Bovine Diarrhea Virus

IV. Experimental Infection of Cattle

Abstract

The bovine diarrhea (BD) virus isolates from Japanese cattle induced an acute illness in experimentally inoculated calves. The disease was characterized by pyrexia, anorexia and depression; most characteristic were a diphasic temperature reaction accompanied by leukopenia and rarity of respiratory and alimentary symptoms and signs. The isolates also induced a similar disease in adult cows. The results of virus reisolation indicated the systemic nature of the infection and viremia was found to be a common feature. Rises of neutralizing antibody titer against BD virus were demonstrated. Infected lactating cows showed diminished lactation accompanied by virus shedding in milk. In infected pregnant cows the fetuses were also infected with virus. The analysis of the present data together with those in the literature indicates that although there are natural cases of the viral diarrhea-mucosal disease complex caused by BD virus, it seems necessary to evaluate the relative importance of BD virus in the etiology of the syndrome complex. Further the possibility exists that some other agent (s) may be involved in the syndrome complex or that BD virus may induce other clinical conditions.