Proventricular Dilatation Disease in Cockatiels (Nymphicus hollandicus) After Infection With a Genotype 2 Avian Bornavirus

Abstract

An isolate of genotype 2 avian bornavirus (ABV) was recovered from a cockatiel (Nymphicus hollandicus) that was euthanatized for an unrelated lesion and showing no clinical evidence of proventricular dilatation disease (PDD). On histopathologic examination, mild inflammatory lesions were present in the heart and brain, but gastrointestinal lesions characteristic of classic PDD were not observed. To investigate if this ABV2 isolate had reduced virulence, the virus was propagated in duck embryo fibroblasts and inoculated into 2 adult cockatiels by the oral and intramuscular routes. One bird developed clinical signs on day 33 and was euthanatized on day 36. The second challenged bird developed clinical signs on day 41 and was euthanatized on day 45. At necropsy, the proventriculus of both birds was slightly enlarged. Histopathologic examination showed lesions typical of PDD in the brain, spinal cord, heart, adrenal gland, and intestine. A control, uninoculated cockatiel was apparently healthy when euthanatized on day 50. These results show that ABV2 is now the second ABV genotype to be formally shown to cause PDD.

Pathology and diagnosis of avian bornavirus infection in wild Canada geese (Branta canadensis), trumpeter swans (Cygnus buccinator) and mute swans (Cygnus olor) in Canada: a retrospective study

“…Although our findings strongly suggest that ABV is the cause of the clinical and pathological changes observed, formal proof of a causal relationship typically requires fulfilment of Koch's postulates. This was demonstrated for ABV/PDD in several species of parrots, but has yet to be carried out in waterfowl species Mirhosseini et al, 2011;Payne et al, 2011b;Piepenbring et al, 2012). ABV infection should, nonetheless, be included in the differential diagnosis for any Anseriform exhibiting upper gastrointestinal impaction or non-specific neurological signs and having non-suppurative inflammation of the central, peripheral or autonomic nervous systems.…”

“…ABV was first identified in 2008 and proposed as the aetiology of proventricular dilatation disease (PDD), a significant pathological syndrome that has been reported worldwide in more than 80 species of psittacine birds (Honkavuori et al, 2008;Kistler et al, 2008). Subsequent research, including inoculation studies in birds (Gancz et al, 2009;Gray et al, 2010;Mirhosseini et al, 2011;Payne et al, 2011b;Piepenbring et al, 2012) and investigations of outbreaks Gancz et al, 2010;Wunschmann et al, 2011;Heffels-Redmann et al, 2012), provided strong supporting evidence for a causal relationship. Psittacine birds affected with PDD exhibit various non-specific gastrointestinal and neurological signs with a high case fatality rate once clinical signs develop.…”

Viral vector vaccines expressing nucleoprotein and phosphoprotein genes of avian bornaviruses ameliorate homologous challenge infections in cockatiels and common canaries

“…Among these psittacine viruses, PaBV-2 and PaBV-4 are most widely distributed1013 and both were experimentally confirmed to be causative agents of proventricular dilatation disease (PDD)141516171819.…”

Synergistic antiviral activity of ribavirin and interferon-α against parrot bornaviruses in avian cells

“…To date, 15 avian bornaviruses have been identified in a broad range of avian hosts, including Psittaciformes, Passeriformes and waterfowl (Afonso et al, 2016;Kuhn et al, 2015;Philadelpho et al, 2014). Parrot bornaviruses 2 (PaBV-2) and 4 (PaBV-4) are widely distributed in captive psittacine populations (Heffels-Redmann et al, 2011;Rubbenstroth et al, 2012) and were demonstrated to be the causative agents of proventricular dilatation disease (PDD) in these birds (Gray et al, 2010;Mirhosseini et al, 2011;Piepenbring et al, 2012;Rubbenstroth et al, 2014). Bornaviruses are slowly replicating viruses that can persistently infect neurons and various other cell types in susceptible hosts.…”