Table 3.
Relative (to baseline) changes in the force of infection (FOI) and their 95 % confidence intervals estimated at the point of monitoring (one or two years) after each round of preventive chemotherapy with praziquantel for Schistosoma haematobium areas
| Country | BL Infection Intensity Category | Number in cohort (n) | BL infection Intensity (epg) | BL FOI (wppy) | FY1 ζ1 | FY2 ζ2 | FY3 ζ3 |
|---|---|---|---|---|---|---|---|
| [95 % CI] | [95 % CI] | [95 % CI] | |||||
| Burkina Faso | High | 376 | 124.46 | 20.03 | 0.013 [0.0005, 0.12]a | 0.124 [0.04, 0.21]a | 0.048 [0.02, 0.12]a |
| Burkina Faso | Low | 188 | 17.11 | 1.69 | 0.005 [0.0003, 0.14]a | 0.253 [0.08, 0.56]a | 0.001 [0.0003, 0.10]a |
| Mali | High | 591 | 174.15 | 9.37 | 0.27 [0.11, 0.62]a | 0.30 [0.11, 0.68]a | NA |
| Mali | Low | 561 | 19.67 | 1.53 | 0.70 [0.32, 1.34] | 0.17 [0.05, 0.44]a | NA |
| Niger | High | 270 | 121.87 | 1.91 | 0.70 [0.23, 1.42] | 0.86 [0.23, 1.88] | NA |
| Niger | Low | 1047 | 20.76 | 0.63 | 0.18 [0.10, 0.35]a | 0.36 [0.21, 0.76]a | NA |
| Tanzania | All (Low) | 664 | 11.06 | 1.22 | 0.584 [0.22, 0.91]a | 0.434 [0.21, 0.80]a | |
| Zambia | High | 276 | 89.11 | 1.53 | 0.730 [0.21, 1.65] | NA | NA |
| Zambia | Low | 1169 | 10.01 | 0.38 | 2.129 [0.89, 4.21] | NA | NA |
FOI :force of infection expressed as the mean number of adult female parasites acquired per person per year; e/10 ml: eggs per 10 ml of urine; wppy: worms per person per year; BL: baseline; FY1: follow-up year 1; FY2: follow-up year 2; FY3: follow-up year 3; ζ1, ζ2, ζ3: the relative change in the FOI at FY1, FY2, FY3 respectively, expressed as a proportion of that at baseline; asignificant decreases in FOI from baseline: NA: not available. In Tanzania there was no treatment or survey at FY2 so the data collected at FY3 comprise an average across the previous two years. In Burkina Faso there was no treatment following FY1 so the results at FY1 and FY2 constitute two successive years following a single treatment round