P. multocida is the cause of a range of diseases in mammals and birds, including fowl cholera in poultry, atrophic rhinitis in pigs, and bovine hemorrhagic septicemia in cattle and buffalo.

Many mammals (including domestic cats and dogs) and birds harbor it as part of their normal respiratory microbiota.

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.

High leukocyte and neutrophil counts are typically observed, leading to an inflammatory reaction at the infection site (generally a diffuse, localized cellulitis).

[9] P. multocida expresses a range of virulence factors including a polysaccharide capsule and the variable carbohydrate surface molecule, lipopolysaccharide (LPS).

A study in a serovar 1 strain showed that a full-length LPS molecule was essential for the bacteria to be fully virulent in chickens.

[12] Strains that cause atrophic rhinitis in pigs are unique as they also have P. multocida toxin (PMT) residing on a bacteriophage.

This toxin activates Rho GTPases, which bind and hydrolyze GTP, and are important in actin stress fiber formation.

The quickest and most accurate method for confirming an active P. multocida infection is molecular detection using polymerase chain reaction.

Due to the polymicrobial etiology of P. multocida infections, treatment requires the use of antimicrobials targeted at the elimination of both aerobic and anaerobic, Gram-negative bacteria.

[18] Other research is being done on the effects of protein, pH, temperature, sodium chloride (NaCl), and sucrose on P. multocida development and survival in water.

Findings seem to indicate the bacteria occupy host niches that force them to change their gene expression for energy metabolism, uptake of iron, amino acids, and other nutrients.

[21] The location of these sequences in P. multocida shows a skewed distribution towards genome maintenance genes, such as those involved in DNA repair.