Frequency distributions of pfcrt, pfdhps, pfdhfr, and pfmdr1 alleles in Plasmodium falciparum-infected Papua New Guinean children. The pfdhfr NCSI, NRNI, and NCNI haplotypes denote codons 51, 59, 108, and 164. The pfdhps KAA and EAA haplotypes denote codons 540, 581, and 613. The pfcrt CVMNK, CVIET, and SVMNT haplotypes denote codons 72 to 76. The pfmdr1 NYSND, YYSND, and NFSDD haplotypes denote codons 86, 184, 1034, 1042, and 1246. The numbers of samples demonstrating complete haplotypes for each gene were 376, 254, 273, and 195, respectively.