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Background  Effective treatment remains a mainstay of malaria control, but it is unfortunately strongly compromised by drug resistance, particularly in  Plasmodium falciparum , the most important human malaria parasite. Although  P. falciparum  chemoresistance is well recognized all over the world, limited data are available on the distribution and prevalence of  pfcrt  and  pfmdr1  haplotypes that mediate resistance to commonly used drugs and that show distinct geographic differences.    Methods   Plasmodium falciparum -infected blood samples collected in 2007 at four municipalities of Luanda, Angola, were genotyped using PCR and direct DNA sequencing. Single nucleotide polymorphisms in the  P. falciparum pfcrt  and  pfmdr1  genes were assessed and haplotype prevalences were determined.    Results and Discussion  The most prevalent  pfcrt  haplotype was  S  tct VMN T  (representing amino acids at codons 72-76). This result was unexpected, since the  S  tct VMN T  haplotype has previously been seen mainly in parasites from South America and India. The CV IET , CVMN T  and CV I N T  drug-resistance haplotypes were also found, and one previously undescribed haplotype (CVM DT ) was detected. Regarding  pfmdr1 , the most prevalent haplotype was  Y EYSNVD (representing amino acids at codons 86, 130, 184, 1034, 1042, 1109 and 1246). Wild haplotypes for  pfcrt  and  pfmdr1  were uncommon; 3% of field isolates harbored wild type  pfcrt  (CVMNK), whereas 21% had wild type  pfmdr1  (NEYSNVD). The observed predominance of the  S  tct VMN T  haplotype in Angola could be a result of frequent travel between Brazil and Angola citizens in the context of selective pressure of heavy CQ use.    Conclusions  The high prevalence of the  pfcrt   S VMN T  haplotype and the  pfmdr1  86 Y  mutation confirm high-level chloroquine resistance and might suggest reduced efficacy of amodiaquine in Angola. Further studies must be encouraged to examine the  in vitro  sensitivity of  pfcrt   S VMN T  parasites to artesunate and amodiaquine for better conclusive data.

Plasmodium falciparum isolates from Angola show the StctVMNT haplotype in the pfcrt gene