P. multocida infection usually results from being bitten, licked, or scratched by an infected pet or by sharing food or plates with infected pets. However, the infection may be idiopathic, with no history of pet exposure. Immunosuppression may increase the incidence of the disease.

Complications of pasteurellosis include deep tissue injury such as tenosynovitis, septic arthritis, and osteomyelitis. Severe, disseminating infections, such as endocarditis and meningitis, may (rarely) develop.

The patient may have a positive history of occupational or recreational exposure to animals. Physical findings relate to the infection site. Local infection may show erythema, warmth, pain and tenderness, purulent discharge, lymphadenitis, joint swelling, and decreased range of motion. Respiratory infection may show sinus tenderness, hoarseness, pharyngeal erythema, rales and rhonchi upon chest auscultation, dullness to percussion, and changes in vocal fremitus. If the central nervous system is involved, neurologic deficits may occur, as well as signs of meningeal irritation (nuchal rigidity, Brudzinski’s sign, Kernig’s sign). Abdominal signs include tenderness, guarding and rebound, hepatosplenomegaly, and costovertebral angle tenderness. Ocular symptoms may include corneal ulcer, conjunctival injection, and decreased visual acuity. Cardiovascular symptoms may include hypotension, tachycardia, new cardiac murmur, or embolic phenomenon. Lymph nodes may show regional adenopathy.