Malaria Surveys in Southeast Asia

Surveys were performed in malaria-endemic areas along the Thailand–Myanmar border, in western Cambodia, and south-western Vietnam (Fig. 1). In these areas, malaria transmission is low, heterogeneous, and seasonal with entomological inoculation rates generally below one/person/year. The majority of clinical cases occur during the rainy season between May and December [6 (link)–9 (link)]. Plasmodium vivax and P. falciparum have historically each comprised approximately half the clinical cases, although with recent reductions in overall malaria incidence, P. vivax now predominates [10 (link)]. The region has been recognized as the origin of anti-malarial drug resistance in P. falciparum to chloroquine, sulfadoxine-pyrimethamine and mefloquine. More recently, P. falciparum strains with reduced susceptibility to artemisinins have been detected in this region [11 (link)–14 (link)].Fig. 1

South East Asia, with markers for the position of the study sites in Thailand–Myanmar border areas, Cambodia and two sites in Vietnam