Peripheral distribution of virus in dogs inoculated with two strains of rabies virus

Abstract

Forty-seven Beagles were inoculated IM with an Ethiopian strain or a Mexican strain of rabies virus to study the pathogenesis of street rabies virus in dogs. Thirty-nine dogs died of rabies, with incubation periods lasting 9 to 69 days. Of the dogs that died, 82% had shown typical signs of rabies, but 18% died without any noticeable signs of illness. Eight dogs that remained healthy during an observation period lasting more than 2 years did not produce detectable amounts of rabies virus-neutralizing antibodies; however, when challenge exposed with a large dose of the homologous rabies virus inoculum, these 8 dogs responded with high antibody titers, but challenge-exposed control dogs died of rabies. Infective virus was isolated from the saliva and cerebrospinal fluid of dogs before any signs of rabies were noticed; rabies virus-neutralizing antibodies were not detected in the serum and cerebrospinal fluid before illness. In this study, viral antigen was not detected in the skin biopsy specimens taken before signs of rabies were noticed. At necropsy of the 39 dogs, rabies virus was detected in most tissues examined. Viral antigen was detected in the skin tissues of 14 (36.8%) of the 38 dogs examined. The presence of viral antigen in the skin seemed to correlate with the presence of virus in the salivary glands, but virus in the salivary glands did not indicate the presence of virus in the skin. Eleven (44%) of the 25 dogs which had virus in the salivary glands did not have any detectable amount of viral antigen in the skin.(ABSTRACT TRUNCATED AT 250 WORDS)