Table 2. Apparent prevalence of low pathogenic avian influenza virus in Blue-winged Teal (Anas discors) in Canada and the United States, 2007–2010.
| Proportion | n | % AIV positive | 95% CI |
|---|---|---|---|
| Overall | 13574 | 17.8 | 17.17, 18.45 |
| By age | |||
| HY | 9113 | 21.4 | 20.57, 22.25 |
| AHY | 4461 | 10.4 | 9.59, 11.38 |
| By sex | |||
| Female | 7491 | 17.6 | 16.78, 18.51 |
| Male | 6083 | 18.0 | 17.05, 18.99 |
| By season | |||
| Nov-June | 1463 | 9.5 | 8.12, 11.06 |
| July-Aug | 3395 | 22.9 | 21.51, 24.38 |
| Sept-Oct | 8716 | 19.3 | 18.49, 20.15 |
| By year | |||
| 2007 | 3347 | 19.21 | 17.91, 20.58 |
| 2008 | 3636 | 12.24 | 11.21, 13.35 |
| 2009 | 3085 | 18.41 | 17.08, 19.82 |
| 2010 | 3506 | 21.68 | 20.35, 23.07 |
| By flyway (ref = Atlantic) | |||
| Pacific | 40 | 7.5 | 2.6, 19.8 |
| Central | 7311 | 20.8 | 19.87, 21.73 |
| Mississippi | 4934 | 15.6 | 14.62, 16.65 |
| Atlantic | 1289 | 9.6 | 8.13, 11.35 |
Abbreviations: HY = hatch year (including SY), AHY = after hatch year (including ASY), AIV = Avian influenza virus matrix protein gene.