Avian Bornaviruses in Psittacine Birds from Europe and Australia with Proventricular Dilatation Disease

Herbert Weissenböck,János Gál,Károly Erdélyi,Robert J.T Doneley,Karin Sekulin,Norbert Nowotny,Ralf Dürrwald,Felix Ehrensperger,Richard Hoop,Tamás Bakonyi,Jolanta Kolodziejek

doi:10.3201/eid1509.090353

Abstract

To determine whether avian bornaviruses (ABVs) were a factor in proventricular dilatation disease (PDD), we used immunohistochemistry, reverse transcription-PCR, and nucleotide sequence analysis to examine paraffin wax-embedded or frozen tissue samples of 31 psittacine birds with this disease. PDD is a fatal disease of psittacine birds associated with nonsuppurative encephalitis and ganglioneuritis of the upper intestinal tract. Tissue samples had been collected from 1999 through 2008 in Austria, Switzerland, Hungary, and Australia. Immunohistochemical demonstration of viral antigen within the brain and vegetative nerve system of the gastrointestinal tract provides strong evidence for a causative role of ABVs in this condition. Partial sequences of nucleoprotein (p40) and matrix protein (gp18) genes showed that virus in most of our cases belonged to the ABV-2 and ABV-4 groups among the 5 genogroups described so far. Viral sequences of 2 birds did not match any of the described sequences and clustered together in a new branch termed ABV-6.

Highlights

To determine whether avian bornaviruses (ABVs) were a factor in proventricular dilatation disease (PDD), we used immunohistochemistry, reverse transcription–PCR, and nucleotide sequence analysis to examine paraffin wax– embedded or frozen tissue samples of 31 psittacine birds with this disease
Tissue Samples For this study, we had access to paraffin wax–embedded tissue samples from 25 psittacine birds (20 species) from Austria (N = 13), Switzerland (N = 11), and Australia (N = 1), which were obtained for pathologic examination from 1999 through 2007
The successful IHC demonstration of ABV antigens in birds with PDD by using a polyclonal serum against the nervous system, centrifugal spread of virus into peripheral nerves and autonomic nerve fibers and ganglia has been shown in experimentally infected rats [19,20]

Summary

Introduction

To determine whether avian bornaviruses (ABVs) were a factor in proventricular dilatation disease (PDD), we used immunohistochemistry, reverse transcription–PCR, and nucleotide sequence analysis to examine paraffin wax– embedded or frozen tissue samples of 31 psittacine birds with this disease. Using advanced molecular genetic technologies, they found sequences of at least 5 genetic subgroups of ABV in clinical specimens from most birds with PDD, but in none of the controls. These outstanding pioneer achievements have opened the doors to further research into the epizootiology, pathogenesis, and prevention of the disease. We describe tools for detecting viral signatures in archived paraffin wax–embedded tissue samples that are useful for retrospective studies

Methods

Results

Conclusion