US scientists reports discovery of a new mechanism¹ of avian influenza²（禽流感） virus circulation and transmission in nature A team of scientists, led by Mauro Delogu, virologist（滤过性病原体学者） from the Veterinary Faculty³ of the Bologna University and researchers from the Istituto Superiore di Sanità, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia and St. Jude Children's Research Hospital (Memphis, Tennessee) have discovered a new way of avian influenza transmission. The study, which offers new insights into ecology, surveillance and prevention strategies of avian influenza viruses (AIVs), may ultimately be important in the fight against influenza. The study has been published in a recent issue (June, 25/2010) of PLoS ONE, a highly reputed（名誉好的） international Journal.

The scientists actually discovered that the preen⁴ oil gland⁵（油腺） secretions⁷（分泌物） , by which all aquatic⁸ birds（水鸟） make their feathers waterproof⁹, support a natural mechanism that concentrates（精矿，浓缩物） AIVs from water onto birds' bodies. They found that a progressive virus "sticking" on feathers occurs because AIV-contaminated（污染的） waters interact with the preen oil gland secretion⁶. Since waterbirds use to spread preen oil over their own (self-preening¹⁰) or other birds' (allo-preening) plumage（翅膀，鸟类羽毛） , it is easily understandable how these preening activities could facilitate the diffusion¹¹ of the viruses in nature.

The discovery, adds Delogu, has also important implications in the surveillance of avian influenza viruses.

In fact, virus on feathers could escape detection by the current surveillance strategies which assay¹²（分析，化验） the virus secreted¹³ in the cloacal（阴沟的，泄殖腔的） and tracheal（气管的，导管的） samples only. Lack of detection of these viruses may greatly complicate¹⁴ surveillance and rapid responses to new virus emergence¹⁵ and spread. For this reason, Delogu said, in routine surveillance programs, additional sampling methods could be necessary to detect AIVs on birds' bodies. Our results also suggest that a preened¹⁶ body surface could be the common denominator（公分母） that explains how AIV infection occurs in different taxonomic（分类的） groups of aquatic birds and future studies are needed to determine the common uropygial（尾羽） component¹⁷ that could promote interaction with AIVs in all aquatic bird species. Studies to reproduce the preening-mediated AIV infection mechanism in the animal model are in progress.

Finally, Delogu concludes, our discovery really opens a door to explain the highly pathogenic（致病的，病原的） H5N1 circulation and persistence¹⁸ in Eurasia, as well as the only recorded human case of fatal infection passed from wild birds in February 2006. All infected humans were involved in defeathering of dead wild swans after a massive die-off of these aquatic birds occurred in Azerbaijan.