Pasteurella multocida is a Gram-negative bacterium. P. multocida is the cause of a range of diseases in mammals and birds.
P. multocida causes a range of diseases in wild and domesticated animals, as well as humans. The bacterium can be found in birds, cats, dogs, rabbits, cattle, and pigs. In birds, P. multocida causes avian or fowl cholera disease; a significant disease present in commercial and domestic poultry flocks worldwide, particularly layer flocks and parent breeder flocks. P. multocida strains that cause fowl cholera in poultry typically belong to the serovars 1, 3, and 4. In the wild, fowl cholera has been shown to follow bird migration routes, especially of snow geese. The P. multocida serotype-1 is most associated with avian cholera in North America, but the bacterium does not linger in wetlands for extended periods of time. P. multocida causes atrophic rhinitis in pigs; it also can cause pneumonia or bovine respiratory disease in cattle. It may be responsible for mass mortality in saiga antelopes.
In humans, P. multocida is the most common cause of wound infections after dog or cat bites. The infection usually shows as soft tissue inflammation within 24 hours. It can also infect other locales, such as the respiratory tract, and is known to cause regional lymphadenopathy (swelling of the lymph nodes). In more serious cases, a bacteremia can result, causing an osteomyelitis or endocarditis. The bacteria may also cross the blood–brain barrier and cause meningitis.