Intranuclear Hepatic Inclusion Bodies in an African Grey Parrot

Abstract

Pacheco's parrot disease (2) was described in the early thirties, with nothing recorded in the literature since then (1). This disease, shown by Rivers and Schwentker (3) to be caused by a virus, was reported only from South America. The postmortem findings were similar to those of psittacosis, although intranuclear eosinophilic inclusion bodies were present in liver, spleen, kidney, and occasionally the lungs (3). The livers of 14 african grey parrots (Psittacus erithacus) were examined histologically at this laboratory during the last four years. Lesions similar to that of Pacheco's parrot disease were seen in the liver of one bird. This was 1 of 11 immature parrots imported from Ghana six weeks previously. The keeper noticed ruffling of the feathers, a slight nasal discharge, and apathy. He treated the birds with oxytetracycline. There was no apparent response. Seven of these parrots died and showed lesions of mycopneumonia on autopsy. In sections of the pneumonic lesions, branching septated hyphae were seen similar to those described for Aspergillus sp. (4). Escherichia coli was isolated from the liver of the parrot in question. No cultures were made for fungi and viruses. The liver of the parrot was enlarged, hyperemic with small, irregularly distributed foci of necrosis (Fig. 1). There was no inflammatory reaction in the liver. A few monocytes were observed between the liver cell cords. The cytoplasm of many liver cells possessed vacuoles of various sizes indicative of fatty infiltration. Many nuclei of hepatocytes showed margination of chromatin, and a few, karyorrhexis. Intranuclear eosinophilic inclusion bodies, often with a halo, were widespread in the liver cells (Figs. 2, 3). The Kupffer cells were often vesicular. No inclusion bodies were seen in the lungs.