The effect of improved housing on indoor mosquito density and exposure to malaria in the rural community of Minkoameyos, Centre Region of Cameroon.

BACKGROUND: This study evaluated the effectiveness of improved housing on indoor residual mosquito density and exposure to infected Anophelines in Minkoameyos, a rural community in southern forested Cameroon. METHODS: Following the identification of housing factors affecting malaria prevalence in 2013, 218 houses were improved by screening the doors and windows, installing plywood ceilings on open eaves and closing holes on walls and doors. Monthly entomological surveys were conducted in a sample of 21 improved and 21 non-improved houses from November 2014 to October 2015. Mosquitoes sampled from night collections on human volunteers were identified morphologically and their parity status determined. Mosquito infectivity was verified through Plasmodium falciparum CSP ELISA and the average entomological inoculation rates determined. A Reduction Factor (RF), defined as the ratio of the values for mosquitoes collected outdoor to those collected indoor was calculated in improved houses (RFI) and non-improved houses (RFN). An Intervention Effect (IE = RFI/RFN) measured the true effect of the intervention. Chi square test was used to determine variable significance. The threshold for statistical significance was set at P < 0.05. RESULTS: A total of 1113 mosquitoes were collected comprising Anopheles sp (58.6%), Culex sp (36.4%), Aedes sp (2.5%), Mansonia sp (2.4%) and Coquillettidia sp (0.2%). Amongst the Anophelines were Anopheles gambiae sensu lato (s.l.) (95.2%), Anopheles funestus (2.9%), Anopheles ziemanni (0.2%), Anopheles brohieri (1.2%) and Anopheles paludis (0.5%). Anopheles gambiae sensu stricto (s.s.) was the only An. gambiae sibling species found. The intervention reduced the indoor Anopheles density by 1.8-fold (RFI = 3.99; RFN = 2.21; P = 0.001). The indoor density of parous Anopheles was reduced by 1.7-fold (RFI = 3.99; RFN = 2.21; P = 0.04) and that of infected Anopheles by 1.8-fold (RFI = 3.26; RFN = 1.78; P = 0.04). Indoor peak biting rates were observed between 02 a.m. to 04 a.m. in non-improved houses and from 02 a.m. to 06 a.m. in improved houses. CONCLUSION: Housing improvement contributed to reducing indoor residual anopheline density and malaria transmission. This highlights the need for policy specialists to further evaluate and promote aspects of house design as a complementary control tool that could reduce indoor human-vector contact and malaria transmission in similar epidemiological settings.

Malaria prevalence and treatment of febrile patients at health facilities and medicine retailers in Cameroon.

OBJECTIVE: To investigate the quality of malaria case management in Cameroon 5 years after the adoption of artemisinin-based combination therapy (ACT). Treatment patterns were examined in different types of facility, and the factors associated with being prescribed or receiving an ACT were investigated. METHODS: A cross-sectional cluster survey was conducted among individuals of all ages who left public and private health facilities and medicine retailers in Cameroon and who reported seeking treatment for a fever. Prevalence of malaria was determined by rapid diagnostic tests (RDTs) in consenting patients attending the facilities and medicine retailers. RESULTS: Among the patients, 73% were prescribed or received an antimalarial, and 51% were prescribed or received an ACT. Treatment provided to patients significantly differed by type of facility: 65% of patients at public facilities, 55% of patients at private facilities and 45% of patients at medicine retailers were prescribed or received an ACT (P = 0.023). The odds of a febrile patient being prescribed or receiving an ACT were significantly higher for patients who asked for an ACT (OR = 24.1, P < 0.001), were examined by the health worker (OR = 1.88, P = 0.021), had not previously sought an antimalarial for the illness (OR = 2.29, P = 0.001) and sought treatment at a public (OR = 3.55) or private facility (OR = 1.99, P = 0.003). Malaria was confirmed in 29% of patients and 70% of patients with a negative result were prescribed or received an antimalarial. CONCLUSIONS: Malaria case management could be improved. Symptomatic diagnosis is inefficient because two-thirds of febrile patients do not have malaria. Government plans to extend malaria testing should promote rational use of ACT; though, the introduction of rapid diagnostic testing needs to be accompanied by updated clinical guidelines that provide clear guidance for the treatment of patients with negative test results.