Malaria situation in the Greater Mekong Subregion.

The epidemiology of malaria in the Greater Mekong Subregion is complex and rapidly evolving. Malaria control and elimination efforts face a daunting array of challenges including multidrug-resistant parasites. This review presents secondary data collected by the national malaria control programs in the six countries between 1998 and 2010 and examines trends over the last decade. This data has a number of limitations: it is derived exclusively from public sector health facilities; falciparum-specific and then pan-specific rapid diagnostic tests were introduced during the period under review; and, recently there has been a massive increase in case detection capability as a result of increased funding. It therefore requires cautious interpretation. A series of maps are presented showing trends in incidence, mortality and proportion of cases caused by Plasmodium falciparum over the last decade. A brief overview of institutional and implementation arrangements, historical background, demographics and key issues affecting malaria epidemiology is provided for each country. National malaria statistics for 2010 are presented and their robustness discussed in terms of the public sector's share of cases and other influencing factors such as inter-country variations in risk stratification, changes in diagnostic approach and immigration. Targets are presented for malaria control and where appropriate for elimination. Each country's artemisinin resistance status is described. The epidemiological trends presented reflect the improvement in the malaria situation, however the true malaria burden is as yet unknown. There is a need for continuing strengthening and updating of surveillance and response systems.