Impacts of ivermectin mass drug administration for onchocerciasis on mosquito populations of Ogun state, Nigeria.

BACKGROUND: The impact of single-dose mass drug administration (MDA) of ivermectin for onchocerciasis on mosquito populations was investigated in Ogun State, Nigeria. METHODS: Indoor and outdoor collection of mosquitoes was carried out in two intervention (IC) and two control communities (CC) at three different periods: pre-MDA (baseline), 2-3 days after MDA and 13-14 days after MDA. The density and parity rate of female Anopheles and Culex mosquitoes were determined and compared. Environmental and climatic data of study locations were obtained to perform generalized linear model analysis. RESULTS: A total of 1399 female mosquitoes were collected, including 1227 Anopheles and 172 Culex mosquitoes. There was a similar magnitude of reduction in the indoor density of Anopheles by 29% in the IC and CC 2-3 days post-MDA but the reduction in indoor parity rate was significantly higher (p = 0.021) in the IC, reducing by more than 50%. In the IC, observation of a significant reduction at 2-3 days post-MDA was consistent for both the indoor density (1.43 to 1.02) and indoor parity rate (95.35% to 44.26%) of Anopheles mosquitoes. The indoor parity rate of Anopheles remained significantly reduced (75.86%) 13-14 post-MDA. On the other hand, the indoor density of Culex increased from 0.07 to 0.10 at 2-3 days post-MDA while the indoor parity rate of Culex did not change. The outdoor density of Anopheles in the IC increased (p = 0.394) from 0.58 to 0.90 at 2-3 days post-MDA; a similar observation was consistent for the outdoor density (2.83 to 3.90) and outdoor parity rate (70.59% to 97.44%) of Culex, while the outdoor parity rate of Anopheles reduced from 85.71 to 66.67% at 2-3 days post-MDA. A generalized linear model showed that ivermectin MDA significantly caused a reduction in both the indoor density (p < 0.001) and indoor parity rate (p = 0.003) of Anopheles in the IC. CONCLUSION: Ivermectin MDA resulted in the reduction of both the survival and density of Anopheles mosquitoes. This has strong implications for malaria transmission, which depends strongly on vector survival.

Schisto and Ladders version 2: a health educational board game to support compliance with school-based mass drug administration with praziquantel - a pilot study.

BACKGROUND: We redesigned the Schisto and Ladders health educational board game and evaluated its potential to encourage compliance to school-based mass drug administration with praziquantel. METHODS: Two hundred and seventy-five children from six schools who rejected praziquantel treatment were divided into intervention and control groups. Before the intervention, preassessment interviews were conducted on their knowledge about praziquantel treatment and schistosomiasis. The Schisto and Ladders version 2 game as an intervention, and the Snakes and Ladders game as a control, were played for 6 mo. Postassessment interviews, including focus group discussions, were conducted. RESULTS: At preassessment, 0/98 (0.0%) children in the intervention group had heard of praziquantel compared with 2/177 (1.1%) in the control group. Similarly, 0/98 (0.0%) children in the intervention group did not know that praziquantel does not kill compared with 4/177 (2.3%) in the control group. The postassessment showed that 53/78 (67.9%) in the intervention group were aware of praziquantel compared with 2/177 (1.1%) in the control group (p=0.000). Similarly, 53 (69.7%) in the intervention group knew about the safety of praziquantel compared with 0/177 (0.0%) in the control group (p=0.000). Sixty-four children (65.3%) from the intervention group sought praziquantel treatment after the trial. CONCLUSIONS: Schisto and Ladders version 2 is a useful sensitisation tool with which to encourage compliance to praziquantel treatment in schools.