Average prevalence of M gene rRT-PCR positive samples plotted against latitudinal degree of collection site.

<p>Circle diameter represents samples size at each latitudinal degree.</p

Percentage of samples collected for wild bird influenza virus surveillance by avian functional group (a); and the proportion of samples by avian functional group (b) that were influenza virus positive by M gene rRT-PCR (n = 197,885).

<p>Percentage of samples collected for wild bird influenza virus surveillance by avian functional group (a); and the proportion of samples by avian functional group (b) that were influenza virus positive by M gene rRT-PCR (n = 197,885).</p

Hunter-harvested and live wild birds were sampled for avian influenza virus throughout the USA.

<p>Samples were collected in shaded counties and testing occurred at starred NALHN laboratory locations.</p

Continental scale map showing spatial clustering hot spots of avian influenza virus M gene positive wild birds.

<p>Z-score results from the Getis-Ord Gi* analyses: >1.65 = 90% significant, 1.66–1.96 = 90%–95% significant, 1.97–2.58 = 95%–99% significant, >2.58 = 99% significant.</p

BWTE_data

BWTE_dat

Locations of capture sites of Blue-winged Teal sampled for low pathogenic avian influenza virus across Canada and the United States, from 2007 to 2010.

<p>Locations of capture sites of Blue-winged Teal sampled for low pathogenic avian influenza virus across Canada and the United States, from 2007 to 2010.</p

Predicted risk of avian influenza virus infection in after hatch year Blue-winged Teal in Canada and the US from 2007–2010 at different stages of the annual life cycle.

<p>Natural neighbor interpolation spatial analysis was applied to predicted probability values calculated for all after hatch year birds based on the best-supported model (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130662#pone.0130662.t003" target="_blank">Table 3</a>), and averaged across all years and both sexes for each sampling site (circles).</p

Annual and seasonal means of predicted probability of avian influenza virus infection in Blue-winged Teal in Canada and the US from 2007–2010.

<p>Point predictions were based on the best-supported model (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130662#pone.0130662.t003" target="_blank">Table 3</a>) and were averaged across both sexes, and all flyways and latitudes of data. Confidence intervals are calculated based on the variance around the group-mean within each year-season-age category. Hatch year (HY) and after hatch year (AHY) age groups shown separately.</p

Probability of avian influenza virus infection in Blue-winged Teal as a function of latitude of sampling location.

<p>Predicted probability was calculated based on the best-supported model (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130662#pone.0130662.t003" target="_blank">Table 3</a>) with Age, Sex, Flyway, Season and Year set at hatch year, male, central, July-August and 2010 categories, respectively. Error bars represent 95% confidence intervals.</p

List of outcome and explanatory variables used in models examining demographic and spatiotemporal determinants of low pathogenic avian influenza virus infection in Blue-winged Teal in Canada and the United States, 2007–10.

<p>List of outcome and explanatory variables used in models examining demographic and spatiotemporal determinants of low pathogenic avian influenza virus infection in Blue-winged Teal in Canada and the United States, 2007–10.</p