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Ducks as sentinels for avian influenza in wild birds Friday, 10.23.2009, 06:57pm (GMT3) To determine the effectiveness of ducks as sentinels for avian
influenza virus (AIV) infection, we placed mallards in contact with
wild birds at resting sites in Germany, Austria, and Switzerland.
Infections of sentinel birds with different AIV subtypes confirmed the
value of such surveillance for AIV monitoring. As a consequence of
infections of wild birds and poultry with highly pathogenic avian
influenza virus (HPAIV) subtype H5N1, surveillance of wild birds for
avian influenza viruses (AIVs) has intensified in Europe since 2005.
Reporting of results is compulsory in the European Union. HPAIV
surveillance includes investigation of dead or sick wild birds with the
aim of early detection of HPAIV (H5N1) complemented by sampling of
healthy wild birds to monitor for low pathogenicity (LP) AIV strains.
Previously, sentinel birds were used successfully to obtain information
about AIV subtypes circulating in wild birds, but results of those
studies are now outdated. Also, the effectiveness of sentinel birds has
not yet been documented for AIV strains that emerged during the past
decade.
Although our study was conducted in areas where HPAIV (H5N1) had circulated in wild birds in 2006, this subtype was not found by screening live wild birds or by using sentinel birds during the study period. Therefore, persistent circulation of HPAIV (H5N1) in the wild bird populations is unlikely for the area of Lake Constance, the coastal area of Mecklenburg–Western Pomerania, and the region of the Oder Valley in Brandenburg. However, because of the limited sample sizes, a low prevalence cannot be excluded. Although HPAIV (H5N1) was found only rarely in apparently healthy birds, e.g., in a pochard (Aythya ferina) in Switzerland in 2008, regular testing of sentinel birds could increase the probability of detecting sporadic transmission of HPAIV in healthy wild water birds even in the absence of detectable deaths. Emerging Infectious Diseases October 6, 2009 http://www.vetscite.org/publish/items/005483/index.html
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