Detection of rabies virus RNA isolated from several species of animals in Brazil by RT-PCR

Brain samples from different animal species including humans: five vampire bats, 14 cattle, 12 dogs, 11 cats, two horses, one pig, one sheep and three humans collected from various geographical regions of Brazil were found to be positive for rabies by means of the fluorescent antibody test (FAT) and the mouse inoculation test (MIT). The brain samples were retested for rabies by means of the reverse transcription and polymerase chain reaction (RT-PCR) with 2 primer sets (P1/P2 and RHNI/RHNS3), which amplified full or partial regions on the nucleoprotein (N) gene of the rabies virus, respectively. Brain samples from five vampire bats, 13 cattle, one horse and one sheep failed to yield PCR products when the RHN1/RHNS3 primer pair was used, but all brain samples successfully yielded the products when the P1/P2 primer pair was used. These results suggest that Brazilian rabies virus isolates could be principally divided into two populations according to genetic difference.