Experimental infection with bovine coronavirus (BCV) in lactating cows

Clinical disease, viral excretion, interferon-[alpha] and antibody response

Abstract

Four bovine coronavirus (BCV)-antibody negative lactating cows were infected with a Swedish field strain of BCV through 1 h of contact with an experimentally infected calf. The cows developed a short febrile response, moderate to profuse watery diarrhoea, respiratory symptoms and a marked reduction in milk yield. The incubation period until diarrhoea was 4 to 5 days. There was a transient leukopenia and neutropenia 2 days after infection. A peak of interferon-α was detected using a viral inhibition bioassay in serum and nasal secretions 2 to 4 and in milk 4 to 7 days after infection. Using a capture ELISA, antigen was detected in faeces for 2 to 4 days in all cows, mainly during the diarrhoea. IgM, IgA and IgG1 antibody responses were detected after infection in serum and milk samples from all cows using isotype-specific ELISA.