Table 1.

Encephalitic alphaviruses.

	Venezuelan encephalitis viruses (VEEV)	Western encephalitis viruses (WEEV)	Eastern equine encephalitis viruses (EEEV)
Transmission	Rodents, mosquitos (Aedes, Culex, Psorophora etc.)	Birds, mosquitos (Aedes, Culex, etc.)	Rodents/birds, mosquito (Aedes, Culiesta, etc.)
Average incubation time	1–5 days	2–7 days	3–10 days
Initial symptoms	Asymptomatic, febrile illness	Asymptomatic, febrile illness	Asymptomatic, febrile illness
Clinical syndrome	Encephalitis	Encephalitis	Encephalitis
Case-fatality (%)	1	3–7	50–75
Associated neurological sequelae	Convulsions, somnolence, confusion, photophobia, coma, intellectual disability, and emotional instability/behavioral changes	Confusion, visual disturbances, photophobia, seizures, somnolence, coma, intellectual disability, and emotional instability/behavioral changes, and spastic paresis	Convulsions, seizures, paralysis, intellectual disability, and behavioral changes
% Survivors with neurological sequelae	4–14	15–30	50–90