Cross-Seasonal Patterns of Avian Influenza Virus in Breeding and Wintering Migratory Birds: A Flyway Perspective

Abstract

The spread of avian influenza viruses (AIV) in nature is intrinsically linked with the movements of wild birds. Wild birds are the reservoirs for the virus and their migration may facilitate the circulation of AIV between breeding and wintering areas. This cycle of dispersal has become widely accepted; however, there are few AIV studies that present cross-seasonal information. A flyway perspective is critical for understanding how wild birds contribute to the persistence of AIV over large spatial and temporal scales, with implications for how to focus surveillance efforts and identify risks to public health. This study characterized spatio-temporal infection patterns in 10,389 waterfowl at two important locations within the Pacific Flyway-breeding sites in Interior Alaska and wintering sites in California's Central Valley during 2007-2009. Among the dabbling ducks sampled, the northern shoveler (Anas clypeata) had the highest prevalence of AIV at both breeding (32.2%) and wintering (5.2%) locations. This is in contrast to surveillance studies conducted in other flyways that have identified the mallard (Anas platyrhynchos) and northern pintail (Anas acuta) as hosts with the highest prevalence. A higher diversity of AIV subtypes was apparent at wintering (n = 42) compared with breeding sites (n = 17), with evidence of mixed infections at both locations. Our study suggests that wintering sites may act as an important mixing bowl for transmission among waterfowl in a flyway, creating opportunities for the reassortment of the virus. Our findings shed light on how the dynamics of AIV infection of wild bird populations can vary between the two ends of a migratory flyway.

Evolutionary Dynamics and Global Diversity of Influenza A Virus

“…Much of the observed subtype diversity can be linked to wild migratory birds, in particular, mallards, from which the greatest number of unique subtypes (n ϭ 94) of any bird species have been reported. Extensive breeding and wintering grounds found in temperate zones bring large numbers of migratory birds, often of mixed species, in close contact for large parts of the year, resulting in the maintenance of existing subtypes as well as the establishment of new subtypes through reassortment (32)(33)(34). A concerted effort to monitor the IAV subtypes circulating among wild birds in these temperate zones may help to identify emerging subtypes before they make their way into domestic birds.…”

Diffusion of influenza viruses among migratory birds with a focus on the Southwest United States

“…Arizona, in particular is part of the Pacific flyway which starts in Alaska and extends as far as South America (2013b). While there are four migratory flyways in the United States, the Pacific flyway is believed to pose the greatest risk of introduction of avian influenza (AIV) H5N1 virus due to mixing of birds from Asian countries (Hill et al, 2012b). Conversely, New Mexico is in the Central flyway that includes Colorado, Montana, Texas, Oklahoma, Wyoming, Kansas, North and South Dakota, and north into Canada (2013a).…”

“…Here, geospatial data such as location of the infected host is used in the model to infer diffusion. While there have been many studies that have characterized influenza viruses in migratory birds in the United States (Bahl et al, 2013; Chen and Holmes, 2009; Cross et al, 2013; Dugan et al, 2008; Girard et al, 2012; Henaux et al, 2012; Hill et al, 2012b; Huang et al, 2014; Ip et al, 2008; Jackwood and Stallknecht, 2007; Koehler et al, 2008; Krauss et al, 2004; Lee et al, 2011; Lewis et al, 2013; Pearce et al, 2010; Ramey et al, 2011; Spackman et al, 2005; Suarez et al, 1999; Widjaja et al, 2004; Wille et al, 2011), none have focused on the Southwestern United States. Lam et al (2012) studied the migration of influenza viruses among a variety of migratory birds in the United States.…”

Vigilância epidemiológica dos vírus da influenza aviária em aves migratórias na região costeira da Amazônia

“…Foram conduzidas seis expedições científicas a três localidades no estado do Pará: i) , 1988;WEBSTER et al, 1992;FOUCHIER et al, 2007;WEBSTER et al, 2007;SALOMON;WEBSTER, 2009;FEREIDOUNI et al, 2010;HANSBRO et al, 2010;DAOUST et al, 2011;GAIDET et al, 2012;BROWN et al, 2013 É sabido que os subtipos de AIV podem exibir tropismos teciduais distintos e serem preferencialmente excretados pela via respiratória ou digestiva (FEREIDOUNI et al, 2010;HOYE et al, 2010;PARMLEY et al, 2011;ZOWALATY et al, 2011; SPACKMAN et al, 2002;KRAUSS et al, 2004;FOORD et al, 2009;FAIX et al, 2009;DELOGU et al, 2010;GILBERT et al, 2012;GONZÁLEZ-REICHE et al, 2012;HILL et al, 2012;GERLOFF et al, 2013).…”

“…Neste estudo, não foi possível correlacionar a prevalência aparente de AIV com a idade das aves amostradas em função do baixo número de indivíduos positivos. Hanson et al (2008) (HURT et al, 2006;FERRO et al, 2010;GONZÁLEZ-REICHE et al, 2012;HILL et al, 2012).…”