RESUMO
The conditions of maintenance of YF virus in brazilian Amazonia are not yet elucidated. Generally, the presence of the virus is attested by human cases of sylvatic origin. During a survey done at the exact place where a man have probably been contaminated, it was possible for the first time in South America, to estimate the mean parity rate of a population of the potential vector Haemagogus janthinomys, from which the YF virus was actually isolated. The survival rate (Ts = 0.96), the biting rate (0.60 mosquitoes/man x hour), and the infection rate (1.71%) were also determinated for the same mosquitoes and have values compatible with the probable conditions of the human contamination. However, more data are needed, in particular in relation with other possible human contaminations and/or circulation of the YF virus in the monkey population (extension and duration of the epizootic episode), in order to know what maintenance cycle is prevalent in this region: a low level transmission, with the mosquito being a "vector-reservoir", or a "constantly moving epizootic wave".
Assuntos
Culicidae , Entomologia , Insetos Vetores , Febre Amarela/epidemiologia , Vírus da Febre Amarela/isolamento & purificação , Adolescente , Animais , Brasil/epidemiologia , Culicidae/classificação , Culicidae/crescimento & desenvolvimento , Culicidae/microbiologia , Coleta de Dados , Reservatórios de Doenças , Água Doce , Haplorrinos/microbiologia , Humanos , Masculino , Árvores , Febre Amarela/microbiologia , Febre Amarela/transmissãoRESUMO
The authors describe the occurrence of outbreaks caused by Oropouche virus (ORO) in the states of Maranhão and Goiás, Brazil in 1988. 36 strains of the virus were obtained from the intracerebral inoculation of the blood of 120 patients into 2-3 day-old infant mice. The illness was characterized by headache, fever, pain in the muscles, joints and back, photophobia, retrobulbar pain, nausea and dizziness. 128 of 197 people examined in Porto Franco, MA, had hemagglutination-inhibiting antibodies to the agent, while 106 of them had IgM antibodies by MAC ELISA test. All age groups were infected, although the incidence was higher among who had 10 to 19 years old. There was no difference, in relation to sex infections. Recurrence of symptoms was reported in 56% of sick people. Mice inoculated with 3624 Culicoides paraensis (Ceratopogonidae) and 1970 Culex (Cux.) quinquefasciatus (Culicidae) collected in Porto Franco resulted in one single isolation of ORO virus, from the Culicoides. These are the first confirmed cases of ORO infection in Maranhão and Goiás states.