Pathogenicity of fowl enteroviruses.

The pathogenicity of avian nephritis virus, entero-like particles described by McNulty et al. (Avian Pathology, 13: 429), the entero PV2 and entero 3 isolated in our laboratory, was studied by oral inoculation of one-day-old specific pathogen-free chickens. All viruses were shown by immunofluorescence and transmission electron microscopy to multiply in the cytoplasm of enterocytes but histological lesions of the intestine were only observed in chickens infected with McNulty's entero-like particles, entero PV2 and entero 3. Those lesions were present from 3 days post inoculation but were most prominent on the 7th day post inoculation. Variable histological lesions of the pancreas, proventriculus or kidneys were observed 14 days post inoculation with McNulty's entero-like particles, entero PV2 or entero 3. Avian nephritis virus principally induced kidney lesions. This demonstrates that members of a same species of fowl enteroviruses may have different tropisms and could induce different clinical signs and pathology as nephritis or malabsorption syndrome.