Biological and immunological studies of five Brazilian rabies virus isolates

Aspects of biological behavior of Brazilian rabies virus isolated from canine, bovine, equine, vampire and insectivorous bats were studied in mice. The oral infection occurred in mice fed with infected brain of insectivours bat (8.82%), canine (8.57%) and equine (3.03%). The mean period of incubation to all the isolates was 6 days after mice intracerebral inoculation, however, symptoms were variable, since hyperexcitability (canine sample), progressive paralysis of lower limbs and prolonged clinical course until death (equine sample), and mice without clinical signs before death (insectivorous bat). By immunohistochemistry IFN was detected in brains of mice inoculated with bovine and insectivorous bat samples, TNF and iNOS were detected in brains of those inoculated with insectivorous bat, bovine and canine samples, and positive GFAP astrocytes were found in all five samples. Two commercial inactivated rabies vaccines, one imported (vaccine 1) and another manufactured in Brazil (vaccine 2) were compared to evaluate their efficacy to protect against experimental rabies infection in mice, through the NIH and the CDC potency tests, using these street isolates as challenge virus. There was no statistical significant difference between the efficaccy of both vaccines, when comparing the same potency test and challenge virus strain suggesting no need to produce specific vaccines with street isolates. Estudou-se em camundongos aspectos do comportamento biológico de amostras brasileiras de virus rábico isoladas de cão, bovino, eqüino, morcegos hematófago e insetívoro. Observou-se transmissão oral em camundongos alimentados com cérebros infectados de morcego insetívoro (8,82%), cão (8,57%) e eqüino (3,03%). O período de incubação médio para todas as amostras foi de 6 dias após a inoculação intracerebral, com sintomas variando, desde hiperexitabilidade (amostra canina), paralisia progressiva principalmente de membros posteriores e maior duração do curso clínico até a morte (eqüino) e morte repentina, sem sintomas aparentes (morcego insetívoro). Pela imunoistoquímica detectou-se produção de IFN nos cérebros dos camundongos inoculados com amostra de bovino e morcego insetívoro, TNF e iNOS nos animais infectados com amostra de cão, bovino e morcego insetívoro e reação astrocitária com aumento da expressão de GFAP em todas as cinco amostras. A eficácia de 2 vacinas comerciais inativadas, uma nacional e outra importada, para a proteção contra a infecção experimental em ca