Staphylococcosis in captive exotic waterfowl.

Pathological and epidemiological findings are presented on Staphylococcus aureus infections in 10 genera of waterfowl kept at the National Zoological Park, USA. Of 2450 Anseriformes necropsied between 1975 and 1992, 43 birds had local or systemic forms of staphylococcosis. Of these 28 (65.1%) were males and 15 (34.9%) were females and most of the deaths occurred between January and June (38 birds, 88.4%). Gross and histopathological lesions were seen in the heart, liver, spleen, kidneys, joints and central nervous system. They were consistent with multiple acute to chronic patterns of inflammatory reaction, ranging from mild to severe necrotizing suppurative exudation. Granulomatous responses were noted in many cases, mainly in the spleen and liver. Amyloidosis occurred concurrently in 14 birds, affecting mainly liver, spleen, kidneys, thyroids, pancreas and adrenals. The epidemiological factors indicate that the most likely route of infection was through the skin, secondary to the naturally aggressive anseriform breeding behaviour. This probably accounted for the greater prevalence of staphylococcosis in the males.