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Changes in the inflow of water into the Thamalakane River had been predicted to alter snail population dynamics and influence the risk of schistosomiasis transmission in Maun. We determined the abu...

Introduction Ebola virus (EBOV), species Zaire ebolavirus, may persist in the semen of male survivors of Ebola virus disease (EVD). We conducted a study of male survivors of the 2014–2016 EVD outbreak in Liberia and evaluated their immune responses to EBOV. We report here findings from the serologic testing of blood for EBOV-specific antibodies, molecular testing for EBOV in blood and semen, and serologic testing of peripheral blood mononuclear cells (PBMCs) in a subset of study participants. Methods We tested for EBOV RNA in blood by quantitative reverse transcription polymerase chain reaction (qRT-PCR), and for anti-EBOV-specific immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies by enzyme-linked immunosorbent assay (ELISA) for 126 study participants. We performed PBMC analysis on a subgroup of 26 IgG-negative participants. Results All 126 participants tested negative for EBOV RNA in blood by qRT-PCR. The blood of 26 participants tested negative for EBOV-specific IgG antibodies by ELISA. PBMCs were collected from 23/26 EBOV IgG-negative participants. Of these, 1/23 participants had PBMCs that produced anti-EBOV-specific IgG antibodies upon stimulation with EBOV-specific glycoprotein (GP) and nucleoprotein (NP) antigens. Conclusions The blood of EVD survivors, collected when they did not have symptoms meeting the case definition for acute or relapsed EVD, is unlikely to pose a risk for EBOV transmission. We identified 1 IgM/IgG negative participant who had PBMCs that produced anti-EBOV-specific antibodies upon stimulation. Immunogenicity following acute EBOV infection may exist along a spectrum, and absence of antibody response should not be exclusionary in determining an individual’s status as a survivor of EVD.

This study aimed to explore the effects of parasitic infections, demographic, and contextual factors on verbal memory and learning potential. Applying a cross sectional, experimental, and comparati...

The structure of the first ubiquitin-associated domain from HHR23A, UBA(1), was determined by X-ray crystallography at 1.60 Å resolution, and its stability, folding kinetics and residual structure under denaturing conditions have been investigated. The concentration dependence of thermal denaturation and size-exclusion chromatography indicate that UBA(1) is monomeric. Guanidine hydrochloride (GdnHCl) denaturation experiments reveal that the unfolding free energy, ΔG(u)°′(H(2)O), of UBA(1) is 2.4 kcal mol(−1). Stopped-flow folding kinetics indicates sub-millisecond folding with only proline isomerization phases detectable at 25 °C. The full folding kinetics are observable at 4 °C, yielding a folding rate constant, k(f), in the absence of denaturant of 13,000 s(−1) and a Tanford β-value of 0.80, consistent with a compact transition state. Evaluation of secondary structure via circular dichroism shows that residual helical structure in the denatured state is replaced by polyproline II structure as GdnHCl concentration increases. Analysis of NMR secondary chemical shifts for backbone (15)NH, (13)CO, and (13)Cα atoms between 4 and 7 M GdnHCl shows three islands of residual helical secondary structure that align in sequence with the three native-state helices. Extrapolation of the NMR data to 0 M GdnHCl demonstrates that helical structure would populate to 17 – 33% in the denatured state under folding conditions. Comparison with NMR data for a peptide corresponding to helix 1 indicates that this helix is stabilized by transient tertiary interactions in the denatured state of UBA(1). The high helical content in the denatured state, which is enhanced by transient tertiary interactions, suggests a diffusion-collision folding mechanism.

Background Long-term persistence of Ebola virus (EBOV) in immunologically privileged sites has been implicated in recent outbreaks of Ebola virus disease (EVD) in Guinea and the Democratic Republic of Congo. This study was designed to understand how the acute course of EVD, convalescence, and host immune and genetic factors may play a role in prolonged viral persistence in semen. Methods A cohort of 131 male EVD survivors in Liberia were enrolled in a case-case study. “Early clearers” were defined as those with 2 consecutive negative EBOV semen test results by real-time reverse-transcription polymerase chain reaction (rRT-PCR) ≥2 weeks apart within 1 year after discharge from the Ebola treatment unit or acute EVD. “Late clearers” had detectable EBOV RNA by rRT-PCR >1 year after discharge from the Ebola treatment unit or acute EVD. Retrospective histories of their EVD clinical course were collected by questionnaire, followed by complete physical examinations and blood work. Results Compared with early clearers, late clearers were older (median, 42.5 years; P < .001) and experienced fewer severe clinical symptoms (median 2, P = .006). Late clearers had more lens opacifications (odds ratio, 3.9 [95% confidence interval, 1.1–13.3]; P = .03), after accounting for age, higher total serum immunoglobulin G3 (IgG3) titers (P = .005), and increased expression of the HLA-C*03:04 allele (0.14 [.02–.70]; P = .007). Conclusions Older age, decreased illness severity, elevated total serum IgG3 and HLA-C*03:04 allele expression may be risk factors for the persistence of EBOV in the semen of EVD survivors. EBOV persistence in semen may also be associated with its persistence in other immunologically protected sites, such as the eye.

Timely uptake of Antiretroviral therapy considerably improves the health of people living with the Human Immunodeficiency virus. We conducted a cross-sectional study of newly HIV diagnosed individuals in four clinics in eThekwini municipality, KwaZulu-Natal. Data was collected between June 2020 and December 2020. Participants completed an interviewer-administered questionnaire after HIV testing, on the day of HIV diagnosis. We evaluated factors influencing uptake of same-day ART initiation in eThekwini clinics, KwaZulu Natal, South Africa. Demographic information, health status, sexual behaviour, knowledge of universal test and treat (UTT), ART initiation uptake, and disclosure data was collected. Among the 403 participants, same-day initiation (SDI) was 69.2% (n = 279). We observed the number of sexual partners (aOR 0.35; 95% CI 0.15-0.81), HIV status of the partner (aOR 5.03; 95% CI 2.74-9.26) and knowledge of UTT (aOR 1.97; 95% CI 1.34-2.90) were identified as major factors influencing uptake of same-day ART initiation. More strategies are needed to achieve the SDI uptake within the framework of UTT.

Background Treatment and control of hypertension are associated with a substantial reduction in adverse cardiovascular disease outcomes. Although South Africa aims to reduce the burden of cardiovascular diseases, there is limited evidence on the hypertension care cascade (HCC) performance in rural areas where stroke and hypertension are high. This study estimated HCC performance and identified predictors of hypertension screening among adults in the Ingwavuma community of KwaZulu-Natal, South Africa. Methods This was a cross-sectional study. Data were collected using the WHO STEPwise approach to surveillance (STEPS) questionnaire from 400 adult participants, excluding pregnant women and those with physical or cognitive impairments. Three hundred and ninety-three participants had complete data, and 131 had high blood pressure. We calculated progression rates for screening, diagnosis, treatment and control of hypertension from the sub-sample of participants with high blood pressure and assessed the bivariate association between HCC stages and participant characteristics and their effect sizes. We used binary and multivariable logistic regression to identify predictors of hypertension screening. Results Eighty-eight per cent of participants reported prior screening for hypertension. However, only 53.5% of patients under pharmacological treatment for hypertension had controlled blood pressure. In bivariate regression, employed participants were 80.3% (COR = 0.197, 95% CI [0.042–0.921]) more likely to be screened. In multivariable regression, the likelihood of hypertension screening was 82.4% (AOR = 0.176, 95% CI [0.047–0.655]) lower among participants in a cohabiting union than single participants. Similarly, employed participants were 87.4% (AOR = 0.129, 95% CI [0.017–0.952]) less likely to be screened than their unemployed counterparts. Conclusions The considerable attrition from the HCC across socio-demographic categories indicates a need for community-wide interventions. Empowering health care workers for community-based health promotion and hypertension management through point-of-care diagnostic tools could improve HCC performance. Efforts to improve the HCC should also focus on social determinants of health, notably gender and formal educational attainment.

Background With ambitious targets to eliminate lymphatic filariasis over the coming years, there is a need to identify optimal strategies to achieve them in areas with different baseline prevalence and stages of control. Modelling can assist in identifying what data should be collected and what strategies are best for which scenarios. Methods We develop a new individual-based, stochastic mathematical model of the transmission of lymphatic filariasis. We validate the model by fitting to a first time point and predicting future timepoints from surveillance data in Kenya and Sri Lanka, which have different vectors and different stages of the control programme. We then simulate different treatment scenarios in low, medium and high transmission settings, comparing once yearly mass drug administration (MDA) with more frequent MDA and higher coverage. We investigate the potential impact that vector control, systematic non-compliance and different levels of aggregation have on the dynamics of transmission and control. Results In all settings, increasing coverage from 65 to 80 % has a similar impact on control to treating twice a year at 65 % coverage, for fewer drug treatments being distributed. Vector control has a large impact, even at moderate levels. The extent of aggregation of parasite loads amongst a small portion of the population, which has been estimated to be highly variable in different settings, can undermine the success of a programme, particularly if high risk sub-communities are not accessing interventions. Conclusion Even moderate levels of vector control have a large impact both on the reduction in prevalence and the maintenance of gains made during MDA, even when parasite loads are highly aggregated, and use of vector control is at moderate levels. For the same prevalence, differences in aggregation and adherence can result in very different dynamics. The novel analysis of a small amount of surveillance data and resulting simulations highlight the need for more individual level data to be analysed to effectively tailor programmes in the drive for elimination. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1152-3) contains supplementary material, which is available to authorized users.

Rhodopseudomonas palustris cytochrome c', a four-helix bundle, and the second ubiquitin-associated domain, UBA(2), a three-helix bundle from the human homologue of yeast Rad23, HHR23A, deviate from random coil behavior under denaturing conditions in a fold-specific manner. The random coil deviations in each of these folds occur near interhelical turns and loops in their tertiary structures. Here, we examine an additional three-helix bundle with an identical fold to UBA(2), but a highly divergent sequence, the first ubiquitin-associated domain, UBA(1), of HHR23A. We use histidine-heme loop formation methods, employing eight single histidine variants, to probe for denatured state conformational bias of a UBA(1) domain fused to the N-terminus of iso-1-cytochrome c (iso-1-Cytc). Guanidine hydrochloride (GuHCl) denaturation shows that the iso-1-Cytc domain unfolds first, followed by the UBA(1) domain. Denatured state (4 and 6 M GuHCl) histidine-heme loop formation studies show that as the size of the histidine-heme loop increases, loop stability decreases, as expected for the Jacobson-Stockmayer relationship. However, loops formed with His35, His31, and His15, of UBA(1), are 0.6-1.1 kcal/mol more stable than expected from the Jacobson-Stockmayer relationship, confirming the importance of deviations of the denatured state from random coil behavior near interhelical turns of helical domains for facilitating folding to the correct topology. For UBA(1) and UBA(2), hydrophobic clusters on either side of the turns partially explain deviations from random coil behavior; however, helix capping also appears to be important.

Background The prevalence of allergic diseases is increasing in Zimbabwe and the data relate to local as well as exotic allergen sources. As entomophagy, the practice of eating insects, is a recognised source of local allergens, we sought to measure the prevalence of and risk factors for sensitisation to Imbrasia belina (mopane worm), a popular edible insect. This was investigated alongside other locally relevant allergens in a rural community in Gwanda district, south of Zimbabwe. Methods A cross sectional study was conducted among 496 adults and children aged 10 years and above in Gwanda district, a mopane worm harvesting area in Zimbabwe. Data on individual characteristics and mopane worm exposure factors were collected using questionnaires. Sensitivity to allergens was assessed by performing skin prick tests at a local clinic using 10 different commercial allergen extracts (Stallergenes, France) and in-house extracts of mopane worm (Imbrasia belina) and mopane leaves (Colophospermum mopane). Data were analysed using Stata version 13 software. Results The prevalence of sensitisation to at least one allergen was 31.17% (n = 144). The prevalence of atopy was higher in adults (33.33%) than in children (23.53%) (p = 0.059). The commonest inhalant allergen sources were mopane worm (14.29%), Tyrophagus putrescentiae (14.29%), mopane leaves (13.42%), Alternaria alternata (6.49%) and Dermatophagoides pteronyssinus (6.49%). Polysensitisation was demonstrated in the study population and of the 108 participants (75%) who were sensitised to two or more allergens, 66 (61%) were women. Sensitisation to mopane worm and mopane leaves often clustered with Tyrophagus putrescentiae amongst adults. Adjusted logistic regression analyses between mopane worm sensitisation and self-reported exposure variables showed that sensitisation was more likely amongst mopane worm harvesters (OR = 1.92, 95%CI = 0.77–4.79), those who cooked or roasted mopane worms during harvesting (OR = 2.69, 95%CI = 0.78–9.31) and harvesting without personal protective equipment (PPE) (OR = 2.12, 95%CI = 0.83–5.44) compared to non-harvesters. Conclusion Atopic sensitization was common in this mopane worm harvesting community in Gwanda district of Zimbabwe. There was frequent co-sensitisation of mopane worm and mopane leaves with Tyrophagus putrescentiae in children and adults. It is important to determine the clinical relevance of our findings, particularly relating to mopane worm sensitisation.

Schistosomiasis affects more than 4 million school-aged children in Zambia, mostly in rural communities due to unsafe water and inadequate sanitation facilities. Although several studies were done in Zambia between 1976 and 2019, empirical estimates of the disease burden remain unavailable. Therefore, appraisal of the current schistosomiasis burden is pertinent in the re-evaluation of schistosomiasis-control strategies in Zambia. A random-effect model was used to estimate the prevalence of schistosomiasis infection in Zambia across different age groups for the period between 1976 and 2019. A literature search was done in the following databases: PubMed, ISI Web of Science, Google Scholar, CINAHL, and African Journals Online. Twenty-eight studies with relevant prevalence data were identified and included in the analysis. The pooled prevalence estimate of Schistosoma haematobium and Schistosoma mansoni across studies for the entire period was 35.5% (95% CI: 25.8–45.9) and 34.9% (95% CI: 20.7–50.6), respectively. Prevalence estimates among school-aged children for S. haematobium and S. mansoni were 32.2% (95% CI: 21.1–44.7) and 18.1% (95% CI: 3.0–38.4), respectively. The reported pooled prevalence estimate for S. haematobium among the adults was 54% (95% CI: 23.2–83.7). Only two studies collected information from preschool aged children. Substantial heterogeneity (I2 = 100%, p < 0.0001) was observed among the studies. Although a reduction in disease prevalence was observed from 1990 to 2010, this was not sustained after 2010. In this meta-analysis, S. haematobium was more prevalent compared to S. mansoni, with more cases observed among school-aged children (SAC). Thus, control programs should target age groups that are highly infected or are at high risk of infection.

Recent disease outbreaks have demonstrated the severe health, economic and political crises that epidemics can trigger. The rate of emergence of infectious diseases is accelerating and, with deepening globalisation, pathogens are increasingly mobile. Yet the 2014–2015 West African Ebola epidemic exposed major gaps in the world’s capacity to prevent and respond to epidemics. In the midst of the world’s second largest ever recorded Ebola outbreak in the Democratic Republic of the Congo, we reflect on six of the many lessons learnt from the epidemic in West Africa, focusing on progress made and the challenges ahead in preparing for future threats. While Ebola and other emerging epidemics will remain a challenge in the years to come, by working in partnership with affected communities and across sectors, and by investing in robust health systems, it is within our power to be better prepared when they strike.

Background Asthma is a major worldwide public health problem affecting an estimated 334 million people with over 300,000 deaths annually. Twenty-two million disability-adjusted life years (DALYs) are lost annually due to asthma. The condition may present many challenges if not managed well and effectively. This systematic review will provide a comprehensive synthesis of qualitative literature regarding the challenges experienced in the management of asthma and strategies adopted to counter these challenges. The review will answer the following questions: (i) what challenges have been experienced in the treatment of asthma in Sub-Saharan Africa (SSA)? and (ii) what strategies have been used to overcome asthma treatment challenges in SSA? Methods The reviewers will search for the following databases for relevant qualitative studies: PubMed/MEDLINE, Scopus/Embase (Elsevier), EbscoHost, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Google Scholar, using the Medical Subject Headings (MeSH) and controlled vocabulary. These articles must have been published in the English language between January 2008 and December 2018. The identified papers will then be assessed for meeting eligibility criteria. Two independent reviewers will screen titles and abstracts of articles and then review the full texts of the selected research articles. Standard data extraction forms will be utilised, and the quality of the included studies will be assessed using the Joanna Briggs checklist for qualitative research appraisal tool. Results from eligible articles will be qualitatively synthesised using the framework synthesis approach and reported according to the Enhancing transparency in reporting the synthesis of qualitative research (ENTREQ) statement. Discussion This systematic review will provide an overview of reported challenges in the treatment of asthma in Sub-Saharan Africa from 2008 to 2018. The review is expected to provide information that will help form the basis for future research, policy development and practice in treatment of asthma. Systematic review registration PROSPERO CRD42018095802 Electronic supplementary material The online version of this article (10.1186/s13643-019-1068-7) contains supplementary material, which is available to authorized users.

Background Despite efforts to control neglected tropical diseases (NTDs), schistosomiasis and soil-transmitted helminthiases remain widely prevalent in sub-Saharan Africa. Recent data suggest that these infections are prevalent among preschool aged children (PSAC) in poor communities. Evidence of schistosomiasis and soil-transmitted helminths (STH) infection patterns and prevalence among PSAC is essential for effective treatment and control programmes. The aim of the study was to determine the prevalence, intensity and risk factors of schistosomiasis and STH infection among PSAC in the Ingwavuma area of uMkhanyakude District, South Africa. Methods A cross-sectional study was conducted among 1143 PSAC aged 1–5 years in 34 preschools and early childhood development (ECD) centres. Data on risk factors was collected using a semi-structured questionnaire. A Kruskal–Wallis test was used to compare the differences in infection intensity with age. Pearson Chi-square test and multivariate logistic regression were performed to assess the association between PSAC infection status, sociodemographic, household, water and sanitation variables and hygiene practices of PSAC and their caregivers. Results We observed a low prevalence of Schistosoma haematobium (1.0%) and S. mansoni (0.9%). The prevalence of Ascaris lumbricoides (18.3%) was high compared to Trichuris trichiura (1.2%), hookworms (1.6%) and Taenia (6.4%). The odds of schistosome infection were lowest among PSAC under younger (15–24 years) caregivers (0.1, 95% CI: 0.02–0.54) and those who used tap water (0.3, 95% CI: 0.09–0.78) for domestic purposes. Schistosome infection was however higher among PSAC who bathed in river water (17.4, 95% CI: 5.96–51.04). STH infection on the other hand was lowest among PSAC who did not play in soil (0.1, 95% CI: 0.51–0.28), were from households that used tap water for domestic purposes (0.5, 95% CI: 0.27–0.80) and PSAC under the care of younger (25–35 years) caregivers (0.3, 95% CI: 0.10–0.75). The risk of STH infection was highest among PSAC who did not wash their hands with soap (3.5, 95% CI: 1.04–11.67) and PSAC whose nails were not trimmed (3.6, 95% CI: 1.75–7.26). Conclusions The findings show low prevalence and infection intensity of schistosomiasis and STH infection except A. lumbricoides among PSAC. Factors predicting schistosomiasis and STH infection among PSAC were related to caregivers’ age, educational status, water and hygiene practices. STH infection was exclusively associated with PSAC playing and handwashing habits. These findings highlight the need to include PSAC caregivers in schistosomiasis and STH prevention and control programmes. Electronic supplementary material The online version of this article (10.1186/s40249-019-0561-5) contains supplementary material, which is available to authorized users.

Male genital schistosomiasis (MGS) may result in eggs lodged in the prostate causing persistent inflammation that may play a major role in prostate carcinogenesis. Globally, prostate cancer (PCa) is one of the most common cancers and the global distribution of PCa overlaps with that of schistosomiasis infections, suggesting a probable causal relationship. Objectives of this review were to assess evidence of co-existence of schistosomiasis and PCa and possible causal association between the two diseases. Relevant literature published between 1950 and 2019 yielded 20 publications on schistosomiasis and PCa co-existence. Schistosoma (S.) haematobium and S. mansoni were associated with MGS manifestation and mostly prostate adenocarcinoma diagnosis. Effects of prostatic MGS infection progressed over time with high Schistosoma egg burden thought to contribute to the development of PCa. Causal association and mechanistic pathways of MGS on PCa development and the role of Schistosoma eggs on the development of PCa remains unestablished.

Background Snakebite has become better recognized as a significant cause of death and disability in Sub-Saharan Africa, but the health economic consequences to victims and health infrastructures serving them remain poorly understood. This information gap is important as it provides an evidence-base guiding national and international health policy decision making on the most cost-effective interventions to better manage snakebite. Here, we assessed hospital-based data to estimate the health economic burden of snakebite in three regions of Burkina Faso (Centre-Ouest, Hauts Bassins and Sud-Ouest). Methodology Primary data of snakebite victims admitted to regional and district health facilities (eg, number of admissions, mortality, hospital bed days occupied) was collected in three regions over 17 months in 2013/14. The health burden of snakebite was assessed using Disability-Adjusted Life Years (DALYs) calculations based upon hospitalisation, mortality and disability data from admitted patients amongst other inputs from secondary sources (eg, populations, life-expectancy and age-weighting constants). An activity-based costing approach to determine the direct cost of snake envenoming included unit costs of clinical staff wages, antivenom, supportive care and equipment extracted from context-relevant literature. Findings The 10,165 snakebite victims admitted to hospital occupied 28,164 hospital bed days over 17 months. The annual rate of hospitalisation and mortality of admitted snakebite victims was 173 and 1.39/100,000 population, respectively. The estimated annual (i) DALYs lost was 2,153 (0.52/1,000) and (ii) cost to hospitals was USD 506,413 (USD 49/hospitalisation) in these three regions of Burkina Faso. These costs appeared to be influenced by the number of patients receiving antivenom (10.90% in total) in each area (highest in Sud-Ouest) and the type of health facility. Conclusion The economic burden of snake envenoming is primarily shouldered by the rural health centres closest to snakebite victims–facilities that are typically least well equipped or resourced to manage this burden. Our study highlights the need for more research in other regions/countries to demonstrate the burden of snakebite and the socioeconomic benefits of its management. This evidence can guide the most cost-effective intervention from government and development partners to meet the snakebite-management needs of rural communities and their health centres., Author summary The World Health Organisation has established a strategy to halve snakebite mortality and morbidity by 2030. Achieving this ambitious target within a decade will require substantial investment from governments of countries most affected by snakebite. The burden of snakebite however, is typically greatest in low-middle income countries with already limited health budgets. Acquiring government support to prioritise snakebite over other prevailing diseases will require evidence of the scale, causes, precise geographies and health economic impacts of snakebite. While the snakebite research community has progressed the delivery of some of these evidence types, it has been weak at providing evidence of the health economic burden of snakebite. Our hospital-based study identifies the health (Disability-Adjusted Life Years) and financial burdens of snakebite to three districts of Burkina Faso. We argue that funding of more health economic research, performed at greater depth and that includes cost-effectiveness of snakebite treatment and other remedial interventions is arguably the most effective tool to advocate for the policy support and investment required of national and international health agencies to deliver WHO’s laudable 2030 target for snakebite.