PREVALENCE OF PFHRP2/3 GENE DELETIONS AMONG SYMPTOMATIC MALARIA PATIENTS IN KEBBI STATE, NIGERIA

Abstract

Malaria remains a global health challenge, with Plasmodium falciparum accounting for the
majority of morbidity and mortality, particularly in sub-Saharan Africa. The reliability of rapid
diagnostic tests (RDTs) based on the Histidine-Rich Protein 2 (HRP2) antigen has been
threatened by deletions in the pfhrp2 and pfhrp3 genes, leading to false-negative results and
diagnostic failure. In Nigeria, evidence of pfhrp2/3 deletions is emerging, but data from Kebbi
State remain limited. A cross-sectional descriptive study was conducted among 423 symptomatic
outpatients in selected public health facilities across three Local Government Areas of Kebbi
State between June and October 2024. Finger-prick blood samples were collected for HRP2-
based RDTs and microscopy. Socio-demographic data were recorded using structured
questionnaires. Data were analyzed using IBM SPSS version 26. Descriptive statistics
summarized demographic and diagnostic characteristics. Logistic regression was used to assess
associations between suspected gene deletions, parasite density, and RDT outcomes, with
statistical significance set at p < 0.05. Of the 423 participants tested, 312 (73.7%) were positive
for P. falciparum by microscopy, while 290 (68.6%) were positive by RDTs. Twenty-two (5.2%)
samples were positive by microscopy but negative by RDTs, indicating suspected pfhrp2/3 gene
deletions. False negatives were most common among patients with low parasite densities (<200
parasites/µL) and children under 10 years of age. Logistic regression revealed a significant
association between parasite density and RDT outcomes (p = 0.03). The study demonstrates
evidence of suspected pfhrp2/3 deletions among symptomatic P. falciparum infections in Kebbi
State. These deletions may compromise the accuracy of HRP2-based RDTs, leading to
misdiagnosis and delayed treatment. The findings highlight the need for molecular surveillance
and diversification of diagnostic strategies to maintain effective malaria control.