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*Venezuelan EEV: ''Culex melanconium'', ''Aedes'' spp., ''Phosphora'' spp.
*Venezuelan EEV: ''Culex melanconium'', ''Aedes'' spp., ''Phosphora'' spp.
''Culiseta melanura'' is another vector for Eastern EEV. It feeds mostly on swamp birds, completing an enzootic cycle of viral transmission. ''C.melanura'' is thus an inhabitant of freshwater swamps and is not usually found in areas densely populated by equids. Epizootics and epidemics of Eastern EEV disease are propagated by ''Aedes'' spp. Western EEV persists in an enzootic cycle with passerine birds, transmitted by ''C.tarsalis''. Other vectors or overwintering hosts for this serotype may include [[Dermacentor spp.|''Dermacentor andersoni'']] ticks, ''Triatoma sanguisuga'' (the assassin bug), and the cliff swallow bug (''Oeciacus vicarius''). Epidemic strains of Venezuelan EEV have infected mosquito species from several genera and this viral serotype may also be transmitted by ticks.
''Culiseta melanura'' is another vector for Eastern EEV. It feeds mostly on swamp birds, completing an enzootic cycle of viral transmission. ''C.melanura'' is thus an inhabitant of freshwater swamps and is not usually found in areas densely populated by equids. Epizootics and epidemics of Eastern EEV disease are propagated by ''Aedes'' spp. Western EEV persists in an enzootic cycle with passerine birds, transmitted by ''C.tarsalis''. Other vectors or overwintering hosts for this serotype may include [[Dermacentor spp.|''Dermacentor andersoni'']] ticks, ''Triatoma sanguisuga'' (the assassin bug), and the cliff swallow bug (''Oeciacus vicarius''). Epidemic strains of Venezuelan EEV have infected mosquito species from several genera and this viral serotype may also be transmitted by ticks.
==Virus Identification==
Viruses can be identified by complement fixation, immunofluorescence, PCR, ELISA, or virus isolation.
*The complement fixation test can be used to identify Eastern or Western EEV in infected mouse or chicken brains, cell culture fluid or amniotic-allantoic fluid
*Virus may be identified in brain tissue or cell culture using direct immunofluorescent staining.
*EEE and WEE viral RNA in mosquitoes and equine tissues may be detected by reverse-transcription PCR.
*ELISA can be used to detect virus in brain tissue. An antigen-capture ELISA, developed for EEE surveillance in mosquitoes, can be used where virus isolation and PCR facilities are unavailable (Brown ''et al''., 2001).
*Virus isolation is the most definitive diagnostic method for EEE or WEE. Brain is preferred, but virus has also been isolated from the liver and spleen. Samples of these tissues should be taken in duplicate, one set for virus isolation and the other placed in formalin for histopathology. Viral isolation specimens should be sent frozen unless they can be received refrigerated within 48 hours of sampling. Unless clinical signs persist for more than 5days prior to death, EEE virus is frequently isolated from equine brain tissue. WEE virus, however, is rarely isolated from tissues of infected horses. Newborn mice, chicken embryos and a number of cell culture systems can be used for virus isolation. Virus may also be isolated from cerebrospinal fluid (CSF) of acutely infected horses.
==References==
==References==