Table 5.
Changes in infection rates with O. volvulus in blackflies in the sentinel communities
| Sentinel community | 1995 | 2000 | 2004 | |||
| Blackflies analysed (N) | Infection rate | Blackflies analysed (N) | Infection rate | Blackflies analysed (N) | Infection rate | |
| Corriente Grande | NP | NP | 23500 | 2.1 (0.7–5.0) | 12700 | 0 |
| El Tigre | 2550 | 72.7 (42.0–116.0) | 17000 | 9.0 (4.5–16.1) | 10100 | 6.0 (2.05–13.3) |
| San Miguel | 3550 | 65.0 (39.0–101.0) | 9600 | 1.1 (0.03–6.4) | 12500 | 0.8 (0.02–4.1) |
| Playa de Oro | NP | NP | 10250 | 0 | 9500 | 0 |
| Guayabal | NP | NP | 9950 | 0 | 10000 | 0 |
| Angostura | NP | NP | 9700 | 0 | 11400 | 0 |
| Naranjal | NP | NP | 20450 | 0.5 (0.01–2.8) | 26050 | 0 |
Infection rates (number of flies infected per 10000 flies) with O. volvulus among Simulium blackflies collected before the start of ivermectin distribution (1995), and during the 2000 and 2004 surveys. Infection rates were calculated using Poolscreen 2.0 software. NP – not performed.