Coronavirus infection of the bovine respiratory tract.

Two viruses, morphologically resembling coronaviruses and antigenically indistinguishable from bovine enteric coronavirus, were isolated in bovine tracheal organ cultures from the lungs and trachea of young calves with respiratory disease. Intranasal and intratracheal inoculation of these viruses into neonatal calves resulted in a predominantly upper respiratory tract infection, which was associated with the development of mild respiratory symptoms.