In the past decade, massive scale-up of insecticide-treated nets (ITN) and indoor residual spraying (IRS), together with the introduction of artemisinin-combination treatments, have led to substantial reductions in malaria prevalence and incidence in African highlands. However, rising insecticide resistance and increased outdoor transmission have greatly hampered the effectiveness of ITN and IRS because the current indoor-based interventions do not target the outdoor-biting mosquitoes. Consequently, most highland sites maintain sustained low- level transmission while some others have recently experienced resurgence in malaria rates. Therefore, new supplemental interventions that can tackle outdoor transmission and pyrethroid insecticide resistance are urgently needed. The central objective of this competing renewal application is to determine the efficacy and cost-effectiveness of EPA-approved long-lasting microbial larvicides in reducing malaria transmission and clinical malaria incidence in western Kenya highlands. The three specific aims are: 1) to examine mechanisms regulating larval habitat productivity, 2) to determine the efficacy of long-lasting microbial larvicides on the reduction of malaria transmission and clinical malaria incidence using a cluster randomized study, and 3) to determine the cost-effectiveness of the long-lasting microbial larviciding program as compared to other malaria control interventions and evaluate its impact on non-target organisms. Through comprehensive evaluation of potentially cost-effective long-lasting microbial larvicides, this project will provide critically needed data on whether long-lasting microbial larvicides can be scaled up as a supplemental malaria control tool to further reduce malaria incidence in African highlands. Malaria outdoor transmission control is presently a highly significant and urgent issue in malaria control across Africa, and thus, our results will have broad implications on malaria prevention and control in endemic and epidemic regions of Africa.

Public Health Relevance

Insecticide resistance and outdoor transmission are major new challenges in malaria control in Africa today. This project will determine the efficacy and cost-effectiveness of long-lasting microbial larvicides in malaria control in western Kenya highland, proving critically needed data on whether of long-lasting microbial larviciding should be scaled up to supplement existing malaria control tools.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Vector Biology Study Section (VB)
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Costero-Saint Denis, Adriana
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University of California Irvine
Public Health & Prev Medicine
Schools of Public Health
United States
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Degefa, Teshome; Yewhalaw, Delenasaw; Zhou, Guofa et al. (2017) Indoor and outdoor malaria vector surveillance in western Kenya: implications for better understanding of residual transmission. Malar J 16:443
Lo, Eugenia; Nguyen, Kristie; Nguyen, Jennifer et al. (2017) Plasmodium malariae Prevalence and csp Gene Diversity, Kenya, 2014 and 2015. Emerg Infect Dis 23:601-610
Kapesa, Anthony; Kweka, Eliningaya J; Atieli, Harrysone et al. (2017) Why some sites are responding better to anti-malarial interventions? A case study from western Kenya. Malar J 16:498
Ototo, Ednah N; Zhou, Guofa; Kamau, Lucy et al. (2017) Age-specific Plasmodium parasite profile in pre and post ITN intervention period at a highland site in western Kenya. Malar J 16:466
Zhou, Guofa; Wiseman, Virginia; Atieli, Harrysone E et al. (2016) The impact of long-lasting microbial larvicides in reducing malaria transmission and clinical malaria incidence: study protocol for a cluster randomized controlled trial. Trials 17:423
Afrane, Yaw A; Mweresa, Nixon G; Wanjala, Christine L et al. (2016) Evaluation of long-lasting microbial larvicide for malaria vector control in Kenya. Malar J 15:577
Zhou, Guofa; Lee, Ming-Chieh; Githeko, Andrew K et al. (2016) Insecticide-Treated Net Campaign and Malaria Transmission in Western Kenya: 2003-2015. Front Public Health 4:153
Dixit, Amruta; Lee, Ming-Chieh; Goettsch, Brittany et al. (2016) Discovering the cost of care: consumer, provider, and retailer surveys shed light on the determinants of malaria health-seeking behaviours. Malar J 15:179
Ototo, Ednah N; Mbugi, Jenard P; Wanjala, Christine L et al. (2015) Surveillance of malaria vector population density and biting behaviour in western Kenya. Malar J 14:244
Wanjala, Christine L; Mbugi, Jernard P; Ototo, Edna et al. (2015) Pyrethroid and DDT Resistance and Organophosphate Susceptibility among Anopheles spp. Mosquitoes, Western Kenya. Emerg Infect Dis 21:2178-81

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