EXPERIMENTAL TRANSMISSION WITH OVINE RINDERPEST VIRUS

The behaviour of ovine rinderpest virus in experimentally infected cro ssbred calves and indigenous sheep was studied in two phases. In the f irst phase, clinical manifestations were more pronounced in calves tha n in sheep. Leukopenia was significantly higher. However, there were n o differences in duration of leukopenia between the two species. There was a positive correlation of leukopenia with fever in calves, which showed predominant lymphopenia. No mortality was noticed in sheep, whe reas one calf died on Day 10 post-infection. In the second phase of th e experiment, virus recovered from the reactor calf was subinoculated into another calf and sheep. The calf showed classical signs of rinder pest. In sheep, anorexia and diarrhoea were the only two signs noticed . Duration of leukopenia associated with reduced lymphocytes was 3 day s in sheep whereas in calves for 8 days. Comparative responses of the two species suggest that calves may serve as a better indicator host t han sheep in in vivo characterization of rinderpest isolates of ovine origin.