Papovavirus infection in hand-fed parrots: virus isolation and pathology.

Papovavirus infection was diagnosed in 44 parrots of at least 18 species exclusive of the budgerigar (Melopsittacus undulatus). The birds were 14 days to 4 months old and had been removed from parental care and hand-fed as nestlings. The birds had been unexpectedly found dead after having evidenced no premonitory signs of illness, or they died following a short (12-to-48-hour) period of lassitude and anorexia. In most cases, necropsies revealed pallor, multiple hemorrhages, splenomegaly, and hepatomegaly with multifocal necrosis. Histological lesions included multifocal to diffuse hepatic necrosis that spared the periportal hepatocytes, karyomegaly of splenic reticuloendothelial cells and cells in other tissues, membranous glomerulopathy, and necrosis of bursal medullary lymphocytes. Papovaviruses were isolated from two cases, and papovavirus infection was confirmed in 27 of the birds by the fluorescent-antibody test using a conjugate against a papovavirus isolated from a budgerigar.