Lesions associated with Pasteurella multocida infection in raptors.

Several case reports attest to the pathogenicity of Pasteurella multocida in raptors; however, the pathologic syndromes have not been fully described. We describe here the lesions encountered in 22 avian cholera cases in raptors. Besides septicemia-related lesions, a unique syndrome of esophageal abscesses was noted in 8 of the 11 (73%) Buteo hawks that succumbed to avian cholera. Esophageal abscesses were not noted in birds belonging to the order Strigiformes (owls) or family Falconidae (falcons and their relatives). Thus, the presence of white plaques in both the oropharynx and esophagus of Buteo hawks may indicate a possible P. multocida infection and should be considered in the differential diagnosis. This study also documents the first cases of avian cholera in a rough-legged hawk (Buteo lagopus) and a flammulated owl (Otus flammeolus).