis virus in Florida, conducted between 1955 and 1976, suggest that the virus is (1) an endemic arbordae, (2) transmitted in a continuous cycle throughout the year by Culiseta melanura mosquitoes, and (3) restricted to fresh water swamps and waterways in central, north, and northwest Florida.
Production of Venezuelan equine encephalitis virus in cells grown on artificial capillaries. Primary cell cultures, a continuous cell line, and a diploid cell line were grown on an artificial capillary system. The cells were subsequently infected with Venezuelan equine encephalitis virus, and viral replication was studied. Extracellular fluids harvested from this system contained high titers of virus and were relatively free of cell debris.
Nucleolar fragmentation in cells infected with alphaviruses (39886). No abstract available
Chromatographic separations of alphavirus strains by hydroxylapatite. Hydroxylapatite column chromatography methods were developed to characterize selected alphavirus populations. Different conditions of pH and phosphate molarity were required to obtain satisfactory elution profiles and separations for Western equine encephalomyelitis virus strains, compared with Eastern equine encephalomyelitis virus and Semliki Forest virus strains. Raising the pH of the buffers effected earlier elutions of all viruses. Selection of phosphate gradients with more gentle slopes and adjustment to the proper pH effected better separations of virus subpopulations. Elution profiles ...
Antibody studies in ponies vaccinated with Venezuelan equine encephalomyelitis (strain TC-83) and other alphavirus vaccines. Serologic studies in 24 ponies indicated that prevaccination antibodies to Venezuelan equine encephalomyelitis (VEE) virus (strain TC-83) had no influence on hemagglutination-inhibition (HI) antibody stimulation by western equine encephalomyelitis (WEE) or eastern equine encephalomyelits (EEE)-WEE vaccines. However, studies of the effects of VEE neutralizing antibodies on neutralizing antibody stimulation by the heterologous alphavirus vaccines were inconclusive. The VEE, WEE, and EEE antibody responses were studied in 18 VEE-vaccinated (strain TC-83) animals (13 ponies and 5 horses) at 9 to 1...
Endemic eastern equine encephalomyelitis in Florida: a twenty-year analysis, 1955-1974. Research and surveillance programs relating to the circulation of eastern equine encephalomyelitis (EEE) virus in Florida between 1955 and 1974 are summarized. All available data suggest that EEE virus is 1) endemic in many Florida fresh water swamps and waterways, 2) active in a continuous cycle throughout the year with a peak between May and August, and 3) circulating in Culiseta melanura. It has been isolated also from eight other mosquito species.
Equine viral encephalitis. The most important neurotropic viral infections of the horse are the arthropod-borne encephalitides. These include Venezuelan encephalitis (VE), eastern encephalitis (EE) and western encephalitis (WE), which are found in the Americas, and Japanese B encephalitis which occurs in the Far East. All the viruses cause encephalitis in man. Between 1969 and 1972 an epidemic of VE occurred in Central America. In 1971 the disease was reported in Texas, where it was brought under control by the vaccination of susceptible horses with an attenuated live virus vaccine and by the reduction of the mosquito p...
Comparative analyses of members of the Venezuelan equine encephalomyelitis virus complex. Polyacrylamide gel electrophoretic examination of viruses selected from the Venezuelan equine encephalomyelitis (VEE) complex revealed distinct strain to strain differences in profiles of the two virion envelope proteins. The core protein was identical in all viruses tested. We detected five electrophoretic patterns into which the virus strains could be classified and these were designated alpha (alpha), beta (beta), gamma (gamma), delta (delta), and episolon (episolon). Isolates representing variant E of subtype I exhibited a profile characterized by only one apparent envelope band. The epizo...
Investigations on the presence of antibodies to several alphaviruses in humans and domestic animals of a region with elevated epidemiological potential. The paper reports on serological results obtained by HAI tests against several alphaviruses - eastern equine encephalitis (EEE), western equine encephalitis (WEE), Chikungunya, Midlebourg, Semliki Forest, Sindbis, and Ilheus viruses - carried out in humans and some domestic animals in a region with an intensive circulation of migratory birds. It was possible to detect in human antibodies to EEE, WEE, and Sindbis viruses, but in very low proportions (1.8%, 0.4%, and 0.6%, respectively). Serological results obtained in animals were practically negative: antibodies to EEE virus were found only in...