Virology

Surveying Influenza

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Science  21 Oct 2005:
Vol. 310, Issue 5747, pp. 407
DOI: 10.1126/science.310.5747.407a

Wild influenza viruses circulate in waterfowl, and mallard ducks (Anas platyrhynchos) are particularly good reservoirs, capable of transmitting most of the 16 known hemagglutinin (HA) subtypes of influenza A. Viruses of HA subtype H5 and H7, commonly found in mallards, can transform into highly pathogenic forms when introduced into domesticated poultry via the addition of basic amino acid residues in the HA cleavage site, including that of H5N1, responsible for more than 100 human deaths in Southeast Asia and the current source of fears of a human pandemic. Over 4 years, Munster et al. have been surveying and sequencing influenza A subtypes circulating in migrant mallards in northern Europe. Unsurprisingly, but nonetheless alarming, they have discovered that highly related H5 and H7 were circulating in wild ducks before epidemics of highly pathogenic influenza in poultry in Italy (1997 and 2000) and the Netherlands (2003). This sort of surveillance could be a valuable early warning system, allowing time to make vaccines up-to-date. The World Health Organization has also been surveying H5N1 avian influenza viruses with a view to monitoring adamantane drug resistance and antigenic drift, and hence to developing a predictive strategy for vaccine preparation. — CA

Emerg. Infect. Dis. 11, 1545; 1515 (2005).

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