Publications by authors named "Isaac Ngere"

Although the highlands of East Africa lack the geo-ecological landmarks of Rift Valley fever (RVF) disease hotspots to participate in cyclic RVF epidemics, they have recently reported growing numbers of small RVF clusters. Here, we investigated whether RVF cycling occurred among livestock and humans in the central highlands of Kenya during inter-epidemic periods. A 2-year prospective hospital-based study among febrile patients (March 2022-February 2024) in Murang'a County of Kenya was followed by a cross-sectional human-animal survey.

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During the coronavirus disease 2019 pandemic, alcohol-based hand rub (ABHR) availability and use increased as a prevention measure. ABHR is a convenient, effective way to kill microbes on hands but is hampered by the presence of organic material, whereas handwashing with water and soap (HWWS) can physically remove microbes and dirt. Although ABHR is preferred in most health care settings, the suitability of ABHR use in community settings has not been measured.

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Quality improvements and reduction of disease risk for low-resource shared sanitation facilities require cleanliness assessment approaches that are both rigorous and practical. Using Adenosine Triphosphate (ATP) bioluminescence testing, we assessed contamination on high-touch (HT) surfaces (inner door handles) at 32 shared toilet sites in Kisumu, Kenya. In public toilets, contamination was lowest after cleaning and disinfection (C&D) with 0.

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Cholera continues to cause many outbreaks in low and middle-income countries due to inadequate water, sanitation, and hygiene services. We describe a protracted cholera outbreak in Nairobi City County, Kenya in 2017. We reviewed the cholera outbreak line lists from Nairobi City County in 2017 to determine its extent and factors associated with death.

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We examined the association between serum aflatoxin B1-lysine adduct (AFB1-lys) levels in pregnant women and adverse pregnancy outcomes (low birthweight, miscarriage and stillbirth) through a nested matched case-control study of pregnant women enroled at ≤28 weeks' gestation in Mombasa, Kenya, from 2017 to 2019. Cases comprised women with an adverse birth outcome, defined as either delivery of a singleton infant weighing <2500 g, or a miscarriage, or a stillbirth, while controls were women who delivered a singleton live infant with a birthweight of ≥2500 g. Cases were matched to controls at a ratio of 1:2 based on maternal age at enrolment, gestational age at enrolment and study site.

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Background: Recent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease. We investigated factors associated with the phenomenon by characterising recent RVF disease events in East Africa.

Methods: Data on 100 disease events (2008-2022) from Kenya, Uganda and Tanzania were obtained from public databases and institutions, and modelled against possible geoecological risk factors of occurrence including altitude, soil type, rainfall/precipitation, temperature, normalised difference vegetation index (NDVI), livestock production system, land-use change and long-term climatic variations.

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Background: Recent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease. We investigated factors associated with the phenomenon by characterizing recent RVF disease events in East Africa.

Methods: Data on 100 disease events (2008 - 2022) from Kenya, Uganda, and Tanzania were obtained from public databases and institutions, and modeled against possible geo-ecological risk factors of occurrence including altitude, soil type, rainfall/precipitation, temperature, normalized difference vegetation index (NDVI), livestock production system, land-use change, and long-term climatic variations.

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Article Synopsis
  • Tracking livestock abortion patterns can help develop policies to reduce disease risk and reproductive losses in Kenya's livestock industry.
  • A year-long active surveillance study covered 52% of Kenya’s land area, with significant abortion rates particularly in arid and semi-arid regions, where sheep and goats accounted for the majority of the cases.
  • The findings highlight the need for more research on the true scale of livestock abortions and the relationship between pathogens, climate, and environmental factors in these areas.
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Background: High rates of sexual and reproductive health (SRH) harms and interrupted schooling are global challenges for adolescent girls, requiring effective interventions. We assessed the impact of menstrual cups (MCs) or cash transfers conditioned on school attendance (CCTs), or both, on SRH and schooling outcomes in western Kenya.

Methods: In this cluster-randomised Cups or Cash for Girls (CCG) trial, adolescent girls in Forms two and three at 96 secondary schools in Siaya County (western Kenya) were randomised to receive either CCT, MC, combined CCT and MC, or control (1:1:1:1) for an average of 30 months.

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Objective: Identifying factors that may influence aflatoxin exposure in children under 5 years of age living in farming households in western Kenya.

Design: We used a mixed methods design. The quantitative component entailed serial cross-sectional interviews in 250 farming households to examine crop processing and conservation practices, household food storage and consumption and local understandings of aflatoxins.

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Background: Understanding healthcare-seeking patterns for respiratory illness can help improve estimation of disease burden and target public health interventions to control acute respiratory disease in Kenya.

Methods: We conducted a cross-sectional survey to determine healthcare utilization patterns for acute respiratory illness (ARI) and severe pneumonia in four diverse counties representing urban, peri-urban, rural mixed farmers, and rural pastoralist communities in Kenya using a two-stage (sub-locations then households) cluster sampling procedure. Healthcare seeking behavior for ARI episodes in the last 14 days, and severe pneumonia in the last 12 months was evaluated.

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Considering the early inequity in global COVID-19 vaccine distribution, we compared the level of population immunity to SARS-CoV-2 with vaccine uptake and refusal between rural and urban Kenya two years after the pandemic onset. A population-based seroprevalence study was conducted in the city of Nairobi (n = 781) and a rural western county (n = 810) between January and February 2022. The overall SARS-CoV-2 seroprevalence was 90.

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Using data collected from previous (n = 86) and prospective (n = 132) anthrax outbreaks, we enhanced prior ecological niche models (ENM) and added kernel density estimation (KDE) approaches to identify anthrax hotspots in Kenya. Local indicators of spatial autocorrelation (LISA) identified clusters of administrative wards with a relatively high or low anthrax reporting rate to determine areas of greatest outbreak intensity. Subsequently, we modeled the impact of vaccinating livestock in the identified hotspots as a national control measure.

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Objective: To analyze the relative value of providing menstrual cups and sanitary pads to primary schoolgirls.

Design: Cost-effectiveness and cost-benefit analyses of three-arm single-site open cluster randomized controlled pilot study providing menstrual cups or sanitary pads for 1 year.

Participants: Girls 14-16 years of age enrolled across 30 primary schools in rural western Kenya.

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Background: Understanding and accurately predicting the environmental limits, population at risk and burden of podoconiosis are critical for delivering targeted and equitable prevention and treatment services, planning control and elimination programs and implementing tailored case finding and surveillance activities.

Methods: This is secondary analysis of a nationwide podoconiosis mapping survey in Kenya. We combined national representative prevalence survey data of podoconiosis with climate and environmental data, overlayed with population figures in a geostatistical modelling framework, to predict the environmental suitability, population living in at-risk areas and number of cases of podoconiosis in Kenya.

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Article Synopsis
  • A study of over 3 million camels in Kenya found that many have antibodies against MERS-CoV, although human infections in Africa are quite rare.
  • Researchers followed 243 camels from 33 homesteads for two years, testing nasal swabs for the virus and documenting illnesses, primarily respiratory issues among the camels.
  • Out of the camels tested, a small percentage showed positive results for MERS-CoV, and there was evidence of sporadic transmission to humans, particularly during outbreaks.
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Article Synopsis
  • - WASH infrastructure and practices, particularly hand hygiene, are essential for preventing the spread of infectious diseases like COVID-19 and other respiratory illnesses, with guidance tailored to COVID-19 built upon existing WASH standards.
  • - Collaborating with local organizations, tools were created to assess WASH conditions and practices, leading to interventions aimed at mitigating COVID-19 in healthcare and community settings within low- and middle-income countries.
  • - Observations showed gaps in access to hand hygiene materials despite improved water supply, and adherence to hand hygiene was significantly better after patient contact, highlighting the need for better management of handwashing stations and enforcement of global WASH standards in communal spaces.
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Urban informal settlements may be disproportionately affected by the COVID-19 pandemic due to overcrowding and other socioeconomic challenges that make adoption and implementation of public health mitigation measures difficult. We conducted a seroprevalence survey in the Kibera informal settlement, Nairobi, Kenya, to determine the extent of SARS-CoV-2 infection. Members of randomly selected households from an existing population-based infectious disease surveillance (PBIDS) provided blood specimens between 27 November and 5 December 2020.

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Background: Using classical and genomic epidemiology, we tracked the COVID-19 pandemic in Kenya over 23 months to determine the impact of SARS-CoV-2 variants on its progression.

Methods: SARS-CoV-2 surveillance and testing data were obtained from the Kenya Ministry of Health, collected daily from 306 health facilities. COVID-19-associated fatality data were also obtained from these health facilities and communities.

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Background: Adolescence is a sensitive time for girls' sexual and reproductive health (SRH), as biological changes occur concurrently with heightening pressures for sexual activity. In western Kenya, adolescent girls are vulnerable to acquiring sexually transmitted infections (STIs), such as HIV and herpes simplex virus type 2 (HSV-2), and to becoming pregnant prior to reaching adulthood. This study examines associations between individual, household, and partner-related risk factors and the prevalence of sex, adolescent pregnancy, HIV, and HSV-2.

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Background: The lower than expected COVID-19 morbidity and mortality in Africa has been attributed to multiple factors, including weak surveillance. This study estimated the burden of SARS-CoV-2 infections eight months into the epidemic in Nairobi, Kenya.

Methods: A population-based, cross-sectional survey was conducted using multi-stage random sampling to select households within Nairobi in November 2020.

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Podoconiosis is a type of tropical lymphedema that is clinically distinguished from lymphatic filariasis (LF) because it is ascending and commonly bilateral but asymmetric. The disease is a result of a genetically determined inflammatory reaction to long-term exposure to mineral particles in irritant red clay soils derived mainly from volcanic soils. We conducted the first nationwide mapping of the prevalence and risk factors of podoconiosis in Kenya.

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Article Synopsis
  • Researchers studied 262 camel handlers in Kenya from April 2018 to March 2020 to monitor for Middle East respiratory coronavirus syndrome (MERS-CoV).
  • Despite high seroprevalence of MERS-CoV in African camels, no zoonotic transmission was detected among the handlers during the study period.
  • However, PCR testing confirmed MERS-CoV in 3 asymptomatic handlers, indicating the presence of the virus even in those showing no symptoms.
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Article Synopsis
  • This study focuses on using historical data from livestock anthrax events in Kenya (1957-2017) to create disease risk maps, aiding in effective disease management in resource-limited countries.
  • By analyzing 666 reported anthrax cases, researchers identified patterns of disease occurrence over time and space, emphasizing areas with higher risks.
  • The findings indicate that anthrax events are spatially clustered, with specific agro-ecological zones being more affected, particularly high-risk areas for cattle, and a noticeable seasonality in case occurrences.
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