Pasteurella multocida is a gram-negative bacillus. Pasteurella are commensals of the mucous membrane of the upper respiratory tract. Factors that reduce resistance, such as overpopulation or a bad stable environment, provide a predisposition to infections with toxigenic strains. Co-infections with Bordetella bronchiseptica are common and lead to particularly severe symptoms.
Pasteurella multocida, either as a mono-infection or together with Bordetella bronchiseptica, leads to “snuffles” in rabbits. Normally, this disease is a stock problem and is often recurrent.
In pigs, Pasteurella multocida toxin is the aetiological agent that causes progressive atrophic rhinitis, with especially the toxigenic pasteurella types A and D being involved. The cytotoxic toxin (PMT) inhibits the osteoblasts. With the activity of the osteoclasts being maintained, it leads to atrophy of the nasal conchae and deformation of the nasal septum. The importance of the toxin in pneumonia in cattle and pigs has not yet been clarified.