Lack of virus transmission from bovine viral diarrhoea virus infected calves to susceptible peers

None of 14 calves not previously exposed to BVDV became infected after bein g forced to have nose-to-nose contact with a group of 5 calves primarily in fected with BVDV. These were 5 male calves primarily infected with a type I BVDV strain, after nose-to-nose contact with a persistently viraemic calf. All 5 became infected and were clinically affected. They were slightly dep ressed and pyretic at 8-9 days post-infection, with a body temperature of u p to 41.6 degrees C, but no medical treatment was required. Seroconversions to BVDV were detected in these calves at 14 to 21 days post-infection. The 14 healthy calves, proved to be free from BVD virus - as well as antibodie s, were introduced 2 by 2 into the group of 5 primarily infected calves on days 4, 7, 14, 21, 28, 35 and 42 after the 5 calves had been in contact wit h the persistently BVDV-infected calf. Each pair of calves stayed within th e primarily infected group for 2 days. None of these 14 calves seroconverte d to BVDV.