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Routine surveillance of clinical efficacy and molecular\u2011resistance markers is therefore essential. Piperaquine (PPQ), the partner drug in dihydroartemisinin\u2013piperaquine (DHA\u2011PPQ) is already compromised in Southeast\u202fAsia, and key PPQ\u2011resistance mutations have begun to surface in parts of Africa. No such data are available from Nigeria. Three PPQ\u2011resistanceassociated singlenucleotide polymorphisms (SNPs)\u2014T93S, H97Y and\u202fF145Ilocated in exons\u202f2\u202fand\u202f3 of the <jats:italic>P. falciparum<\/jats:italic> chloroquineresistance transporter gene (<jats:italic>pfcrt<\/jats:italic>), and copy\u2011number variation of plasmepsin\u202f2\/3 (<jats:italic>pfpm2\/3<\/jats:italic>), were retrospectively investigated using 299 archived patient isolates collected in Awka (n\u2009=\u2009200) and Onitsha (n\u2009=\u200999), South\u2011East Nigeria (2018\u20132019).<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Methods<\/jats:title>\n            <jats:p>Allelic states at <jats:italic>pfcrt<\/jats:italic> codons\u00a093,\u00a097 and\u202f145 were determined by nested PCR followed by Sanger sequencing. <jats:italic>Pfpm2\/3<\/jats:italic> copy number was quantified by real\u2011time qPCR, using <jats:italic>\u03b2\u2011tubulin<\/jats:italic> as the single\u2011copy reference. All assays incorporated PPQ\u2011resistant RF7 and wild\u2011type 3D7 control strains, plus no\u2011template controls.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Results<\/jats:title>\n            <jats:p>High\u2011quality amplification was achieved for 268 of 299 isolates (89.6%). None harboured the <jats:italic>pfcrt<\/jats:italic> T93S, H97Y or\u202fF145I mutations, and all exhibited single\u2011copy <jats:italic>pfpm2<\/jats:italic> and <jats:italic>pfpm3<\/jats:italic>. Two novel exon\u20112 variants (K115I and synonymous\u202fL111L) were each detected once (0.4%) and are regarded as neutral polymorphisms without known phenotypic impact.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Conclusions<\/jats:title>\n            <jats:p>The complete absence of validated PPQresistance markers indicates that piperaquine remains a viable partner drug in DHA\u2011PPQ for South\u2011East Nigeria. Nonetheless, because DHA\u2011PPQ is increasingly available over the counter, ongoing molecular and therapeutic\u2011efficacy surveillance is imperative to detect any future emergence of resistance.<\/jats:p>\n          <\/jats:sec>","DOI":"10.1186\/s12936-025-05579-0","type":"journal-article","created":{"date-parts":[[2025,9,23]],"date-time":"2025-09-23T04:27:17Z","timestamp":1758601637000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["No evidence of molecular markers of piperaquine resistance in southeastern Nigeria"],"prefix":"10.1186","volume":"24","author":[{"given":"Moses","family":"Ikegbunam","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vasileios","family":"Tzirtziganis","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miriam","family":"Rodi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linda","family":"Anagu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lais","family":"Pessanha de Carvalho","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juliana","family":"Inoue","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jana","family":"Held","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2025,9,23]]},"reference":[{"key":"5579_CR1","volume-title":"National guidelines for diagnosis and treatment of malaria\u202f\u2013\u202f3rd\u202fedn","author":"Federal Ministry of Health (Nigeria)","year":"2005","unstructured":"Federal Ministry of Health (Nigeria). 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