In Practice 7: 145-149 (1985)
© 1985 British Veterinary Association

Diagnosis of pasteurellosis in sheep

Confirmation of a clinical diagnosis of either form of pasteurellosis depends on laboratory examination of specimens taken at necropsy. The gross pathological changes of the disease may be confused with other diseases or obscured by autolysis or hypostatic congestion. Laboratory confirmation depends on the culture of significant numbers of P haemolytica from lesions and, or, the presence of specific histological changes.

Serotyping of a number of strains from flock outbreaks is necessary when investigations into the efficacy of vaccination are being made. It cannot be assumed that all deaths are caused by one particular serotype or, indeed, by pasteurellosis.

The recovery of P haemolytica from nasal swabs does not warrant a diagnosis of pasteurellosis and the serotypes present in the nose are not always representative of those causing the disease.