Falciparum malaria in the north of Laos: the occurrence and implications of the Plasmodium falciparum chloroquine resistance transporter (pfcrt) gene haplotype SVMNT

Summary Objective The Pfcrt‐gene encodes a transmembrane protein located in the Plasmodium falciparum digestive vacuole. Chloroquine resistant (CQR) strains of African and Southeast Asian origin carry the Pfcrt‐haplotype (c72–76) CVIET, whereas most South American and Papua New Guinean CQR stains carry the SVMNT haplotype. Method Eighty‐eight samples from an area with reported in vivo Chloroquine and in vitro Amodiaquine‐resistance were screened for the K76T mutation and their Pfcrt‐haplotype (c72–76) using a new SSOP‐ELISA. Results Hundred percent of the analysed samples showed the K76T mutation which is highly associated with in vivo drug failure. This very high rate of a CQR‐marker is alarming in an area were CQ is still used as first line drug. The distribution of the three main Pfcrt‐haplotypes was as follows: 68% CVIET, 31% SVMNT, 0% CVMNT. Conclusions These data show, for the first time, the South American/PNG ‐haplotype (SVMNT) on mainland Southeast Asia. SVMNT‐haplotype and others might be associated with a decreased efficacy of Amodiaquine and could therefore be potential markers for of amodiaquine resistance (AQR). If there is a correlation between AQR and the SVMNT‐haplotype as suggested, 31% prevalence of a potential resistance marker is cause for concern.