GENETIC-CHARACTERIZATION OF RABIES FIELD ISOLATES FROM VENEZUELA

Twenty samples from cases of rabies in humans and domestic animals dia gnosed in Venezuela between 1990 and 1994 and one sample from a vampir e bat collected in 1976 were characterized by reactivity to monoclonal antibodies against the viral nucleoprotein and by patterns of nucleot ide substitution in the nucleoprotein gene. Three antigenic variants w ere found: 1, 3, and 5. Antigenic variant 1 included all samples from dogs and humans infected by contact with rabid dogs. Unique substituti ons permitted identification of two separate outbreaks of dog rabies i n the Maracaibo Depression and Los Llanos region and in the Andean reg ion of Venezuela. Samples from the vampire bat and two head of cattle were characterized as antigenic variant 3 and showed a nucleotide sequ ence homology of 96 to 98% to each other and to samples of vampire bat -associated rabies throughout Latin America. Ten of the remaining 12 s amples were characterized as antigenic variant 5. Genetic studies indi cated that 11 of these samples formed a highly homologous and distinct ive group but were closely related to samples of vampire bat-associate d rabies. The 12th sample of variant 5 (from a cat) showed only 78 to 80% genetic homology to samples of rabies associated with vampire bats . The application of antigenic and genetic typing to rabies surveillan ce in Latin America is essential to improve control programs. Recognit ion of the source of outbreaks of dog rabies and identification of wil dlife species maintaining sylvatic cycles of rabies transmission permi t better utilization of public health resources.