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The effect of improved housing on indoor mosquito density and exposure to malaria in the rural community of Minkoameyos, Centre Region of Cameroon.
Malar J. 2020 May 03; 19(1):172.MJ

Abstract

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.

Authors+Show Affiliations

Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon. rachelnguela@yahoo.com. Department of Public Health, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon. rachelnguela@yahoo.com. National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon. rachelnguela@yahoo.com.National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon. Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon.Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon.Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon.National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon.Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon.Architecture for Health in Vulnerable Environments (ARCHIVE Global), New York, USA.Architecture for Health in Vulnerable Environments (ARCHIVE Global), New York, USA.Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon. National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon. Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon. roseleke@yahoo.com. National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon. roseleke@yahoo.com.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32362282

Citation

Nguela, Rachel L., et al. "The Effect of Improved Housing On Indoor Mosquito Density and Exposure to Malaria in the Rural Community of Minkoameyos, Centre Region of Cameroon." Malaria Journal, vol. 19, no. 1, 2020, p. 172.
Nguela RL, Bigoga JD, Armel TN, et al. The effect of improved housing on indoor mosquito density and exposure to malaria in the rural community of Minkoameyos, Centre Region of Cameroon. Malar J. 2020;19(1):172.
Nguela, R. L., Bigoga, J. D., Armel, T. N., Esther, T., Line, D., Boris, N. A., Frederic, T., Kazi, R., Williams, P., Mbacham, W. F., & Leke, R. G. F. (2020). The effect of improved housing on indoor mosquito density and exposure to malaria in the rural community of Minkoameyos, Centre Region of Cameroon. Malaria Journal, 19(1), 172. https://doi.org/10.1186/s12936-020-03232-6
Nguela RL, et al. The Effect of Improved Housing On Indoor Mosquito Density and Exposure to Malaria in the Rural Community of Minkoameyos, Centre Region of Cameroon. Malar J. 2020 May 3;19(1):172. PubMed PMID: 32362282.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The effect of improved housing on indoor mosquito density and exposure to malaria in the rural community of Minkoameyos, Centre Region of Cameroon. AU - Nguela,Rachel L, AU - Bigoga,Jude D, AU - Armel,Tedjou N, AU - Esther,Tallah, AU - Line,Dongmo, AU - Boris,Njeambosay A, AU - Frederic,Tchouine, AU - Kazi,Riksum, AU - Williams,Peter, AU - Mbacham,Wilfred F, AU - Leke,Rose G F, Y1 - 2020/05/03/ PY - 2019/12/04/received PY - 2020/04/09/accepted PY - 2020/5/5/entrez PY - 2020/5/5/pubmed PY - 2020/5/5/medline KW - Anopheles density KW - Cameroon KW - Housing improvement KW - Malaria transmission KW - Rural community SP - 172 EP - 172 JF - Malaria journal JO - Malar J VL - 19 IS - 1 N2 - 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. SN - 1475-2875 UR - https://www.unboundmedicine.com/medline/citation/32362282/The_effect_of_improved_housing_on_indoor_mosquito_density_and_exposure_to_malaria_in_the_rural_community_of_Minkoameyos_Centre_Region_of_Cameroon_ L2 - https://malariajournal.biomedcentral.com/articles/10.1186/s12936-020-03232-6 DB - PRIME DP - Unbound Medicine ER -