In sub-Saharan Africa, malaria interventions over the last decades have been successful in reducing both mortality and morbidity. In western Kenya however some areas experience contrasting outcomes of the ongoing interventions while the causes for this observation remains not yet clearly known.
The WHO insecticide (deltamethrin) susceptibility test of the common malaria vectors was studied. Multiple surveys on household use and hospital prescriptions of antimalarial drugs from 2003 to 2015 were done. Along with this, cross sectional surveys on their availability in the local drug dispensing outlets were also done in 2015. Monthly precipitations and air temperature data was collected along with systematic review on abundance and composition of common malaria vectors in the study area before and during interventions. The above factors were used to explain the possible causes of contrasting outcome of malaria interventions between the three study sites.
Areas with malaria resurgence or sustained high transmission (Kombewa and Marani) showed higher composition of Anopheles funestus sensu lato (s.l.) than the previously abundant Anopheles gambiae sensu stricto (s.s.) and the later had higher composition to an area with a sustained infection decline (Iguhu). Anopheles gambiae s.l. from Kombewa showed highest resistance (50% mortality) upon exposure to WHO deltamethrin discriminating dosage of 0.75% while those from Marani and Iguhu had reduced resistance status (both had a mean mortality of 91%). Sampled An. funestus s.l. from Marani were also highly resistant to deltamethrin as 57% of the exposed vectors survived. An increasing of mean air temperature by 2 °C was noted for Marani and Iguhu from 2013 to 2015 and was accompanied by an increased rainfall at Marani. Community drug use and availability in selling outlets along with prescription in hospitals were not linked to the struggling control of the disease.
The malaria vector species composition shift, insecticide resistance and climatic warming were the likely cause of the contrasting outcome of malaria intervention in western Kenya. Surveillance of malaria parasite and vector dynamics along with insecticide resistance and vector biting behaviour monitoring are highly recommended in these areas.
WHO. World malaria report 2016. Geneva: World Health Organization; 2017.
Minstry of Health. Kenya Malaria Monitoring and Evaluation Plan 2009–2018. Nairobi: Ministry of Health; 2014. https://www.medbox.org/kenya-malaria-monitoring-andevaluation2009-2018/download.pdf. Accessed 20 Nov 2017.
Centre for Disease Control (CDC), USAID, Department of Health and Human Service. A decade of progress, Presidents malaria initiative: Tenth Annual Report to Congress. CDC, USAD, Department of health and human service, USA; 2016. https://www.pmi.gov/docs/default-source/default-document-library/pmi-reports/pmi-tenth-annual-report-congress.pdf. Accessed 20 Nov 2017.
Gimnig JE, Otieno P, Were V, Marwanga D, Abong’o D, Wiegand R, et al. The effect of indoor residual spraying on the prevalence of malaria parasite infection, clinical malaria and anemia in an area of perennial transmission and moderate coverage of insecticide treated nets in western Kenya. PLoS ONE. 2016;11:e0145282. CrossRefPubMedPubMedCentral
Mends-Brew E, Fletcher AE. Indoor residual spraying (IRS) and its impact on malaria prevalence in West Africa using the panel data regression model. Sci J Appl Math Stat. 2016;4:12–20. CrossRef
National Malaria Control Programme (NMCP), Kenya National Beural of Statistics (KNBS), ICF International. Kenya Malaria indicator Survey 2015. Nairobi, Kenya, and Rockville, Maryland, USA: NMCP, KNBS, and ICF International; 2016.
Ministry of Health. 2010 Malaria indicator survey. Nairobi: Ministry of Health, Kenya; 2011.
Juma EA, Obonyo CO, Akhwale WS, Ogutu BR. A randomized, open-label, comparative efficacy trial of artemether–lumefantrine suspension versus artemether–lumefantrine tablets for treatment of uncomplicated Plasmodium falciparum malaria in children in western Kenya. Malar J. 2008;7:190. CrossRef
Ministry of Health. National Malaria Treatment Guidelines. Nairobi: Ministry of Health (MOH), Kenya; 2006.
WHO. Test procedures for insecticide resistance monitoring in malaria vector mosquitoes. Geneva: World Health Organization; 2013.
Omukunda E, Githeko A, Ndong’a MF, Mushinzimana E, Atieli H, Wamae P. Malaria vector population dynamics in highland and lowland regions of western Kenya. J Vector Borne Dis. 2013;50:85. PubMed
Centre for disease control (CDC), Department of state health and human service. President’s Malaria initiative, Kenya Malaria Operational Plan FY 2016. Edited by USAID; 2016. http://www.pmi.gov/docs/default-source/default-document-library/malaria-operational. Accessed 21 Sept 2016.
Mulamba C, Irving H, Riveron JM, Mukwaya LG, Birungi J, Wondji CS. Contrasting Plasmodium infection rates and insecticide susceptibility profiles between the sympatric sibling species Anopheles parensis and Anopheles funestus s.s.: a potential challenge for malaria vector control in Uganda. Parasit Vectors. 2014;7:71. CrossRefPubMedPubMedCentral
Lucchi NW, Komino F, Okoth SA, Goldman I, Onyona P, Wiegand RE, et al. In vitro and molecular surveillance for antimalarial drug resistance in Plasmodium falciparum parasites in western Kenya reveals sustained artemisinin sensitivity and increased chloroquine sensitivity. Antimicrob Agents Chemother. 2015;59:7540–7. CrossRefPubMedPubMedCentral
Ngalah BS, Ingasia LA, Cheruiyot AC, Chebon LJ, Juma DW, Muiruri P, et al. Analysis of major genome loci underlying artemisinin resistance and pfmdr1 copy number in pre-and post-ACTs in western Kenya. Sci Rep. 2015;5:8306. CrossRef
Shah M, Kariuki S, Eng JV, Blackstock AJ, Garner K, Gatei W, et al. Effect of transmission reduction by insecticide-treated bednets (ITNs) on antimalarial drug resistance in western Kenya. PLoS ONE. 2011;6(e26746):47.
Kenya National Bureau of Statistics, Nairobi, Kenya National Bureau of Statistics, Society for International Development-East Africa; 2013. http://inequalities.sidint.net/kenya/wp-content/uploads/sites/3/2013. Accessed 19 Feb 2017.
Odhiambo F, Buff AM, Moranga C, Moseti CM, Wesongah JO, Lowther SA, et al. Factors associated with malaria microscopy diagnostic performance following a pilot quality-assurance programme in health facilities in malaria low-transmission areas of Kenya, 2014. Malar J. 2017;16:371. CrossRefPubMedPubMedCentral
- Why some sites are responding better to anti-malarial interventions? A case study from western Kenya
Eliningaya J. Kweka
Andrew K. Githeko
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