Multiple Occurrences of Mucosal Disease and Persistent Infection with Bovine diarrhea virus 1 on a Farm

Abstract

On a farm keeping 12 Japanese Black cows, mucosal disease occurred in a calf in August 1993 and again in 3 calves and a cow during December 2000 to February 2001. In order to clarify factors related to these multiple occurrences, all animals on the farm were subjected to virological and pathologicalexaminations. Calves and the cow with the disease developed diarrhea and erosions in the oral-cavitymucosa. Cytopathic and noncytopathic (NCP) strains ofBovine diarrhea virus1 (BVDV-1) were isolated from the sera of animals with no antibody to the virus. Multiple erosions and ulcers were observed throughout the alimentary tract, including the tongue, esophagus, and gastrointestinal tract. Investigation of the remaining animals on the farm for BVDV-1 showed that 3 cows were persistently viremic (NCP strain only). Four animals demonstrating mucosal disease after December 2000 were offspring (daughter or granddaughter) of a cow persistently viremic with the NCP strain. These findings suggest that the presence of animals persistently infected with BVDV-1 may be a serious factor in multiple occurrences of mucosal disease on a farm.