Molecular surveillance of pfhrp2 and pfhrp3 deletions in Plasmodium falciparum isolates from Mozambique

Background: Malaria programmes use Plasmodium falciparum histidine-rich protein-2 (PfHRP2) based rapid diagnostic tests (RDTs) for malaria diagnosis. The deletion of this target antigen could potentially lead to misdiagnosis, delayed treatment and continuation of active transmission.

Methods: Plasmodium falciparum isolates (n = 1162) collected in Southern Mozambique were assessed by RDTs, microscopy and/or 18SrRNA qPCR. pfhrp2 and pfhrp3 deletions were investigated in isolates from individuals who were negative by RDT but positive by microscopy and/or qPCR (n = 69) using gene-specific PCRs, with kelch13 PCR as the parasite DNA control.

Results: Lack of pfhrp2 PCR amplification was observed in one of the 69 isolates subjected to molecular analysis [1.45% (95% CI 0.3-7.8%)].

Conclusions: The low prevalence of pfhrp2 deletions suggests that RDTs will detect the vast majority of the P. falciparum infections. Nevertheless, active surveillance for changing deletion frequencies is required.