Table 4. Immunoglobulin G anti-West Nile virus group-level prevalence in equines by group size, Camargue, France, 2000a.
Size class | Total | Positive (%) | Prevalence Ratio | 95% CI |
---|---|---|---|---|
1–2 | 1,006 | 149 (14.8%) | Ref. | |
3–6 | 294 | 73 (24.8%) | 1.9 | 1.4-2.6 |
7–25 | 98 | 40 (40.8%) | 4.0 | 2.6-6.1 |
>25 | 31 | 12 (38.7%) | 3.6 | 1.7-7.6 |
Total | 1,429 | 274 (19.2%) |
a Chi square = 55.68 (3 degrees of freedom), p<0.0001.