Dr. James M Mutunga, PhD - USAMRD-A/K Walter Reed Project, Kisumu - Senior Research Officer

Dr. James M Mutunga

PhD

USAMRD-A/K Walter Reed Project, Kisumu

Senior Research Officer

Kisumu, Nyanza | Kenya

Additional Specialties: Medical Entomology, Insect Physiology & Toxicology, Arthropod Biocontainment


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Dr. James M Mutunga, PhD - USAMRD-A/K Walter Reed Project, Kisumu - Senior Research Officer

Dr. James M Mutunga

PhD

Introduction

Primary Affiliation: USAMRD-A/K Walter Reed Project, Kisumu - Kisumu, Nyanza , Kenya

Additional Specialties:

Research Interests:


View Dr. James M Mutunga’s Resume / CV

Experience

Feb 2013
Project Coordinator
Coordination of laboratory work and field entomology teams
Working with multiple stakeholders in field mosquito research

Publications

20Publications

478Reads

306Profile Views

2PubMed Central Citations

Optimizing a Gravid Mosquito Resting Box to Enhance Auto-dissemination of Larvicides under Semi-field Conditions in Western Kenya

9(4): 25-34 (doi: 10.5376/jmr.2019.09.0004)

Journal of Mosquito Research

Malaria control strategies are challenged by emergence of insecticide resistance and behavioral changes of the vector. New vector management tools are required to avert control failure. The aim of this study was to optimize a mosquito resting box that act as contamination station for auto-dissemination of novel chemicals by female Anopheles gambiae to their oviposition sites. In this study, cotton fabrics (red, black, blue, white), circular & rectangular boxes of different sizes were tested for resting preference. Optimal box size and shape, aligned with most attractive colour, was dusted with red fluorescent dye (larvicide proxy). Two artificial oviposition sites were set up in a screen house, one of which was treated with Cedrol, the other had tap water only. Two to three days old bloodfed mosquitoes were used for resting preference whereas gravid females were used for auto-dissemination experiments. A high resting preference was observed in red and black fabrics (28.08 ± 3.211), (28.00 ±3.922) respectively, compared to white (4.67±0.890). Choice of colour was found to influence mosquito landing (P=0.000<0.05). With the choice of most preferred colour, the rectangular black box (45m×30m×45m) attracted high proportion (60%) of mosquitoes. The box effectively transferred dye to the resting mosquitoes and to the oviposition site, with 67% visited oviposition site, having dye on their body. These results reveal that the black rectangular box attracted adult blood-fed and gravid mosquitoes high enough showing great potential as future malaria vector control and/or sampling tool, and is recommended for further field-based evaluation. 

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September 2019
12 Reads

Community knowledge and perceptions on malaria prevention and house screening in Nyabondo, Western Kenya.

BMC Public Health 2019 Apr 23;19(1):423. Epub 2019 Apr 23.

International Centre of Insect Physiology and Ecology (ICIPE), P.O. Box 30772, Nairobi, Kenya.

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http://dx.doi.org/10.1186/s12889-019-6723-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6480882PMC
April 2019
7 Reads
2.264 Impact Factor

Mosquito Acetylcholinesterase as a Target for Novel Phenyl-Substituted Carbamates.

Int J Environ Res Public Health 2019 04 28;16(9). Epub 2019 Apr 28.

Emerging Pathogens Institute, Entomology and Nematology Department, University of Florida, Gainesville, FL 32610, USA.

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http://dx.doi.org/10.3390/ijerph16091500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6539584PMC
April 2019
7 Reads
2.063 Impact Factor

Diversity and Molecular Characterization of Mosquitoes (Diptera: Culicidae) in selected ecological regions in Kenya

F1000Research 2019, 8:262

F1000Research

Mosquitoes play a predominant role as leading agents in the spread of vector-borne diseases and consequent mortality in humans. Despite reports on increase of new and recurrent mosquito borne-disease outbreaks such as chikungunya, dengue fever and Rift valley fever in Kenya little is known about the genetic characteristics and diversity of the vector species that have been incriminated in transmission of disease pathogens. In this study, we identified mosquito species across Kisumu, Kilifi and Nairobi Counties and determined their genetic diversity and phylogenetic relationships. PCR was used to amplify and sequence the partial cytochrome oxidase subunit 1 (CO1) gene of mosquito samples. Molecular-genetic and phylogenetic analysis of the partial cytochrome oxidase subunit 1 (CO1) gene was employed to identify their relationships with known mosquito species. Fourteen (14) haplotypes belonging to genus Aedes, nine (9) haplotypes belonging to genusAnopheles and twelve (12) haplotypes belonging to genus Culex were identified in this study. Findings from this study revealed a potentially new haplotype belonging to Anopheles genus and reported the first molecular characterization of Aedes cummnisii in Kenya. Sequence results revealed variation in mosquito species from Kilifi, Kisumu and Nairobi. Since vector competence varies greatly across species and species-complexes and is strongly associated with specific behavioural adaptations, proper species identification is important for vector control programs.

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March 2019
9 Reads

Select β- and γ-branched 1-alkylpyrazol-4-yl methylcarbamates exhibit high selectivity for inhibition of versus human acetylcholinesterase.

Pestic Biochem Physiol 2018 Oct 13;151:32-39. Epub 2018 Feb 13.

Emerging Pathogens Institute and Department of Entomology and Nematology, University of Florida, Gainesville, FL 32610, USA.

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http://dx.doi.org/10.1016/j.pestbp.2018.02.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6277143PMC
October 2018
13 Reads
2.014 Impact Factor

Select β- and γ-branched 1-alkylpyrazol-4-yl methylcarbamates exhibit high selectivity for inhibition of Anopheles gambiae versus human acetylcholinesterase

https://doi.org/10.1016/j.pestbp.2018.02.003

Pesticide Biochemistry and Physiology

The widespread emergence of pyrethroid-resistant Anopheles gambiae has intensified the need to find new contact mosquitocides for indoor residual spraying and insecticide treated nets. With the goal of developing new species-selective and resistance-breaking acetylcholinesterase (AChE)-inhibiting mosquitocides, in this report we revisit the effects of carbamate substitution on aryl carbamates, and variation of the 1-alkyl group on pyrazol-4-yl methylcarbamates. Compared to aryl methylcarbamates, aryl dimethylcarbamates were found to have lower selectivity for An. gambiae AChE (AgAChE) over human AChE (hAChE), but improved tarsal contact toxicity to G3 strain An. gambiae. Molecular modeling studies suggest the lower species-selectivity of the aryl dimethylcarbamates can be attributed to a less flexible acyl pocket in AgAChE relative to hAChE. The improved tarsal contact toxicity of the aryl dimethylcarbamates relative to the corresponding methylcarbamates is attributed to a range of complementary phenomena. With respect to the pyrazol-4-yl methylcarbamates, the previously observed low An. gambiae-selectivity of compounds bearing α-branched 1-alkyl groups was improved by employing β- and γ-branched 1-alkyl groups. Compounds 22a (cyclopentylmethyl), 21a (cyclobutylmethyl), and 26a (3-methylbutyl) offer 250-fold, 120-fold, and 96-fold selectivity, respectively, for inhibition of AgAChE vs. hAChE. Molecular modeling studies suggests the high species-selectivity of these compounds can be attributed to the greater mobility of the W84 sidechain in the choline-binding site of AgAChE, compared to that of W86 in hAChE. Compound 26a has reasonable contact toxicity to G3 strain An. gambiae (LC50 = 269 μg/mL) and low cross-resistance to Akron strain (LC50 = 948 μg/mL), which bears the G119S resistance mutation.

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February 2018
22 Reads

Spatial panorama of malaria prevalence in Africa under climate change and interventions scenarios.

Int J Health Geogr 2018 01 16;17(1). Epub 2018 Jan 16.

Human Health Division, International Center of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya.

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http://dx.doi.org/10.1186/s12942-018-0122-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5771136PMC
January 2018
30 Reads

Containment Studies of Transgenic Mosquitoes in Disease Endemic Countries: The Broad Concept of Facilities Readiness

Vector Borne Zoonotic Dis. 2018 Jan 1; 18(1): 14–20.

Vector Borne and Zoonotic Diseases

Genetic strategies for large scale pest or vector control using modified insects are not yet operational in Africa, and currently rely on import of the modified strains to begin preliminary, contained studies. Early involvement of research teams from participating countries is crucial to evaluate candidate field interventions. Following the recommended phased approach for novel strategies, evaluation should begin with studies in containment facilities. Experiences to prepare facilities and build international teams for research on transgenic mosquitoes revealed some important organizing themes underlying the concept of “facilities readiness,” or the point at which studies in containment may proceed, in sub-Saharan African settings. First, “compliance” for research with novel or non-native living organisms was defined as the fulfillment of all legislative and regulatory requirements. This is not limited to regulations regarding use of transgenic organisms. Second, the concept of “colony utility” was related to the characteristics of laboratory colonies being produced so that results of studies may be validated across time, sites, and strains or technologies; so that the appropriate candidate strains are moved forward toward field studies. Third, the importance of achieving “defensible science” was recognized, including that study conclusions can be traced back to evidence, covering the concerns of various stakeholders over the long term. This, combined with good stewardship of resources and appropriate funding, covers a diverse set of criteria for declaring when “facilities readiness” has been attained. It is proposed that, despite the additional demands on time and resources, only with the balance of and rigorous achievement of each of these organizing themes can collaborative research into novel strategies in vector or pest control reliably progress past initial containment studies.

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January 2018
18 Reads

Green tea proanthocyanidins cause impairment of hormone-regulated larval development and reproductive fitness via repression of juvenile hormone acid methyltransferase, insulin-like peptide and cytochrome P450 genes in Anopheles gambiae sensu stricto

PLOS ONE

Successful optimization of plant-derived compounds into control of nuisance insects would benefit from scientifically validated targets. However, the close association between the genotypic responses and physiological toxicity effects mediated by these compounds remains underexplored. In this study, we evaluated the sublethal dose effects of proanthocyanidins (PAs) sourced from green tea (Camellia sinensis) on life history traits of Anopheles gambiae (sensu stricto) mosquitoes with an aim to unravel the probable molecular targets. Based on the induced phenotypic effects, genes selected for study targeted juvenile hormone (JH) biosynthesis, signal transduction, oxidative stress response and xenobiotic detoxification in addition to vitellogenesis in females. Our findings suggest that chronic exposure of larval stages (L3/L4) to sublethal dose of 5 ppm dramatically extended larval developmental period for up to 12 days, slowed down pupation rates, induced abnormal larval-pupal intermediates and caused 100% inhibition of adult emergence. Further, females exhibited significant interference of fecundity and egg hatchability relative to controls (p < 0.001). Using reverse transcription quantitative polymerase chain reaction (RT-qPCR), our findings show that PA-treated larvae exhibited significant repression of AgamJHAMT (p < 0.001), AgamILP1 (p < 0.001) and AgamCYP6M2 (p < 0.001) with up-regulation of Hsp70 (p < 0.001). Females exposed as larvae demonstrated down-regulation of AgamVg (p = 0.03), AgamILP1 (p = 0.009), AgamCYP6M2 (p = 0.05) and AgamJHAMT (p = 0.02). Our findings support that C. sinensis proanthocyanidins affect important vectorial capacity components such as mosquito survival rates and reproductive fitness thus could be potentially used for controlling populations of malaria vectors.

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August 2017
24 Reads

Bivalent Carbamates as Novel Control Agents of the Malaria Mosquito, Anopheles gambiae.

Chimia (Aarau) 2016 Oct;70(10):704-708

Department of Entomology and Nematology Emerging Pathogens Institute University of Florida, Gainesville, FL 32610, USA.

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http://dx.doi.org/10.2533/chimia.2016.704DOI Listing
October 2016
38 Reads
1 Citation
1.350 Impact Factor

Potential of Camellia sinensis proanthocyanidins-rich fraction for controlling malaria mosquito populations through disruption of larval development.

Parasit Vectors 2016 Sep 22;9(1):512. Epub 2016 Sep 22.

Present Address: Fritz Lipmann Institute (FLI) - Leibniz Institute for Age Research, D-07745, Jena, Germany.

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http://parasitesandvectors.biomedcentral.com/articles/10.118
Publisher Site
http://dx.doi.org/10.1186/s13071-016-1789-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5034625PMC
September 2016
71 Reads
3.430 Impact Factor

Carbamate and pyrethroid resistance in the akron strain of Anopheles gambiae.

Pestic Biochem Physiol 2015 Jun 9;121:116-21. Epub 2015 Mar 9.

Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL 32610, USA. Electronic address:

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http://dx.doi.org/10.1016/j.pestbp.2015.03.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4457939PMC
June 2015
37 Reads
2.014 Impact Factor

Neurotoxicology of bis(n)-tacrines on Blattella germanica and Drosophila melanogaster acetylcholinesterase.

Arch Insect Biochem Physiol 2013 Aug 5;83(4):180-94. Epub 2013 Jun 5.

Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.

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http://dx.doi.org/10.1002/arch.21104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4739519PMC
August 2013
48 Reads
1.021 Impact Factor