Analysis of Histidine Rich Protein 2 And 3 Gene Deletion Polymorphisms in Northern Ghana
Date
2017-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
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.
Description
Keywords
Polymorphisms, Northern Ghana, Rich Protein, Kassena-Nankana Districts, Plasmodium falciparum