Venezuelan equine encephalitis virus
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220625890
2008-06-20T19:40:24Z
Epbr123
1395162
Reverted edits by [[Special:Contributions/160.36.198.242|160.36.198.242]] to last version by Persian Poet Gal (using [[WP:HG|Huggle]])
{{Taxobox | color=violet
| name = ''Venezuelan equine encephalitis virus''
| image = Venezuelan equine encephalitis virus.jpg
| virus_group = iv
| familia = ''[[Togaviridae]]''
| genus = ''[[Alphavirus]]''
| species = '''''Venezuelan equine encephalitis virus'''''
}}
'''Venezuelan equine encephalitis virus''' is a [[mosquito]]-borne [[virus|viral]] pathogen that causes '''Venezuelan equine encephalitis''' or '''encephalomyelitis''' (VEE). VEE can affect all equine species, such as [[horse]]s, [[donkey]]s, and [[zebra]]s. After infection, equines may suddenly die or show progressive [[central nervous system]] disorders. Humans also can contract this disease. Healthy adults who become infected by the virus may experience [[flu]]-like symptoms, such as high fevers and headaches. People with weakened immune systems and the young and the elderly can become severely ill or die from this disease.
The virus that causes VEE is transmitted primarily by mosquitoes that bite an infected animal and then bite and feed on another animal or human. The speed with which the disease spreads depends on the subtype of the VEE virus and the density of mosquito populations. [[Enzootic]] subtypes of VEE are diseases endemic to certain areas. Generally these serotypes do not spread to other localities. Enzootic subtypes are associated with the rodent-mosquito transmission cycle. These forms of the virus can cause human illness but generally do not affect equine health.
[[Epizootic]] subtypes, on the other hand, can spread rapidly through large populations. These forms of the virus are highly pathogenic to equines and can also affect human health. Equines, rather than rodents, are the primary animal species that carry and spread the disease. Infected equines develop an enormous quantity of virus in their circulatory system. When a blood-feeding insect feeds on such animals, it picks up this virus and transmits it to other animals or humans. Although other animals, such as cattle, swine, and dogs, can become infected, they generally do not show signs of the disease or contribute to its spread.
The virion is spherical and approximately 70 nm in diameter. It has a lipid membrane with glycoprotein surface proteins spread around the outside. Surrounding the nuclear material is a nucleocapsid that has an icosohedral symmetry of T = 4, and is approximately 40 nm in diameter.
== Viral subtypes ==
[[Serology]] testing has been performed on this [[virus]] and has shown the presence of six different subtypes (classified I to VI). These have been given names, including Mucambo, Tonate, and Pixuna subtypes. There are seven different variants in subtype I, and three of these variants, A, B, and C are the epizootic strains.
== Venezuelan Equine Encephalitis Outbreaks ==
Outbreaks of Venezuelan equine encephalitis virus occurred in Central American and South American countries. This virus was isolated in 1938, and outbreaks have been reported in many different countries since then. Mexico, Colombia, Venezuela, and the United States are just some of the countries that have reported outbreaks.
Between December of 1992 and January 1993, the Venezuelan state of Trujillo experienced an outbreak of this virus. Overall, 28 cases of the disease were reported along with 12 deaths.
June of 1993 saw a bigger outbreak, as 55 humans died as well as 66 [[equine]] deaths.
A much larger outbreak in Venezuela and Colombia occurred in 1995. On May 23, 1995, equine [[encephalitis]]-like cases were reported in the northwest portion of the country. Eventually, the outbreak spread more towards the north as well as to the south. The outbreak caused about 11,390 febrile cases in humans as well as 16 deaths. About 500 equine cases were reported with 475 deaths.
An outbreak of this disease occurred on Colombia in September of 1995. This outbreak resulted in 14,156 human cases that were attributable to Venezuelan equine encephalitis virus with 26 human deaths.
A possible explanation for the serious outbreaks was the particularly heavy rain that had fallen. This could have caused increased numbers of mosquitoes that could serve as vectors for the disease. A more likely explanation is that deforestation caused a change in mosquito species. [[Culex taenopius]] which prefer rodents were replaced by [[Ochlerotatus Taeniorhynchus]] which are more likely to bite humans and large equine animals.
==References==
*APHIS. 1996. [http://www.aphis.usda.gov/lpa/pubs/fsvee.html Venezuelan Equine Encephalomyelitis]
{{Cite web
| title = PAHO: Equine Encephalitis in the Event of a Disaster
| url =http://www.paho.org/English/DD/PED/te_equi.htm
| accessdate = 2007-03-17 }}
{{Cite web
| title = PAHO Epidemiological Bulletin: Outbreak of Venezuelan Equine Encephalities
| url = http://www.paho.org/english/sha/epibul_95-98/be954out.htm
| accessdate = 2007-03-17 }}
{{Cite web
| title = PATHINFO: Venezuelan Equine Encephalitis Virus
| url =http://pathport.vbi.vt.edu/pathinfo/pathogens/VEEV_complex_Info.shtml
| accessdate = 2007-03-17 }}
*Esparza, J., et al. (1975) Multiplication of Venezuelan Equine Encephalitis (Mucambo) virus in cultured mosquito cells. ''Biomedical and Life Sciences and Medicine'' 49, 2/3, 273-280
[[Category:Togaviruses]]
[[Category:Horse diseases]]
[[Category:Animal virology]]
[[de:Venezolanische Pferdeenzephalomyelitis]]