Malaria causes almost half a million deaths worldwide every year, with Plasmodium falciparum accounting for most of the deaths . In Haiti, roughly 30,000 people contract malaria annually , making it a significant public health concern for the country. The treatment for malaria in Haiti has relied on chloroquine (CQ) for several decades [3, 4]. However, there is evidence that CQ-resistance genotypes may be emerging in Haiti [5, 6] and there are ongoing discussions about the need to incorporate alternative treatments for the management of malaria.
Many malaria endemic countries that reported CQ resistance switched to antifolate treatments, especially the combination treatment of pyrimethamine (PYR) and sulphadoxine (SDX) . In Haiti, PYR was first introduced in the early 1960s during the global effort to eliminate malaria . The Haiti Ministry of Health, in partnership with the World Health Organization, worked to reduce malaria in Haiti by incorporating PYR in addition to CQ which was already being used  and insecticide spraying to kill mosquitoes. After a decade of use, PYR-resistant strains of P. falciparum were reported in Haiti based on in vitro studies , but no SP resistance was observed in vivo. Since 1985, there have been no additional comprehensive studies to examine SP resistance in Haiti .
The in vitro and in vivo resistance of P. falciparum to PYR and SDX has been associated with single point mutations in the dihydrofolate reductase (dhfr) [10–12] and dihydropteroate synthase (dhps) genes [13–15], respectively. These same point mutations have also been associated with SP resistances. Correlations have been found between SP resistance and point mutations at dhfr codons 51, 59, 108, and 164 and dhps codons 436, 437, and 540 [16–20]. The mutation at codon 108 in dhfr is the first to develop in a population under pressure from PYR use [21, 22]. The stepwise evolution of additional mutations, particularly at codons 51 and 59, directly correlates with increased resistance to PYR [10, 12, 23, 24]. To date, no comprehensive molecular studies on dhfr and dhps genotypes associated with resistance to PYR and SDX, respectively have been conducted in Haiti beyond a single study that examined only three samples .
In this study, genetic markers for SP resistance in the dhfr and dhps genes were assayed in P. falciparum samples from Haiti. The data obtained from this study are important for future anti-malaria drug health policy discussions for Haiti and for understanding the evolution of drug resistance in P. falciparum.