Rocio viral encephalitis

Rocio viral encephalitis is an epidemic flaviviral disease of man first observed in São Paulo State, Brazil, in 1975. Rocio virus was responsible for several epidemics of meningoencephalitis in coastal communities in southern São Paulo, Brazil, during 1975 and 1976. The outbreak affected over 1,000 people and killed about 10% of those infected, but apparently responded well to treatment for viral encephalitides. The disease progresses rapidly after onset, with patients dying within 5 days of symptoms first appearing. The disease first presents with fever, headache, vomiting, and conjunctivitis, then progresses to neurological symptoms (confusion, disorientation, etc.) and muscle weakness; about one-third of cases enter a coma, and a third of them die, though supportive care such as intensive nursing and symptomatic treatment might reduce the case fatality rate to 4%. Survivors show neurological and psychological after-effects (sequelae) in about 20% of cases. It is hypothesized that Rocio virus is a mosquito-borne arbovirus with the potential for transmission by two prevalent Culex species mosquitoes, should it be introduced into North America.