Molecular detection of human malaria parasites using high resolution melting analysis in Morogoro municipality, Tanzania
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Date
2019
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Publisher
Sokoine University of Agriculture
Abstract
Microscopy and rapid diagnostic tests (RDTs) are common tools for diagnosing
malaria, but are deficient in detecting low Plasmodium parasitaemia and mixed
infections. Molecular detection has overcome the limitations by providing greater
sensitivity and specificity in Plasmodium species detection. This study was
conducted in Morogoro region employing a new molecular diagnostic tool that
combines the high sensitivity and specificity of nested PCR (nPCR) and high
resolution melting analysis (HRMA). Samples were collected from 301 malaria
suspected patients from SUA Health Centre between August-October, 2018 and
Sabasaba Health Centre between October-December, 2018. Samples were screened
for malaria parasites by microscopy at SUA and mRDTs at Sabasaba, and later
analysed by nPCR-HRMA for P. falciparum, P. malariae and P. ovale. Data was
analysed using EPI info version 7 and IBM SPSS version 20 software. Sensitivity
and specificity of the three diagnostic methods were assessed, variables calculated
with 95% confidence interval (CI). Microscopy had a lower sensitivity in diagnosing
malaria compared to nPCR-HRMA (p ≤ 0.0361). Among all samples which tested
malaria positive by microscopy, only 68.75% were positive by nPCR-HRMA and the
rest negative. Similarly, 6.45% samples which were initially found to be malaria
negative by microscopy were positive by nPCR-HRMA. Most of the results from
mRDTs were in agreement with nPCR-HRMA results (p ≤ 0.2987). Among the
samples which tested positive by mRDT, 83% were also positive by nPCR-HRMA
while only 1.9% of the samples which had tested negative by mRDT were positive
by nPCR-HRMA. In addition nPCR-HRMA provided accurate diagnosis of infecting single or mixed Plasmodium species in samples that were missed by mRDT and
microscopy. Deployment of improved malaria diagnostic methods like the nPCR-
HRMA might help in improvement and better understanding of the epidemiology of
Plasmodium species, with a particular focus on identifying asymptomatic carriers
and for designing appropriate treatment.
Description
Masters Dissertation 2019
Keywords
Molecular detection, Malaria parasites, Melting analysis, Morogoro municipality, Tanzania