Outbreak of Listeria Monocytogenes in Pheasants

Listeria monocytogenes is capable of infecting almost all animals. However, outbreaks of listeriosis are infrequent in birds. This report describes an outbreak of listeriosis in a small pheasant (Phasianus colchicus) breeder farm with more than 2,000 pheasants from Hubei province of the People's Republic of China. The affected flock consisted of adult and young birds. Approximately 300 young birds and a few adult birds were found dead within a few days of the onset of clinical signs. Twenty-five dead birds were collected for further examination. Histopathological lesions in the visceral organs were characterized by monocyte infiltration and proliferation. Localized encephalitis and meningitis were detected in the brains of dead birds. Gram-positive organisms were observed in heart blood smear, liver, and brain impression smears. The organisms were isolated from fresh liver and were identified as L. monocytogenes serotype 4b based on multiplex polymerase chain reaction (PCR) and hlyA gene sequence analysis. This is the first report describing outbreak of listeriosis in pheasant flock.