Artemisinin resistance in Plasmodium falciparum, which compromises the therapeutic efficacy of artemisinin combination treatments (ACTs), is the greatest threat to control and eliminate malaria. If not eliminated, resistant parasites could spread, as happened with resistance to other antimalarials in the past. Conventional descriptions of the epidemiology of malaria in low transmission settings suggested that malaria prevalence was low (<10%) and heterogeneous. Most infections were thought to be symptomatic so the focus of malaria control activities was on the identification and treatment of symptomatic individuals. Recently developed highly sensitive quantitative PCR methods (uPCR) of parasite detection16 have found that even in many low transmission settings, the majority of people with malaria parasitaemia are asymptomatic, and therefore do not seek treatment. Most of these infected individuals have low parasitaemias, below the detection threshold of routine testing methods. These sub-patent parasitaemias can persist for months, and many will fluctuate intermittently generating transmissible densities of gametocytes. This explains why malaria is sustained during the dry season when vector densities are very low. Additional rapidly acting control and elimination activities will be needed to accelerate elimination efforts.
Mass drug administration (MDA) aims to treat everyone in a community, regardless of symptoms. The treatment clears the infections from the people carrying parasites asymptomatically and prevents reinfection while the slowly eliminated partner drug is providing post treatment prophylaxis.
We performed a cluster-randomised controlled trial to determine the operational effectiveness and impact of MDA using dihydroartemisinin-piperaquine and primaquine in a region with artemisinin resistance in Southeast Myanmar. We assessed MDA safety and its impact on P. falciparum malaria prevalence, incidence and on artemisinin resistance.