Fowl cholera in broilers

Pasteurella multocida, the etiologic agent of fowl cholera, was isolated from six broiler flocks in Georgia during summer 1988. The flocks ranged in age from 20 to 46 days, represented four companies, and spanned a distance of 50 miles. Increased mortality and lameness were the clinical signs present in all affected flocks. Bacterial isolation and agar gel precipitation for somatic antigen serotyping revealed that three of the cases were caused by serotype 1,3, two by serotype 3,4, and one by serotype 3. To prove the virulence of these organisms, two isolates were selected to challenge 5-week-old broilers. Mortality and lameness resulted from this challenge, and P. multocida was reisolated.