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Community-based surveys for the detection of glucose-6-phosphate dehydogenase (G6PD) deficiency were conducted at three villages in central and northern Vietnam from 2001 to 2006. A total of 799 male individuals belonging to three ethnic groups (Raglai, Pako, and Khomu) were tested for G6PD enzyme activity and 32 G6PD deficient individuals were detected. The prevalence of G6PD deficiency in Raglai, Pako, and Khomu was 2.1% (9/ 438), 7.7% (16/208), and 4.6% (7/153), respectively. In Raglai, G6PD Viangchan was found to be dominant (8/9, 88.9%), followed by G6PD Canton (1/9, 11.1%). In Pako, a total of 16 G6PD deficient cases showed G6PD Viangchan variant. All analyzed samples (7/7, 100%) showed the G6PD Union variant in the Khomu ethnic group. Our study suggests that the Raglai and Pako people share a common ancestry with Cambodians, Laotians, and Thais. On the other hand, the appearance of G6PD Union among Khomu people suggests that they originate from a different ancestry. [ABSTRACT FROM AUTHOR]

Recent reports on the decline of the efficacy of artemisinin-based combination therapies (ACTs) indicate a serious threat to malaria control. The endoplasmic/sarcoplasmic reticulum Ca(2+)-ATPase ortholog of Plasmodium falciparum (PfSERCA) has been suggested to be the target of artemisinin and its derivatives. It is assumed that continuous artemisinin pressure will affect polymorphism of the PfSERCA gene (serca) if the protein is the target. Here, we investigated the polymorphism of serca in parasite populations unexposed to ACTs to obtain baseline information for the study of potential artemisinin-driven selection of resistant parasites. Analysis of 656 full-length sequences from 13 parasite populations in Africa, Asia, Oceania, and South America revealed 64 single nucleotide polymorphisms (SNPs), of which 43 were newly identified and 38 resulted in amino acid substitutions. No isolates showed L263E and S769N substitutions, which were reportedly associated with artemisinin resistance. Among the four continents, the number of SNPs was highest in Africa. In Africa, Asia, and Oceania, common SNPs, or those with a minor allele frequency of ≥0.05, were less prevalent, with most SNPs noted to be continent specific, whereas in South America, common SNPs were highly prevalent and often shared with those in Africa. Of 50 amino acid haplotypes observed, only one haplotype (3D7 sequence) was seen in all four continents (64%). Forty-eight haplotypes had frequencies of less than 5%, and 40 haplotypes were continent specific. The geographical difference in the diversity and distribution of serca SNPs and haplotypes lays the groundwork for assessing whether some artemisinin resistance-associated mutations and haplotypes are selected by ACTs.