Parasito-Clinical Characterization of Sites

In Mali, Nigeria and Benin, data on malaria prevalence in the study sites was collected through surveys and, in some cases, from local community health centres. The surveys included demographic data, such as age and gender, in order to understand which groups were most affected by malaria. Data of malaria cases was cross-analysed against net use, net types, the physical quality of nets, insecticide residues on nets, and the sleeping behaviours of net users.

• Cross-sectional surveys reported lower values in all parasitological indices, including Plasmodium falciparum prevalence, gametocyte rate and incidence in the indoor residual spraying (IRS) sites compared to non-IRS sites.

• The expected seasonal peak in the parasitological indices at the end of the transmission season was suppressed in sites with IRS, while it was apparent in sites without IRS.

• The incidence rate was 2.5 times higher in non-IRS sites (6.8 episodes for 100 person-month) than in IRS sites (2.7 for 100 person-month).

• Children living in IRS sites were more likely to be protected against malaria than those in non-IRS sites.

• Baseline malaria prevalence surveys showed a similarity in malaria prevalence across the three resistance villages - Imota, Bayeku, and Oreta.

• The control village, Igbokuta, had a prevalence of 14.9% to 16.8% in children aged 1 to 10 years and 23.2% to 27.8% in people aged 11 to 60 years.

• Recorded parasito-clinical results revealed that more cases of severe malaria were recorded in Kpome (6.92%) than Ketonou (0%).

• In both localities, communities were protected with treated nets (>75% in both); but mosquitoes from Kpome were more resistant (through multi-resistance mechanisms) than those from Ketonou.

• Despite the high net coverage recorded in both study sites, several malaria cases were recorded in households, which could have been due to the high resistance level of mosquitoes to insecticides (multiple insecticide resistance).