Clinical signs observed in Swiss sheep after experimental bluetongue virus serotype 8 infection

Clinical disease of bluetongue (BT) in sheep may differ depending oil breed, age and immunity of infected sheep and may also vary between serotype and strain of BT virus (BTV). Since there are no data available oil the susceptibility of Swiss sheep breeds for BT, we performed experimental infection of the 4 most Common Swiss sheep breeds and the highly susceptible Poll Dorset sheep with the BTV serotype 8 (BTV-8) circulating in Northern Europe since 2006. Clinical signs were assessed regarding severity, localisation, progression and time point of their appearance. The results clearly show that the Swiss sheep breeds investigated were susceptible to BTV-8 infection. They developed moderate, BT-characteristic symptoms, which were similar to those observed ill Poll Dorset sheep. Regardless of breed, the majority of infected animals showed fever, swelling , of the head as xvell aserosions of the mouth and subcutaneous haemorrhages.