STUDY ON THE PARVOVIRUS INFECTION OF MUSCOVY DUCKS

Parvovirus infection was diagnosed in Muscovy duck flocks consisting o f 4000 to 5000 two to seven weeks old ducks. The disease was character ized by 10 to 60% morbidity and mortality rates (Fig. 1). The affected birds showed severe diarrhoea, weakness of the legs, locomotor distur bances, and later on paralysis and nervous symptoms (spasm, lateral ho lding of the head, opisthotonus), lag in development, and imperfect fe athering (Fig. 2). Besides intestinal catarrh, the pathological examin ations revealed degeneration in the kidneys and skeletal (breast and f emoral) muscles. The most characteristic light-microscopic features we re, as follows: necrosis of skeletal muscles (Fig. 3), mononucleo-cell ular neuritis in the peripheral nerves (e.g. in the nervus ischiadicus , (Fig. 7), marked tubulonephrosis in the kidneys (Figs 4 and 5), acid ophilic intranuclear inclusions in certain epithelial cells of affecte d renal tubules, circumscribed lymphocytic encephalomyelitis accompani ed by necrosis of neurocytes and neurocytophagia (Fig. 6), as well as pancreatitis with multiplex nodular necrosis (Fig. 8). The recovered b irds had high (> 1 : 1000) titres of antibodies against parvovirus (Fi g. 12). The disease was reproduced by an experimental infection. Econo mic losses could significantly be reduced by vaccination of breeding s tock against Derzsy's disease, as well as by serum treatment of day-ol d ducklings. Characteristic of Derzsy's disease in geese and parvoviru s infection of Muscovy ducks have been summarized in the Table. The mo re characteristic differences have been framed.