Evaluation of a novel RT-PCR test for Plasmodium falciparum detection.

ABSTRACT

The effort to eliminate malaria is hampered not only by the lack of effective drugs, but also by the lack of sensitive diagnostic tools to detect infections with low parasite density. As a result, more sensitive and specific high-throughput molecular diagnostic approaches are needed for accurate malaria diagnosis in order to destroy potential Plasmodium reservoirs.

In the present study, the performance of the EXP1 based RT-PCR assay was evaluated for the detection of Plasmodium falciparum infection. After obtaining ethical clearance N° 2018/09/1104/CE/CNERSH/SP from the Research Ethics Committee for Human health and Authorization of Academic Research N°810/ARA/JO5-02/SP from the Divisional officer of Esse subdivision, 134 Samples were taken in three government schools at Esse from children aged between five and fifteen suspected of having malaria for the population screening, and a parasite culture at the Malaria Research Unit of Centre Pasteur of Cameroon for analytical testing.

The detection limit of the test RT-PCR in terms of Concentration and in terms of parasitaemia is 1415×10⁻⁷ ng and 0.0012 parasites/µl respectively. For the PCR multiplex, the limit of detection in terms of concentration is 1815×10⁻⁶ ng and in terms of parasitaemia 1.2 parasites/µl. Plasmodium falciparum was detected in 125 individuals (93.28%) by RT-PCR and in 122 individuals (91.04%) by PCR multiplex. In comparison to the PCR multiplex test, the RT-PCR test has a sensitivity of 90.35%, a specificity of 5.00%, a Positive Predictive Value of 84.43% and a Negative Predictive Value of 8.33%.

These results demonstrate the importance of using the EXP1 based RT-PCR assay as a tool for the rapid diagnosis and early detection of malaria. The test uses primers specific to Plasmodium falciparum. It is reliable, simple, rapid and highly sensitive. It can be used on the field in malaria-endemic areas with limited resources.