Lack of selection of antimalarial drug resistance markers after intermittent preventive treatment of schoolchildren (IPTsc) against malaria in northeastern Tanzania

Objective: Intermittent Preventive Treatment of schoolchildren (IPTsc) is recommended by WHO as a strategy to protect against malaria; to explore whether IPTsc with dihydroartemisinin-piperaquine (DP) or artesunate-amodiaquine (ASAQ) cause a selection of molecular markers in Plasmodium falciparum genes associated with resistance in children in seven schools in Tanga region, Tanzania. Methods: SNPs in P. falciparum genes Pfmdr1, Pfexo, Pfkelch13 , and Pfcrt and copy number variations in Pfplasmepsin-2 and Pfmdr1 were assessed in samples collected at 12 months (visit 4, n = 74) and 20 months (visit 6, n = 364) after initiation of IPTsc and compared with the baseline prevalence (n = 379). Results: The prevalence of Pfmdr1 N86 and Pfexo 415G was > 99% and 0%, respectively without any temporal differences observed. The prevalence of Pfmdr1 184F changed significantly from baseline (52.2%) to visit 6 (64.6%) (chi 2 = 6.11, P = 0.013), but no differences were observed between the treatment arms (chi 2 = 0.05, P = 0.98). Finally, only minor differences in the amplification of Pfmdr1 were observed; from 10.2% at baseline to 16.7% at visit 6 (chi 2 = 0.98, P = 0.32). Conclusions: The IPTsc strategy does not seem to pose a risk for the selection of markers associated with DP or ASAQ resistance. Continuously and timely surveillance of markers of antimalarial drug resistance is recommended. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )