Venezuelan equine encephalitis virus is an rna virus. Wee, and venezuelan equine encephalomyelitis vee viruses are mosquitoborne pathogens that can cause nonspecific illnesses and encephalitis in equids horses, mules, burros, donkeys and zebras and humans in the americas. Venezuelan equine encephalitis virus and its replication. Pdf icon to the left to view a copy of this virus entry in pdf format. Nov 05, 2009 venezuelan equine encephalitis virus and its replication. Enzootic, equine avirulent, serotype id veev strains appear to alter their serotype to iab or ic, and. Venezuelan equine encephalitis virus veev has caused sporadic outbreaks since the early part of the 20th century, with some epidemics affecting 100,000 persons. Venezuelan equine encephalitis and upper gastrointestinal. Eastern equine encephalitis eee, commonly called triple e or sleeping sickness not to be confused with african trypanosomiasis, is a disease caused by a zoonotic mosquito vectored togavirus that is present in north, central, and south america, and the caribbean. Endemic venezuelan equine encephalitis in the americas.
The safety and genetic stability of v4020, a novel venezuelan equine encephalitis virus veev vaccine based on the investigational veev tc83 strain, was evaluated in mice. We strongly recommend that you talk with a trusted. Venezuelan equine encephalitis virus cultures only 3. Eastern, western and venezuelan equine encephalomyelitis result from infection. Association of tonate virus subtype iiib of the venezuelan. Venezuelan equine encephalitis vee is a mosquitoborne illness caused by an alphavirus of the togaviridae family.
Our data showed that exposure of the virus to 65 degrees c for 515 min resulted in a 56 log reduction of virus infectivity. Venezuelan equine encephalitis virus nucleic acid can also be amplified from the blood or pharynx the eighth day of illness by pcr. Venezuelan equine encephalitis virus veev is a positivesense virus rna of the family togaviridae and the genus alphavirus, within this same group are the equine encephalitis viruses eev of the east and west, mayaro, madariaga, mucambo, and everglades 1,2. Western equine encephalitis fact sheet pdf what is western equine encephalitis. Vee virus subtype id in peru has not been previously.
Human and equine disease results from equine amplified, mosquitoborne outbreaks that expose hundreds of thousands of people to spillover infections. Pdf venezuelan equine encephalitis juancarlos navarro. Genetically engineered, live, attenuated vaccines protect nonhuman primates against aerosol challenge with a virulent ie strain of venezuelan equine encephalitis virus douglas s. Evolution and spread of venezuelan equine encephalitis complex. Apr 15, 2016 venezuelan equine encephalitis is an acute viral disease characterized by fever, chills, headache, nausea, vomiting, lumbosacral pain, and myalgia, which may progress to encephalitis. The western equine encephalomyelitis virus complex contains western equine. Western equine encephalitis fact sheet minnesota dept. The viruses of the vee antigenic complex are currently classified into 6 antigenic subtypes by crossneutralization and hemagglutinationinhibition tests. There are at least 14 subtypes and varieties within the vee complex but only subtype i, varieties ab and c have been associated with major equine epizootics and epidemics aguilar et al. Veev is highly infectious in aerosol form and a known biowarfare agent that can cause severe encephalitis in humans. Recurrent emergence of venezuelan equine encephalomyelitis.
These include venezuelan equine encephalitis, western equine encephalitis, west nile equine encephalitis, african horse sickness, rabies, tetanus, and bacterial meningitis. Venezuelan equine encephalitis virus an overview sciencedirect. The virus is an alphavirus and is closely related to eastern equine encephalitis and venezuelan equine encephalitis viruses. Guidelines for travel pandemic h1n1 in the last 18 years, epizootics of venezuelan equine encephalitis have not occurred in places with historic epidemic register in the guajira peninsula, colombia. These viruses belong to the alphavirus genus in the family togavir idae. Clinical and serological findings of madariaga and. Humans are primarily exposed to vee through the bite of an infected mosquito. Venezuelan equine encephalitis and 2 human deaths, peru cdc.
Venezuelan equine encephalitis virus is a mosquitoborne viral pathogen that causes venezuelan equine encephalitis or encephalomyelitis vee. Venezuelan equine encephalitis aetiology epidemiology diagnosis prevention and control references aetiology classification of the causative agent venezuelan equine encephalomyelitis vee viruses are taxonomically classified within the genus alphavirus of the family togaviridae formerly the group a arboviruses. Pathogenesis of venezuelan equine encephalitis virus. Western equine encephalitis wee has been isolated from argentina to western canada and in u. Little is known about the longterm consequences of either alphavirus infection. Venezuelan equine encephalitis bioterrorism agent profiles.
Equine encephalitis fast fact iowa state university. While endemic strains circulating in rodents are generally unable to cause disease in humans, mutations in certain veev subtypes can create an epizootic strain, carried by mosquitos, that is capable of infection. Venezuelan equine encephalitis vee is an emerging zoonotic arboviral disease that affects equines and humans in the americas. Japanese encephalitis aetiology epidemiology diagnosis prevention and control references aetiology classification of the causative agent japanese encephalitis je virus is a member of the family flaviviridae, genus flavivirus. Venezuelan equine encephalitis virus from south florida. Genetically engineered, live attenuated vaccines protect. Definitive diagnosis can be made by isolating the virus in a laboratory or by testing blood for the. Equine epizootics of venezuelan equine encephalitis vee occurred in the southern mexican states of chiapas in 1993 and oaxaca in 1996. Pdf venezuelan equine encephalitis virus veev remains a naturally emerging disease threat as well as a highly developed biological weapon. Novel antivirals for venezuelan equine encephalitis. Kinetic, mutational, and structural studies of the venezuelan. Author summary the venezuelan equine encephalitis vee complex. Schmaljohn the united states army medical research institute of infectious diseases, fort detrick, maryland, united states of america. Jan 01, 2000 the venezuelan equine encephalitis vee complex is an antigenically related group of arboviruses in the family togaviridae, genus alphavirus.
This is a pdf file of an unedited manuscript that has been. You can get a copy of the pdf viewer by clicking here. Veev complex is a group of 14 antigenic varieties divided into 7 species. Venezuelan equine encephalitis virus veev is an alphavirus in the family togaviridae.
Veev is actually a complex of 7 different species as well as multiple subtypes and varieties 3. Venezuelan equine encephalitis is an acute viral disease characterized by fever, chills, headache, nausea, vomiting, lumbosacral pain, and myalgia, which may progress to encephalitis. V4020 was generated from infectious dna, contains a stabilizing mutation in the e2120 glycoprotein, and includes rearrangement of structural genes. Highresolution functional mapping of the venezuelan.
Venezuelan equine encephalitis virus was first isolated in 1938 from the brain of a horse that died of encephalitis 1,2. Venezuelan equine encephalitis virus veev, western equine encephalitis virus weev, and eastern equine encephalitis virus eeev are nonsegmented, positivesense rna viruses of the genus alphavirus in the family togaviridae 1. Author summary the venezuelan equine encephalitis vee complex comprises a broadly distributed group of alphaviruses in the americas that have the potential to emerge and cause severe disease. In addition, public health reporting of other emerging arboviral disease is encouraged. Venezuelan equine encephalitis and upper gastrointestinal bleeding in child stalin vilcarromero, v. Historically, vee complex viruses have caused recurring outbreaks of human and equine encephalitis in central and south america as well as mexico, with at least one outbreak resulting in movement of the. Methods for inactivation of venezuelan equine encephalitis virus. The venezuelan equine encephalitis vee viru s com plex is a group ofserologically related arthropod borne viruses that are im portant pathogens ofhuman beings and horses in the americas. The 5 twothirds of the genome encodes four nonstructural proteins nsp1 to nsp4 that form an enzyme complex required for viral replication. Vaccines free fulltext advanced safety and genetic. This map shows the distribution of eastern equine encephalitis virus neuroinvasive disease average annual incidence by county of residence from 2009 through 2018. Highresolution functional mapping of the venezuelan equine encephalitis virus genome by insertional mutagenesis and massively parallel sequencing brett f. May 2017 importance eastern equine encephalomyelitis eee, western equine encephalomyelitis wee, and venezuelan equine encephalomyelitis vee viruses are mosquitoborne.
Depending on the subtype, veev maintains either an enzootic or an epizootic life cycle. The alphavirus venezuelan equine encephalitis virus veev was first identified as the causative agent of an equine disease in 1938 and later was found to be a human pathogen. Venezuelan equine encephalitis virus veev, alphavirus in the togaviridae family is an enveloped virus with a nonsegmented, positivesense rna genome of approximately 11. Venezuelan equine encephalitis virus, southern mexico. Venezuelan equine encephalitis genetic and rare diseases. The veev nsp2 protease is a member of merops clan cn and characteristically contains a papainlike protease linked to an sadenosyllmethioninedependent rna methyltransferase sam. Molecular and cellular evidence of natural venezuelan. List of virus strains used in the study and known metadata. Venezuelan equine encephalitis virus veev, alphavirus in the togaviridae. Venezuelan equine encephalitis virus pathogenesis and vaccine. Evolution and spread of venezuelan equine encephalitis.
Molecular and cellular evidence of natural venezuelan equine. Venezuelan equine encephalitis bioterrorism agent profiles for health care workers causative agent. Enhanced vector infection from a single amino acid substitution in the envelope glycoprotein aaron c. Mar 28, 2018 the alphavirus venezuelan equine encephalitis virus veev was first identified as the causative agent of an equine disease in 1938 and later was found to be a human pathogen.
Venezuelan equine encephalitis virus veev remains a naturally emerging disease threat as well as a highly developed biological weapon. Kochel venezuelan equine encephalitis vee is reemerging in peru. Eastern equine encephalitis virus eeev is a member of the genus alphavirus, family togaviridae. Venezuelan equine encephalitis is an emerging infectious disease in latin america.
Louis encephalitis, west nile, and western equine encephalitis. Recently, progress has been made in understanding the. Eee was first recognized in massachusetts, united states, in 1831, when 75 horses died mysteriously of viral encephalitis. Human cases of madariaga virus madv infection were first detected during an outbreak in 2010 in eastern panama, where venezuelan equine encephalitis virus veev also circulates. Venezuelan equine encephalitis virus veev is an important animal and human pathogen found only in the americas the new world. Counties are shaded according to incidences ranging from less than 0. Venezuelan equine encephalitis is the most important arboviral etiology of central nervous system disease in the americas. Venezuelan equine encephalitis vee is an emerging zoonotic disease in the amazon region of peru. Aerosol infection of cynomolgus macaques with enzootic. Vaccines for venezuelan equine encephalitis ncbi nih. Novel antivirals for venezuelan equine encephalitis science.
Specific antibody was present in 16 of 28 peromyscus gossypinus cotton mice and 3 of 16 sigmodon hispidus cotton rats sampled from one of the infected sites in january 1964. Venezuelan equine encephalitis viruses veevs are a group family, togaviridae. Venezuelan equine encephalitis epidemic cdc stacks. Nov 29, 20 pathogenesis of venezuelan equine encephalitis. Venezuelan equine encephalomyelitis vee viruses are taxonomically classified. Western equine encephalitis is a viral illness that is transmitted to people and horses through the bite of an infected mosquito. Vector saliva enhances infection with many pathogens 18, and mosquito saliva is reported to enhance infec. To assess the impact of continuing circulation of vee virus veev on human and animal populations, serologic and viral isolation studies were conducted in 2000 to 2001 in chiapas state. Assessment of listing and categorisation of animal diseases. After intracranial inoculation ic, replication of v4020 was more. Research venezuelan equine encephalitis virus transmission. Infected mice developed paralysis, and the majority died by 9 days after inoculation. Periodic outbreaks of veev occur predominantly in central and south america.
We used venezuelan equine encephalitis vee virus strain tc83 as a model to study the effects of chemical, thermal, and irradiation conditions on infectivity of singlestranded positive rna viruses. Venezuelan equine encephalitis virus is an alphavirus that was originally isolated from the brains of dead horses. The pathogenesis of venezuelan equine encephalitis vee virus infection was compared in intraperitoneally inoculated mice n 24, 6 to 8 weeks old and hamsters n 9, 90110 g using histopathology and immunohistochemical localization of vee virus antigen. A followup study of the 2010 outbreak was undertaken in 2015.
Classification of the causative agent resistance to. Mar 15, 2004 because venezuelan equine encephalitis viruses veevs are infectious by aerosol, they are considered to be a biologicalweapons threat. The pathogenesis of venezuelan equine encephalitis vee virus infection was compared in intraperitoneally inoculated mice n 24, 6 to 8 weeks old and hamsters n 9, 90110 g using histopatho. Venezuelan equine encephalitis virus was isolated three times from the culex melanoconion species of mosquitoes collected in south florida in june, july, and october, 1963.
It is caused by the venezuelan equine encephalitis virus and is a significant disease in the americas. Venezuelan equine encephalitis virus veev is a member of genus alphavirus in the family togaviridae. As the names suggest, eastern equine encephalitis eee most commonly occurs in the eastern united states and canada. The ia and ib strains are considered genetically indistinguishable and are thus classi. Venezuelan equine encephalitis definition of venezuelan. Six subtypes containing 9 varieties of veevs have been identified by serology. Venezuelan equine encephalomyelitis vee, peste loca, venezuelan equine encephalitis, venezuelan encephalitis, venezuelan equine fever last updated. Venezuelan equine encephalomyelitis vee is caused by the vee virus veev. Nonhumanprimate models are needed to evaluate the efficacy of candidate vaccines. The veev species include four antigenic varieties namely iab, ic, id, and ie, all of which cause human disease.
Natural enzootic vectors of venezuelan equine encephalitis. Because it can be easily weaponized, human venezuelan equine encephalitis virus disease is designated as reportable in missouri. Kinetic, mutational, and structural studies of the. An outbreak of equine encephalitis occurred in venezuela in 1936, and a viruslater desig nated as venezuelan equine encephalitis vee viruswas. Venezuelan equine encephalitis virus pathogenesis and. Sindbis virus is the prototype virus in this group. Equine encephalids have high mortality rates and represent a significant zoonotic public health threat. This is a pdf file of an unedited manuscript that has been accepted for publication. Only a single serotype of je virus has been identified and subtipification has been described. Venezuelan equine encephalitis the human infective dose for vee is considered to be 10100 organisms, which is one of the principal reasons that vee is considered a militarily effective biowarfare agent.
Recently, progress has been made in understanding the complex ecological and viral genetic mechanisms that coincide in time and space to generate outbreaks. Other medically important alphaviruses found in the americas include, venezuelan equine encephalitis virus veev, chikungunya virus chikv, mayaro virus mayv, and madariaga madv. Dec 03, 2019 eastern equine encephalitis virus eeev is a member of the genus alphavirus, family togaviridae. Pdf on jul 22, 20, katherine g taylor and others published pathogenesis of venezuelan equine encephalitis find, read and cite all the. During an outbreak of venezuelan equine encephalitis virus in venezuela and colombia in 1995, approximately 3000 cases of neurologic disease were reported. Vee can affect all equine species, such as horses, donkeys, and zebras.