A new arenavirus,

We report five cases of human disease caused by arbovirus in 5 patients from the State of São Paulo, Brazil, residing in the municipalities of Osasco, Atibaia, Guarujá, and the capital São Paulo, respectively. One of the patients resides in São Luis, capital of the State of Maranhão. The sites of infection probably were the states of Parana and Goiás, both in cave regions, the State of Amazonas, and Rondônia in two cases. Laboratory tests for malaria were negative and 1 patient showed a positive serum reaction for leptospirosis. Serum samples from the acute and convalescent phases were tested by hemagglutination inhibition, complement fixation, and neutralization in mice. Acute phase samples were inoculated into suckling mice by the intracerebral route. A close antigenic relationship was observed between the five agents isolated and the flavivirus Ilheus. Serologic tests demonstrated the absence of antibodies in all samples from the 5 patients during convalescence and even for more than 1 year after infection in 1 of them.

A new virus, SP An 71686, was isolated from sentinel mice exposed in a forest area in Iguape county, São Paulo state, Brazil, in 1979. The results suggest [hemagglutination inhibition (HI), complement fixation, neutralization, and ELISA] that SP An 71686 virus is a new arbovirus and that it demonstrates some cross-reactivity with other members of the family Flaviviridae, but can be differentiated from them. Although there is an intensive circulation of several arboviruses in the area, the only diagnosed cases of human disease were caused by Rocio virus during and after the epidemic of encephalitis that occurred in 1975-1977, one case of febrile illness by Caraparu virus in 1983, and by subtype IF of Venezuelan equine encephalitis virus in soldiers during jungle survival training in 1990. Wild animals had a prevalence of SP An 71686 HI monotype antibodies: 46% of birds captured in 1990, 40% in 1991 and 19.5% in 1992. These results suggested that wild birds may play a role in the virus transmission cycle. Mammals (rodents and marsupials) must also be considered potential hosts. However, the virus reservoir-vector relationships need further studies which would help to clarify the ecology of this virus.

No abstract

The clinical and laboratory data of a disease in a resident of Ribeira Valley, São Paulo State, southeastern Brazil, caused by an agent close or identical to Caraparu, a Group C arbovirus, was described. Although there is evidence of an intensive circulation of several arboviruses in the area, no diagnosis of human disease by these agents has been made, except the encephalitis cases caused by Rocio virus during an epidemic in 1975-1977. An antigenic difference between Caraparu strains isolated in São Paulo and in Pará States and a close antigenic relationship between Caraparu strain from São Paulo and Bruconha virus were suggested by the serological tests.