Consideration of mass drug administration for the containment of artemisinin-resistant malaria in the Greater Mekong subregion
Report of a consensus meeting, 27-28 September 2010, Geneva, Switzerland
Plasmodium falciparum parasites in the border region of western Cambodia and eastern Thailand have shown evidence of resistance to artemisinins. This region has historically given rise to other drug-resistant strains of P. falciparum that eventually spread through Asia to Africa. A deterioration of the susceptibility of P. falciparum to artemisinins and the possibility that resistance will spread beyond the Greater Mekong subregion are significant threats to global strategies for the control and elimination of malaria. Since 2009, WHO and its partners have been working to contain artemisinin- resistant parasites at the Cambodia–Thailand border. This activity is referred to in this report as the ‘artemisinin resistance containment project’.
Despite considerable achievements, the current strategies have their limitations (see related link). Mass blood surveys using the polymerase chain reaction (PCR) have shown that a significant number of people with Plasmodium parasitaemia are asymptomatic, and many have low parasite densities that cannot be detected by microscopy or rapid diagnostic tests. A potential approach for treating infections that escape diagnosis is mass drug administration (MDA).
MDA is the practice of treating a whole population within a given geographical area, irrespective of the presence of symptoms and without diagnostic testing. In general, WHO has discour-aged MDA for routine malaria control because studies suggest that the impact on transmission is short-lived and because of the likelihood that it will result in selection for drug-resistant genotypes. However, given the tremendous public health risks associated with artemisinin resistance, MDA has been proposed for eliminating hard-to-reach parasite populations, such as those in asymptomatic patients. In September 2010, the WHO Global Malaria Programme convened a meeting of experts to evaluate the appropriateness of including MDA as part of the strategy to contain artemisinin-resistant parasites in the Greater Mekong subregion. This report reflects the discussions, conclusions and recommendations of the expert group.