Prevalence of pfhrp2 and pfhrp3 gene deletions and genetic diversity of PfHRP2 among Plasmodium falciparum isolates from Iran

Malaria remains a major public-health burden in tropical regions, and rapid diagnostic tests (RDTs) based on Plasmodium falciparum histidine-rich protein 2 (PfHRP2) are widely used in endemic settings. Gene deletions ( pfhrp2 , pfhrp3 ) and antigenic diversity can compromise RDT sensitivity. This study assessed the prevalence of pfhrp2 and pfhrp3 exon-1/2 deletions and the antigenic diversity of PfHRP2 in 139 P. falciparum isolates from Chabahar district, a malaria-endemic region of Iran. PCR amplification of exons 1 and 2 revealed that 13.67% of isolates lacked both exons of pfhrp2 , while 1.44% exhibited single-exon deletions. pfhrp3 deletions were more common: 31.66% had complete loss of both exons, and 5.75% and 6.47% of isolates had exon-1 or exon-2 deletions, respectively. Combined analysis showed that 98.56% of isolates retained at least one exon-2 of either gene; whereas only two isolates (1.44%) exhibited simultaneous exon 2 deletions in both the pfhrp2 and pfhrp3 genes. Sequencing of 26 samples identified 12 haplotypes in PfHRP2 proteins (10 singletons); as repeat type 2 (AHHAHHAAD) was the most frequent, followed by type 7 (AHHAAD). All isolates contained the epitopes recognized by the C1-13 and 3A4 monoclonal antibodies. Thus, despite modest exon-specific pfhrp2/pfhrp3 deletion frequencies and substantial PfHRP2 sequence variability, the molecular findings indicate that key PfHRP2 epitope motifs targeted by HRP2-based RDTs remain widely represented among the Iranian isolates analyzed. However, no direct evaluation of HRP2-based RDT performance was performed in this study. Therefore, the potential impact of these molecular findings on diagnostic sensitivity cannot be determined from the present data alone. Continued molecular surveillance, together with clinical evaluation of HRP2-based RDT performance, is warranted to monitor emerging deletions and ensure reliable malaria diagnosis.