Evaluation of two different swab transport systems in the detection of avian influenza virus excretion from infected Pekin ducks (Anas platyrhynchos).

The role of wild birds in the epidemiology and ecology of influenza A viruses has long been recognised (Alexander, 2007a). As a result of the emergence of a H5N1 highly pathogenic avian influenza (HPAI) virus and the apparent role of wild birds in its spread across Asia, Europe and Africa, avian influenza (AI) wild bird surveillance has been implemented in many countries including, since February 2006, a mandatory programme in the European Union (CEC, 2006a). In the present study the detection of virus excreted from Pekin ducks (Anas platyrhynchos) infected experimentally with A/mallard/England/2126/07 (H3N6) was investigated over a fourteen day period post-infection using cloacal and oropharyngeal swabs, with (wet) and without (dry) viral transport medium which were collected from each duck in alternating order. For influenza A virus matrix gene RNA detection, wet oropharyngeal swabs were significantly more sensitive than dry oropharyngeal on days 4-5 after infection. For cloacal samples, dry swabs were equivalent or superior to wet swabs throughout the study. Although differences in detection between dry and wet swabs were observed, the qualitative bird-level results were unaffected, meaning that the infection status of individual birds was correctly determined.

Suppression of avian influenza transmission in genetically modified chickens.

Infection of chickens with avian influenza virus poses a global threat to both poultry production and human health that is not adequately controlled by vaccination or by biosecurity measures. A novel alternative strategy is to develop chickens that are genetically resistant to infection. We generated transgenic chickens expressing a short-hairpin RNA designed to function as a decoy that inhibits and blocks influenza virus polymerase and hence interferes with virus propagation. Susceptibility to primary challenge with highly pathogenic avian influenza virus and onward transmission dynamics were determined. Although the transgenic birds succumbed to the initial experimental challenge, onward transmission to both transgenic and nontransgenic birds was prevented.