[Experimental infection of lambs with strains of the bovine respiratory syncytial virus].

Lambs were successfully infected with bovine strains of a respiratory syncytial virus. When the Nomi reference strain and the local Antonovo strain of the RSV were used i/v and via the trachea the animals reacted on the 3rd to 5th day with dizziness, dyspnea, conjunctivitis, nasal discharges, etc., more strongly manifested with the use of the Antonovo strain. The temperature reaction started on the 3rd day and receded on the 7th day, with a second peak on the 8h day. Serologically, RSV-antibodies were released on the 14th day, and that correlated in dependence on the severity of the clinical manifestations. Such observations made it possible to use lambs as a sensitive animal species to differentiate the virulence of the tested strains. Testing along these lines rendered is feasible to obtain attenuated strains and use various immunoprophylactic agents against the respiratory syncytial virus.