Abstract
To assess the importance of transiently infected (TI) cattle in the epidemiology of bovine viral diarrhoea virus (BVDV) type 2 infections and to describe the clinical signs caused by such an infection, a transmission experiment was performed. Three calves were intranasally infected with a hypervirulent BVDV-2c field strain isolated during a severe BVDV outbreak in Germany and housed together with seven susceptible animals. The clinical signs of the BVDV infected animals varied from very mild disease (fever, loss of appetite) to severe watery and haemorrhagic diarrhoea and death. The clinical signs and the level of BVDV excretion depended on the degree of viraemia. The basic reproduction ratio (R0) was estimated to be 0.49 (95% CI 0.06; 2.99), suggesting a limited viral spread using the BVDV-2c strain. This suggests that this BVDV-2 infection in TI animals resulted in limited transmission towards other animals.