A5050876898- Mosquito-borne diseases and control
- Malaria Research and Control
- Insect Pest Control Strategies
- Parasites and Host Interactions
- Global Maternal and Child Health
- Viral Infections and Vectors
- Insect Resistance and Genetics
- Travel-related health issues
- Child Nutrition and Water Access
- Vibrio bacteria research studies
- Poverty, Education, and Child Welfare
- Zoonotic diseases and public health
- Entomopathogenic Microorganisms in Pest Control
- Insect symbiosis and bacterial influences
- Eosinophilic Esophagitis
- Primate Behavior and Ecology
- Parasite Biology and Host Interactions
- Species Distribution and Climate Change
- Hemoglobinopathies and Related Disorders
- Virology and Viral Diseases
- Environmental Toxicology and Ecotoxicology
- Parasitic Diseases Research and Treatment
- Hepatitis Viruses Studies and Epidemiology
- Indigenous Health and Education
- Insect and Pesticide Research
Centers for Disease Control and Prevention
2016-2025
Kenya Medical Research Institute
2000-2024
Division of Parasitic Diseases and Malaria
2015-2024
Centers for Disease Control and Prevention
2024
Maseno University
2024
Government of the United States of America
2023
Center for Global Health
2013-2023
Duke University
2023
Ministry of Health
2023
National Museums of Kenya
2023
Spatial analyses of the effect insecticide (permethrin)-treated bed nets (ITNs) on nearby households both with and without ITNs was performed in context a large-scale, group-randomized, controlled mortality trial Asembo, western Kenya. Results illustrate protective compounds lacking located within 300 meters for child mortality, moderate anemia, high-density parasitemia, hemoglobin levels. This community is approximately as strong observed villages ITNs. implies that areas intense malaria...
Abstract Background High coverage of insecticide-treated bed nets in Asembo and low Seme, two adjacent communities western Nyanza Province, Kenya; followed by expanded as the Kenya national malaria programme rolled out; provided a natural experiment for quantification changes relative abundance primary vectors this holoendemic region. Both belong to Anopheles gambiae sensu lato (s.l.) species complex, namely A. stricto (s.s.) arabiensis . Historically, former was proportionately dominant...
Abstract Background Insecticide-treated nets (ITNs) contributed significantly to the decline in malaria since 2000. Their protective efficacy depends not only on access, use, and net integrity, but also location of people within home environment mosquito biting profiles. Anopheline human data were integrated identify potential gaps protection better understand transmission dynamics Busia County, western Kenya. Methods Direct observation activities landing catches (HLC) performed hourly...
A longitudinal survey of mosquito larval habitats was carried out in Asembo Bay, western Kenya, during the rainy season 1998. All pools standing water along a 700-m transect were sampled twice per week. For each habitat, eight environmental variables recorded and sample anopheline larvae collected for identification. In total, 1,751 Anopheles gambiae s.l. 2,784 funestus Giles identified. Identification An. by polymerase chain reaction (PCR) indicated that 240 (14.7%) 858 (52.4%) arabiensis...
A group-randomized controlled trial of insecticide (permethrin)-treated bed nets (ITNs) was conducted in an area high perennial malaria transmission western Kenya to test the effect ITNs on all-cause mortality children 1-59 months age. Child deaths were monitored over a two-year period by biannual household census Asembo (1997-1998) and Gem (1998-1999). Overall, 1,722 occurred followed for 35,932 child-years. Crude rates/1,000 child-years 51.9 versus 43.9 control ITN villages old. The...
The growth and development of Anopheles gambiae Giles larvae were studied in artificial habitats western Kenya. Larvae responded to increasing densities by extending their time emerging as smaller adults, although survival was not significantly affected. Addition nutrients the form cow dung collected near study site had no impact on larval development. Regression analysis showed that female increased 0.020 d dry mass decreased 0.74 μg with each additional larva. By fitting data pupation...
The effect of permethrin-treated bed nets (ITNs) on malaria vectors was studied as part a large-scale, randomized, controlled trial in western Kenya. Indoor resting densities fed Anopheles gambiae s.l. and An. funestus intervention houses were 58.5% ( P = 0.010) 94.5% 0.001) lower, respectively, compared with control houses. sporozoite infection rate 0.8% areas 3.4% 0.026) areas, while the rates not significantly different between two areas. We estimated overall transmission Plasmodium...
Adherence with permethrin-treated bed net (ITN) use and their proper deployment was directly observed in 2,178 individuals (784 households) participating a large-scale trial of ITNs on child mortality western Kenya. The were distributed free charge to ensure high coverage, resulting ratio 1.46 persons per ITN. Approximately 30% present unused. overall percentage adherence 72.3%. probability by depended strongly age (relative risk [RR] = 0.86, 95% confidence limit [CL] 0.78-0.94), which...
Background Insecticide-treated nets (ITNs) and indoor residual spraying (IRS) are highly effective tools for controlling malaria transmission in Africa because the most important vectors, from Anopheles gambiae complex A. funestus group, usually prefer biting humans indoors at night. Methods Matched surveys of mosquito human behaviour six rural sites Burkina Faso, Tanzania, Zambia, Kenya, with ITN use ranging 0.2% to 82.5%, were used calculate proportion exposure An. sensu lato s.l. that...
It has been speculated that widespread and sustained use of insecticide treated bed nets (ITNs) for over 10 years in Asembo, western Kenya, may have selected changes the location (indoor versus outdoor) time (from late night to earlier evening) biting predominant species human malaria vectors (Anopheles funestus, Anopheles gambiae sensu stricto, arabiensis). Mosquitoes were collected by landing catches a six week period June July, 2011, indoors outdoors from 17 h 07 h, 75 villages Kenya....
Abstract Background Malaria vector control in Africa depends upon effective insecticides bed nets and indoor residual sprays. This study investigated the extent of insecticide resistance Anopheles gambiae s.l., s.s. arabiensis western Kenya where ownership insecticide-treated has risen steadily from late 1990s to 2010. Temporal spatial variation frequency a knock down ( kdr ) allele A. was quantified, as phenotypic among geographic populations s.l. Methods To investigate temporal frequency,...
The human landing catch (HLC) has long been the gold standard for estimating malaria transmission by mosquitoes, but come under scrutiny because of ethical concerns exposing collectors to infectious bites. We estimated incidence Plasmodium falciparum infection in a cohort 152 persons conducting HLCs and compared it with that 147 non-collectors western Kenya. Participants were presumptively cleared Coartem™ (artemether-lumefantrine) tested every 2 weeks 12 weeks. HLC collections conducted...
Insecticide-treated bed nets (ITNs) are the cornerstone of malaria control in sub-Saharan Africa but their effectiveness may be compromised by spread pyrethroid resistance among vectors. The objective this investigation was to assess ITNs prevent an area Malawi with moderate resistance. One deltamethrin ITN distributed study for every two individuals each household plus one extra households odd number residents. A fixed cohort 1,199 children aged six 59 months seen monthly year and at sick...
Historically, the malaria vectors in western Kenya have been Anopheles funestus, gambiae s.s., and arabiensis. Of these species, An. funestus populations declined most after introduction of insecticide-treated bed nets (ITNs) 1990s Asembo, collections region remained low until at least 2008. Contrary to findings during early years ITN use majority collected here 2010 2011 were funestus. Female had characteristically high Plasmodium falciparum sporozoite rates showed nearly 100%...
Long-lasting insecticide-treated mosquito nets (LLINs) are a primary malaria prevention strategy in sub-Saharan Africa. However, emergence of insecticide resistance threatens the effectiveness LLINs. Cross-sectional surveys LLINs were conducted houses seven and four villages Gem Bungoma Districts western Kenya, respectively. Condition (number area holes nets), number species mosquitoes resting inside them, insecticidal activity quantified. Mosquitoes collected allowed to lay eggs progeny...
Abstract Indoor residual spraying (IRS) of insecticides is a major vector control strategy for malaria prevention. We evaluated the impact single round IRS with organophosphate, pirimiphos-methyl (Actellic 300CS), on entomological and parasitological parameters in Migori County, western Kenya 2017, an area where primary vectors are resistant to pyrethroids but susceptible compound. Entomological monitoring was conducted by indoor CDC light trap, pyrethrum spray catches (PSC) human landing...
Effective targeting and evaluation of interventions that protect against adult malaria vectors requires an understanding how gaps in personal protection arise. An improved human mosquito behaviour, they overlap time space, is critical to estimating the impact insecticide-treated nets (ITNs) determining when where supplemental tools are needed. Methods for weighting estimates exposure biting Anopheles mosquitoes according people spend their were first developed over half a century ago....
Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) target night-time biting mosquitoes effectively reduce malaria transmission in rural settings across Africa, but additional vector control tools are needed to interrupt transmission. Attractive targeted sugar baits (ATSBs) attract kill mosquitoes, including those outdoors. Deployment of ATSBs incorporating the insecticide dinotefuran was associated with major reductions mosquito density longevity Mali. The impact this...
Abstract The Anopheles stephensi mosquito is an invasive malaria vector recently reported in Djibouti, Ethiopia, Sudan, Somalia, Nigeria, and Ghana. World Health Organization has called on countries Africa to increase surveillance efforts detect report this institute appropriate effective control mechanisms. In Kenya, the Division of National Malaria Program conducted entomological counties at risk for An. invasion. addition, Kenya Medical Research Institute molecular all sampled mosquitoes...
The effect of insecticide (permethrin)-treated bed nets (ITNs) on the spatial distribution malaria vectors in neighboring villages lacking ITNs was studied during a randomized controlled trial western Kenya. There trend decreased abundance Anopheles gambiae with decreasing distance from intervention both before ( P = 0.027) and after 0.002) introduction ITNs, but this significantly stronger were introduced 0.05). For An. funestus , no pre-intervention observed 0.373), intervention, closer...
ContextInsecticide-treated bednets reduce malaria transmission and child morbidity mortality in short-term trials, but this impact may not be sustainable. Previous investigators have suggested that bednet use might paradoxically increase older children through delayed acquisition of immunity to malaria.ObjectivesTo determine whether adherence public health benefits insecticide-treated can sustained over time during infancy increases all-cause rates an area intense perennial...