Masters Candidates

Thesis / Project  Title: Prevalence of Polymorphisms in Plasmodium falciparum Parasites in Pregnant and non-Pregnant Women and Potential Resistance to Antimalarial Drugs in Western Kenya

Thesis / Project  Abstract

In regions having high malaria transmission, majority of the population are presumed immune to malaria, with non-pregnant women showing quicker clearance of parasites in comparison to the pregnant. Study genotyped SNPs in Plasmodium falciparum genes associated with antimalarial drugs resistance to determine mutations in parasites with varying clearance using Sanger sequencing and MassARRAY. Pregnant women did not carry parasites strains having mutations conferring resistance to artemisinin. The study did not find statistical differences between the pregnant and non-pregnant women groups to support suggestions that low immunity in pregnancy could be a source of resistant parasites strains or their reservoir.

Thesis Project Title: Evaluation of Plasmodium falciparum histidine rich protein 2 and 3 genes deletion prevalence in Kenya and its implication to RDTs use

Thesis Project Abstract:

Globally, Rapid Diagnostic Tests (RDTs) diagnoses about 75% of all suspected malaria cases. The accuracy of the most frequently used Pfhrp2 based RDTs can be compromised by deletion in Pfhrp2 gene or cross-reaction with Pfhrp3 antigens. The WHO criteria necessitate accuracy above 95 % as the threshold for selection or withdrawal of RDTs advocating for vigorous Pfhrp2 gene deletions mapping. This study investigated the prevalence of Pfhrp2/3 genes deletion as well as their polymorphisms in three of five malaria transmission zones in Kenya.
Generally, 350 samples (255 Post-RDTs and 95 Pre-RDTs) from the epidemiology of malaria drug resistance study were diagnosed for malaria by microscopy, Pfhrp2/pan RDTs and P. falciparum PCR. All P. falciparum PCR positive samples, were genotyped and sequenced using primers targeting Pfhrp2 and Pfhrp3 genes.
The prevalence of single Pfhrp2 gene deletion was 0.3% while that of Pfhrp3 was 2.1% of the 327 P. falciparum PCR positive samples. No sample had double deletion of both Pfhrp2 and Pfhrp3 genes. Twenty one (10.8%) of the 195 samples positive by P. falciparum PCR (with 30 parasites per microliter) and pan RDTs were negative by Pfhrp2 based RDTs. However, all the 21 samples had Pfhrp2 and only one sample (4.8%) had deletion of Pfhrp3 gene. Thirty-eight of the 69 Pfhrp3 sequences had partial deletion while the rest had no deletion. Amino acid repeat type 4 and type 16 were the most frequent.
This study findings shows that Pfhrp2 and Pfhrp3 genes deletion are indeed present in Kenya among the symptomatic individuals enrolled. However, these genes deletion could not be associated to false negative RDTs results.

Thesis / Project  Title: Characterization of circulating Coxsackieviruses in Kenya in 2007

Thesis / Project  Abstract:

Coxsackieviruses (CVs) infect humans and cause various Coxsackievirus infections (CVIs). CVs are classified in Picornaviridaefamily, genus Enterovirus and are of species A and B. Currently,CVIs have no specific cure but are managed by various methods. Unmanaged CVIs may be fatal. In 2007, a high prevalence of influenza-like illnesses (ILI) was detected by clinicians engaged to carry out ILI survey in selected regions of Kenya by the US Army Medical Research Directorate Kenya (USAMD-K). Twenty-two (22) out of 2925 nasopharyngeal samples collected from patients were positive for CVIs through IFA procedure. Whereas CVs caused some of the ILIs, the prevalence of CVIs, the identity of the CVs and other virologic characteristics were unknown. To begin to address this knowledge gap, this study was carried out with the main objective being to serologically and molecularly characterize CVs in the 22 samples to determine the prevalence of CVIs, species, serotypes, the phylogeny, and the evolution of the CVs to relate the data to ILIs of 2007. The CVs were multiplied in Rhabdomyosarcoma (RD) cells, their RNAs extracted and their partial VP1 genes amplified and sequenced. Twelve (12) CVs of CV_B species; serotypes CV_B2-CV_B5 were identified, 11NS were assigned accession no.s MH522779 - MH522789 and uploaded on GeneBank servers on 10th March 2019. Seroprevalence nice actual prevalence of CVIs were 0.74% and 0.41% respectively. All the CVs had mutations and only of CVs of serotypes CV_B2 and CV_B3 had evolved divergent VP1 proteins with high infectivity that partly caused the high prevalence of ILIs in 2007. Data from this study enriches the information base on CVs in Kenya and can be used to develop diagnostics and therapeutics against CVIs.

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