Table 2.
Calculation of the relative number of West Nile virus (WNV) infections and the modified mosquito inoculation index among four abundant species of birds in the study area in the East Valley of Maricopa County, AZ
| Species | Relative abundance* A (95% CI) | WNV antibody prevalence S (95% CI) | Estimated relative no. of infections = A × S (95% CI) | Competence C (95% CI) | Mosquito inoculation index = A × S2 × C (95% CI) |
|---|---|---|---|---|---|
| Mourning dove† | 63.9 (60.5–67.3) | 0.35 (0.24–0.48) | 22.5 (16.2–33.4) | 0.096 (0.012–0.18) | 0.8 (0.3–7.1) |
| House finch | 8.8 (3.8–13.8) | 1.00 (0.57–1.00) | 8.8 (3.8–18.2) | 1.19 (0.77–1.61) | 10.4 (4.3–24.4) |
| House sparrow | 11.4 (9.1–13.6) | 0.51 (0.42–0.61) | 5.9 (4.4–7.7) | 1.12 (0.43–1.81) | 3.4 (1.8–9.7) |
| Great-tailed grackle | 13.3 (8.8–17.8) | 0.86 (0.49–0.97) | 11.4 (7.4–21.5) | 1.28 (0.49–2.07) | 12.5 (2.8–24.8) |
*
Calculated as birds per party-hr.
†
Only infection rate for hatch-year mourning doves is used for this analysis because statistical analysis infers that numerous adult doves were already seropositive from transmission in previous years. For the other species, the infection rate for all ages is used.
CI = confidence interval.