Virological, clinical and serological responses of sheep infected with tissue culture adapted bluetongue virus serotypes 10, 11, 13 and 17.

Sheep were experimentally infected with cloned strains of tissue culture adapted bluetongue virus (BTV) serotypes 10, 11, 13 and 17. All the infected animals developed viremia by Day 2 or 3 post-inoculation (P.I.) and reached maximum viremia on Day 7 P.I. The viremia lasted for 2 to 3 weeks. Animals infected with the different serotypes showed mild clinical bluetongue (BT) responses, characterized by pyrexia and leukopenia, which coincided with the peak of viremia. Antibodies appeared by Day 10 P.I. and reached maximum by Day 28 P.I. There was a temporal relationship between the increase in neutralizing antibody titer, the drop in titer and clearance of virus from the peripheral circulation. Recovery from primary infection protected the animals against secondary challenge with homologous virus.