Pathology of experimental Histophilus ovis infection in sheep. I. Lambs.

Inoculation of lambs either intravenously or intranasally with Histophilus ovis resulted in septicaemia. There was bacterial thrombosis and vasculitis in the liver, lung, kidneys and heart. These lesions were similar to those in natural cases of the disease. With intravenous inoculation of a less virulent isolate there were abscesses in the subcutaneous tissues, muscle fascia and joint bursae.