Confirmation of nephrotropism and nephropathogenicity of three low-pathogenic chicken-origin influenza viruses for chickens.

Specific pathogen-free chickens were inoculated intravenously with one of three low-pathogenic chicken-origin influenza virus isolates. On day 5 post-inoculation, most chickens had gross and histological kidney lesions. Influenza virus of high titre was recovered from the kidneys and influenza nucleoprotein, detected immunohistochemically, was localized in necrotic renal tubule epithelium. These data indicate low-pathogenic influenza viruses can be nephrotropic and nephropathogenic, and corroborate gross observations from some low-pathogenic influenza outbreaks in laying hens.