Why Continue Studying HRP2 and HRP3 in Malaria?

The main malaria control strategy is rapid and accurate diagnosis followed by effective treatment. The quality of the diagnosis is relevant, since an erroneous diagnosis can generate an increase in morbidity and mortality significantly. The World Health Organization (WHO) has recommended that all patients with suspected malaria be diagnosed by microscopy or a Rapid Diagnostic Test (RDT) before treatment. Microscopy and RDT are the main options for diagnosing malaria in the field and in remote areas of endemic countries. This is in line with pillar 1 of the elimination strategy "Achieve universal access to malaria prevention, diagnosis and treatment". Most of the RDTs available on the market detect an antigen from the parasite produced throughout the life cycle of P. falciparum; this corresponds to the Histidine-Rich Protein 2 (HRP2). In general, HRP2-based RDTs are more sensitive and stable than those based on other Plasmodium antigens, making them the best choice in most endemic countries where P. falciparum malaria predominates. In this review we present evidence on the genetic variability of PfHRP2 and 3 and its potential effect on the efficacy of rapid tests routinely used to diagnose malaria and as main methodological tool elimination programs worldwide.