Enumerating the Yield and Purity of PfDNA from Archived, Newly Used mRDTs and Comparison with DBS from a Malaria-Endemic Focus

DOI: 10.2478/amma-2020-0008

Objective: Archived malaria rapid diagnostic test strips (mRDTs) serves as an important source of plasmodium Deoxyribose Nucleic Acid (DNA) in epidemiological studies. The presence of Plasmodium falciparum DNA (PfDNA) in mRDTs (yr. 2016-2017) and newly used ones (yr. 2018) were enumerated with a view to establish the parasite’s optimum genomic DNA volume. Methods: A retrospective study to determine the yield and purity of used mRDTs was carried out on randomly selected mRDTs (2016 – 2018). Both positive and negative mRDTs samples were analyzed with nested Polymerase chain reaction (nPCR). Dried blood spots (DBS) were obtained from study enrolments and analyzed molecularly. nPCR and Agarose gel electrophoresis were used to determine P. falciparum DNA. Results: Agarose gel electrophoresis results showed that only 26 out of the 50 samples eligible for screening were PCR positive for P. falciparum. The following was observed; yrs.: 2016 – 17(34%) with 2.06 X 103 yield, 1.7235 purity; 2017 – 16(32%) with 1.03 X 103 yield, 1.7619 purity and 2018 – 17(34%) with 1.42 X 103 yield, 1.6194 purity. Molecular analysis (P.f. 18Ss rRNA) was determined to ascertain positive result that appeared negative using mRDTs or microscopy. The DNA yield of the DBS for 2018 was 1.66 X 103 and a purity (Optical Density 260/280) of 1.69. The purity was higher than that of the mRDTs with a DNA yield of 1.42 X 103 and 1.62 purity. Conclusion: PfDNA extraction is an important process for malaria PCR screening and the reliability is dependent on pureness and concentration.

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