Browsing by Author "Kimani, T Francis"

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    PublicationOpen Access
    Fitness cost of resistance for lumefantrine and piperaquine-resistant Plasmodium berghei in a mouse model
    (Mount Kenya University, 2015) Gimode, R Winnie; Miboi, M Daniel; Kimani, T Francis; Wamakima, N Hannah; Burugu, W Marion; Francis, W Muregi
    The evolution of drug-resistant parasites is a major hindrance to malaria control, and thus understanding the behaviour of drug-resistant mutants is of clinical relevance. The study aimed to investigate how resistance against lumefantrine (LU) and piperaquine (PQ), anti-malarials used as partner drugs in artemisinin-based combination therapy (ACT), impacts parasite fitness. This is important since resistance to ACT, the first-line anti-malarial regimen is increasingly being reported.
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    PublicationOpen Access
    Mapping of DBL a Squence Tags of Field Isolates from Two Malaria Endemic Sites in Kenya
    (Mount Kenya University, 2015) Makokha, W Francis; Magoma, Gabriel; Bull, C Peter; Kimani, T Francis; Shaviya, Nathan; Hungu, Charity; Ahmed, O Sabah
    Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) found on the surface of infected erythrocytes (IEs) mediate antigenic variation during P. falciparum infection enabling the parasite evade host immune responses and prolong infection. These molecules mediate binding of IEs to host endothelial cells and uninfected erythrocytes. Cytoadhesion of IE to host cells leads to sequestration in tissues and PfEMP1 is thought to play an important role in parasite virulence. Here we analysed 1725 sequence tags sampled from the DBLa region of PfEMP1 encoding “var” genes from 27 patients in two different geographical regions in Kenya, Mbita in Western Kenya and Twiga on the Kenyan coast. The objective of this study was to construct a network to assess the extent of shared position specific polymorphic blocks (PSPBs) in sequences isolated from genomic DNA of field isolates from the two malaria endemic sites in Kenya. Sequences from Mbita study site and those from Tiwi largely clustered into separate giant networks with only a limited number of sequences from the two sites linking to each other. This observation suggests that the parasite populations from the two endemic sites could be genetically varied and that PfEMP1 sequencing could be a useful tool of understanding the genetics of parasite populations. Thus the network approach of studying relationships between DBLα sequences is a useful tool of uncovering the genetic structure of parasite populations circulating in different malaria endemic regions. Keywords: PfEMP1, Networks, Position Specific Polymorphic Groups, DBLα, Malaria, P. falciparum
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    PublicationOpen Access
    PfEMP1 DBLα Sequence Tags in Genomic DNA of P. falciparum Field Isolates from Two Malaria Endemic Sites in Kenya
    (Mount Kenya University, 2015) Makokha, W Francis; Omar, A Sabah; Kimani, T Francis; Magoma, Gabriel; Udu, Rahma; Too, Edwin; Shaviya, Nathan; Hungu, Charity
    Malaria caused by Plasmodium falciparum remains a major cause of childhood morbidity and mortality in sub- Saharan Africa. PfEMP1 protein, coded for by a family of about sixty variant var genes, is a parasite protein found on infected erythrocyte membrane. PfEMP1 protein mediates cytoadherence of infected erythrocytes on endothelial cells which may lead to severe symptoms of malaria. Although PCR amplification of the whole gene is difficult due to high variability, primers targeting the DBLα domain have been designed and used to study pfemp1 genes. This objective of this study was to establish the distribution of DBLα sequence tags in isolates of Plasmodium falciparum from two malaria endemic sites in Kenya.