Avian Bornaviruses and Proventricular Dilatation Disease: AAV 2009

Ady Y. Gancz, DVM, MSc, DVSc, Dipl ABVP (Avian), Amy L. Kistler, PhD, MPH, Alexander Greninger, MPhil, MS, Yigal Farnoushi, DVM, Sara Mechani, DVM, Shmuel Perl, DVM, Asaf Berkovitch, DVM, Noa Perez,
Susan Clubb, DVM, Dipl ABVP (Avian), Don Ganem, MD, Joseph L. DeRisi, PhD, and Avishai Lublin, DVM, PhD

Session #220

Summary Style Manuscript

Affiliation: From The Exotic Clinic, Herzlyia, 46875, Israel (Gancz), University of California, San Francisco, 94143, USA (Kistler, Greninger, Ganem, DeRisi), Kimron Veterinary Institute, Bet Dagan, 50250, Israel (Farnoushi, Mechani, Perl, Berkovitch, Lublin), Koret School of Veterinary Medicine, POB 12, Rehovot 76100, Israel (Perez), and the Rainforest Clinic for Birds and Exotics, 3319 E Road, Loxahatchee, FL 33470, USA (Clubb).

Proventricular dilation disease (PDD) is a fatal disorder of psittacine birds, characterized by lymphoplasmacytic infiltration of the central and peripheral nervous system. The disease has been documented in multiple continents in over 50 different species of psittacines as well as captive and free-ranging species in at least 5 other orders of birds. For >30 years, a viral etiology for PDD has been suspected, but no etiologic agent has been reproducibly linked to the disease. Recently, we reported on the discovery of a novel clade of bornaviruses that are strongly associated with PDD. We proposed the name avian bornavirus (ABV) for this group clade, and were able to show that ABVs are significantly divergent from previously known bornaviruses. These findings have since been supported by 2 independent studies; however, despite the rapidly accumulating circumstantial evidence of the ABV-PDD association, no direct evidence of causation has yet been published.

Here we report for the first time on the successful induction of PDD in cockatiels (Nymphicus hollandicus) by inoculation with a brain homogenate containing avian bornavirus 4 (ABV4). Ultra-high throughput pyrosequenc- ing in combination with RT-PCR were used to get in-depth information on the viral content of the inoculum and to rule out the involvement of other viruses. Domestic chickens inoculated by the intracerebral route with the same ABV4(+) homogenate remained asymptomatic, but developed non-suppurative encephalitis and ABV-RNA was detectable in most of their organs for at least 110 days postinoculation. A cockatiel, naturally infected with avian bornavirus 2, has been shown to persistently shed ABV-RNA for at least 95 days, and to remain symptom- free for >7 months.