Molecular methods & serology

Photo: Dr Lucio Freitas Junior

Molecular methods

Techniques used for detecting DNA, such as polymerase chain reaction (PCR) and loop mediated isothermal amplification (LAMP), have been used for detecting P. vivax infections at low densities. 

PCR is a method used to make many copies of a specific DNA segment through a process called ‘amplification.’ The amplification of DNA allows for detection of the presence or absence of genes, which may lead to the identification of pathogens. 

While PCR requires a well-equipped laboratory, LAMP, also a technique used to amplify DNA, can be deployed in much simpler settings. LAMP only requires access to a source of electricity as well as simple, yet robust equipment. LAMP kits are for the detection of all human-infecting Plasmodium species and for the specific detection of P. falciparum. They use freeze-dried reagents which are stable at varying temperature levels. 

However, there is currently no  P. vivax specific kit.1 It is anticipated that this will become available in the future.1

Serology

Serology only detects antibodies to the parasite and is, therefore, not suitable for diagnosis. Nonetheless, these methods are valuable research tools and may be useful in low prevalence areas for mapping sub-microscopic infections. These can assist in the development of more targeted interventions contributing to malaria elimination.2 Serology has been employed in the recent past to identify markers of P. vivax exposure; this has been used to determine linkages with the risk of relapse and could form the basis of an indirect hypnozoite detection test.2