30 results on '"Cheruiyot, P"'
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2. Increased sensitivity of malaria parasites to common antimalaria drugs after the introduction of artemether-lumefantrine: Implication of policy change and implementation of more effective drugs in fight against malaria.
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Winnie Okore, Collins Ouma, Raphael O Okoth, Redemptah Yeda, Luicer O Ingasia, Edwin W Mwakio, Douglas O Ochora, Duncan M Wakoli, Joseph G Amwoma, Gladys C Chemwor, Jackline A Juma, Charles O Okudo, Agnes C Cheruiyot, Benjamin H Opot, Dennis Juma, Timothy E Egbo, Ben Andagalu, Amanda Roth, Edwin Kamau, and Hoseah M Akala
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Medicine ,Science - Abstract
Single nucleotide polymorphisms (SNPs) in the Plasmodium falciparum multi-drug resistance protein 1 (Pfmrp1) gene have previously been reported to confer resistance to Artemisinin-based Combination Therapies (ACTs) in Southeast Asia. A total of 300 samples collected from six sites between 2008 and 2019 under an ongoing malaria drug sensitivity patterns in Kenya study were evaluated for the presence of SNPs at Pfmrp1 gene codons: H191Y, S437A, I876V, and F1390I using the Agena MassARRAY® platform. Each isolate was further tested against artemisinin (ART), lumefantrine (LU), amodiaquine (AQ), mefloquine (MQ), quinine (QN), and chloroquine (CQ) using malaria the SYBR Green I-based method to determine their in vitro drug sensitivity. Of the samples genotyped, polymorphism at Pfmrp1 codon I876V was the most frequent, with 59.3% (163/275) mutants, followed by F1390I, 7.2% (20/278), H191Y, 4.0% (6/151), and S437A, 3.3% (9/274). A significant decrease in median 50% inhibition concentrations (IC50s) and interquartile range (IQR) was noted; AQ from 2.996 ng/ml [IQR = 2.604-4.747, n = 51] in 2008 to 1.495 ng/ml [IQR = 0.7134-3.318, n = 40] (P
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- 2024
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3. Safety and immunogenicity of ChAdOx1 nCoV-19 (AZD1222) vaccine in adults in Kenya: a phase 1/2 single-blind, randomised controlled trial [version 2; peer review: 2 approved]
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Mainga Hamaluba, Cynthia Mauncho, Neema Mturi, Henry Karanja, Daisy Mugo, James Nyagwange, Caroline Ngetsa, Bernadette Kutima, Samuel Sang, John N. Gitonga, Benjamin Tsofa, Philip Bejon, Naomi Kamau, George Warimwe, Benedict Orindi, Irene Njau, Mwaganyuma Mwatasa, Lynette Ochola-Oyier, Donwilliams Omuoyo, Elizaphan Oloo, Stanley Cheruiyot, Eunice W. Nduati, Roselyne Namayi, Anthony Etyang, Nadia Aliyan, Adrian Hill, Amy Boyd, Marianne Munene, Alexander Douglas, Amek Nyaguara, Sarah Gilbert, Daniel Wright, Teresa Lambe, Charles Agoti, Kadondi Kasera, Alun Davies, Andrew Pollard, and Noni Mumba
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COVID-19 ,vaccine ,ChAdOx1-nCoV-19 ,Kenya ,eng ,Medicine ,Science - Abstract
Background There are limited data on the immunogenicity of coronavirus disease 2019 (COVID-19) vaccines in African populations. Here we report the immunogenicity and safety of the ChAdOx1 nCoV-19 (AZD1222) vaccine from a phase 1/2 single-blind, randomised, controlled trial among adults in Kenya conducted as part of the early studies assessing vaccine performance in different geographical settings to inform Emergency Use Authorisation. Methods We recruited and randomly assigned (1:1) 400 healthy adults aged ≥18 years in Kenya to receive ChAdOx1 nCoV-19 or control rabies vaccine, each as a two-dose schedule with a 3-month interval. The co-primary outcomes were safety, and immunogenicity assessed using total IgG enzyme-linked immunosorbent assay (ELISA) against SARS-CoV-2 spike protein 28 days after the second vaccination. Results Between 28th October 2020 and 19th August 2021, 400 participants were enrolled and assigned to receive ChAdOx1 nCoV-19 (n=200) or rabies vaccine (n=200). Local and systemic adverse events were self-limiting and mild or moderate in nature. Three serious adverse events were reported but these were deemed unrelated to vaccination. The geometric mean anti-spike IgG titres 28 days after second dose vaccination were higher in the ChAdOx1 group (2773 ELISA units [EU], 95% CI 2447, 3142) than in the rabies vaccine group (61 EU, 95% CI 45, 81) and persisted over the 12 months follow-up. We did not identify any symptomatic infections or hospital admissions with respiratory illness and so vaccine efficacy against clinically apparent infection could not be measured. Vaccine efficacy against asymptomatic SARS-CoV-2 infection was 38.4% (95% CI -26.8%, 70.1%; p=0.188). Conclusions The safety, immunogenicity and efficacy against asymptomatic infection of ChAdOx1 nCoV-19 among Kenyan adults was similar to that observed elsewhere in the world, but efficacy against symptomatic infection or severe disease could not be measured in this cohort. Pan-African Clinical Trials Registration PACTR202005681895696 (11/05/2020)
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- 2023
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4. Impact of parasite genomic dynamics on the sensitivity of Plasmodium falciparum isolates to piperaquine and other antimalarial drugs
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Dancan M. Wakoli, Bartholomew N. Ondigo, Douglas O. Ochora, Joseph G. Amwoma, Winnie Okore, Edwin W. Mwakio, Gladys Chemwor, Jackeline Juma, Raphael Okoth, Charles Okudo, Redemptah Yeda, Benjamin H. Opot, Agnes C. Cheruiyot, Dennis Juma, Amanda Roth, Benhards R. Ogutu, Daniel Boudreaux, Ben Andagalu, and Hoseah M. Akala
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Artemisinin combined therapy ,Antimalarial ,Drug resistance ,Sensitivity ,Genomic ,Plasmodium falciparum ,Medicine - Abstract
Abstract Background Dihydroartemisinin-piperaquine (DHA-PPQ) is an alternative first-line antimalarial to artemether-lumefantrine in Kenya. However, recent reports on the emergence of PPQ resistance in Southeast Asia threaten its continued use in Kenya and Africa. In line with the policy on continued deployment of DHA-PPQ, it is imperative to monitor the susceptibility of Kenyan parasites to PPQ and other antimalarials. Methods Parasite isolates collected between 2008 and 2021 from individuals with naturally acquired P. falciparum infections presenting with uncomplicated malaria were tested for in vitro susceptibility to piperaquine, dihydroartemisinin, lumefantrine, artemether, and chloroquine using the malaria SYBR Green I method. A subset of the 2019–2021 samples was further tested for ex vivo susceptibility to PPQ using piperaquine survival assay (PSA). Each isolate was also characterized for mutations associated with antimalarial resistance in Pfcrt, Pfmdr1, Pfpm2/3, Pfdhfr, and Pfdhps genes using real-time PCR and Agena MassARRAY platform. Associations between phenotype and genotype were also determined. Results The PPQ median IC50 interquartile range (IQR) remained stable during the study period, 32.70 nM (IQR 20.2–45.6) in 2008 and 27.30 nM (IQR 6.9–52.8) in 2021 (P=0.1615). The median ex vivo piperaquine survival rate (IQR) was 0% (0–5.27) at 95% CI. Five isolates had a PSA survival rate of ≥10%, consistent with the range of PPQ-resistant parasites, though they lacked polymorphisms in Pfmdr1 and Plasmepsin genes. Lumefantrine and artemether median IC50s rose significantly to 62.40 nM (IQR 26.9–100.8) (P = 0.0201); 7.00 nM (IQR 2.4–13.4) (P = 0.0021) in 2021 from 26.30 nM (IQR 5.1–64.3); and 2.70 nM (IQR 1.3–10.4) in 2008, respectively. Conversely, chloroquine median IC50s decreased significantly to 10.30 nM (IQR 7.2–20.9) in 2021 from 15.30 nM (IQR 7.6–30.4) in 2008, coinciding with a decline in the prevalence of Pfcrt 76T allele over time (P = 0.0357). The proportions of piperaquine-resistant markers including Pfpm2/3 and Pfmdr1 did not vary significantly. A significant association was observed between PPQ IC50 and Pfcrt K76T allele (P=0.0026). Conclusions Circulating Kenyan parasites have remained sensitive to PPQ and other antimalarials, though the response to artemether (ART) and lumefantrine (LM) is declining. This study forms a baseline for continued surveillance of current antimalarials for timely detection of resistance.
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- 2022
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5. Real-time energy consumption and air pollution emission during the transpacific crossing of a container ship
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Chin-Ko Yeh, Chitsan Lin, Hsueh-Chen Shen, Nicholas Kiprotich Cheruiyot, Duy-Hieu Nguyen, and Chi-Chung Chang
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Medicine ,Science - Abstract
Abstract This study presents the real-time energy consumption of a container ship’s generator engine on two round-trips from the West Coast of the US to the East Asian ports and analyzes the ship’s PM10, PM2.5, NOx, SOx, CO, and HC emissions, shore power usage, and factors affecting energy consumption. The average total energy consumption and air emissions for the two round trips were 1.72 GWh and 42.1 tons, respectively. The transpacific crossing segment had the highest average energy consumption (2848 ± 361 kWh) and pollutant emission rate (78.9 ± 10.0 kg h−1). On the other hand, the West Coast of the US had the least energy consumption due to shore power adoption. Furthermore, switching from heavy fuel oil (HFO) to ultra-low-sulfur fuel oil (ULSFO) greatly reduced the emissions of PM and SOx by > 96% and NOx by 17.0%. However, CO and HC increased by 16.9% and 36.1%, respectively, implying incomplete combustion. In addition, the energy consumption was influenced by the number of reefers and wind. Therefore, this study recommends further research on energy-efficient reefers, generator engine optimization, and shore power adoption to reduce emissions from container ships.
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- 2022
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6. An optimization of four SARS-CoV-2 qRT-PCR assays in a Kenyan laboratory to support the national COVID-19 rapid response teams [version 2; peer review: 2 approved]
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Shadrack Mutua, Brian Bartilol, Shaban J. Mwangi, Debra Riako, Lydia Nyamako, Bonface M. Gichuki, Henry Karanja, Angela Karani, John N. Gitonga, Daisy Mugo, Brian Tawa, Wilson Gumbi, Wesley Cheruiyot, Metrine Tendwa, John K. Nyambu, Yiakon Sein, Thani Suleiman Thani, Shem O. Patta, Benson Kitole, Eric K. Maitha, Barke S. Muslih, Mohamed S. Mwakinangu, Philip Bejon, Benjamin Tsofa, Joyce U. Nyiro, John Ochieng Otieno, Leonard Ndwiga, Patience Kiyuka, Johnstone Makale, Kevin Wamae, Victor Osoti, John Mwita Morobe, Calleb Odundo, Arnold W. Lambisia, Martin Mutunga, Salim Mwarumba, Lynette Isabella Ochola-Oyier, Charles N. Agoti, Clement Lewa, Elijah Gicheru, Jennifer Musyoki, Susan Njuguna, Horace Gumba, Domtila Kimani, Jedidah Mwacharo, Zaydah R. de Laurent, Khadija Said Mohammed, Robinson Cheruiyot, and Donwilliams O. Omuoyo
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COVID-19 ,SARS-CoV-2 ,coronavirus ,qRT-PCR ,diagnosis ,optimization ,eng ,Medicine ,Science - Abstract
Background: The COVID-19 pandemic relies on real-time polymerase chain reaction (qRT-PCR) for the detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), to facilitate roll-out of patient care and infection control measures. There are several qRT-PCR assays with little evidence on their comparability. We report alterations to the developers’ recommendations to sustain the testing capability in a resource-limited setting. Methods: We used a SARS-CoV-2 positive control RNA sample to generate several 10-fold dilution series that were used for optimization and comparison of the performance of the four qRT-PCR assays: i) Charité Berlin primer-probe set, ii) European Virus Archive – GLOBAL (EVAg) primer-probe set, iii) DAAN premixed commercial kit and iv) Beijing Genomics Institute (BGI) premixed commercial kit. We adjusted the manufacturer- and protocol-recommended reaction component volumes for these assays and assessed the impact on cycle threshold (Ct) values. Results: The Berlin and EVAg E gene and RdRp assays reported mean Ct values within range of each other across the different titrations and with less than 5% difference. The DAAN premixed kit produced comparable Ct values across the titrations, while the BGI kit improved in performance following a reduction of the reaction components. Conclusion: We achieved a 2.6-fold and 4-fold increase in the number of tests per kit for the commercial kits and the primer-probe sets, respectively. All the assays had optimal performance when the primers and probes were used at 0.375X, except for the Berlin N gene assay. The DAAN kit was a reliable assay for primary screening of SARS-CoV-2 whereas the BGI kit’s performance was dependent on the volumes and concentrations of both the reaction buffer and enzyme mix. Our recommendation for SARS-CoV-2 diagnostic testing in resource-limited settings is to optimize the assays available to establish the lowest volume and suitable concentration of reagents required to produce valid results.
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- 2022
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7. Maintaining laboratory quality assurance and safety in a pandemic: Experiences from the KEMRI-Wellcome Trust Research Programme laboratory’s COVID-19 response [version 2; peer review: 2 approved]
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Shadrack Mutua, Brian Bartilol, Debra Riako, Lydia Nyamako, Angela Karani, Daisy Mugo, Brian Tawa, Michael Opiyo, Wesley Cheruiyot, Metrine Tendwa, Oscar Kai, Caroline Ngetsa, Yiakon Sein, Nelson Ouma, Arnold W. Lambisia, Bonface M. Gichuki, Boniface Karia, John M. Morobe, Shaban Mwangi, Benjamin Tsofa, Philip Bejon, Alfred Mwakubia, Fredrick Mitsanze, Kelly Ominde, Patience Kiyuka, Martin Rono, Johnstone Makale, Agnes Mutiso, Perpetual Wanjiku, Victor Osoti, John N. Gitonga, Alfred Mwanzu, Calleb Odundo, Martin Mutunga, Salim Mwarumba, Donwilliams O. Omuoyo, Amek Nyaguara, Clement Lewa, Elijah Gicheru, Wilson Gumbi, Jennifer Musyoki, Susan Njuguna, Moses Mosobo, Lynette Isabella Ochola-Oyier, Horace Gumba, Wilfred Nyamu, Khadija Said Mohammed, Janet Thoya, Edward Otieno, Domtila Kimani, Jedidah Mwacharo, David Amadi, Charles N. Agoti, Zaydah R. de Laurent, and Robinson Cheruiyot
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Quality management system ,laboratory pandemic response ,quality assurance ,coronavirus disease ,COVID-19 testing ,COVID-19 pandemic ,eng ,Medicine ,Science - Abstract
Laboratory diagnosis plays a critical role in the containment of a pandemic. Strong laboratory quality management systems (QMS) are essential for laboratory diagnostic services. However, low laboratory capacities in resource-limited countries has made the maintenance of laboratory quality assurance, especially during a pandemic, a daunting task. In this paper, we describe our experience of how we went about providing diagnostic testing services for SARS-CoV-2 through laboratory reorganization, redefining of the laboratory workflow, and training and development of COVID-19 documented procedures, all while maintaining the quality assurance processes during the COVID-19 pandemic at the Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme (KWTRP) laboratory. The KWTRP laboratory managed to respond to the COVID-19 outbreak in Kenya by providing diagnostic testing for the coastal region of the country, while maintaining its research standard quality assurance processes. A COVID-19 team comprising of seven sub-teams with assigned specific responsibilities and an organizational chart with established reporting lines were developed. Additionally, a total of four training sessions were conducted for county Rapid Response Teams (RRTs) and laboratory personnel. A total of 11 documented procedures were developed to support the COVID-19 testing processes, with three for the pre-analytical phases, seven for the analytical phase, and one for the post-analytical phase. With the workflow re-organization, the development of appropriate standard operating procedures, and training, research laboratories can effectively respond to pandemic outbreaks while maintaining research standard QMS procedures.
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- 2022
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8. Climate change poses a threat to nutrition and food security in Kilifi County, Kenya
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Susan J. Cheruiyot, Mary Kimanthi, Jacob S. Shabani, Nelson F. Nyamu, Catherine Gathu, Felix Agoi, and Fleur De Meijer
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climate change ,nutrition ,food security ,communities’ experience ,kenya. ,Medicine ,Public aspects of medicine ,RA1-1270 - Abstract
Over the last decades, increased emission of greenhouse gases has led to hot weather extremes, heavy precipitation and worsening of agricultural and ecological droughts. Although Africa’s contribution to climate change is minimal, the continent is especially vulnerable to its effects. This report aims to describe the effect of climate change leading to drought in Kilifi County, Kenya, and the communities’ experiences of this effect on food availability. During their community rotation, residents from a university in Nairobi, Kenya, evaluated changes in weather patterns and nutrition indicators in Kilifi County and conducted focus group discussions (FGDs) with community members and health care stakeholders to explore challenges in access to adequate nutrition and possible local solutions. Kilifi County has one of the highest rates of undernutrition in Kenya, with one in five under-5 children being underweight. County data showed that rainfall in the last 4 years has become increasingly unpredictable, resulting in reduced household milk production, one of the indicators of nutrition security. Three major themes emerged from the FGDs: lack of food variety, collapse of drought mitigating projects and increasing poverty levels. Possible solutions to these problems include promoting alternatives to the current diet that are culturally sensitive and adaptable to recent climate changes, ensuring continuity of agricultural and financial support projects and improved local leadership and governance.
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- 2022
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9. New loci and neuronal pathways for resilience to heat stress in cattle
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Evans K. Cheruiyot, Mekonnen Haile-Mariam, Benjamin G. Cocks, Iona M. MacLeod, Ruidong Xiang, and Jennie E. Pryce
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Medicine ,Science - Abstract
Abstract While understanding the genetic basis of heat tolerance is crucial in the context of global warming’s effect on humans, livestock, and wildlife, the specific genetic variants and biological features that confer thermotolerance in animals are still not well characterized. We used dairy cows as a model to study heat tolerance because they are lactating, and therefore often prone to thermal stress. The data comprised almost 0.5 million milk records (milk, fat, and proteins) of 29,107 Australian Holsteins, each having around 15 million imputed sequence variants. Dairy animals often reduce their milk production when temperature and humidity rise; thus, the phenotypes used to measure an individual’s heat tolerance were defined as the rate of milk production decline (slope traits) with a rising temperature–humidity index. With these slope traits, we performed a genome-wide association study (GWAS) using different approaches, including conditional analyses, to correct for the relationship between heat tolerance and level of milk production. The results revealed multiple novel loci for heat tolerance, including 61 potential functional variants at sites highly conserved across 100 vertebrate species. Moreover, it was interesting that specific candidate variants and genes are related to the neuronal system (ITPR1, ITPR2, and GRIA4) and neuroactive ligand–receptor interaction functions for heat tolerance (NPFFR2, CALCR, and GHR), providing a novel insight that can help to develop genetic and management approaches to combat heat stress.
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- 2021
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10. Characterization of sulfated polysaccharide activity against virulent Plasmodium falciparum PHISTb/RLP1 protein [version 2; peer review: 2 approved]
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Dennis W. Juma, Benjamin H. Opot, Hosea M. Akala, Amanda L. Roth, Ben M. Andagalu, Jennifer M. Mutisya, Johnson K. Kinyua, Victor A. Mobegi, Raphael O. Okoth, Martha N. Kivecu, Edwin W. Mwakio, Gladys C. Chemwor, Redempta A. Yeda, Agnes C. Cheruiyot, Jackline A. Juma, and Charles O. Okello
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Exported proteins ,Sulfated polysaccharides ,PHISTb/RLP1 ,Interactions ,P. falciparum ,Anti-malarials ,eng ,Medicine ,Science - Abstract
Background: The emergence of artemisinin resistance in South East Asia calls for urgent discovery of new drug compounds that have antiplasmodial activity. Unlike the classical compound screening drug discovery methods, the rational approach involving targeted drug discovery is less cumbersome and therefore key for innovation of new antiplasmodial compounds. Plasmodium falciparum (Pf) utilizes the process of host erythrocyte remodeling using Plasmodium-helical interspersed sub-telomeric domain (PHIST) containing proteins, which are amenable drug targets. The aim of this study is to identify inhibitors of PHIST from sulfated polysaccharides as new antimalarials. Methods: 251 samples from an ongoing study of epidemiology of malaria and drug resistance sensitivity patterns in Kenya were sequenced for PHISTb/RLP1 gene using Sanger sequencing. The sequenced reads were mapped to the reference Pf3D7 protein sequence of PHISTb/RLP1 using CLC Main Workbench. Homology modeling of both reference and mutant protein structures was achieved using the LOMETs tool. The models were refined using ModRefiner for energy minimization. Ramachandran plot was generated by ProCheck to assess the conformation of amino acids in the protein model. Protein binding sites predictions were assessed using FT SITE software. We searched for prospective antimalarials from PubChem. Docking experiments were achieved using AutoDock Vina and analysis results visualized in PyMOL. Results: Sanger sequencing generated 86 complete sequences. Upon mapping of the sequences to the reference, 12 non-synonymous single nucleotide polymorphisms were considered for mutant protein structure analysis. Eleven drug compounds with antiplasmodial activity were identified. Both modeled PHISTb/RLP1 reference and mutant structures had a Ramachandran score of >90% of the amino acids in the favored region. Ten of the drug compounds interacted with amino acid residues in PHISTb and RESA domains, showing potential activity against these proteins. Conclusion: This research identifies inhibitors of exported proteins that can be used in in vitro tests against the Plasmodium parasite.
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- 2022
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11. Species-informative SNP markers for characterising freshwater prawns of genus Macrobrachium in Cameroon.
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Judith G Makombu, Evans K Cheruiyot, Francesca Stomeo, David N Thuo, Pius M Oben, Benedicta O Oben, Paul Zango, Eric Mialhe, Jules R Ngueguim, and Fidalis D N Mujibi
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Medicine ,Science - Abstract
Single Nucleotide Polymorphisms (SNPs) are now popular for a myriad of applications in animal and plant species including, ancestry assignment, conservation genetics, breeding, and traceability of animal products. The objective of this study was to develop a customized cost-effective SNP panel for genetic characterisation of Macrobrachium species in Cameroon. The SNPs identified in a previous characterization study were screened as viable candidates for the reduced panel. Starting from a full set of 1,814 SNPs, a total of 72 core SNPs were chosen using conventional approaches: allele frequency differentials, minor allele frequency profiles, and Wright's Fst statistics. The discriminatory power of reduced set of informative SNPs were then tested using the admixture analysis, principal component analysis, and discriminant analysis of principal components. The panel of prioritised SNP markers (i.e., N = 72 SNPs) distinguished Macrobrachium species with 100% accuracy. However, large sample size is needed to identify more informative SNPs for discriminating genetically closely related species, including M. macrobrachion versus M. vollenhovenii and M. sollaudii versus M. dux. Overall, the findings in this study show that we can accurately characterise Macrobrachium using a small set of core SNPs which could be useful for this economically important species in Cameroon. Given the results obtained in this study, a larger independent validation sample set will be needed to confirm the discriminative capacity of this SNP panel for wider commercial and research applications.
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- 2022
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12. Pooled testing conserves SARS-CoV-2 laboratory resources and improves test turn-around time: experience on the Kenyan Coast [version 2; peer review: 3 approved]
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Charles N. Agoti, Martin Mutunga, Arnold W. Lambisia, Domtila Kimani, Robinson Cheruiyot, Patience Kiyuka, Clement Lewa, Elijah Gicheru, Metrine Tendwa, Khadija Said Mohammed, Victor Osoti, Johnstone Makale, Brian Tawa, Calleb Odundo, Wesley Cheruiyot, Wilfred Nyamu, Wilson Gumbi, Jedidah Mwacharo, Lydia Nyamako, Edward Otieno, David Amadi, Janet Thoya, Angela Karani, Daisy Mugo, Jennifer Musyoki, Horace Gumba, Salim Mwarumba, Bonface M. Gichuki, Susan Njuguna, Debra Riako, Shadrack Mutua, John N. Gitonga, Yiakon Sein, Brian Bartilol, Shaban J. Mwangi, Donwilliams O. Omuoyo, John M. Morobe, Zaydah R. de Laurent, Philip Bejon, Lynette Isabella Ochola-Oyier, and Benjamin Tsofa
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Medicine ,Science - Abstract
Background. International recommendations for the control of the coronavirus disease 2019 (COVID-19) pandemic emphasize the central role of laboratory testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent, at scale. The availability of testing reagents, laboratory equipment and qualified staff are important bottlenecks to achieving this. Elsewhere, pooled testing (i.e. combining multiple samples in the same reaction) has been suggested to increase testing capacities in the pandemic period. Methods. We discuss our experience with SARS-CoV-2 pooled testing using real-time reverse transcription polymerase chain reaction (RT-PCR) on the Kenyan Coast. Results. In mid-May, 2020, our RT-PCR testing capacity for SARS-CoV-2 was improved by ~100% as a result of adoption of a six-sample pooled testing strategy. This was accompanied with a concomitant saving of ~50% of SARS-CoV-2 laboratory test kits at both the RNA extraction and RT-PCR stages. However, pooled testing came with a slight decline of test sensitivity. The RT-PCR cycle threshold value (ΔCt) was ~1.59 higher for samples tested in pools compared to samples tested singly. Conclusions. Pooled testing is a useful strategy to increase SARS-CoV-2 laboratory testing capacity especially in low-income settings.
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- 2021
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13. Pooled testing conserves SARS-CoV-2 laboratory resources and improves test turn-around time: experience on the Kenyan Coast [version 1; peer review: 3 approved]
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Charles N. Agoti, Martin Mutunga, Arnold W. Lambisia, Domtila Kimani, Robinson Cheruiyot, Patience Kiyuka, Clement Lewa, Elijah Gicheru, Metrine Tendwa, Khadija Said Mohammed, Victor Osoti, Johnstone Makale, Brian Tawa, Calleb Odundo, Wesley Cheruiyot, Wilfred Nyamu, Wilson Gumbi, Jedidah Mwacharo, Lydia Nyamako, Edward Otieno, David Amadi, Janet Thoya, Angela Karani, Daisy Mugo, Jennifer Musyoki, Horace Gumba, Salim Mwarumba, Bonface M. Gichuki, Susan Njuguna, Debra Riako, Shadrack Mutua, John N. Gitonga, Yiakon Sein, Brian Bartilol, Shaban J. Mwangi, Donwilliams O. Omuoyo, John M. Morobe, Zaydah R. de Laurent, Philip Bejon, Lynette Isabella Ochola-Oyier, and Benjamin Tsofa
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Medicine ,Science - Abstract
Background. International recommendations for the control of the coronavirus disease 2019 (COVID-19) pandemic emphasize the central role of laboratory testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent, at scale. The availability of testing reagents, laboratory equipment and qualified staff are important bottlenecks to achieving this. Elsewhere, pooled testing (i.e. combining multiple samples in the same reaction) has been suggested to increase testing capacities in the pandemic period. Methods. We discuss our experience with SARS-CoV-2 pooled testing using real-time reverse transcription polymerase chain reaction (RT-PCR) on the Kenyan Coast. Results. In mid-May, 2020, our RT-PCR testing capacity for SARS-CoV-2 was improved by ~100% as a result of adoption of a six-sample pooled testing strategy. This was accompanied with a concomitant saving of ~50% of SARS-CoV-2 laboratory test kits at both the RNA extraction and RT-PCR stages. However, pooled testing came with a slight decline of test sensitivity. The RT-PCR cycle threshold value (ΔCt) was ~1.59 higher for samples tested in pools compared to samples tested singly. Conclusions. Pooled testing is a useful strategy to increase SARS-CoV-2 laboratory testing capacity especially in low-income settings.
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- 2020
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14. Human immunodeficiency virus (HIV) type 1 genetic diversity in HIV positive individuals on antiretroviral therapy in a cross sectional study conducted in Teso, Western Kenya
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Maureen Adhiambo, Olipher Makwaga, Ferdinard Adungo, Humphrey Kimani, David Hughes Mulama, Jackson Cheruiyot Korir, and Matilu Mwau
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hiv-1 ,subtypes ,recombinants ,phylogenetic ,Medicine - Abstract
INTRODUCTIOM: High HIV-1 infection rates and genetic diversity especially in African population pose significant challenges in HIV-1 clinical management and drug design development. HIV-1 is a major health challenge in Kenya and causes mortality and morbidity in the country as well as straining the healthcare system and the economy. This study sought to identify HIV-1 genetic subtypes circulating in Teso, Western Kenya which borders the Republic of Uganda. METHODS: a cross sectional study was conducted in January 2019 to December 2019. Sequencing of the partial pol gene was carried out on 80 HIV positive individuals on antiretroviral therapy. Subtypes and recombinant forms were generated using the jumping profile hidden Markov model. Alignment of the sequences was done using ClustalW program and phylogenetic tree constructed using MEGA7 neighbor-joining method. RESULTS: sixty three samples were successful sequenced. In the analysis of these sequences, it was observed that HIV-1 subtype A1 was predominant 43 (68.3%) followed by D 8 (12.7%) and 1 (1.6%) each of C, G and B and inter-subtype recombinants A1-D 3 (4.8%), A1-B 2 (3.2%) and 1 (1.6%) each of A1-A2, A1-C, BC and BD. Phylogenetic analysis of these sequences showed close clustering of closely related and unrelated sequences with reference sequences. CONCLUSION: there was observed increased genetic diversity of HIV-1 subtypes which not only pose a challenge in disease control and management but also drug design and development. Therefore, there is need for continued surveillance to enhance future understanding of the geographical distribution and transmission patterns of the HIV epidemic.
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- 2021
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15. A seven-year surveillance of epidemiology of malaria reveals travel and gender are the key drivers of dispersion of drug resistant genotypes in Kenya
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Moureen Maraka, Hoseah M. Akala, Asito S. Amolo, Dennis Juma, Duke Omariba, Agnes Cheruiyot, Benjamin Opot, Charles Okello Okudo, Edwin Mwakio, Gladys Chemwor, Jackline A. Juma, Raphael Okoth, Redemptah Yeda, and Ben Andagalu
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Malaria ,Drug resistance ,Chloroquine ,Gender ,Travel ,Plasmodium falciparum ,Medicine ,Biology (General) ,QH301-705.5 - Abstract
Malaria drug resistance is a global public health concern. Though parasite mutations have been associated with resistance, other factors could influence the resistance. A robust surveillance system is required to monitor and help contain the resistance. This study established the role of travel and gender in dispersion of chloroquine resistant genotypes in malaria epidemic zones in Kenya. A total of 1,776 individuals presenting with uncomplicated malaria at hospitals selected from four malaria transmission zones in Kenya between 2008 and 2014 were enrolled in a prospective surveillance study assessing the epidemiology of malaria drug resistance patterns. Demographic and clinical information per individual was obtained using a structured questionnaire. Further, 2 mL of blood was collected for malaria diagnosis, parasitemia quantification and molecular analysis. DNA extracted from dried blood spots collected from each of the individuals was genotyped for polymorphisms in Plasmodium falciparum chloroquine transporter gene (Pfcrt 76), Plasmodium falciparum multidrug resistant gene 1 (Pfmdr1 86 and Pfmdr1 184) regions that are putative drug resistance genes using both conventional polymerase chain reaction (PCR) and real-time PCR. The molecular and demographic data was analyzed using Stata version 13 (College Station, TX: StataCorp LP) while mapping of cases at the selected geographic zones was done in QGIS version 2.18. Chloroquine resistant (CQR) genotypes across gender revealed an association with chloroquine resistance by both univariate model (p = 0.027) and by multivariate model (p = 0.025), female as reference group in both models. Prior treatment with antimalarial drugs within the last 6 weeks before enrollment was associated with carriage of CQR genotype by multivariate model (p = 0.034). Further, a significant relationship was observed between travel and CQR carriage both by univariate model (p = 0.001) and multivariate model (p = 0.002). These findings suggest that gender and travel are significantly associated with chloroquine resistance. From a gender perspective, males are more likely to harbor resistant strains than females hence involved in strain dispersion. On the other hand, travel underscores the role of transport network in introducing spread of resistant genotypes, bringing in to focus the need to monitor gene flow and establish strategies to minimize the introduction of resistance strains by controlling malaria among frequent transporters.
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- 2020
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16. Organizational leadership perspectives in implementation of the One Health approach: A case of the Zoonotic Disease Unit and core One Health implementers in Kenya
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Thomas Manyibe Nyariki, Mathew Muturi, Athman Mwatondo, Michael Cheruiyot, Harry Oyas, Vincent Obanda, Francis Gakuya, Rees Murithi Mbabu, and Mercy Muthoni Mugambi
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cross-sectoral collaboration ,One Health approach ,organizational leadership ,sensitization ,Medicine ,Medicine (General) ,R5-920 - Abstract
Aim: This study examined organizational leadership as a cross-sectoral collaboration factor in the implementation of the One Health (OH) approach using Kenya’s Zoonotic Disease Unit and its core OH implementers as an example. Materials and Method: The study used a mixed methods research design. A semi-structured questionnaire was administered to 71 respondents, and key informants were interviewed using an interview guide. All the seven key informants and 53 (74%) of the respondents participated in the study. Data were checked for consistency, coded, entered into the Statistical Package for the Social Sciences, and analyzed using descriptive and correlational statistics. Interview data were transcribed and analyzed thematically. Results: From the analysis, 41/53 (77.2%) of the respondents were senior personnel, 51/53 (85%) of them had worked for 5 years and above in their organizations, and 38/53 (71.7%) had at least a Master’s degree. The study established that although most leaders in the organizations had embraced the OH approach, they were not actively involved in its implementation due to constraints such as inadequate funding. There were moderate and statistically significant positive correlations between participation in leadership roles in implementing the OH approach and the level of awareness (Rs (51)=0.54, p
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- 2017
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17. Yield-phenology relations and water use efficiency of maize (Zea mays L.) in ridge-furrow mulching system in semiarid east African Plateau
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Fei Mo, Jian-Yong Wang, Feng-Min Li, Simon N. Nguluu, Hong-Xu Ren, Hong Zhou, Jian Zhang, Charles W. Kariuki, Patrick Gicheru, Levis Kavagi, Wesly K. Cheruiyot, and You-Cai Xiong
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Medicine ,Science - Abstract
Abstract Yield-phenology relation is a critical issue affecting rainfed maize field productivity in semiarid east African Plateau (EAP). We first introduced Chinese ridge-furrow mulching (RFM) system to EAP, using three maize cultivars with early-, mid- and late-maturing traits as test materials. A two-year field experiment was conducted in a semiarid farm of Kenya from 2012 to 2013. Three treatments were designed: alternative ridge and furrow with transparent plastic mulching (FT), with black plastic mulching (FB) and without mulching (CK). We found that FT and FB significantly increased soil moisture and accelerated crop maturity across two growing seasons. Leaf area and shoot biomass were increased by 30.2% and 67.5% in FT, 35.2% and 73.5% in FB, respectively, compared with CK. Grain yield, water use efficiency and economic output were increased by 55.6%, 57.5% and 26.7% in FT, and 50.8%, 53.3% and 19.8% in FB, respectively. Optimal yield and economic benefit were observed in late-maturing cultivar due to increased topsoil temperature in FT in 2012 (cool), and in early-maturing cultivar owing to cooling effect in FB in 2013 (warm). Our study suggested RFM system, combined with crop phenology selection, be a promising strategy to boost maize productivity and profitability in semiarid EAP.
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- 2017
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18. Medroxyprogesterone acetate alters the vaginal microbiota and microenvironment in women and increases susceptibility to HIV-1 in humanized mice
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Jocelyn M. Wessels, Julie Lajoie, Maeve I. J. Hay Cooper, Kenneth Omollo, Allison M. Felker, Danielle Vitali, Haley A. Dupont, Philip V. Nguyen, Kristen Mueller, Fatemeh Vahedi, Joshua Kimani, Julius Oyugi, Juliana Cheruiyot, John N. Mungai, Alexandre Deshiere, Michel J. Tremblay, Tony Mazzulli, Jennifer C. Stearns, Ali A. Ashkar, Keith R. Fowke, Michael G. Surette, and Charu Kaushic
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dmpa ,glycogen ,amylase ,polymicrobial vaginal microbiota ,humanized mouse ,Medicine ,Pathology ,RB1-214 - Abstract
The hormonal contraceptive medroxyprogesterone acetate (MPA) is associated with increased risk of human immunodeficiency virus (HIV), via incompletely understood mechanisms. Increased diversity in the vaginal microbiota modulates genital inflammation and is associated with increased HIV-1 acquisition. However, the effect of MPA on diversity of the vaginal microbiota is relatively unknown. In a cohort of female Kenyan sex workers, negative for sexually transmitted infections (STIs), with Nugent scores
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- 2019
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19. Effects of single and integrated water, sanitation, handwashing, and nutrition interventions on child soil-transmitted helminth and Giardia infections: A cluster-randomized controlled trial in rural Kenya.
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Amy J Pickering, Sammy M Njenga, Lauren Steinbaum, Jenna Swarthout, Audrie Lin, Benjamin F Arnold, Christine P Stewart, Holly N Dentz, MaryAnne Mureithi, Benard Chieng, Marlene Wolfe, Ryan Mahoney, Jimmy Kihara, Kendra Byrd, Gouthami Rao, Theodora Meerkerk, Priscah Cheruiyot, Marina Papaiakovou, Nils Pilotte, Steven A Williams, John M Colford, and Clair Null
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Medicine - Abstract
BackgroundHelminth and protozoan infections affect more than 1 billion children globally. Improving water quality, sanitation, handwashing, and nutrition could be more sustainable control strategies for parasite infections than mass drug administration, while providing other quality of life benefits.Methods and findingsWe enrolled geographic clusters of pregnant women in rural western Kenya into a cluster-randomized controlled trial (ClinicalTrials.gov NCT01704105) that tested 6 interventions: water treatment, improved sanitation, handwashing with soap, combined water treatment, sanitation, and handwashing (WSH), improved nutrition, and combined WSH and nutrition (WSHN). We assessed intervention effects on parasite infections by measuring Ascaris lumbricoides, Trichuris trichiura, hookworm, and Giardia duodenalis among children born to the enrolled pregnant women (index children) and their older siblings. After 2 years of intervention exposure, we collected stool specimens from 9,077 total children aged 2 to 15 years in 622 clusters, including 2,346 children in an active control group (received household visits but no interventions), 1,117 in the water treatment arm, 1,160 in the sanitation arm, 1,141 in the handwashing arm, 1,064 in the WSH arm, 1,072 in the nutrition arm, and 1,177 in the WSHN arm. In the control group, 23% of children were infected with A. lumbricoides, 1% with T. trichiura, 2% with hookworm, and 39% with G. duodenalis. The analysis included 4,928 index children (median age in years: 2) and 4,149 older siblings (median age in years: 5); study households had an average of 5 people, 90% had dirt floors. Compared to the control group, Ascaris infection prevalence was lower in the water treatment arm (prevalence ratio [PR]: 0.82 [95% CI 0.67, 1.00], p = 0.056), the WSH arm (PR: 0.78 [95% CI 0.63, 0.96], p = 0.021), and the WSHN arm (PR: 0.78 [95% CI 0.64, 0.96], p = 0.017). We did not observe differences in Ascaris infection prevalence between the control group and the arms with the individual interventions sanitation (PR: 0.89 [95% CI 0.73, 1.08], p = 0.228), handwashing (PR: 0.89 [95% CI 0.73, 1.09], p = 0.277), or nutrition (PR: 86 [95% CI 0.71, 1.05], p = 0.148). Integrating nutrition with WSH did not provide additional benefit. Trichuris and hookworm were rarely detected, resulting in imprecise effect estimates. No intervention reduced Giardia. Reanalysis of stool samples by quantitative polymerase chain reaction confirmed the reductions in Ascaris infections measured by microscopy in the WSH and WSHN groups. Trial limitations included imperfect uptake of targeted intervention behaviors, limited power to detect effects on rare parasite infections, and that it was not feasible to blind participants and sample collectors to treatment status. However, lab technicians and data analysts were blinded to treatment status. The trial was funded by the Bill & Melinda Gates Foundation and the United States Agency for International Development.ConclusionsIntegration of improved water quality, sanitation, and handwashing could contribute to sustainable control strategies for Ascaris infections, particularly in similar settings with recent or ongoing deworming programs. Combining nutrition with WSH did not provide further benefits, and water treatment alone was similarly effective to integrated WSH. Our findings provide new evidence that drinking water should be given increased attention as a transmission pathway for Ascaris.Trial registrationClinicalTrials.gov NCT01704105.
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- 2019
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20. Genetic diversity, breed composition and admixture of Kenyan domestic pigs.
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Fidalis Denis Mujibi, Edward Okoth, Evans K Cheruiyot, Cynthia Onzere, Richard P Bishop, Eric M Fèvre, Lian Thomas, Charles Masembe, Graham Plastow, and Max Rothschild
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Medicine ,Science - Abstract
The genetic diversity of African pigs, whether domestic or wild has not been widely studied and there is very limited published information available. Available data suggests that African domestic pigs originate from different domestication centers as opposed to international commercial breeds. We evaluated two domestic pig populations in Western Kenya, in order to characterize the genetic diversity, breed composition and admixture of the pigs in an area known to be endemic for African swine fever (ASF). One of the reasons for characterizing these specific populations is the fact that a proportion of indigenous pigs have tested ASF virus (ASFv) positive but do not present with clinical symptoms of disease indicating some form of tolerance to infection. Pigs were genotyped using either the porcine SNP60 or SNP80 chip. Village pigs were sourced from Busia and Homabay counties in Kenya. Because bush pigs (Potamochoerus larvatus) and warthogs (Phacochoerus spp.) are known to be tolerant to ASFv infection (exhibiting no clinical symptoms despite infection), they were included in the study to assess whether domestic pigs have similar genomic signatures. Additionally, samples representing European wild boar and international commercial breeds were included as references, given their potential contribution to the genetic make-up of the target domestic populations. The data indicate that village pigs in Busia are a non-homogenous admixed population with significant introgression of genes from international commercial breeds. Pigs from Homabay by contrast, represent a homogenous population with a "local indigenous' composition that is distinct from the international breeds, and clusters more closely with the European wild boar than African wild pigs. Interestingly, village pigs from Busia that tested negative by PCR for ASFv genotype IX, had significantly higher local ancestry (>54%) compared to those testing positive, which contained more commercial breed gene introgression. This may have implication for breed selection and utilization in ASF endemic areas. A genome wide scan detected several regions under preferential selection with signatures for pigs from Busia and Homabay being very distinct. Additionally, there was no similarity in specific genes under selection between the wild pigs and domestic pigs despite having some broad areas under similar selection signatures. These results provide a basis to explore possible genetic determinants underlying tolerance to infection by ASFv genotypes and suggests multiple pathways for genetically mediated ASFv tolerance given the diversity of selection signatures observed among the populations studied.
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- 2018
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21. Compound C inhibits nonsense-mediated RNA decay independently of AMPK.
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Abigael Cheruiyot, Shan Li, Andrew Nickless, Robyn Roth, James A J Fitzpatrick, and Zhongsheng You
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Medicine ,Science - Abstract
The nonsense mediated RNA decay (NMD) pathway safeguards the integrity of the transcriptome by targeting mRNAs with premature translation termination codons (PTCs) for degradation. It also regulates gene expression by degrading a large number of non-mutant RNAs (including mRNAs and noncoding RNAs) that bear NMD-inducing features. Consequently, NMD has been shown to influence development, cellular response to stress, and clinical outcome of many genetic diseases. Small molecules that can modulate NMD activity provide critical tools for understanding the mechanism and physiological functions of NMD, and they also offer potential means for treating certain genetic diseases and cancer. Therefore, there is an intense interest in identifying small-molecule NMD inhibitors or enhancers. It was previously reported that both inhibition of NMD and treatment with the AMPK-selective inhibitor Compound C (CC) induce autophagy in human cells, raising the possibility that CC may be capable of inhibiting NMD. Here we show that CC indeed has a NMD-inhibitory activity. Inhibition of NMD by CC is, however, independent of AMPK activity. As a competitive ATP analog, CC does not affect the kinase activity of SMG1, an essential NMD factor and the only known kinase in the NMD pathway. However, CC treatment down-regulates the protein levels of several NMD factors. The induction of autophagy by CC treatment is independent of ATF4, a NMD target that has been shown to promote autophagy in response to NMD inhibition. Our results reveal a new activity of CC as a NMD inhibitor, which has implications for its use in basic research and drug development.
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- 2018
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22. The Genotypic and Phenotypic Stability of Plasmodium falciparum Field Isolates in Continuous In Vitro Culture.
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Redemptah Yeda, Luicer A Ingasia, Agnes C Cheruiyot, Charles Okudo, Lorna J Chebon, Jelagat Cheruiyot, Hoseah M Akala, and Edwin Kamau
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Medicine ,Science - Abstract
The Plasmodium falciparum in vitro culture system is critical for genotypic and phenotypic analyses of the parasites. For genotypic analysis, the genomic DNA can be obtained directly from the patient blood sample or from culture adapted parasites whereas for phenotypic analysis, immediate ex vivo or in vitro culture adapted parasites are used. However, parasite biology studies have not investigated whether culture adaptation process affects genotypic and/or phenotypic characteristics of the parasites in short- or long-term cultures. Here, we set out to study the dynamics and stability of parasite genetic and phenotypic profiles as field isolate parasites were adapted in continuous cultures. Parasites collected from three different patients presenting with uncomplicated malaria were adapted and maintained in drug-free continuous cultures. Aliquots from the continuous cultures were collected every 24-48 hours for analyses. Each aliquot was treated as a separate parasite sample. For genetic analysis, microsatellite (MS) typing and single nucleotide polymorphism (SNP) analyses of 23 drug resistance markers were done. The 50% inhibitory concentrations (IC50) for some of the samples were also established for four antimalarial drugs. Samples from each patient (parasite-line) were compared as they were passed through the continuous culture. Data revealed genotypic and phenotypic profiles for the three parasite-lines fluctuated from one generation to the next with no specific pattern or periodicity. With few exceptions, multilocus analysis revealed samples from each parasite-line had high genetic diversity with unique haplotypes. Interestingly, changes in MS and SNP profiles occurred simultaneously. The difference in the IC50s of samples in each parasite-line reached statistical significance. However, phenotypic changes did not correspond or correlate to genotypic changes. Our study revealed parasite genetic and phenotypic characteristics fluctuates in short- and long-term cultures, which indicates parasite genetic information obtained even in short cultures is likely to be different from the natural infection parasites.
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- 2016
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23. Target-similarity search using Plasmodium falciparum proteome identifies approved drugs with anti-malarial activity and their possible targets.
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Reagan M Mogire, Hoseah M Akala, Rosaline W Macharia, Dennis W Juma, Agnes C Cheruiyot, Ben Andagalu, Mathew L Brown, Hany A El-Shemy, and Steven G Nyanjom
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Medicine ,Science - Abstract
Malaria causes about half a million deaths annually, with Plasmodium falciparum being responsible for 90% of all the cases. Recent reports on artemisinin resistance in Southeast Asia warrant urgent discovery of novel drugs for the treatment of malaria. However, most bioactive compounds fail to progress to treatments due to safety concerns. Drug repositioning offers an alternative strategy where drugs that have already been approved as safe for other diseases could be used to treat malaria. This study screened approved drugs for antimalarial activity using an in silico chemogenomics approach prior to in vitro verification. All the P. falciparum proteins sequences available in NCBI RefSeq were mined and used to perform a similarity search against DrugBank, TTD and STITCH databases to identify similar putative drug targets. Druggability indices of the potential P. falciparum drug targets were obtained from TDR targets database. Functional amino acid residues of the drug targets were determined using ConSurf server which was used to fine tune the similarity search. This study predicted 133 approved drugs that could target 34 P. falciparum proteins. A literature search done at PubMed and Google Scholar showed 105 out of the 133 drugs to have been previously tested against malaria, with most showing activity. For further validation, drug susceptibility assays using SYBR Green I method were done on a representative group of 10 predicted drugs, eight of which did show activity against P. falciparum 3D7 clone. Seven had IC50 values ranging from 1 μM to 50 μM. This study also suggests drug-target association and hence possible mechanisms of action of drugs that did show antiplasmodial activity. The study results validate the use of proteome-wide target similarity approach in identifying approved drugs with activity against P. falciparum and could be adapted for other pathogens.
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- 2017
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24. Association of high-risk sexual behaviour with diversity of the vaginal microbiota and abundance of Lactobacillus.
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Jocelyn M Wessels, Julie Lajoie, Danielle Vitali, Kenneth Omollo, Joshua Kimani, Julius Oyugi, Juliana Cheruiyot, Makubo Kimani, John N Mungai, Maureen Akolo, Jennifer C Stearns, Michael G Surette, Keith R Fowke, and Charu Kaushic
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Medicine ,Science - Abstract
To compare the vaginal microbiota of women engaged in high-risk sexual behaviour (sex work) with women who are not engaged in high-risk sexual behaviour. Diverse vaginal microbiota, low in Lactobacillus species, like those in bacterial vaginosis (BV), are associated with increased prevalence of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) acquisition. Although high-risk sexual behaviour increases risk for STIs, the vaginal microbiota of sex workers is understudied.A retrospective cross-sectional study was conducted comparing vaginal microbiota of women who are not engaged in sex work (non-sex worker controls, NSW, N = 19) and women engaged in sex work (female sex workers, FSW, N = 48), using Illumina sequencing (16S rRNA, V3 region).Bacterial richness and diversity were significantly less in controls, than FSW. Controls were more likely to have Lactobacillus as the most abundant genus (58% vs. 17%; P = 0.002) and composition of their vaginal microbiota differed from FSW (PERMANOVA, P = 0.001). Six microbiota clusters were detected, including a high diversity cluster with three sub-clusters, and 55% of women with low Nugent Scores fell within this cluster. High diversity was observed by 16S sequencing in FSW, regardless of Nugent Scores, suggesting that Nugent Score may not be capable of capturing the diversity present in the FSW vaginal microbiota.High-risk sexual behaviour is associated with diversity of the vaginal microbiota and lack of Lactobacillus. These factors could contribute to increased risk of STIs and HIV in women engaged in high-risk sexual behaviour.
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- 2017
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25. Effect of Harvesting Stage on Sweet Sorghum (Sorghum bicolor L.) Genotypes in Western Kenya
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Moses Owuor Oyier, James O. Owuoche, Maurice E. Oyoo, Erick Cheruiyot, Betty Mulianga, and Justice Rono
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Technology ,Medicine ,Science - Abstract
Harvesting stage of sweet sorghum (Sorghum bicolor L. Moench) cane is an important aspect in the content of sugar for production of industrial alcohol. Four sweet sorghum genotypes were evaluated for harvesting stage in a randomized complete block design. In order to determine sorghum harvest growth stage for bioethanol production, sorghum canes were harvested at intervals of seven days after anthesis. The genotypes were evaluated at different stages of development for maximum production of bioethanol from flowering to physiological maturity. The canes were crushed and juice fermented to produce ethanol. Measurements of chlorophyll were taken at various stages as well as panicles from the harvested canes. Dried kernels at 14% moisture content were also weighed at various stages. Chlorophyll, grain weight, absolute ethanol volume, juice volume, cane yield, and brix showed significant (p=0.05) differences for genotypes as well as the stages of harvesting. Results from this study showed that harvesting sweet sorghum at stages IV and V (104 to 117 days after planting) would be appropriate for production of kernels and ethanol. EUSS10 has the highest ethanol potential (1062.78 l ha−1) due to excellent juice volume (22976.9 l ha−1) and EUSS11 (985.26 l ha−1) due to its high brix (16.21).
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- 2017
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26. Genetically Determined Response to Artemisinin Treatment in Western Kenyan Plasmodium falciparum Parasites.
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Lorna J Chebon, Bidii S Ngalah, Luicer A Ingasia, Dennis W Juma, Peninah Muiruri, Jelagat Cheruiyot, Benjamin Opot, Emmanuel Mbuba, Mabel Imbuga, Hoseah M Akala, Wallace Bulimo, Ben Andagalu, and Edwin Kamau
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Medicine ,Science - Abstract
Genetically determined artemisinin resistance in Plasmodium falciparum has been described in Southeast Asia. The relevance of recently described Kelch 13-propeller mutations for artemisinin resistance in Sub-Saharan Africa parasites is still unknown. Southeast Asia parasites have low genetic diversity compared to Sub-Saharan Africa, where parasites are highly genetically diverse. This study attempted to elucidate whether genetics provides a basis for discovering molecular markers in response to artemisinin drug treatment in P. falciparum in Kenya. The genetic diversity of parasites collected pre- and post- introduction of artemisinin combination therapy (ACT) in western Kenya was determined. A panel of 12 microsatellites and 91 single nucleotide polymorphisms (SNPs) distributed across the P. falciparum genome were genotyped. Parasite clearance rates were obtained for the post-ACT parasites. The 12 microsatellites were highly polymorphic with post-ACT parasites being significantly more diverse compared to pre-ACT (p < 0.0001). The median clearance half-life was 2.55 hours for the post-ACT parasites. Based on SNP analysis, 15 of 90 post-ACT parasites were single-clone infections. Analysis revealed 3 SNPs that might have some causal association with parasite clearance rates. Further, genetic analysis using Bayesian tree revealed parasites with similar clearance phenotypes were more closely genetically related. With further studies, SNPs described here and genetically determined response to artemisinin treatment might be useful in tracking artemisinin resistance in Kenya.
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- 2016
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27. Adaptability and Stability Study of Selected Sweet Sorghum Genotypes for Ethanol Production under Different Environments Using AMMI Analysis and GGE Biplots
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Justice Kipkorir Rono, Erick Kimutai Cheruiyot, Jacktone Odongo Othira, Virginia Wanjiku Njuguna, Joseph Kinyoro Macharia, James Owuoche, Moses Oyier, and Alex Machio Kange
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Technology ,Medicine ,Science - Abstract
The genotype and environment interaction influences the selection criteria of sorghum (Sorghum bicolor) genotypes. Eight sweet sorghum genotypes were evaluated at five different locations in two growing seasons of 2014. The aim was to determine the interaction between genotype and environment on cane, juice, and ethanol yield and to identify best genotypes for bioethanol production in Kenya. The experiments were conducted in a randomized complete block design replicated three times. Sorghum canes were harvested at hard dough stage of grain development and passed through rollers to obtain juice that was then fermented to obtain ethanol. Cane, juice, and ethanol yield was analyzed using the additive main effect and multiplication interaction model (AMMI) and genotype plus genotype by environment (GGE) biplot. The combined analysis of variance of cane and juice yield of sorghum genotypes showed that sweet sorghum genotypes were significantly (P
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- 2016
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28. The role of Pfmdr1 and Pfcrt in changing chloroquine, amodiaquine, mefloquine and lumefantrine susceptibility in western-Kenya P. falciparum samples during 2008-2011.
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Fredrick L Eyase, Hoseah M Akala, Luiser Ingasia, Agnes Cheruiyot, Angela Omondi, Charles Okudo, Dennis Juma, Redemptah Yeda, Ben Andagalu, Elizabeth Wanja, Edwin Kamau, David Schnabel, Wallace Bulimo, Norman C Waters, Douglas S Walsh, and Jacob D Johnson
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Medicine ,Science - Abstract
Single Nucleotide Polymorphisms (SNPs) in the Pfmdr1, and Pfcrt, genes of Plasmodium falciparum may confer resistance to a number of anti-malaria drugs. Pfmdr1 86Y and haplotypes at Pfcrt 72-76 have been linked to chloroquine (CQ) as well as amodiaquine (AQ) resistance. mefloquine (MQ) and lumefantrine (LU) sensitivities are linked to Pfmdr1 86Y. Additionally, Pfcrt K76 allele carrying parasites have shown tolerance to LU. We investigated the association between Pfmdr1 86/Pfcrt 72-76 and P. falciparum resistance to CQ, AQ, MQ and LU using field samples collected during 2008-2011 from malaria endemic sites in western Kenya. Genomic DNA from these samples was genotyped to examine SNPs and haplotypes in Pfmdr1 and Pfcrt respectively. Additionally, immediate ex vivo and in vitro drug sensitivity profiles were assessed using the malaria SYBR Green I fluorescence-based assay. We observed a rapid but steady percent increase in wild-type parasites with regard to both Pfmdr1 and Pfcrt between 2008 and 2011 (p
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- 2013
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29. The cost-effectiveness of prophylaxis strategies for individuals with advanced HIV starting treatment in Africa
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Walker, SM, Cox, E, Revill, P, Musiime, V, Bwakura‐Dangarembizi, M, Mallewa, J, Cheruiyot, P, Maitland, K, Ford, N, Gibb, DM, Walker, AS, Soares, M, Mugyenyi, P, Kityo, C, Wavamunno, P, Nambi, E, Ocitti, P, Ndigendawani, M, Kabahenda, S, Kemigisa, M, Acen, J, Olebo, D, Mpamize, G, Amone, A, Okweny, D, Mbonye, A, Nambaziira, F, Rweyora, A, Kangah, M, Kabaswahili, V, Abach, J, Abongomera, G, Omongin, J, Aciro, I, Philliam, A, Arach, B, Ocung, E, Amone, G, Miles, P, Adong, C, Tumsuiime, C, Kidega, P, Otto, B, Apio, F, Baleeta, K, Mukuye, A, Abwola, M, Ssennono, F, Baliruno, D, Tuhirwe, S, Namisi, R, Kigongo, F, Kikyonkyo, D, Mushahara, F, Tusiime, J, Musiime, A, Nankya, A, Atwongyeire, D, Sirikye, S, Mula, S, Noowe, N, Lugemwa, A, Kasozi, M, Mwebe, S, Atwine, L, Senkindu, T, Natuhurira, T, Katemba, C, Ninsiima, E, Acaku, M, Kyomuhangi, J, Ankunda, R, Tukwasibwe, D, Ayesiga, L, Hakim, J, Nathoo, K, Reid, A, Chidziva, E, Mhute, T, Tinago, GC, Bhiri, J, Mudzingwa, S, Phiri, M, Steamer, J, Nhema, R, Warambwa, C, Musoro, G, Mutsai, S, Nemasango, B, Moyo, C, Chitongo, S, Rashirai, K, Vhembo, S, Mlambo, B, Nkomani, S, Ndemera, B, Willard, M, Berejena, C, Musodza, Y, Matiza, P, Mudenge, B, Guti, V, Etyang, A, Agutu, C, Berkley, J, Njuguna, P, Mwaringa, S, Etyang, T, Awuondo, K, Wale, S, Shangala, J, Kithunga, J, Mwarumba, S, Said Maitha, S, Mutai, R, Lozi Lewa, M, Mwambingu, G, Mwanzu, A, Kalama, C, Latham, H, Shikuku, J, Fondo, A, Njogu, A, Khadenge, C, Mwakisha, B, Siika, A, Wools‐Kaloustian, K, Nyandiko, W, Sudoi, A, Wachira, S, Meli, B, Karoney, M, Nzioka, A, Tanui, M, Mokaya, M, Ekiru, W, Mboya, C, Mwimali, D, Mengich, C, Choge, J, Injera, W, Njenga, K, Cherutich, S, Anyango Orido, M, Omondi Lwande, G, Rutto, P, Mudogo, A, Kutto, I, Shali, A, Jaika, L, Jerotich, H, Pierre, M, Kaunda, S, Van Oosterhout, J, O'Hare, B, Heydermann, R, Gonzalez, C, Dzabala, N, Kelly, C, Denis, B, Selemani, G, Nyondo Mipando, L, Chirwa, E, Banda, P, Mvula, L, Msuku, H, Ziwoya, M, Manda, Y, Nicholas, S, Masesa, C, Mwalukomo, T, Makhaza, L, Sheha, I, Bwanali, J, Limbuni, M, Gibb, D, Thomason, M, Pett, S, Szubert, A, Griffiths, A, Wilkes, H, Rajapakse, C, Spyer, M, Prendergast, A, Klein, N, Rauchenberger, M, Van Looy, N, Little, E, Fairbrother, K, Cowan, F, Seeley, J, Bernays, S, Kawuma, R, Mupambireyi, Z, Kyomuhendo, F, Nakalanzi, S, Peshu, J, Ndaa, S, Chabuka, J, Mkandawire, N, Matandika, L, Kapuya, C, Weller, I, Malianga, E, Mwansambo, C, Miiro, F, Elyanu, P, Bukusi, E, Katabira, E, Mugurungi, O, Peto, T, Musoke, P, Matenga, J, Phiri, S, Lyall, H, Johnston, V, Fitzgerald, F, Post, F, Ssali, F, Arenas‐Pinto, A, Turkova, A, Bamford, A, Academic Medical Center, and DiFDMRCWellcome Trust
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Male ,Antifungal Agents ,Cost effectiveness ,Cost-Benefit Analysis ,Human immunodeficiency virus (HIV) ,HIV Infections ,medicine.disease_cause ,Cohort Studies ,0302 clinical medicine ,late‐presenters ,fluconazole ,Advanced disease ,Global health ,030212 general & internal medicine ,Child ,Research Articles ,health care economics and organizations ,education.field_of_study ,cost‐effectiveness ,3. Good health ,Infectious Diseases ,Child, Preschool ,Female ,Quality-Adjusted Life Years ,prophylaxis ,0305 other medical science ,Post-Exposure Prophylaxis ,medicine.drug ,Research Article ,Adult ,medicine.medical_specialty ,Tuberculosis ,Antigens, Fungal ,Adolescent ,Cryptococcal antigen ,Anti-HIV Agents ,Population ,late-presenters ,1117 Public Health and Health Services ,03 medical and health sciences ,medicine ,Humans ,education ,cost-effectiveness ,030505 public health ,AIDS-Related Opportunistic Infections ,business.industry ,Public Health, Environmental and Occupational Health ,HIV ,1103 Clinical Sciences ,medicine.disease ,CD4 Lymphocyte Count ,Cryptococcus ,Emergency medicine ,Africa ,business ,Fluconazole ,1199 Other Medical and Health Sciences - Abstract
Introduction: Many HIV-positive individuals in Africa have advanced disease when initiating antiretroviral therapy (ART) so have high risks of opportunistic infections and death. The REALITY trial found that an enhanced-prophylaxis package including fluconazole reduced mortality by 27% in individuals starting ART with CD4
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- 2020
30. Feasibility and safety of cervical biopsy sampling for mucosal immune studies in female sex workers from Nairobi, Kenya.
- Author
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Klara Hasselrot, Juliana Cheruiyot, Joshua Kimani, Terry B Ball, Rupert Kaul, and Taha Hirbod
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Medicine ,Science - Abstract
There is an urgent need to improve our understanding of the mucosal immuno-pathogenesis of HIV acquisition in the female genital tract, particularly in high-risk women such as female sex workers (FSWs). Cervical biopsy samples offer technical advantages over cytobrush sampling, but there are concerns that this might increase HIV acquisition, particularly if healing is slow and/or women do not abstain from sex during healing.Cervical biopsy samples and cervico-vaginal swabs for co-infection diagnostics, prostate specific antigen (PSA) and immune studies were collected from 59 women, including HIV seropositive and HIV-exposed seronegative (HESN) FSWs as well as lower risk women from Nairobi, Kenya. A clinical-demographic questionnaire was administered and women were instructed to avoid sexual intercourse, douching and the insertion of tampons for 14 days. All participants underwent a repeat exam to assess healing within the 14 days, and had HIV diagnostics at six months. Cervical sampling was well tolerated, and 82% of participants had healed macroscopically by 5 days. Both self-report and PSA screening suggested high levels of compliance with pre- and post-procedure abstinence. Delayed healing was associated with vulvovaginal candidiasis (VVC) and HESN status. At six-month follow up all low-risk and HESN participants remained HIV seronegative.Cervical biopsy sampling is a safe and well-tolerated method to obtain cervical biopsies in this context, particularly if participants with VVC are excluded. As healing could be delayed up to 11 days, it is important to support (both financially and with rigorous counseling) a period of post-procedure abstinence to minimize HIV risk.
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- 2012
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