Japanese B Encephalitis Virus in the Blood of Experimentally Inoculated Chickens.

As a result of inoculating Japanese B encephalitis virus subcutaneously in chickens, virus can frequently be detected in the serum 24 hours to 7 days later. Even the subcutaneous inoculation of minute amounts of virus frequently resulted in viremia. In addition, it was demonstrated that following the bite of 4 infected mosquitoes infection with viremia occurred in the one chicken used. In these experiments, when employing a “brain-adapted” strain of virus and 2- to 3-months-old chickens, the titer of virus in the serum was relatively low. It was lower using this agent, than in similar experiments with strains of St. Louis and Western equine viruses recently isolated from mosquitoes. In 2 test feedings on chickens inoculated with Japanese B virus no mosquitoes became infected, but we feel that no conclusions should be drawn from such a limited test. Virus did not persist in the spleen of inoculated chickens over 8 days nor in the brain over 40 days (not tested earlier). These experiments do not conclusively demonstrate that the chicken can or cannot be a source of Japanese B virus infection for mosquitoes, but indicate that such a possibility exists. We feel that chickens and other birds should be considered potential sources of mosquito infection and that they deserve further study with recently isolated strains of virus.