Table 4. Schistosomiasis infection intensity and egg reduction rates in Huambo, Uige and Zaire as determined by microscopy.
| Huambo | Uige | Zaire | |
|---|---|---|---|
| S. mansoni | |||
| Prevalence, %(95%CI) | |||
| Light intensity | 0.2 (0.05, 0.6) | 2.1 (0.9, 5.0) | 0.7 (0.1, 3.0) |
| Moderate intensity | 0.1 (0.05, 0.4) | 1.7 (0.6, 4.6) | 0.2 (0.02, 1.2) |
| Heavy intensity | 0.07 (0.02, 0.3) | 1.4 (0.5, 4.0) | 0.08 (0.02, 0.3) |
| Intensity comparison | |||
| IA mean epg (95%CI) | 342.5 (80.3, 604.8) | 337.7 (225.5, 449.9) | 139.1 (25.9, 252.2) |
| Baseline mean epg (95%CI) | 36.0 (0, 188.5) | 310.4 (248.4, 372.4) | 144a |
| Egg reduction rate (95%CI) | -8.5 (-18.3, 1.3) | -0.1 (-0.9, 0.7) | 0.03 (-2.5, 2.5) |
| S. haematobium, %(95%CI) | |||
| Prevalence, %(95%CI) | |||
| Light intensity | 1.7 (1.0, 3.1) | 0.2 (0.06, 0.7) | 0.5 (0.2, 1.2) |
| Heavy intensity | 0.4 (0.1, 0.9) | 0 | 0.2 (0.03, 0.8) |
| Intensity comparison | |||
| IA mean epg (95%CI) | 21.8 (14.8, 28.9) | 9.7 (0, 34.2) | 119.1 (0, 242.9) |
| Baseline mean epg (95%CI) | 248.6 (123.1, 374.2) | 563.2 (0, 1,722.8) | 107.0 (61.6, 152.4) |
| Egg reduction rate, %(95%CI) | 91.2 (80.5, 101.9) | 98.3 (34.8, 161.8) | -0.1 (-66.8, 66.6) |
a95% confidence interval could not be calculated due to only one observation contributing data. Egg reduction rate = (mean intensity in 2014 –mean intensity in 2021) / mean intensity in 2014; positive values represent a relative reduction in mean intensity and negative values represent a relative increase in mean intensity. Prevalence calculations adjusted for clustering at school level. CI = confidence interval. epg = eggs per gram. IA = impact assessment.