Malaria; risk factors within urban and rural settings in the Sahelian region of Cameroon and the role of insecticide resistance in mosquitoes

ABSTRACT Background Cameroon is among the 11 countries that account for 92 % of malaria infection in sub-Saharan-Africa in 2018, and Maroua III Health District and her environs witnessed a malaria outbreak in 2013 with hundreds of deaths. This study was aimed at understanding the risk factors of malaria in the urban and rural population and to investigate the level of mosquito’s resistance to Deltamethrin and Permethrin. Methods It was a cross-sectional community-based study carried out from August to October 2019, in which questionnaires were administered to 500 participants, to obtain information on demographics, socioeconomic, behavioral, and environmental factors thought to be associated with malaria infection in both rural and urban settings. Blood samples were collected for the diagnosis of malaria. Logistic regression analysis was used to identify risk factors for malaria. Mosquito resistance to Deltamethrin and Permethrin were investigated using the CDC Bottle Bioassay test. Results Malaria prevalence was 52.2%, which was significantly higher (p = 0.016) in rural areas (57.6%) as compared to urban areas (46.8%). The overall prevalence of asymptomatic malaria parasitemia in the population was 43.4% in contrast to symptomatic malaria which was 8.8%. In rural areas, risk factors were households using treated bed nets older than 3 years (AOR: 2.45 95% CI: 1.30 to 4.61 P-value: 0.006); households whose water source are unprotected wells (AOR: 3.04 95% CI: 1.21 to 7.64 P-value: 0.018). In urban areas, risk factors were households surrounded by farmland with crops (AOR: 2.08 95% CI: 1.14 to 3.80 P-value 0.017) and households using treated bed nets older than 3 years (AOR: 2.70 95% CI: 1.52 to 4.78 P-value 0.001). The age group 2-10years was significantly associated (p<0.001) with malaria in both rural and urban settings of the district. The geometric mean parasite density was found to decrease with increasing age of participants in the entire health district. The overall mortality of Anopheles species was 93.57% (91.19% in rural and 95.83% in urban areas) for deltamethrin, which was more sensitive than 83.85% (85.24% in rural and 82.46% in urban areas) for permethrin. Conclusion Relevant data for malaria control in Maroua III health district, a typical Sahelian environment, has been generated, and indicates that most of the burden of malaria is borne by school children. Deltamethrine was more effective than permethrine in the control of mosquito populations within these areas.