Abstract. The polymorphisms in the Plasmodium falciparum multidrug resistance 1 (pfmdr1) and P. falciparum chloroquine resistance transporter (pfcrt) genes, which are associated with chloroquine resistance, were examined in 48 P. falciparum isolates from uncomplicated malaria patients from the West Lombok District in Indonesia. The point mutation N86Y in pfmdr1 was present in 35.4% of the isolates and mutation K76T in pfcrt was found in all but one of the samples studied. Identified pfcrt haplotypes were mainly identical to the Papua New Guinea type S agt VMNT (42 of 48, 87.5%), and a few isolates had the Southeast Asia type CVIET (5 of 48, 10.4%). Moreover, one P. falciparum isolate harbored the K76N mutation, giving rise to the haplotype CVMNN, which was not previously reported in field isolates. Our findings suggest that chloroquine resistance in this area might have the same origin as in Papua New Guinea.

Malaria epidemiological surveys were carried out in two subdistricts; Meninting of Lombok island and Utan of Sumbawa island, Indonesia in 2002 through 2003. In Meninting, distribution of hypo-to meso-endemicity was observed mainly in hilly forested areas and partially in coastal areas with no distribution in the more densely populated flat areas surrounded by rice fields. In contrast, in Utan the distribution was limited to the coastal areas. In Utan, treatment follow-up studies revealed the prevalence of chloroquine resistant Plasmodium falciparum (P. f.). Although the degree of malaria endemicity in the two areas was regarded as hypo-to meso-endemic, the majority of affected individuals were under the age of ten, and the number of positive cases declined with increasing age. Interestingly, age dependence to species-specific infection was observed, younger children being more prone to P. vivax infections than to P. f.