Diagnostic Detection of H7N3 Low Pathogenicity Avian Influenza in a Commercial Game Bird Flock.

Abstract

Low pathogenicity avian influenza (LPAI) H7N3 was diagnosed in a flock of commercially raised Japanese quail (Coturnix japonica) breeder hens. The birds were submitted with an initial complaint of a drop in egg production and watery droppings. Initial PCR testing of the flock for avian influenza (AI) was negative; however, mortality started increasing drastically, prompting further examination and the submission of more birds to the diagnostic laboratory. On antemortem examination, the birds appeared lethargic, with ruffled feathers, and had labored breathing. Gross examination revealed poor body condition, moderate dehydration, splenomegaly, ovarian regression, and airsacculitis. Several hens produced thin-shelled and shell-less eggs. Microscopically, lymphoplasmacytic encephalitis with neuronal cell necrosis, fibrinoheterophilic pneumonia, and splenic lymphoid depletion with amyloid deposition were seen. AI virus was detected in a follow-up submission and characterized as LPAI H7N3. Quail are a species of interest in the pathobiology of avian influenza viruses, underlined by the ability to serve as an amplification host.