Newcastle disease in geese: natural occurrence and experimental infection.

A novel disease entity in domestic geese with unusual epidemiology and pathological changes has emerged in some regions of China since the late 1990s. Velogenic Newcastle disease (ND) viruses were isolated from visceral organs and cloacal swabs of diseased birds in the field. Gross lesions of diseased geese were characterized by extensive necrotic foci in intestinal mucosa, spleen and pancreas. Histological examination revealed multisystemic distribution of lesions. Similar disease was reproduced experimentally in geese not only with two field isolates of goose origin, but also with ND viruses belonging to genotypes VI, VII, VIII and IX. These led us to define the novel disease as clinical ND in geese. Additionally, the goose-originated ND virus isolates could be transmitted from geese to specific pathogen free chickens, illustrating the potential threat they posed to the chicken industry. This is the first detailed report of the natural outbreaks and experimental reproduction of ND in geese, providing evidence that geese could play an important role in the epidemiology of ND.