26 August 2015
Eniyou Cheryll Oriero is a PhD student at the Medical research Council Unit, The Gambia and she is the first author of a recent publication titled “Validation of an apicoplast genome target for the detection of Plasmodium species using polymerase chain reaction and loop mediated isothermal amplification”.
The article, which was first published in the Clinical Microbiology and Infection Journal, describes the development and validation of a novel molecular diagnostic tool that has high sensitivity to detect low-density parasite infections, is specific to detect only the malaria parasite and also has potential for use in field settings.
As molecular techniques, which are able to detect these low-density infections, are too expensive and complicated for use in most resource-limited settings, the primary aim of the analysis reported in this paper, was to evaluate new and more sensitive diagnostic tools to achieve malaria elimination, needed to detect low parasite density infections, which can still contribute to malaria transmission.
As part of her PhD work, Eniyou designed new primers targeting the apicoplast genome, which is unique to the parasite, and evaluated them using different high throughput molecular tests such as single-step PCR (ssPCR), nested PCR (nPCR) and loop-mediated isothermal amplification (LAMP) for parasite detection.
The results from this publication shows that as low as 2 parasites/μL were detected with this new target in all the molecular tests, using replicates of ten-fold serial dilutions of Plasmodium DNA. With a panel of archived DNA samples extracted from either EDTA whole blood or dried blood spots, from across West Africa and South East Asia, the diagnostic performance of the new molecular tests were also very good. The LAMP test, which has potential for use in field settings, can be further evaluated for this purpose.
“Assay development studies are not usually done or initiated from developing countries. Thus, following the recent recommendation by WHO, that molecular methods can be used for the diagnosis of malaria in low-endemic settings, we hope to be in a position to implement the routine use of molecular tests, in light of the reported continuous decline of malaria in The Gambia”.