Malaria and Molecular Diagnosis

It is an endemic vector-borne parasitic disease caused by protozoan parasites of the genus Plasmodium in tropical and subtropical regions worldwide. In each endemic area, malaria is transmitted by a specific set of Anopheles species. Plasmodium consists of over 200 species, infecting mammals, birds, and reptiles, and malaria parasites generally tend to be host-specific. Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, and Plasmodium knowlesi are the five known species of the genus Plasmodium that causes malaria in humans. Of the five Plasmodium species that cause malaria in humans, P. falciparum causes severe malaria. P. vivax is the most widespread malaria parasite globally. P. malariae is the least frequent and pathogenic, causing mainly asymptomatic infections with submicroscopic parasitemia, leading to low morbidity and mortality, although it can occasionally evolve with chronic renal disease. Different malaria species require distinct treatment regimens. Early and accurate diagnosis to specifically identify the infecting agent among all five malarial species is thus crucial for correct treatment and disease control. Prompt treatment is key to averting severe malaria and relies on access to accurate diagnosis and effective therapeutics. Several methods, such as microscopy-based analysis, rapid diagnostic test (RDT), serological methods, and molecular methods are available to diagnose malaria. Nucleic acid amplification tests (NAATs), which have advantages, such as high sensitivity and processivity and the capacity to identify drug-resistant strains, despite being more time consuming and expensive than microscopy and RDTs. PCR-based tests are also ideal for diagnosing mixed Plasmodium infections. However, PCR reliance on electricity, costly reagents and laboratory facilities for sample preparation have limited PCR to reference laboratories. To eliminate malaria, control and prevention efforts are necessary to reduce the prevalence of the disease and limit the development of drug resistance of the parasite. This requires a robust monitoring and surveillance system. Vector surveillance, larvae and vector control are also important. Vaccines and more recently, the use of monoclonal antibodies is needed for control of the disease. Enhanced surveillance and investigation of Plasmodium spp. genetic variations will contribute to the successful diagnosis and treatment of malaria in future.