327 research outputs found

    School-based malaria control in Kenya: Evaluating heterogeneity in risk, impact and process

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    School children are increasingly recognised as an important target for malaria control. However, limited evidence exists on the relative benefits of alternative school-based malaria control interventions or how impact may vary according to transmission intensity. Nested within the first evaluation of school-based intermittent screening and treatment (IST), in a region of low-to-moderate transmission, this thesis aimed to investigate the influence of heterogeneity in underlying transmission risk and variation in the fidelity of the intervention on the impact and possible operational applications of IST. The thesis utilized data from a cluster-randomised trial, over two years, evaluating the impact of school-based IST on health and education of children in 101 schools in south coast, Kenya. In the intervention children were screened for Plasmodium falciparum infection using rapid diagnostic tests (RDTs) once a term, with those found RDT-positive treated with artemether-lumefantrine. Cross-sectional analysis of baseline data, indicated marked heterogeneity in P. falciparum infection and anaemia at school-level. P. falciparum infection was strongly associated with anaemia, but health status was not associated with educational performance. Subsequent analysis of the impact of IST showed no benefit on the primary health or education outcomes even when stratified by baseline Plasmodium prevalence, or number of treatments received. Latent class analysis suggested reasonable diagnostic performance of RDTs, with seasonal variability observed. Bayesian geostatistical analysis of the spatial and temporal heterogeneity of school-level P. falciparum infection highlighted the relative stability in observed heterogeneity, despite periodic treatment of infection. Analysis at the individual-level suggested overdispersion of P. falciparum infection with prevalence-based models showing a greater proportion of individuals repeatedly infected than expected even after accounting for exposure. Collectively, these findings indicate that, in such a locally heterogeneous transmission setting, school-based IST provided no health or education benefits, with a number of factors identified for lack of impact. The persistence of high infection levels in certain schools despite periodic treatment highlights the importance of fine-scale targeting with a need for community-wide coverage in high-risk clusters. Moreover, the findings suggest a potential role for school-level screenings in both the identification of communities for targeted control, and periodic monitoring of impact

    Why it takes an 'ontological shock' to prompt increases in small firm resilience : sensemaking, emotions and flood risk

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    This article uses a sensemaking approach to understand small firms’ responses to the threat of external shocks. By analysing semi-structured interviews with owners of flooded small firms, we investigate how owners process flood experiences and explore why such experiences do not consistently lead to the resilient adaptation of premises. We, conclude that some of the explanation for low levels of adaptation relates to a desire to defend existing sensemaking structures and associated identities. Sensemaking structures are only revised if these structures are not critical to business identity, or if a flood constitutes an ‘ontological shock’ and renders untenable existing assumptions regarding long-term business continuity. This article has implications for adaptation to the growing risk of flooding, climate change and external shocks. Future research analysing external shocks would benefit from using a sensemaking approach and survey studies should include measurements of ‘ontological’ impact as well as material and financial damage. In addition, those designing information campaigns should take account of small firms’ resistance to information that threatens their existing sensemaking structures and social identities

    Placental DNA methylation signatures of maternal smoking during pregnancy and potential impacts on fetal growth

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    Maternal smoking during pregnancy (MSDP) contributes to poor birth outcomes, in part through disrupted placental functions, which may be reflected in the placental epigenome. Here we present a meta-analysis of the associations between MSDP and placental DNA methylation (DNAm) and between DNAm and birth outcomes within the Pregnancy And Childhood Epigenetics (PACE) consortium (N = 1700, 344 with MSDP). We identify 443 CpGs that are associated with MSDP, of which 142 associated with birth outcomes, 40 associated with gene expression, and 13 CpGs are associated with all three. Only two CpGs have consistent associations from a prior meta-analysis of cord blood DNAm, demonstrating substantial tissue-specific responses to MSDP. The placental MSDP-associated CpGs are enriched for environmental response genes, growth-factor signaling, and inflammation, which play important roles in placental function. We demonstrate links between placental DNAm, MSDP and poor birth outcomes, which may better inform the mechanisms through which MSDP impacts placental function and fetal growth

    Animal-related factors associated with moderate-to-severe diarrhea in children younger than five years in western Kenya: A matched case-control study

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    Background Diarrheal disease remains among the leading causes of global mortality in children younger than 5 years. Exposure to domestic animals may be a risk factor for diarrheal disease. The objectives of this study were to identify animal-related exposures associated with cases of moderate-to-severe diarrhea (MSD) in children in rural western Kenya, and to identify the major zoonotic enteric pathogens present in domestic animals residing in the homesteads of case and control children. Methodology/Principal findings We characterized animal-related exposures in a subset of case and control children (n = 73 pairs matched on age, sex and location) with reported animal presence at home enrolled in the Global Enteric Multicenter Study in western Kenya, and analysed these for an association with MSD. We identified potentially zoonotic enteric pathogens in pooled fecal specimens collected from domestic animals resident at children’s homesteads. Variables that were associated with decreased risk of MSD were washing hands after animal contact (matched odds ratio [MOR] = 0.2; 95% CI 0.08–0.7), and presence of adult sheep that were not confined in a pen overnight (MOR = 0.1; 0.02–0.5). Variables that were associated with increased risk of MSD were increasing number of sheep owned (MOR = 1.2; 1.0–1.5), frequent observation of fresh rodent excreta (feces/urine) outside the house (MOR = 7.5; 1.5–37.2), and participation of the child in providing water to chickens (MOR = 3.8; 1.2–12.2). Of 691 pooled specimens collected from 2,174 domestic animals, 159 pools (23%) tested positive for one or more potentially zoonotic enteric pathogens (Campylobacter jejuni, C. coli, non-typhoidal Salmonella, diarrheagenic E. coli, Giardia, Cryptosporidium, or rotavirus). We did not find any association between the presence of particular pathogens in household animals, and MSD in children. Conclusions and significance Public health agencies should continue to promote frequent hand washing, including after animal contact, to reduce the risk of MSD. Future studies should address specific causal relations of MSD with sheep and chicken husbandry practices, and with the presence of rodents

    Sexual Size Dimorphism and Body Condition in the Australasian Gannet

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    Funding: The research was financially supported by the Holsworth Wildlife Research Endowment. Acknowledgments We thank the Victorian Marine Science Consortium, Sea All Dolphin Swim, Parks Victoria, and the Point Danger Management Committee for logistical support. We are grateful for the assistance of the many field volunteers involved in the study.Peer reviewedPublisher PD

    Implementation of COVID-19 Preventive Measures and Staff Well-Being in a Sample of English Schools 2020-2021.

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    BACKGROUND: We examined fidelity and feasibility of implementation of COVID-19 preventive measures in schools, and explored associations between adherence to these measures and staff well-being, to inform policy on sustainable implementation and staff wellbeing. METHODS: Surveys were conducted across 128 schools in England with 107 headteachers and 2698 staff-members with reference to autumn term 2020, examining school-level implementation of preventive measures, adherence, and teacher burnout (response rates for headteacher and staff surveys were 84% and 59%, respectively). RESULTS: The median number of measures implemented in primary and secondary schools was 33 (range 23-41), and 32 (range 22-40), respectively; most measures presented challenges. No differences were found regarding number of measures implemented by school-level socio-economic disadvantage. High adherence was reported for staff wearing face-coverings, staff regularly washing their hands, (secondary only) desks facing forwards, and (primary only) increased cleaning of surfaces and student hand-washing. Adherence to most measures was reported as higher in primary than secondary schools. Over half of school leaders and 42% (517/1234) of other teaching staff suffered from high emotional exhaustion. Higher teacher-reported school-wide adherence with measures was consistently associated with lower burnout for leaders and other teaching staff. CONCLUSIONS: Findings indicate a tremendous effort in implementing preventive measures and an urgent need to support investments in improving teacher wellbeing

    Zoonotic disease research in East Africa

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    Abstract Background The East African region is endemic with multiple zoonotic diseases and is one of the hotspots for emerging infectious zoonotic diseases with reported multiple outbreaks of epidemic diseases such as Ebola, Marburg and Rift Valley Fever. Here we present a systematic assessment of published research on zoonotic diseases in the region and thesis research in Kenya to understand the regional research focus and trends in publications, and estimate proportion of theses research transitioning to peer-reviewed journal publications. Methods We searched PubMed, Google Scholar and African Journals Online databases for publications on 36 zoonotic diseases identified to have occurred in the East Africa countries of Burundi, Ethiopia, Kenya, Tanzania, Rwanda and Uganda, for the period between 1920 and 2017. We searched libraries and queried online repositories for masters and PhD theses on these diseases produced between 1970 and 2016 in five universities and two research institutions in Kenya. Results We identified 771 journal articles on 22, and 168 theses on 21 of the 36 zoonotic diseases investigated. Research on zoonotic diseases increased exponentially with the last 10 years of our study period contributing more than half of all publications 460 (60%) and theses 102 (61%) retrieved. Endemic diseases were the most studied accounting for 656 (85%) and 150 (89%) of the publication and theses studies respectively, with publications on epidemic diseases associated with outbreaks reported in the region or elsewhere. Epidemiological studies were the most common study types but limited to cross-sectional studies while socio-economics were the least studied. Only 11% of the theses research transitioned to peer-review publications, taking an average of 2.5 years from theses production to manuscript publication. Conclusion Our findings demonstrate increased attention to zoonotic diseases in East Africa but reveal the need to expand the scope, focus and quality of studies to adequately address the public health, social and economic threats posed by zoonoses

    Radiative cooling effects on reverse shocks formed by magnetized supersonic plasma flows

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    We study the structure of reverse shocks formed by the collision of supersonic, magnetized plasma flows driven by an inverse (or exploding) wire array with a planar conducting obstacle. We observe that the structure of these reverse shocks varies dramatically with wire material, despite the similar upstream flow velocities and mass densities. For aluminum wire arrays, the shock is sharp and well-defined, consistent with magneto-hydrodynamic theory. In contrast, we do not observe a well-defined shock using tungsten wires, and instead we see a broad region dominated by density fluctuations on a wide range of spatial scales. We diagnose these two very different interactions using interferometry, Thomson scattering, shadowgraphy, and a newly developed imaging refractometer that is sensitive to small deflections of the probing laser corresponding to small-scale density perturbations. We conclude that the differences in shock structure are most likely due to radiative cooling instabilities, which create small-scale density perturbations elongated along magnetic field lines in the tungsten plasma. These instabilities grow more slowly and are smoothed by thermal conduction in the aluminum plasma

    Effects, equity, and cost of school-based and community-wide treatment strategies for soil-transmitted helminths in Kenya: a cluster-randomised controlled trial

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    Background School-based deworming programmes can reduce morbidity attributable to soil-transmitted helminths in children but do not interrupt transmission in the wider community. We assessed the effects of alternative mass treatment strategies on community soil-transmitted helminth infection. Methods In this cluster-randomised controlled trial, 120 community units (clusters) serving 150 000 households in Kenya were randomly assigned (1:1:1) to receive albendazole through annual school-based treatment targeting 2–14 year olds or annual or biannual community-wide treatment targeting all ages. The primary outcome was community hookworm prevalence, assessed at 12 and 24 months through repeat cross-sectional surveys. Secondary outcomes were Ascaris lumbricoides and Trichuris trichiura prevalence, infection intensity of each soil-transmitted helminth species, and treatment coverage and costs. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT02397772. Findings After 24 months, prevalence of hookworm changed from 18·6% (95% CI 13·9–23·2) to 13·8% (10·5–17·0) in the annual school-based treatment group, 17·9% (13·7–22·1) to 8·0% (6·0–10·1) in the annual community-wide treatment group, and 20·6% (15·8–25·5) to 6·2% (4·9–7·5) in the biannual community-wide treatment group. Relative to annual school-based treatment, the risk ratio for annual community-wide treatment was 0·59 (95% CI 0·42–0·83; p<0·001) and for biannual community-wide treatment was 0·46 (0·33–0·63; p<0·001). More modest reductions in risk were observed after 12 months. Risk ratios were similar across demographic and socioeconomic subgroups after 24 months. No adverse events related to albendazole were reported. Interpretation Community-wide treatment was more effective in reducing hookworm prevalence and intensity than school-based treatment, with little additional benefit of treating every 6 months, and was shown to be remarkably equitable in coverage and effects. Funding Bill & Melinda Gates Foundation, the Joint Global Health Trials Scheme of the Medical Research Council, the UK Department for International Development, the Wellcome Trust, and the Children’s Investment Fund Foundation
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