First detection of pfhrp2 and pfhrp3 gene deletions in Niger Republic: a retrospective sub- analysis of biological samples

Abstract Background Rapid diagnostic tests (RDTs) based on histidine-rich protein 2 (HRP2) are the main diagnostic tool for malaria in Niger and many countries in sub-Saharan Africa. However, deletions of the P. falciparum hrp2 and hrp3 genes can compromise RDT performance, and pose a threat to diagnostic accuracy. Although these deletions were reported in several regions of Africa, Asia and South America, no molecular data on pfhrp2/3 were previously available for Niger. Methods The present study is a retrospective sub-analysis of biological samples derived from a therapeutic efficacy study (TES) conducted in Niger in 2022. Antigen profiling was performed using a multiplex bead-based assay to identify samples with weak or undetectable HRP2 signal. Species confirmation was conducted by PET-PCR, and pfhrp2 /3 exon 2 genotyping was performed using one-step PCR. Results Among the 375 P. falciparum mono-infection isolates analyzed, Pfhrp2 deletions were found in 11/375 (3.0%), Pfhrp3 deletions in 41/375 (10.9%), and double deletions in 5/375 (1.3%) samples. The highest prevalence of site-specific Pfhrp2 deletions (5.0%; 4/80) was observed at Baban Tabki (Zinder). Conclusions This is the first molecular evidence of Pfhrp2 and Pfhrp3 deletions in P in Niger. The Pfhrp2 deletion rate remains below the 5% threshold set by WHO for the revision of the RDT policy. It’s important to use WHO protocole for Pfhrp2 /3 deletion to determine the national prevalence of these genes deletion in Niger.