Tissue tropism of highly pathogenic avian influenza virus subtype H5N1 in naturally infected mute swans (Cygnus Olor ), domestic geese (Aser Anser var. domestica), pekin ducks (Anas platyrhynchos) and mulard ducks ( Cairina moschata x anas platyrhynchos).

The 2006 epidemic due to highly pathogenic avian influenza virus (HPAIV) subtype H5N1 in Hungary caused the most severe losses in waterfowl which were, according to the literature at the time, supposed to be the most resistant to this pathogen. The presence of pathological lesions and the amount of viral antigen were quantified by gross pathology, histopathology and immunohistochemistry (IHC) in the organs of four waterfowl species [mute swans (n = 10), domestic geese (n = 6), mulard ducks (n = 6) and Pekin ducks (n = 5)] collected during the epidemic. H5N1 subtype HPAIV was isolated from all birds examined. Quantitative real-time reverse transcriptase-polymerase chain reaction (qRRT-PCR) was also applied on a subset of samples [domestic geese (n = 3), mulard (n = 4) and Pekin duck (n = 4)] in order to compare its sensitivity with IHC. Viral antigen was detected by IHC in all cases. However, the overall presence of viral antigen in tissue samples was quite variable: virus antigen was present in 56/81 (69%) swan, 22/38 (58%) goose, 28/46 (61%) mulard duck and 5/43 (12%) Pekin duck tissue samples. HPAIV subtype H5N1 was detected by qRRT-PCR in all birds examined, in 19/19 (100%) goose, 7/28 (25%) mulard duck and 12/28 (43%) Pekin duck tissue samples. As compared to qRRTPCR, the IHC was less sensitive in geese and Pekin ducks but more sensitive in mulard ducks. The IHC was consistently positive above 4.31 log10 copies/reaction but it gave very variable results below that level. Neurotropism of the isolated virus strains was demonstrated by finding the largest amount of viral antigen and the highest average RNA load in the brain in all four waterfowl species examined.

Molecular analysis of the VP7 gene of pheasant rotaviruses identifies a new genotype, designated G23.

Rotavirus-associated enteritis has been reported in pheasants, but there is no information on the genetic/antigenic features of pheasant rotaviruses. In this study, we sequenced the VP7-encoding genome segment of three pheasant rotavirus strains detected during 2008 in Hungary. The full-length genome segment was 1,070 bp long, while the open reading frame was predicted to encode a 330-aa-long protein. The nucleotide sequence identities among the three pheasant rotavirus strains were high (> or =94%), whereas the range of nucleotide sequence identities to other avian and mammalian rotavirus VP7 genes fell between 68 and 73% and between 60 and 66%, respectively. Our findings indicate that these Hungarian pheasant rotaviruses need to be considered representatives of a new VP7 genotype specificity, designated G23.

Detection of a novel bat gammaherpesvirus in Hungary.

This paper describes the detection of a novel herpesvirus in a Serotine bat (Eptesicus serotinus) in Hungary. The rescued animal showed signs of icterus and anorexia and died within a day, in spite of immediate supportive therapy. Autopsy confirmed the clinical picture by the major lesions observed in the liver. Histopathology revealed vacuolar degeneration in the hepatocytes and leukocytosis in the sinusoidal lumina. By electron microscopy, hydropic degeneration and apoptotic cells with a pycnotic nucleus were found in the liver. Bacteriological examinations gave negative results. As part of a routine screening project, detection of adeno- and herpesviruses from homogenised samples of the liver, lungs and small intestines was attempted by nested polymerase chain reaction (PCR) assays. The adenovirus PCR ended with negative results. The herpesvirus PCR resulted in an amplification product of specific size. The nucleotide sequence of the amplicon was determined and analysed by homology search and phylogenetic analysis. A novel herpesvirus was identified, which seemed to be most closely related to members of the genus Rhadinovirus within the subfamily Gammaherpesvirinae. The causative role of the detected rhadinovirus in the fatal condition of the Serotine bat could not be proven, but it is most likely that reactivation from a latent infection allowed the detection of the virus by PCR.