Eastern westernvenezuelan equine encephalomyelitis aaep. Venezuelan equine encephalitis center for food security and public health 2011 3 s l i d e 9 vee history 1969 1971 largest recorded outbreak covered area from costa rica to rio grande valley in texas thousands of human encephalitis cases over 100,000 horses died 1995 venezuela and colombia over 90,000 human cases. Venezuelan equine encephalitis virus from south florida. Equine encephalids have high mortality rates and represent a significant zoonotic public health threat. Western equine encephalitis is a viral illness that is transmitted to people and horses through the bite of an infected mosquito. This rare but serious disease is transmitted to humans through the bite of an infected mosquito. 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. 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.
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. Vector saliva enhances infection with many pathogens 18, and mosquito saliva is reported to enhance infec. Equine encephalitis definition of equine encephalitis by. Lineage i was considered to be the north american variant of.
Eastern equine encephalomyelitis virus until recently, eastern equine encephalomyelitis virus eeev contained four genetic lineages. Encephalitis viruses are spread by mosquitoes and can affect the. There are 12 nucleotide differences between the genomes of the tc83 attenuated virus and its virulent trd parent strain. Venezuelan equine encephalitis virus veev, alphavirus in the togaviridae family is an enveloped virus with a nonsegmented, positivesense rna genome of approximately 11. Genomes of the trinidad donkey trd and tc83 strains of venezuelan equine encephalitis vee viruses have been cloned and their nucleotide sequences determined. This mosquito is responsible for amplification of the virus during the spring and summer by transmission among viremic wading birds, passerine songbirds, and starlings that are asymptomatic reservoir hosts of the virus fig. You can get a copy of the pdf viewer by clicking here. Other medically important alphaviruses found in the americas include, venezuelan equine encephalitis virus veev, chikungunya virus chikv, mayaro virus mayv, and madariaga madv. Nasci rs, gottfried kl, burkhalter kl, ryan jr, emmerich e, dave k. Supportive care is administered in horses which show clinical signs. The venezuelan equine encephalitis virus was first isolated and fully characterized in 1938. Within a cleft formed at the interface of these two domains, the peptide substrate is thought to bind. Eee was first recognized in massachusetts, united states, in 1831, when 75 horses died mysteriously of viral encephalitis.
Venezuelan equine encephalitis vee is a mosquitoborne illness caused by an alphavirus of the togaviridae family. This virus can be transmitted to horses, other animals, and, in rare cases, people. Pdf icon to the left to view a copy of this virus entry in pdf format. The maps in figures 315 show the historic number of equine eee cases reported in each state from 2003 through 2011. After intracranial inoculation ic, replication of v4020 was more. Western equine encephalitis fact sheet minnesota dept.
Outbreak of venezuelan equine encephalitis, 1995 venezuelan equine encephalitis vee is a disease of horses, mules, and donkeys caused by an alphavirus, which is known to occur only in this hemisphere. Oct 04, 2019 clinical and neuroradiographic manifestations of eastern equine encephalitis. Eastern equine encephalitis eee is an uncommon but serious disease caused by the eee virus. Eastern equine encephalitis virus eee commonly called triple e or, sleeping sickness not to be confused with trypanosomiasis is a zoonotic alphavirus and arbovirus present in north, central and south america and the caribbean. Evolution and spread of venezuelan equine encephalitis. Venezuelan equine encephalitis monovalent viruslike particle vaccine veev the safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Eastern equine encephalitis, also known as triple e, is a dangerous mosquitoborne virus that infects not just horses, but humans, pigs, rodents, whitetailed deer, and a variety of wild birds. A followup study of the 2010 outbreak was undertaken in 2015. Venezuelan equine encephalitis symptoms, diagnosis. Several forms of viral encephalitis can infect equines, and these include. Venezuelan equine encephalomyelitis vee viruses are taxonomically classified within the genus.
Eastern equine encephalitis eee commonly called triple e or, sleeping sickness is a rare but serious viral disease affecting horses and man. Eee is an arbovirus short for arthropodborne virus, meaning spread by insects. The virus is found along the east coast from new england to florida, the gulf coast, and some midwestern areas. Enzootic, equine avirulent, serotype id veev strains appear to alter their serotype to iab or ic, and. Equine encephalitis, severe viral disease of horses and mules. The 5 twothirds of the genome encodes four nonstructural proteins nsp1 to nsp4 that form an enzyme complex required for viral replication. Equine encephalitis an overview sciencedirect topics. Venezuelan equine encephalitis virus pathogen britannica. This map shows the distribution of eastern equine encephalitis virus neuroinvasive disease average annual incidence by county of residence from 2009 through 2018. Sindbis virus is the prototype virus in this group. Recently, progress has been made in understanding the complex ecological and viral genetic mechanisms that coincide in time and space to generate outbreaks. Young, weak and old people may become very sick and in some cases death can occur.
Venezuelan equine encephalitis pathogen safety data sheet infectious substances section i infectious agent name. From 1964 to 1995, 151 cases were reported in the u. Molecular and cellular evidence of natural venezuelan. Eastern equine encephalitis eee questions and answers 2010. Venezuelan equine encephalitis bioterrorism agent profiles for health care workers causative agent. Strains of venezuelan equine encephalitis vee, western equine encephalitis wee, and eastern equine encephalitis eee virus can also cause disease in humans.
Eastern equine encephalitis fact sheet pdf what is eastern equine encephalitis. Counties are shaded according to incidences ranging from less than 0. As the names suggest, eastern equine encephalitis eee most commonly occurs in the eastern united states and canada. Enhanced vector infection from a single amino acid substitution in the envelope glycoprotein aaron c. Eastern equine encephalitis eee, also known as sleeping sickness, is a viral disease of horses that involves transmission between birds or rodents and mosquitoes.
Eastern equine encephalitis virus central ls mosquito. Eastern equine encephalitis virus eeev is a mosquitotransmitted alphavirus with a high case mortality rate in humans. Definitive diagnosis can be made by isolating the virus in a laboratory or by testing blood for the. It was anticipated that one of the enantiomers of carbodine would show enhanced activity and reduced toxicity. It is spread by the bite of a mosquito infected with eee virus eeev.
A horse affected with eee is not contagious and poses no risk to other horses, humans or birds. Eastern equine encephalitis genetic and rare diseases. Research venezuelan equine encephalitis virus transmission. Nov 05, 2009 venezuelan equine encephalitis virus and its replication.
Wee have been recorded more commonly in the western us. Eastern equine encephalitis eee wisconsin department of. The list of treatments mentioned in various sources for venezuelan equine encephalitis includes the following list. Eastern equine encephalitis is a rare but serious disease caused by the bite of an infected mosquito. Epizootic strains are transmitted by mosquitoes to equines, causing high titer viremia figure 1. Equine encephalitis definition is any of three virus diseases chiefly of equines and humans in various parts of north and south america that are transmitted especially by mosquitoes, are characterized in humans by flulike symptoms which often progress to encephalitis and sometimes to coma and death, and are caused by three togaviruses species eastern equine encephalitis virus, venezuelan. The virus that causes eee is usually found only in birds and in the mosquitoes that bite birds. 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. Venezuelan equine encephalitis virus is a mosquitoborne viral pathogen that causes venezuelan equine encephalitis or encephalomyelitis vee. Aerosol infection of cynomolgus macaques with enzootic. We strongly recommend that you talk with a trusted.
Mutation of asn475 in the venezuelan equine encephalitis. Venezuelan equine encephalitis is an emerging infectious disease in latin america. Western equine encephalitis wee has been isolated from argentina to western canada and in u. Eastern equine encephalitis, western equine encephalitis. Eastern equine encephalitis eee is a virus disease transmitted to horses and humans by mosquitoes. Always seek professional medical advice about any treatment or change in treatment plans. The alphaviral nsp2 cysteine protease of the venezuelan equine encephalitis virus veev is a validated antiviral drug target.
Venezuelan equine encephalitis virus veev transmission. Venezuelan equine encephalitis is an acute viral disease characterized by fever, chills, headache, nausea, vomiting, lumbosacral pain, and myalgia, which may progress to encephalitis. Venezuelan equine encephalitis virus is an alphavirus that was originally isolated from the brains of dead horses. Sensitivity of the vectest antigen assay for eastern equine encephalitis and western equine encephalitis viruses. Morbidity rate is 7595% and death usually occurs within 23 days of onset of signs.
Eastern equine encephalitismeningitis summary nndss. Alphavirus of the family togaviridae formerly the group a. Protecting and promoting the health and safety of the people of wisconsin. It is caused by the venezuelan equine encephalitis virus and is a significant disease in the americas. Most people who are infected have no symptoms, but some may develop fever, headaches, and vomiting. Eastern equine encephalitis in latin america n engl j med 369. Eastern equine encephalomyelitis eee, western equine encephalomyelitis wee, and venezuelan equine encephalomyelitis vee viruses are mosquitoborne pathogens that can cause nonspecific illnesses and encephalitis in equids horses. V4020 was generated from infectious dna, contains a stabilizing mutation in the e2120 glycoprotein, and includes rearrangement of structural genes. It is a potentially serious disease that can affect anyone, but children. Little is known about the longterm consequences of either alphavirus infection. The cause of eastern equine encephalitis eee was first identified in the 1930s.
Eastern equine encephalitis is a lifethreatening mosquitoborne arboviral infection found principally along the east and gulf coasts of the united states. Eastern equine encephalitis in latin america article pdf available in new england journal of medicine 3698. Emerging disease issues eastern equine encephalitis. Human eastern equine encephalitis in massachusetts. Nov 29, 20 pathogenesis of venezuelan equine encephalitis. Venezuelan equine encephalitis genetic and rare diseases. Vee can affect all equine species, such as horses, donkeys, and zebras. Equine epizootics of venezuelan equine encephalitis vee occurred in the southern mexican states of chiapas in 1993 and oaxaca in 1996. These diseases are zoonotic, infecting humans, and are a public health concern. In 1943, the first description of vee infection in humans was recorded. Venezuelan equine encephalitis virus, southern mexico. Equine encephalitis is a family of horse diseases that also affect humans.
Eastern equine encephalitis eee is an uncommon but serious disease caused by eee virus. Western equine encephalitis virus is usually less severe. Venezuelan equine encephalitis viruses veevs are a group family, togaviridae. Eastern equine encephalitis virus is maintained in north america in resident birds in freshwater marshes by the ornithophilic mosquito, culiseta melanura. Pathogenesis of venezuelan equine encephalitis virus. Utcvm large animal clinical sciences eastern equine encephalitis. C 2010 equine internal medicine third edition, saunders, chapter 12. 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. Clinical and serological findings of madariaga and. Listing a study does not mean it has been evaluated by the u.
Eastern equine encephalitis and horses introduction eastern equine encephalitis eee and western equine encephalitis wee virus infections occur in horses and other equids in louisiana. Eastern equine encephalitis in horses symptoms, causes. This virus is most commonly seen in horses in the southeastern us with several hundred cases reported each year. Pdf vaccines for venezuelan equine encephalitis scott. Venezuelan equine encephalitis virus epidemic types causes a systemic febrile illness in humans, and about 1% of those affected develop clinical encephalitis. It can infect humans, horses, birds, and other animals. Eastern equine encephalitis eee is an extremely rare but serious and often fatal infection that causes encephalitis or inflammation of the brain. Eastern equine encephalitis virus eeev disease agent characteristics. Febrile illness and encephalitis pdf icon to the left to view a copy of this virus entry in pdf format. Equine encephalitis fast fact iowa state university. History organism venezuelan encephalitis peste loca epidemiology. A mosquitoborne virus that usually affects horses and related animals but may also infect humans.
Vaccines free fulltext advanced safety and genetic. Eastern equine encephalitis fact sheet what is eastern equine encephalitis. Eastern equine encephalitis virus eeev is a member of the genus alphavirus, family togaviridae. 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. Clan cn proteases contain a cysteine protease domain that is intimately packed with an sadenosyllmethioninedependent rna methyltransferase sam mtase domain. Questions about eastern equine encephalitis and horses.
Alphavirus found throughout the western hemisphere. The virus of vee can be transmitted to humans by mosquito. New hampshire health and human services department of fact. Venezuelan equine encephalitis virus synonym or cross reference. Eastern equine encephalitis eee is a mosquitoborne viral disease. History and enhanced surveillance in ontario 1 introduction eastern equine encephalitis virus eeev is a mosquitoborne virus togaviridae.
Carbocyclic cytosine carbodine has broadspectrum activity but toxicity has limited its utility. 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. Eastern equine encephaliuties can infect humans, birds, mosquitoes, horses and some other mammals. 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. Birds and rodents are the primary reservoirs, but unvaccinated horses are particularly susceptible and often serve as sentinels.
Enzootic strains are maintained in a cycle between small rodents and mosquitoes. Venezuelan equine encephalitis virus veev may cause encephalitis in humans, for which no fdaapproved antiviral treatment is available. Humans are primarily exposed to vee through the bite of an infected mosquito. In the united states, equine alphavirus encephalitides for which vaccines are available include eastern equine encephalomyelitis eee, western equine encephalomyelitis wee, and venezuelan equine encephalomyelitis vee. Western equine encephalitis fact sheet pdf what is western equine encephalitis. Eastern equine encephalitis eee is a rare but serious disease that is caused by a virus that can cause inflammation of the brain. Apr 02, 2020 eastern equine encephalitis triple e is an illness caused by a virus that comes from an infected mosquito bite. Six subtypes containing 9 varieties of veevs have been identified by serology. Wee, and venezuelan equine encephalomyelitis vee viruses are mosquito borne pathogens that can. Eastern equine encephalitis eee is more common and tends to occur in outbreak form.
Eastern equine encephalomyelitis eee, western equine encephalomyelitis. Veev infection is characterized by extensive inflammation and studies from other laboratories. Eastern equine encephalitis eee, western equine encephalitis wee and venezuelan equine encephalitis vee are caused by alphaviruses. In the late 1960s some 200,000 people in central colombia were infected with the venezuelan strain, which had also spread north through. 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. Veterinary services january 2008 eastern equine encephalomyelitis eastern equine encephalomyelitis eee is a mosquitobborne viral disease of all equine species such as horses, asses, and zebras. The virus is an alphavirus and is closely related to western equine encephalitis and venezuelan equine encephalitis viruses. Of the several strains of the virus, the most prevalent are the a group, which includes the eastern, western, and venezuelan strains, and the b group, which includes the japanese and. Venezuelan equine encephalitis virus pathogenesis and. The virus can be transmitted to horses, other animals, and in rare cases, people. Eastern equine encephalitis public health and medical. Eastern equine encephalitis collier mosquito control district. 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. Clinical and neuroradiographic manifestations of eastern.
In north america, eeev is restricted to areas east of the mississippi river in the us and southeastern canada. Eee was first recognized in massachusetts, usa in 1831 when 75 horses died mysteriously of viral encephalitis. Eastern equine encephalitis is a viral illness that is transmitted to people and horses through the bite of an infected mosquito. 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. Eastern equine encephalitis virus public health ontario. Symptoms include impaired vision, aimless wandering, head pressing, circling, inability to swallow, irregular staggering gait, paralysis, convulsions and death. Venezuelan equine encephalitis virus veev belongs to the genus alphavirus, family togaviridae. Venezuelan equine encephalitis monovalent viruslike. Pdf eastern equine encephalitis treated with intravenous. Eeev is a biodefence concern because of its potential for aerosol spread. Venezuelan equine encephalitis virus veev remains a naturally emerging disease threat as well as a highly developed biological weapon. Eastern equine encephalitis virus and other mosquitoborne diseases can be a threat to public health, but one that can be minimized through effective vector control efforts. Recently, progress has been made in understanding the.
Enveloped, icosahedral nucleocapsid symmetry, spherical particle, 6065 nm in diameter nucleic acid. Detection of north american eastern and western equine encephalitis viruses by nucleic acid amplification assays. Current and historical conditions indexed list of current and historical nationally notifiable conditions. R 1949 isolation of eastern equine encephalitis virus from naturally infected monkey macacus philippensis, j infect dis 84. Eastern equine encephalitis eee is carried by certain types of mosquitoes in michigan. A few cases of eee have been diagnosed in indiana, all in the northern tier of counties in association with swamps. The virus is an alphavirus and is closely related to eastern equine encephalitis and venezuelan equine encephalitis viruses. Figure 2 shows the number of equine eee cases in each state in 2012, and table 1 provides the number of cases per county or parish in those states in 2012. Until recently, eastern equine encephalomyelitis virus eeev contained four genetic lineages. These include venezuelan equine encephalitis, western equine encephalitis, west nile equine encephalitis, african horse sickness, rabies, tetanus, and bacterial meningitis. Eastern equine encephalitis eee the disease, also called sleeping sickness, causes inflammation or swelling of the brain and spinal cord.
1183 14 733 666 344 1050 857 37 749 1582 672 657 341 68 1583 1542 421 886 1502 1599 1239 291 873 1022 1598 923 1011 1240 668 1419 779 842 176 636 1493 220 1396 172 567 332 542