Targeting malaria in high-risk populations in low endemic regions in northern Namibia

A quasi-experimental controlled trial to reduce malaria in seasonal agricultural workers and cattle herders

Bibliographic Data

ID21879059
AuthorsJennifer L Smith (0000-0001-6376-070X, University of California, San Francisco), Henry Ntuku (0000-0001-7218-2710, University of California, San Francisco), Francois Rerolle (0000-0002-3837-5700, University of California, San Francisco), Ashley Morgan Burke (0000-0002-2779-4678, University of the Witwatersrand), Tabeth Mwema (University of Namibia), Keirstinne Turcios (University of California, San Francisco), Petrina Uusiku (Ministry of Health and Social Services), Justine Kulla Haikali (Ministry of Health and Social Services), Michael Lifasi (Ministry of Health and Social Services), Cara Smith-Gueye (University of California, San Francisco), Elodie Vajda (Malaria Elimination Initiative, University of California San Francisco, San Francisco, California, USA), Élodie A Vajda (0000-0002-7969-066X, University of California, San Francisco), Jerry O Jacobson (0009-0002-6190-0945, University of California, San Francisco), Bryan Greenhouse (0000-0003-0287-9111, University of California, San Francisco), Roly Gosling (0000-0001-6291-0024, University of California, San Francisco), Adam Bennett (0000-0002-7028-311X, University of California, San Francisco), Davis Mumbengegwi (0000-0001-9176-904X, University of Namibia), Davis R Mumbengegwi (University of Namibia)
Year2025
Volume10
Issue2
Pagese015565
Publication date2025-02-01
Peer ReviewedYes
Open AccessYes
TypeARTICLE
VenueBMJ Global Health (JOURNAL)
Journal identifiersISSN: 2059-7908 • E-ISSN: 2059-7908
PublisherBMJ (PUBLISHER • GB)
DOI10.1136/bmjgh-2024-015565
PMID39961693
OpenAlexW4407630509
LanguageEN
References cited37

BACKGROUND: Agricultural worksites are rarely targeted by malaria control programmes, yet may play a role in maintaining local transmission due to workers' high mobility, low intervention coverage and occupational exposures. METHODS: A quasi-experimental controlled intervention study was carried out in farming and cattle herding populations in northern Namibia to evaluate the impact of a targeted malaria intervention package. Eight health facility catchment areas in Zambezi and Ohangwena Regions were randomised to an intervention arm and eligible individuals within worksites in intervention areas received targeted drug administration with artemether-lumefantrine, mop-up indoor residual spraying and long-lasting insecticidal nets, combined with distribution of topical repellent in Zambezi Region. Impact on malaria outcomes and intervention coverage was evaluated over a single transmission season using pre-intervention and post-intervention cross-sectional surveys in a random subset of worksites and community incidence from passively detected cases. Entomological collections and residual efficacy assays on canvas and tarpaulin were conducted. RESULTS: Delivery of a single intervention round was associated with a reduction in the prevalence of malaria (OR 0.24, 95% CI 0.1 to 0.5; risk difference (RD) -6.0%, 95% CI -9.4 to -2.8). Coverage of at least one intervention increased (RD 51.6%, 95% CI 44.4 to 58.2) among the target population in intervention compared with control areas. This effect was largely driven by results in Zambezi Region, which also observed a decline in community incidence (-1.29 cases/1000 person-weeks, 95% CI -2.2 to -0.3). Residual efficacy of pirimiphos-methyl (Actellic) on tarpaulin and canvas was high at 24hours but declined to 44.6% at 4 months. CONCLUSION: transmission in Namibia. TRIAL REGISTRATION NUMBER: NCT04094727

Environmental health · Geography · Indoor residual spraying · Malaria · Plasmodium falciparum · Population · Public health · Malaria Research and Control · Medicine · Parasites and Host Interactions · Pesticide Exposure and Toxicity

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