Avian Polyomavirus Infection in Non-Budgerigar Psittacine Birds in Thailand - A case report

Abstract

One sick 4-week-old Eclectus (Eclectus roratus) and two carcasses of 3-week-old Macaws (Ara macao) from a bird farm near Bangkok were submitted in July 2009 for investigation. Necropsy revealed multifocal hemorrhages at subcutaneous tissue, heart, liver and bursa of Fabricius. The most prominent findings were hepatomegaly and splenomegaly. Histopathologic examination showed severe splenic necrosis with presence of homogeneous pale basophilic intranuclear inclusion body in splenic periarteriolar sheath cells. The liver showed severe necrosis with
occasionally intranuclear inclusion body in sinusoid-lining cells. Intranuclear inclusion bodies were detected in mesangial cells, epithelium of collecting tubules and papillary ducts of kidney and mesenchymal cells of lung and heart. TEM examination revealed tremendous 45 nm icosahedral non-enveloped capsids consistent with virions of polyomavirus in intranuclear inclusion body containing cells in kidney and lung. The diagnosis of avian polyomavirus (APV) infection was made based on histopathologic and electron microscopic results. Avian polyomavirus cause severe disease in a wide range of psittacine and non-psittacine birds. It occurs most frequently in budgerigars, macaws, conures, Eclectus parrots, Ringneck parrots and lovebirds. The disease is more severe in nestlings as also observed in this study. In this report, we document the macroscopic and microscopic findings including TEM feature of a recent case of APV infection in non-budgerigar psittacine birds from a bird farm near Bangkok, Thailand. This report may remind avian veterinarians and breeding aviary farmers about the occurrence of APV infection in this country and make them be aware of the possible outbreak of APV in the future.