Infection of Cattle with Parainfluenza 3 Virus with Special Reference to Udder Infection

I. Virus Isolation from Milk

Abstract

Thirty-seven strains of parainfluenza 3 virus were isolated on bovine kidney cell cultures from Japanese cattle in herds suffering from acute respiratory illness. This finding, together with the clinical and epidemiologic observations and the results of a serologic survey, indicates that in Japan, as in the United States and other countries, this virus is one of the important causes of acute respiratory disease in cattle. A significant finding in the present study is that virus was recovered from milk as well as from nasal secretions. This finding suggests an important role for milk, along with nasal discharges, in disseminating the virus among cattle. In addition, the recovery of virus from milk presents a new problem concerning this infection in cattle, in particu-lar, the potential role of this virus in the pathogenesis of mastitis.