On Thursday, October 5, 2023, Miss Viviane Ongbassomben, a Master student at CRID, successfully defended her Master’s dissertation with distinction at the Faculty of Medicine and Biomedical Sciences of the University of Yaoundé 1. Her study aimed to investigate the deletion of the pfhrp2 gene in P. falciparum strains circulating in Emana-Benyada, a village located in the Centre region of Cameroon, to establish the contribution of this mutation to the occurrence of false-negative RDTs results.
To do so, a cross-sectional survey was conducted in Emana-Benyada village in Cameroon. Blood samples were collected and analysed for malaria detection using SD Bioline PfHRP2/ Pan LDH RDT, thin and thick smear. The exon1-2 portion of the pfhrp2 gene was amplified to investigate deletion. To investigate the genetic diversity of P. falciparum, pfmsp1 and pfmsp2 genes were amplified and sequenced.
The results of this research showed that A total of 89 individuals were included in the study. The prevalence of plasmodium infection was 58.43 % (52/89) by microscopy and 65.17 % by RDTs, P. falciparum being the most represented specie (51/52). Sensitivity and specificity of SD Bioline PfHRP2/Pan LDH RDT were 88.24% and 67.56 %, respectively, for detection of P. falciparum infection. This test failed to detect P. falciparum in 06 samples positive by microscopy and PCR analysis, probably due to the presence of parasites with a deletion of the pfhrp2 gene. However, this study was unable to confirm the presence of this deletion among the six false-negative samples. Of the 24 samples used to investigate the genetic diversity, 19 of them contained more than one clone for one or both genes, and therefore involved mixed infections of P. falciparum, with a mean MOI of 1.79. High haplotype diversity of P. falciparum pfmsp1 (Hd=0.8) and pfmsp2 (Hd=0.9) genes was reported, which indicates the circulation of several genetically different strains of Plasmodium (clones) in areas of high malaria transmission.
Although the observed absence of pfhrp2 partial deletion in the samples screened here is encouraging, continued monitoring of the performance of RDTs for malaria detection in Cameroon is warranted.
