Systemic campylobacteriosis in an American crow chick

Abstract

A wild, male American crow (Corvus brachyrhynchos) nestling found dead in a pond in San Diego, CA, USA, was submitted for postmortem examination. Autopsy revealed that the chick was markedly underweight for the presumed age with no grossly appreciable fat stores. The primary histologic finding was lymphocytic vasculitis throughout the cerebrum and optic tectum, with lymphohistiocytic meningoencephalitis. The areas of inflammation were consistently associated with myriad, argyrophilic, curved bacilli with a characteristic “seagull” morphology. Additional significant findings included severe unilateral heterophilic and lymphohistiocytic pectoral myositis, with similar intralesional bacilli, and evidence of sepsis based on pancarditis, multifocal random hepatitis, and bilateral orchitis. Using conventional PCR and third-generation sequencing, the bacteria in the brain were identified as most closely related to Campylobacter molothri, a recently described species of Campylobacter. Our finding of a novel pathogen inducing encephalitis and sepsis in a wild bird highlights the utility of advanced molecular techniques in diagnostic pathology.