Psittacid Herpesviruses Associated with Internal Papillomatous Disease in Psittacines
Presenting Author: Daryl Styles, MS, DVM
Schubot Exotic Bird Health Center, Texas A&M University, TX
Interpretive Review and comments by Dr. Nemetz:
Dr. Styles continued his research from last year which confirmed the association of Psittacid Herpesvirus (PsHV-1) with mucosal papillomas in exotic avian species (Click Here for more detail on the PsHV-1 virus). Internal papillomatous disease (IPD) is a group of neoplastic conditions affecting the bile ducts in the liver, the pancreatic ducts, the proventriculus, or the ventriculus that are frequently coincidental with chronic mucosal papillomatosis. The question became, now that PsHV-1 was confirmed as the definitive cause of mucosal papillomas, was PsHV-1 also associated with IPD?
Internal papillomatosis disease has been reported mostly in neotropical parrots, particularly Amazon parrots and macaws, but has been described in an African grey parrot, a cockatiel, and an eclectus parrot. Mucosal papillomas have been shown to result from infections by PsHV-1 genotype 1, 2, or 3. Dr. Styles tested his hypothesis by testing birds with lesions consistent with IPD for PsHV-1.
PsHv-1 genotype 3 was found in all adenomas, carcinomas, and papillomas from affected organs but not found in non-affected organs. This supports but does not confirm that the virus is confined to the lesions and not a systemic infection. Genotype 3 viruses may also possess a unique affinity for glandular mucosa and ductal epithelium. Secondly, genotype 3 may exhibit enhanced transforming capacity beyond that observed in other PsHV-1 genotypes that result in only benign mucosal papilloma formation.