Surveillance of Influenza Virus A in Migratory Waterfowl in Northern Europe

Abstract

We conducted large-scale, systematic sampling of influenza type A virus in migratory waterfowl (mostly mallards [Anas platyrhynchos]) at Ottenby Bird Observatory, southeast Sweden. As with previous studies, we found a higher prevalence in fall than spring, and among juveniles compared with adults. However, in contrast to other studies, we found that prevalence in spring was sometimes high (mean 4.0%, highest 9.5%). This finding raises the possibility that ducks are capable of perpetuating influenza A virus of different subtypes and subtype combinations throughout the year and from 1 year to the next. Isolation of the H5 and H7 subtypes was common, which suggests risk for transmission to sensitive domestic animals such as poultry. We argue that wild bird screening can function as a sentinel system, and we give an example of how it could have been used to forecast a remote and deadly outbreak of influenza A in poultry.

Antibodies to Influenza A Virus in Wild Birds across Mongolia, 2006–2009

“…In mixed-species colonies, viruses may readily be transmitted between individuals from the same or different species. Extensive surveillance studies of wild ducks in the northern hemisphere have revealed high prevalence of influenza virus primarily in HY birds, with a peak in virus recovery in early fall prior to southbound migration (Krauss etal., 2004;Fouchier et al, 2007;Wallensten et al, 2007). Similar patterns have been observed in northern Europe and Siberiaprior to winter migration (Okazaki et al, 2000).…”

Spread and Persistence of Influenza A Viruses in Waterfowl Hosts in the North American Mississippi Migratory Flyway

“…Given the degree of reassortment in AIVs observed here, surveillance sites for strains of interest (e.g., HPH5N1, HPH7N3, and LPH7N9) are ideally situated within migratory routes, although gene segments from any one of these viruses may be found in other flyways (61,(75)(76)(77). While targeted surveillance efforts are necessary for rapid responses to disease threats, continued longitudinal studies examining the persistence and evolutionary patterns at regional sites are essential for elucidating the natural history of these viruses in their wild bird hosts (78,79).…”

Identifying crucial gaps in our knowledge of the life-history of avian influenza viruses—an Australian perspective

“…Seasonal changes in the prevalence of infection are a common phenomenon among infectious diseases, both in humans and wildlife (Altizer et al 2006). Several studies in northern temperate biomes have suggested that the frequency of AIV infections in wild birds may also exhibit seasonal fluctuations, with a yearly peak in late summer and early autumn, followed by low prevalence during the winter period (Hinshaw et al 1980;Krauss et al 2004;Munster et al 2007;Wallensten et al 2007).…”