Clinical signs of disease in BTV-8 infected sheep. (A) The clinical symptoms of vaccinated sheep groups (n = 6) were monitored daily following infection with a virulent BTV-8 strain and scored as described in Materials and Methods. Mean values and standard deviations are indicated. (B) The rectal body temperature of the infected animals was determined daily for a total period of 14 days. Body temperatures of up to 39.5 °C were regarded as normal, temperatures between 39.5 °C and 40.5 °C as moderately elevated, and temperatures higher than 40.5 °C were defined as high fever (temperature limits indicated by dashed lines). Mean values and standard deviations are indicated.