Plasmodium falciparum histidine-rich protein 2 and 3 gene deletion in the Mount Cameroon region

OBJECTIVE: Plasmodium falciparum produces histidine-rich protein 2/3 (Pfhrp2/3) genes that accumulate to high levels in the bloodstream and serve as a diagnostic and prognostic marker for falciparum malaria. Pfhrp2/3 gene deletions may lead to false-negative rapid diagnostic test (RDT) results. We aimed to determine the prevalence of pfhrp2/3 gene deletions in P. falciparum isolates and the implications for RDT use in the Mount Cameroon region. METHODS: A cross-sectional hospital-based study with malaria diagnosis performed using microscopy, RDT and nested polymerase chain reaction (nPCR). In total, 324 P. falciparum microscopy positive individuals were enrolled and their samples confirmed positive for P. falciparum using 18SrRNA PCR. Samples that gave false-negative RDT results were analyzed to detect pfhrp2/3 exon 2 deletions. RESULTS: Of 324 positive microscopic and nPCR samples, 16 gave RDT false-negative results. Among the 324 P. falciparum positive isolates, exon 2 deletions were observed in 2.2% (7 of 324); 3 were negative for pfhrp2 gene, 2 for pfhrp3, and 2 for both pfhrp2 and pfhrp3 (double deletions). CONCLUSION: P. falciparum isolates with pfhrp2/3 gene deletion were present in the parasite populations and may contribute to the RDT false-negative results in the Mount Cameroon region.