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Effect of a spatial repellent on malaria incidence in an area of western Kenya characterised by high malaria transmission, insecticide resistance, and universal coverage of insecticide treated nets (part of the AEGIS Consortium): a cluster-randomised, controlled trial.
Get PDFBackgroundSpatial repellent products are used for prevention of insect bites, and a body of evidence exists on spatial repellent entomological efficacy. A new option for vector control, spatial repellent products are designed to release active ingredient into the air for disruption of human–vector contact thereby reducing human exposure to mosquito-borne pathogens. Clinical trials have shown spatial repellent epidemiological efficacy against Aedes-borne viruses but inconclusive outcomes against malaria. We aimed to show and quantify the protective efficacy of spatial repellents in reducing malaria infection incidence in Busia County, Kenya.MethodsA prospective, cluster-randomised, controlled trial in Busia County, western Kenya was done to quantify the efficacy of a transfluthrin-based spatial repellent against human malaria infection following mass distribution of insecticide treated nets. Investigators, staff, and study participants were masked to cluster allocation. Infection incidence was measured by microscopy in children aged 6 months to younger than 10 years during a 4-month baseline (March–July 2021) and 24-month follow-up period with intervention (October, 2021–October, 2023). From 58 clusters (29 intervention, 29 placebo), a total of 1526 and 1546 participants from two consecutive, 12-month cohorts were assessed for first-time malaria infection (primary endpoint) by survival analysis at interim and end-of-trial timepoints, respectively. This trial is registered with ClinicalTrials.gov, NCT04766879 and is complete.FindingsThe outcome of the primary endpoint indicated that spatial repellents significantly reduced the hazard rate of first-time malaria infection by 33·4% (95% CI 11·1–50·1; p=0·0058) and the hazard rate of overall new malaria infections by 32·1% (15·9–45·2; p=0·0004). No reported adverse events and serious adverse events were deemed to be associated with the spatial repellent.InterpretationOur trial provides the first evidence of a demonstrative spatial repellent protective efficacy in reducing risk of malaria infection in an African setting characterised by high malaria transmission, pyrethroid resistant malaria vectors, and high coverage of insecticide treated nets. Results support spatial repellent products as a beneficial component of malaria prevention.</p
Quantifying the potential value of entomological data collection for programmatic decision-making on malaria control in sub-Saharan African settings
Get PDFBackground: The availability of many tools for malaria control leads to complex decisions regarding the most cost-effective intervention package based on local epidemiology. Mosquito characteristics influence the impact of vector control, but entomological surveillance is often limited due to a lack of resources in national malaria programmes. Methods: This study quantified the monetary value of information provided by entomological data collection for programmatic decision-making using a mathematical model of Plasmodium falciparum transmission. The 3-year impact and cost of various intervention packages was simulated in different sub-Saharan African settings, including combinations of scaling-up insecticide-treated nets (ITN), switching to next-generation ITNs, and a treatment and prevention package. The DALYs averted and their net monetary benefit were compared at different cost-effectiveness thresholds and the value of resolving uncertainty in entomological model parameters was calculated. Results: Across transmission settings and at cost-effectiveness thresholds over US0.05 (range 0.02–0.23) and US75 and US250 were higher than current investments into entomological monitoring by the US President’s Malaria Initiative. Conclusions: These results suggest that entomological data collection should not delay implementation of interventions with demonstrated efficacy in most settings, but that sustained investments into and use of entomological surveillance are nevertheless worthwhile and have broad value to national malaria programmes.</p
Clinical features of puff adder envenoming: case series of Bitis arietans snakebites in Kenya and a scoping review of the literature.
Get PDFIntroductionThe puff adder (Bitis arietans) is a medically important snake species found across much of Africa, yet there is limited literature on the clinical features and pathophysiology of envenoming after a puff adder bite.MethodsWe conducted a case-series study to describe the clinical features of patients with puff adder bites who were treated in two primary healthcare facilities in Kenya and complemented our case-series with a scoping review of all published cases of puff adder envenoming that contained sufficient clinical details to highlight the major features.ResultsBetween December 2020 and September 2021, 15 patients were admitted with a suspected puff adder bite (based on the patient’s description of the biting snake or confirmed in patients who brought the dead snake or a picture of the biting snake for identification) at the Chemolingot and Mwingi sub-county hospitals in Baringo and Kitui counties, central Kenya. Common local and systemic features on admission included pain (n=15, 100%), swelling (n=14, 93%), and haemorrhage (n=9, 60%). Coagulopathy (n=2, 13%), blistering (n=1, 8%) and shock (n=1, 8%) were less common. In addition, we conducted a literature review and identified 23 studies with detailed descriptions of the clinical features of puff adder envenoming from 37 patients. Local features were common and consistent across cases—swelling (100%, n=37) and pain (95%, n=35). Systemic features were less consistent, with 10 (27%) patients exhibiting hypotension on admission, 10 (27%) patients reporting a fever, and 13 (35%) developing anaemia. Some complications were more common in patients with bites by captive snakes (amputations), compared to patients with bites by wild snakes (hypotension). Snake identification was easier and more accurate after bites by captive snakes, but more challenging for patients bitten in community settings.ConclusionWe combined clinical cases and a literature review to describe the common and less common clinical features of puff adder envenoming. Further clinical research incorporating serial laboratory assays of patients with definitively identified puff adder bites is crucial to better understand the pathophysiology of envenoming by this medically important snake species.</p
Reaching priority populations with different HIV self-testing distribution models in South Africa: an analysis of programme data
Get PDFBackgroundAs in much of sub-Saharan Africa, substantial HIV testing gaps remain in South Africa, particularly among adult men ages 20–35, young people ages 15–24 and key populations. Innovative strategies, such as HIV self-testing (HIVST), are needed to reach such under-served populations. We evaluated a range of HIV self-test kit distribution models’ potential to reach adult men, young people and key populations in South Africa, to inform targeted approaches.MethodsThis cross-sectional study used data from community and facility-based HIV self-test kit distribution models implemented from October 2017 to April 2020. Self-test kits were distributed as part of the Unitaid-funded Self-Testing AfRica (STAR) programme. Data were collected from individuals who obtained self-test kits through five distribution models. Frequencies and proportions were used to describe the characteristics of the study populations and self-test kit distribution approaches.ResultsOver 2.5 years, 1 071 065 self-test kits were distributed across the five models. Community-based distribution accounted for 63% of total kits distributed, while the private sector (primarily workplace) accounted for 26%. Distribution at public sector health facilities accounted for 7% and distribution through the key population and secondary distribution models accounted for 2% each. Of those obtaining kits, and for whom we collected previous testing data (n = 771 612, 72%), 11% had never tested for HIV, 29% had not tested for at least a year, 41% had tested within the last 4–12 months and 19% had tested within the preceding three months. More men (64%) than women obtained self-test kits across all distribution models. The majority (80%) of men obtaining self-test kits were aged 20–40 years, and primarily received these at public transport terminals (36%), workplaces (18%) and hotspots (14%). A small proportion of men was reached through female sex workers.ConclusionsThis analysis of programme data enabled us to identify HIV self-test kit distribution models that are best suited to reach specific priority and under-tested populations, particularly adult men and young people. Models/sub-models that reach self-test users where they live, work and spend time, are likely to result in higher HIVST uptake. Study findings can inform future HIVST scale-up in South Africa.</p
Condomless sexual encounters among female sex workers included in a longitudinal coital diary study in Zimbabwe
Get PDFBackground: Compared with the general female population, female sex workers (FSWs) experience a greater burden of STIs, including HIV. Consistent condom use reduces HIV risk; however, while many FSWs are aware of condom efficacy, this knowledge does not consistently translate into use. We aimed to estimate the prevalence and patterns of condomless sex by partner type at the sexual encounter level, as well as identify factors associated with condomless sex among FSWs recruited into a diary study in Zimbabwe. Methods: We conducted a longitudinal coital diary study in site A and site B between 25 November 2020 and 30 December 2021. Pictorial diaries were developed in collaboration with FSWs. We recruited participants using snowball sampling and asked them to complete a daily diary of their sexual encounters with each partner for one month, repeated over three non-consecutive months within 12 months. The following FSW characteristics were recorded: FSW age, Key Populations (KP) Programme contact, partner type and age, condom use categorized as none, partial, or full, types of sexual activity, and violence experiences. To identify factors associated with condomless sex, we used hierarchical Poisson regression modelling.Results: 404 FSWs documented 62,559 sex encounters, with 17,325 (27.7%) reported as condomless. Our adjusted analysis showed that encounters with permanent partners had the highest likelihood of being condomless (59.5%; adjusted relative risk [aRR] 3.83, 95% CI: 3.38–4.35), followed by regular partners (25.6%; aRR 1.63, 95% CI: 1.50–1.78), compared to new partners (15.0%). Compared with FSWs aged < 25 years (29.7%), those aged ≥ 35 years were less likely to have condomless sex (22.1%; aRR 0.79, 95% CI: 0.66–0.94), while sex without violence was less likely (24.1%) to be condomless than sex with violence (57.7%; aRR 2.32, 95% CI: 2.00-2.70). FSWs with the KP programme contact reported fewer condomless encounters (25.9%; aRR 0.81, 95% CI: 0.90–0.94) than those without (32.9%). Conclusion: Condomless sex was common and varied based on FSW age, partner type, experiencing violence during sex, and KP programme contact. These findings emphasize the need for continued condom promotion, counseling, violence mitigation, and training in condom negotiation skills especially given the heightened risk of HIV transmission among FSWs.</p
Prevalence, locations and predictors of attitudes accepting both intimate partner violence and additional forms of violence against women and girls in South Sudan: a geospatial analysis
Get PDFMost research on violence against women and girls (VAWG) in South Sudan has focused on intimate partner violence (IPV) neglecting other forms of VAWG. This research aims to determine the prevalence of attitudes accepting IPV and whether it overlaps with attitudes accepting additional forms of VAWG (child marriage, raiding villages for women during cattle rustling or other raids or female genital mutilation) in South Sudanese men and women, or are different attitudinal phenomena. We used data from the National Household Survey South Sudan 2020 (n = 1,732 women, n = 1,730 men aged 15-49 years). We estimated attitudinal prevalences and applied spatial analysis (Global Moran’s I, Getis and Ord’s local Gi*, and Kuldorff’s SatScan) and multilevel regression to assess overlapping attitudes accepting IPV and at least one other form of VAWG studied in the 10 states and three administrative areas comprising the country. The prevalence of attitudes accepting IPV overlapping with the prevalence of attitudes accepting at least one other form of VAWG was 34.72% (95% CI = 33.14%-36.34%). Sub-national results were non-randomly correlated (Global Moran’s I= 0.23). Higher clusters displaying overlaps were located in the counties Kapoeta East, Kapoeta South, Kapoeta North, Budi, Pibor, and Ikotos. People married, cohabiting or living together (aOR = 1.40, 95% CI = 1.04-1.90) as well as people widowed, divorced or separated (aOR = 1.75, 95% CI = 1.05-2.93) were associated with attitudinal overlaps. Conversely, communities with any formal education were associated with a lower odds of overlapping (aOR = 0.26. 95% CI = 0.09-0.70). In South Sudan overlapping acceptance of IPV and at least one other form of VAWG are spatially clustered. Therefore, strategies to understand and tackle them should be strengthened especially in those locations. Essential elements include increasing schooling for children and promoting women’s empowerment, especially among male-female partnerships. These conclusions have national and international policy implications.</p
Cameroonian blackflies (Diptera: Simuliidae) harbour a plethora of (RNA) viruses
Get PDFStrong epidemiological evidence suggests that onchocerciasis may be associated with epilepsy – hence the name onchocerciasis-associated epilepsy (OAE). However, the pathogenesis of OAE still needs to be elucidated, as recent studies failed to detect Onchocerca volvulus in the central nervous system of persons with OAE. Therefore, it was suggested that a potentially neurotropic virus transmitted by blackflies could play a role in triggering OAE. To investigate this hypothesis, adult blackflies were collected in an onchocerciasis-endemic area with a high OAE prevalence in the Ntui Health District, Cameroon. A viral particle-based shotgun sequencing approach was used to detect viral sequences in fifty-five pools of ten blackflies. A very high abundance of viral reads was detected across multiple (novel) viral families, including viral families associated with human disease. Although, no genomes closely related to known neurotropic viruses were found in the blackfly virome, the plethora of novel viruses representing novel species, genera and even families, warrant further exploration for their potential to infect vertebrates. These results could serve as a first step for studying the viruses associated with the hematophagous blackfly, which also could be present in their nematode host O. volvulus. Exploring the diversity of viruses in blackflies should be included in the active surveillance of zoonotic diseases.</p
Comparing apples with apples: A proposed taxonomy for “Community Health Workers” and other front-line health workers for international comparisons
Get PDFThis paper proposes a taxonomy for Community Health Workers (CHWs) and others engaged in front-line community health activities, encompassing formally-employed workers extending government primary health care (PHC) service delivery as well as a range of other actors with roles at the nexus of government PHC and communities. The taxonomy is grounded in current definitions from the World Health Organization and the International Labor Organization, and proposes some refinements for future iterations of guidance from these agencies. The designation, “Community Health Worker” is currently used to cover a broad range of roles. Furthermore, there are programs engaging workers or community members in roles closely adjacent to those generally recognized as CHWs that use other designations, not commonly included under the rubric of “CHW”. This potentially confusing range of roles and nomenclature leads at times to over-generalizations, applying insights and principles relevant for one type of worker or community member that are not necessarily relevant for another. It also leads to a failure to consider occupational groups not commonly thought of as CHWs—but engaged in PHC service delivery at the most peripheral level—in community-based-PHC planning and management arrangements. Building on ILO and WHO classifications and standards, a further clarification of terms and a taxonomy is proposed, with the intention of contributing to clearer communication and shared understanding and, ultimately, sounder community health policy, program planning, and implementation; and more substantial progress towards Universal Health Coverage.</p
Variations in blood pressure after a 75g oral glucose load and their implications for detecting hypertension and postprandial hypotension in Chinese adults: a cross-sectional study
Get PDFAimsCurrent hypertension guidelines fail to discriminate between fasting and postprandial blood pressure (BP) measurements. Meal ingestion often triggers a marked increase in splanchnic blood flow, potentially inducing a sustained fall in systolic BP of ≥20 mmHg, termed postprandial hypotension (PPH). This study aimed to evaluate BP responses to a 75 g glucose drink and its implications for detecting hypertension and PPH in community-dwelling adults.Methods and resultsA stratified multi-stage random sampling method was used to obtain a nationally representative sample of n = 4429 adult residents between April 2020 and January 2021 in China. BP and heart rate (HR) were measured before, and 1 and 2 h after, a 75 g glucose drink. When fasting, 38.4% of the study population had high BP (BP ≥140/90 mmHg). Following the glucose drink, SBP and DBP decreased (SBP by 6.2 [95% CI: 5.8, 6.6] mmHg and 8.1 [7.7, 8.5] mmHg, DBP by 4.7 [4.4, 4.9] mmHg and 6.1 [5.8, 6.4] mmHg), and HR increased (by 4.3 [4.0, 4.5] bpm and 2.6 [2.4, 2.9] bpm) at 1 and 2 h (P < 0.001 for all), with only 30.9% and 27.0% of the study population having high BP at 1 and 2 h, respectively. After adjustment for age and sex distribution, 19.9% of the general population was estimated to have PPH. Postprandial hypotension was associated with an increased risk of combined cardiovascular disease and stroke.ConclusionIngestion of a 75 g glucose drink often lowers BP, frequently leading to PPH and influencing the detection of hypertension. Accordingly, guidelines for measurements of BP and interpretation of outcomes should consider the potential impact of meal ingestion on BP.</p
Advances in the recombinase polymerase amplification platform for urogenital schistosomiasis diagnosis (ShDraI-RPA) towards implementation at the point-of-care
Get PDFAccurate diagnosis of schistosomiasis is crucial to achieve disease elimination as a public health problem. Rapid and highly sensitive diagnostic tools that can be used in decentralized environments and/or at the point-of-care are needed. This work optimises and simplifies an existing isothermal molecular diagnostic platform (recombinase polymerase amplification, RPA) for urogenital schistosomiasis, the ShDraI-RPA, with a focus on delivering a more accurate diagnosis in endemic settings. The standard ShDraI-RPA oligonucleotides were modified, incorporating a phosphorothioate backbone into the reverse primer and inverting the probe fluorophore and quencher, to prevent false positive results due to secondary structure formation. The sensitivity and specificity of the modified assay were evaluated on a donor urine spiked with one S. haematobium egg and an array of other schistosomes and human urinary tract pathogens. The stability of RPA reagents was assessed by storing them at ambient temperature (± 27 °C) in a dark environment for up to 90 days. Sample preparations were explored to develop a simple, rapid and low resource methodology that would complement the ShDraI-RPA platform when used in remote settings. The modified ShDraI-RPA assay was robust, sensitive and specific to S. haematobium group species, detecting down to 10 fg of gDNA and ten synthetic Dra I copies. DNA amplification was achieved at 42 °C within 20 min and results could easily be visualized using a portable fluorometer or under blue light. RPA reagents remained stable when stored in the absence of light at ± 27 °C for up to 30 days. A two-step DNA extraction method proved optimal for extracting DNA from single S. haematobium eggs in spiked urine. The optimized ShDraI-RPA platform shows improved specificity and sensitivity and has now reached several of the target product profile requirements set out by the WHO for the ideal diagnostic test for schistosomiasis.</p