Prevalence and subtypes of Influenza A Viruses in Wild Waterfowl in Norway 2006-2007

The prevalence of influenza A virus infection, and the distribution of different subtypes of the virus, were studied in 1529 ducks and 1213 gulls shot during ordinary hunting from August to December in two consecutive years, 2006 and 2007, in Norway. The study was based on molecular screening of cloacal and tracheal swabs, using a pan-influenza A RT-PCR. Samples found to be positive for influenza A virus were screened for the H5 subtype, using a H5 specific RT-PCR, and, if negative, further subtyped by a RT-PCR for the 3'-part of the hemagglutinin (HA) gene, encompassing almost the entire HA2, and the full-length of the neuraminidase (NA) gene, followed by sequencing and characterization. The highest prevalence (12.8%) of infection was found in dabbling ducks (Eurasian Wigeon, Common Teal and Mallard). Diving ducks (Common Goldeneye, Common Merganser, Red-breasted Merganser, Common Scoter, Common Eider and Tufted Duck) showed a lower prevalence (4.1%). In gulls (Common Gull, Herring Gull, Black-headed Gull, Lesser Black-headed Gull, Great Black-backed Gull and Kittiwake) the prevalence of influenza A virus was 6.1%. The infection prevalence peaked during October for ducks, and October/November for gulls. From the 16 hemagglutinin subtypes known to infect wild birds, 13 were detected in this study. Low pathogenic H5 was found in 17 dabbling ducks and one gull

First outbreak of sleeping disease in Switzerland: disease signs and virus characterization.

Sleeping disease is a contagious disease mainly of freshwater farmed rainbow trout, caused by salmonid alphavirus (SAV) Subtype 2. Here we describe the first case in Switzerland. Pathological changes ranged from acute pancreas necrosis to more chronic lesions with complete loss of exocrine pancreas and simultaneous degenerative, inflammatory and regenerative heart and muscle lesions. The partial sequencing of SAV E2 and nsp3 genes placed the Swiss SAV variant within the Subtype 2 clustering together with freshwater isolates from UK and continental Europe. Although mortality stayed low, growth rates were significantly reduced, making the disease economically relevant

Bayesian phylogenetic tree showing relationships among H10 influenza A viruses isolated in this study and publicly available sequences from GenBank.

<p>The clades containing Portuguese and North American sequences are indicated, and Portuguese isolates are shown in bold. The tree is rooted at the midpoint and numbers at nodes indicate posterior probability support. The scale bar indicates substitutions per site.</p

Bayesian phylogenetic tree showing relationships among H11 influenza A viruses isolated in this study and publicly available sequences from GenBank.

<p>The Portuguese sequence is shown with bold font and the clade containing North American sequences is indicated. The tree is rooted at the midpoint and numbers at nodes indicate posterior probability support. The scale bar indicates substitutions per site.</p

Temporal variation in IAV prevalence among Portuguese ducks during the period 2008–2009.

<p>(A) Overall temporal variation in IAV prevalence among sampled ducks. (B) The percentage of IAV-positives among juvenile and adult ducks in Portugal. Prevalence numbers are derived from sample screenings where IAV was detected by RRT-PCR.</p

Results from IAV screening and isolation of samples taken in Portugal 2008–2009.

a<p>The sequences of two additional H9N2 viruses were determined by sequencing the viral H and N segments in the original sample.</p>b<p>Number of different subtypes identified.</p

Bayesian phylogenetic tree showing relationships among H9 influenza A viruses isolated in this study and publicly available sequences from GenBank.

<p>The clade including the Portuguese sequences, as well as some well-established H9N2 linages (Korea, G1 and Y280) are indicated. In addition, isolates associated with infections in humans and swine have been indicated by underlining and italics, respectively. The tree is rooted at the midpoint and numbers at nodes indicate posterior probability support. The scale bar indicates substitutions per site.</p