ABSTRACT
El grupo de las encefalitis Equina Venezolana, del Este, del Oeste y del Nilo Occidental (EEV, EEE, EEO y ENO respectivamente) son zoonosis transmitidas por mosquitos a humanos y equinos. Este grupo de enfermedades se mantienen en la naturaleza en ciclos enzoóticos de transmisión entre mosquitos y roedores silvestres o aves que son sus hospedadores naturales. La circulación de estos virus es enzoótica y ocurre en áreas geográficas definidas y tienen capacidad de causar epidemias/epizootias con morbilidad y mortalidad que puede ser de importancia significativa. Este artículo describe detalladamente todas las encefalitis virales que afectan a los équidos y sus aspectos clínicos, patológicos y diagnósticos.
The encephalitis of Venezuelan Equine, Eastern, Western and West Nile (VEE, EEE, WEE and ENO respectively) are zoonotic encephalitis transmitted by mosquitoes to humans and horses. This group of diseases is maintained in nature in cycles enzootic transmission between mosquitoes and wild rodents or birds are their natural hosts. The circulation of this virus is enzootic and occurs in defined geographical areas but is capable of causing epidemics / epizootics with morbidity and mortality can be significant importance. This article describes all viral encephalitis affecting equines and their clinical, pathological and diagnostic aspects.
Subject(s)
Humans , Animals , Male , Female , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Viruses/classification , Encephalitis/complications , Encephalitis/pathology , Epidemics/prevention & control , Encephalomyelitis, Equine/transmission , CulicidaeABSTRACT
The transmission cycle of western equine encephalitis (WEE) virus in South America is unknown. A WEE virus strain was isolated from Aedes albifasciatus in Argentina during the WEE epizootic of 1982-83. Also, Culex pipiens from Argentina was reported to be able to transmit WEE virus experimentally, but other results indicate that Cx. pipiens from the USA is refractory to this virus. We determined the susceptibility of Argentina strains of Ae. albifasciatus and Culex pipiens complex mosquitoes to infection by WEE virus by the oral route. Adult females were fed on chicks infected with a WEE virus strain isolated in Cordoba Province, Argentina, or were fed on a blood/virus suspension. Each mosquito ingested between 10(1.6) to 10(6.4) vero cell plaque-forming units of virus. Each of 28 Ae. albifasciatus was positive for virus from the fourth day postfeeding, and there was evidence for virus replication. In contrast, 0/44 Cx. p. quinquefasciatus and only 1/15 Cx. p. pipiens was positive. Aedes albifasciatus is susceptible to infection by WEE virus and should be considered a potential vector of this virus in Argentina. Both subspecies of Cx.pipiens are refractory to peroral infection by WEE virus and probably do not play a role in the WEE virus cicle in Argentina