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Background  Malaria is a major parasitic disease, affecting millions of people in endemic areas.  Plasmodium falciparum  parasites are responsible for the most severe cases and its resistance to anti-malarial drugs is notorious. This is a possible obstacle to the effectiveness of intermittent preventive treatment (IPT) based on sulfadoxine–pyrimethamine (SP) cures administrated to pregnant women (IPTp) during their pregnancy. As this intervention is recommended in Angola since 2006, it has assessed, in this country, the molecular profiles in  P. falciparum  dhfr  and  dhps,  two polymorphic genes associated to pyrimethamine and sulfadoxine resistance, respectively.    Methods  Blood samples from 52 falciparum patients were collected in Lubango, Angola and  pfdhfr  and  pfdhps  polymorphisms were analysed using nested-PCR and DNA sequencing.    Results  In the  pfdhfr  gene, the 108 N  mutation was almost fixed (98 %), followed by 59 R  (63 %), 51 I  (46 %), 50 R  and 164 L  (2 %, respectively). No 16 V / S  mutations were found. The most common double mutant genotype was CN RN  (59 + 108; 46 %), followed by C I C N  (51 + 108; 29 %) whereas  IRN  (51 + 59 + 108; 15 %), CN RN VL (59 + 108 + 164; 2 %) and  RI C N  (50 + 51 + 108; 2 %) triple mutant genotypes were detected. Investigations of the  pfdhps  gene showed that the 437 G  mutation was the most prevalent (97 %). Only two and one samples disclosed the 540 E  (7 %) and the 436 A  (3 %), respectively. Single mutant S G KAA (437; 86 %) was higher than S GE AA (437 + 540; 7 %) or  AG KAA (436 + 437; 3 %) double mutants genotypes. No polymorphism was detected at codons 581 G  and 613 T / S . Combining  pfdhfr  and  pfdhps  alleles two triple mutant haplotypes (double mutant in  dhfr  and single mutant in  dhps ) were observed: the AC  I  C  N  VI/S  G  KAA in 14 (56 %) samples and the ACN  RN  VI/S  G  KAA in five (20 %) samples. One quadruple mutant haplotype was detected (AC  IRN  VI/S  G  KAA) in six (24 %)  P. falciparum  samples. No quintuple  pfdhfr – pfdhps  mutant was noted.    Conclusion   pfdhfr  and  pfdhps  gene mutations in isolates from Lubango are suggestive of a low-grade SP resistance and IPT for pregnant women and infant based on SP treatment could be effective. Routine molecular studies targeting polymorphism in these two genes need to be routinely conducted at country level.

Low-grade sulfadoxine–pyrimethamine resistance in Plasmodium falciparum parasites from Lubango, Angola