In Congo, urgent efforts are needed to help with the revision of the national
antimalarial drug policy. Despite its high resistance level,
chloroquine (CQ) is still extensively used as the first-line treatment for uncomplicated
Plasmodium falciparum malaria. The study was conducted in children under 5 years with uncomplicated
malaria in Pointe-Noire and Brazzaville, the two largest cities that contain approximately 60% of the population of Congo. We investigated by polymerized chain reaction and sequencing methods the frequency distribution of molecular markers for
antimalarial drug resistance, including mutations in P. falciparum
chloroquine resistance transporter (pfcrt) gene associated with CQ resistance and mutations in
dihydrofolate reductase (dhfr) and
dihydropteroate synthetase (dhps) genes conferring resistance to
sulphadoxine/pyrimethamine (SP) among pre-treatment P. falciparum isolates, as well as assessing
antimalarial drug use in the community. pfcrt (K76T) mutation was present in most isolates (96.4%, n = 138) and high frequency (69.2%, n = 133) of triple-mutant dhfr-S108N, N51I, C59R was observed. The quintuple mutant (dhfr-S108N, N51I, C59R and dhps-A437G or S436A, K540E) considered as molecular marker for SP treatment failure was not found because dhps-K540E mutation was absent in isolates tested; this is a clear evidence for the excellent efficacy of SP that we previously described in the same population. The complete absence of the dhps-K540E mutation is a deterrent component for using this molecular marker as an early warning tool for SP resistance testing in that population. Poor compliance issues related to the
antimalarial drug use including inappropriate manufacturing practices reported in this study require intensive attention and should be taken into account when implementing
drug policy change. If Congo changes its treatment policy from CQ to SP monotherapy, this will not last long. The strategy of combining SP with other affordable and effective
antimalarial drugs such as the
artemisinin derivatives to improve efficacy and to delay the development of parasite resistance is essential.