Biology session

Haemorrhagic nephritis an enteritis of geese, caused by the Anser anser polyomavirus 1 (AaPyV1, or previously goose haemorrhagic polyomavirus), was noted in Hungary in 1969. The virus was also found in Muscovy duck and mule duck. The infected birds of these species do not show clinical signs but are considered as potential reservoirs.

AaPyV1 (Polyomaviridae virus family, Gammapolyomavirus genus) has double-stranded DNA genome that, similarly to other polyomaviruses, encodes the early and late genes, and an additional putative gene (ORF-X). Although the viral genome was sequenced, neither the cellular and molecular mechanism of infection nor the function of the viral genes is exactly known.

The aims of our study were determination of representative AaPyV1 genomes circulating in Hungarian goose and duck flocks, preliminary functional analysis of the ORF-X gene, and seeking for potential polyomavirus reservoirs.

Samples were provided by the Veterinary Diagnostic Directorate of the National Food Chain Safety Office, Budapest, Hungary, including domesticated goose and duck tissue (kidney, bursa) specimens with suspected AaPyV1 infection, and cloacal swab samples of wild birds collected for influenza virus surveillance.

Three genomes of AaPyV1 collected in 2015 were amplified and determined using next generation sequencing method. The viral genomes were highly related to reference sequences deposited in the GenBank. The 90 cloacal swab samples were examined by universal polyomavirus specific broad spectrum nested PCR but none of them tested positive for virus presence. In addition, putative mRNA of the ORF-X was reverse transcribed and amplified from domesticated bird tissue samples, but expression of the putative protein could not be certified.

In the future, we plan to carry out mRNA transcriptome analysis to discover viral and host factors of AaPyV1 infection that may provide important data about viral gene expression, concerning the ORF-X as well. We pursue the investigation of circulating AaPyV1 strains and potential reservoirs.