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.

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.