Analysis of Histidine Rich Protein 2 And 3 Gene Deletion Polymorphisms in Northern Ghana

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2017-07

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University of Ghana

Abstract

The use of Plasmodium falciparum histidine rich protein 2 based (PfHRP2-based) Rapid Diagnostic Tests (RDTs) to accurately diagnose falciparum malaria from other febrile cases reporting to health facilities in Ghana plays a vital role in the control of malaria. However, false negatives due to deletion polymorphism in the pfhrp2 gene may lead to misdiagnosis, increased morbidity as a direct result of delayed treatment and ultimately high treatment cost. Therefore, determining the prevelance of parasites that carry these polymorphisms could be of relevance to National Malaria Control Programmes (NMCPs). The aim of this study was to determine the prevalence and geo-spatial distribution of P. falciparum histidine-rich protein 2 and 3 gene deletion polymorphism in the Kassena-Nankana Districts (KNDs). Patients reporting with fever or history of fever were recruited after informed consent was obtained. Thick and thin blood smears were used to assess malaria parasite species and density of parasitemia whilst filter paper dried blood spots (DBS) were made for parasite DNA extraction for detection of deletion polymorphism. DNA was extracted using Qiagen midi kit following the manufacturer’s instructions. The exon 1-2, exon 2 and the flanking genes of pfhrp2, the exon 2 of phrp3 were amplified using specific primer pairs. PCR products were resolved by 2.0 % agarose gel electrophoresis. A total of 197 samples were collected, out of which 99 were found to be positive for P. falciparum. The prevalence of parasites that were found to have deleted exon 1-2 of the pfhrp2 gene was 7.7% (7/99), whilst 14.1% (14/99) were detected to have deleted the upstream gene of pfhrp2 gene. I observed 4.0 % (4/99) of parasites that had deleted exon 2 of the pfhrp2 gene and only one parasite was found to have deleted the entire pfhrp3 gene. Geo-spatial analysis did not reveal location specific differences in prevalence of pfhrp2 deletion polymorphisms. Overall, this study shows a low prevalence pfhrp 2 and/or 3 gene delection in the KNDs of northern Ghana. Evidence that pfhrp2 based RDTsmay still be an effective tool for diagnosing malaria in this region.

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Polymorphisms, Northern Ghana, Rich Protein, Kassena-Nankana Districts, Plasmodium falciparum

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