Goose Hemorrhagic PolyomavirusDetection in Geese Using Real-Time PCR Assay

Molecular epidemiology and phylodynamics of goose haemorrhagic polyomavirus

Goose haemorrhagic polyomavirus (GHPV, or Anser anser polyomavirus 1) is a small dsDNA virus of the Polyomaviridae family. The virus infects the internal organs causing haemorrhagic nephritis and enteritis of geese that may be fatal for goslings. In this study, GHPV positivity was examined in goose and duck samples collected in Hungary between 2005 and 2019. In this period, 384 of the investigated 1,111 specimens were diagnosed as GHPV-positive by PCR assay. Twenty-two GHPV genomes were sequenced and subjected to phylogenetic and evolutionary analysis. Based on the sequence data, the mean evolutionary rates were estimated 6.57 × 10^-6 -5.82 × 10^-5  s/s/y for both GHPV complete genomes and individual genes, with negative selection acting on each gene. When GHPV VP1 sequences originating from wild birds were also included in the analyses, the nt and aa mutations inflated the substitution rate to 1.54 × 10^-4  s/s/y that may imply adaptation of the virus to novel host species. Our data suggested the co-circulation of various GHPV strains in Hungarian goose farms; the source of these may be persistently infected domesticated or migratory wild birds. Detection and characterization of GHPV in wild birds and domestic waterfowls may help to elaborate new strategies for more effective disease control and prevention.

Elaboration of Triplex PCR for Detection of Selected Viral Infections in Waterfowl

Introduction

Viral infections are the greatest threat to waterfowl and cause significant economic losses. Diagnosis and differentiation of three goose viruses is difficult in the field and often requires laboratory confirmation. Therefore, the aim of the study was to develop a triplex PCR and optimise its parameters for simultaneous detection of DNA of goose parvovirus (GPV), goose polyomavirus (GHPV), and goose circovirus (GoCV).

Material and Methods

The DNA of viruses isolated from field cases from the National Veterinary Research Institute’s own collection was used for the study. The primer attachment temperature, the number of reaction cycles, and the Taq DNA polymerase and Mg²⁺ concentrations were optimised. The sensitivity and specificity of this triplex PCR was also determined.

Results

Based on the obtained results, triplex PCR parameters were optimised for simultaneous detection of DNA of GPV, GHPV, and GoCV in one sample. The following PCR products of the expected size were obtained: GPV DNA of 806 bp, GoCV DNA of 571 bp, and GHPV DNA of 180 bp.

Conclusion

The developed triplex PCR method proved to be useful for simultaneous detection of infections with three waterfowl viruses and will be used in relevant laboratory diagnostics.

Genomic characterization of two novel polyomaviruses in Brazilian insectivorous bats

Two novel genomes comprising ≈4.9 kb were identified by next-generation sequencing from pooled organs of Tadarida brasiliensis bats. The overall nucleotide sequence identities between the viral genomes characterized here were less than 80% in comparison to other polyomaviruses (PyVs), members of the family Polyomaviridae. The new genomes display the archetypal organization of PyVs, which includes open reading frames for the regulatory proteins small T antigen (STAg) and large T antigen (LTAg), as well as capsid proteins VP1, VP2 and VP3. In addition, an alternate ORF was identified in the early genome region that is conserved in a large monophyletic group of polyomaviruses. Phylogenetic analysis showed similar clustering with group of PyVs detected in Otomops and Chaerephon bats and some species of monkeys. In this study, the genomes of two novel PyVs were detected in bats of a single species, demonstrating that these mammals can harbor genetically diverse polyomaviruses.