Application of a molecular marker for surveillance of chloroquine-resistant falciparum malaria

Drug-resistant falciparum malaria is increasing in Africa and so methods to map resistance on a broad scale are needed. A molecular marker for chloroquine resistance, pfcrt T76, can be used for surveillance of clinical chloroquine resistance. The prevalence of pfcrt T76 and the prevalence of clinical chloroquine resistance and therapeutic failure were measured at sentinel sites and used to calculate age-adjusted genotype-resistance indices (GRIs) and genotype-failure indices (GFIs). We found stable GRIs and GFIs at different sites in Mali, West Africa. This model permits mapping of chloroquine resistance using molecular tools in rapid and simple cross-sectional surveys.