Predicted changes in habitat suitability for human schistosomiasis intermediate host snails for modelled future climatic conditions in KwaZulu-Natal, South Africa

Introduction: Climate change alters environmental and climatic conditions, leading to expansion or contraction and possible shifts in the geographical distribution of vectors that transmit diseases. Bulinus globosus and Biomphalaria pfeifferi are the intermediate host snails for human schistosomiasis in KwaZulu-Natal (KZN) province, South Africa.Methods: Using the Maximum entropy (MaxEnt) model, we modelled the current and future distribution of human schistosomiasis intermediate host snails in KZN using two representation concentration pathways (RCP4.5 and RCP8.5) for the year 2085. Thirteen and ten bioclimatic variables from AFRICLIM were used to model the habitat suitability for B. globosus and B. pfeifferi, respectively. The Jack-knife test was used to evaluate the importance of each bioclimatic variable.Results: Mean temperature warmest quarter (BIO10, 37.6%), the number of dry months (dm, 32.6%), mean diurnal range in temperature (BIO2, 10.8%), isothermality (BIO3, 6.7%) were identified as the top four bioclimatic variables with significant contribution to the model for predicting the habitat suitability for B. globosus. Annual moisture index (mi, 34%), mean temperature warmest quarter (BIO10, 21.5%), isothermality (BIO3, 20.5%), and number of dry months (dm, 7%) were identified as the four important variables for the habitat suitability of B. pfeifferi. Area under the curve for the receiving operating characteristics was used to evaluate the performance of the model. The MaxEnt model obtained high AUC values of 0.791 and 0.896 for B. globosus and B. pfeifferi, respectively. Possible changes in the habitat suitability for B. globosus and B. pfeifferi were observed in the maps developed, indicating shrinkage and shifts in the habitat suitability of B. pfeifferi as 65.1% and 59.7% of the current suitable habitats may become unsuitable in the future under RCP4.5 and RCP8.5 climate scenarios. Conversely, an expansion in suitable habitats for B. globosus was predicted to be 32.4% and 69.3% under RCP4.5 and RCP8.5 climate scenarios, with some currently unsuitable habitats becoming suitable in the future.Discussion: These habitat suitability predictions for human schistosomiasis intermediate host snails in KZN can be used as a reference for implementing long-term effective preventive and control strategies for schistosomiasis

Malaria incidence trends and their association with climatic variables in rural Gwanda, Zimbabwe, 2005-2015.

BACKGROUND: Malaria is a public health problem in Zimbabwe. Although many studies have indicated that climate change may influence the distribution of malaria, there is paucity of information on its trends and association with climatic variables in Zimbabwe. To address this shortfall, the trends of malaria incidence and its interaction with climatic variables in rural Gwanda, Zimbabwe for the period January 2005 to April 2015 was assessed. METHODS: Retrospective data analysis of reported cases of malaria in three selected Gwanda district rural wards (Buvuma, Ntalale and Selonga) was carried out. Data on malaria cases was collected from the district health information system and ward clinics while data on precipitation and temperature were obtained from the climate hazards group infrared precipitation with station data (CHIRPS) database and the moderate resolution imaging spectro-radiometer (MODIS) satellite data, respectively. Distributed lag non-linear models (DLNLM) were used to determine the temporal lagged association between monthly malaria incidence and monthly climatic variables. RESULTS: There were 246 confirmed malaria cases in the three wards with a mean incidence of 0.16/1000 population/month. The majority of malaria cases (95%) occurred in the > 5 years age category. The results showed no correlation between trends of clinical malaria (unconfirmed) and confirmed malaria cases in all the three study wards. There was a significant association between malaria incidence and the climatic variables in Buvuma and Selonga wards at specific lag periods. In Ntalale ward, only precipitation (1- and 3-month lag) and mean temperature (1- and 2-month lag) were significantly associated with incidence at specific lag periods (p < 0.05). DLNM results suggest a key risk period in current month, based on key climatic conditions in the 1-4 month period prior. CONCLUSIONS: As the period of high malaria risk is associated with precipitation and temperature at 1-4 month prior in a seasonal cycle, intensifying malaria control activities over this period will likely contribute to lowering the seasonal malaria incidence

Modelling the spatial and seasonal distribution of suitable habitats of schistosomiasis intermediate host snails using Maxent in Ndumo area, KwaZulu-Natal Province, South Africa

Abstract Background Schistosomiasis is a snail-borne disease endemic in sub-Saharan Africa transmitted by freshwater snails. The distribution of schistosomiasis coincides with that of the intermediate hosts as determined by climatic and environmental factors. The aim of this paper was to model the spatial and seasonal distribution of suitable habitats for Bulinus globosus and Biomphalaria pfeifferi snail species (intermediate hosts for Schistosoma haematobium and Schistosoma mansoni, respectively) in the Ndumo area of uMkhanyakude district, South Africa. Methods Maximum Entropy (Maxent) modelling technique was used to predict the distribution of suitable habitats for B. globosus and B. pfeifferi using presence-only datasets with ≥ 5 and ≤ 12 sampling points in different seasons. Precipitation, maximum and minimum temperatures, Normalised Difference Vegetation Index (NDVI), Normalised Difference Water Index (NDWI), pH, slope and Enhanced Vegetation Index (EVI) were the background variables in the Maxent models. The models were validated using the area under the curve (AUC) and omission rate. Results The predicted suitable habitats for intermediate snail hosts varied with seasons. The AUC for models in all seasons ranged from 0.71 to 1 and the prediction rates were between 0.8 and 0.9. Although B. globosus was found at more localities in the Ndumo area, there was also evidence of cohabiting with B. pfiefferi at some of the locations. NDWI had significant contribution to the models in all seasons. Conclusion The Maxent model is robust in snail habitat suitability modelling even with small dataset of presence-only sampling sites. Application of the methods and design used in this study may be useful in developing a control and management programme for schistosomiasis in the Ndumo area

Partnership Dynamics in University-Community Engagement:

Cooperation and reciprocity between university actors and community research assistants through university-community engagement has the potential to lead to knowledge creation and improved research uptake.However, there is a paucity of research on the relational dynamics and operating processes in successful partnerships between multi-disciplinary university scientists and community research assistants. This study investigated the case of the Tackling Infections to Benefit Africa (Tiba) research team based at the University of KwaZulu-Natal to identify the attributes associated with constructing and sustaining transformative university-community engagement through multi-disciplinary research teams. Data was collected by means of participant observation, ethnographic conversation interviews, and in-depth interviews with key participants including co- --mmunity research assistants and university-based researchers. The results show that organisational structure and qualities, academic principles and social qualities underpin the success of multi-disciplinary research teams. Based on the findings, we assert that dialogic interaction, respect, ‘demystification of science’ and knowledge plurality facilitate relationships between researchers and community research assistants that can aid in framing sustainable university-community engagement as a way to work with the community rather than ways to work for it. Key words: university-community engagement, social attributes, partnership dynamics, multi-disciplinary research, community research assistants &nbsp

Efficacy of praziquantel treatment regimens in pre-school and school aged children infected with schistosomiasis in sub-Saharan Africa: a systematic review

Abstract Background Schistosomiasis is a serious public health burden in sub-Saharan Africa. Praziquantel is the only drug recommended by the World Health Organization to treat both urogenital and intestinal schistosomiasis. The reliance on a single drug to treat a disease with such a huge burden has raised concerns of possible drug resistance mainly in endemic areas. This systematic review was conducted to identify gaps and recent progress on the efficacy of different regimens of praziquantel in treating schistosomiasis among children in sub-Saharan Africa where Schistosoma mansoni and S. haematobium are endemic. Main text A literature search of peer-reviewed journals was done on Google Scholar, MEDLINE (under EBSCOhost) and PubMed databases using pre-defined search terms and Boolean operators. The search included studies published from 2008 to 2017 (August) with emphasis on the efficacy of praziquantel on S. haematobium and S. mansoni infections among preschool and school children. Nineteen publications satisfied the inclusion criteria for the review. The studies reviewed were from 10 sub-Saharan African countries and 7/19 of the studies (37%) were conducted in Uganda. Seven studies (37%) focused on Schistosoma mansoni, 6/19 (31.5%) on S. haematobium and another 6 on mixed infection. A single standard dose of 40 mg/kg body weight was the most used regimen (9) followed by the repeated single standard dose assessed for efficacy at 3–4 weeks post-treatment. Conclusions A repeated standard dose of 40 mg/kg achieved satisfactory efficacy compared to a single dose against both parasite species. However, findings on efficacy of repeated doses in co-infection of S. mansoni and S. haematobium were not conclusive. Praziquantel administrated at 60 mg/kg was slightly more efficacious than the 40 mg/kg standard dose. Minor and transitory side-effects were reported for both regimens. The review indicates that further investigations are necessary to conclusively determine efficacy of praziquantel on coinfection of S. haematobium and S. mansoni to formulate concrete guidelines on the use of repeated doses at 40 or 60 mg/kg for treating schistosomiasis. We recommend the use of the egg reduction rate (ERR) formula recommended by the WHO for assessing praziquantel efficacy in order for the results to be comparable for different regions

The mediating effects of public genomic knowledge in precision medicine implementation: A structural equation model approach.

Precision medicine emphasizes predictive, preventive and personalized treatment on the basis of information gleaned from personal genetic and environmental data. Its implementation at health systems level is regarded as multifactorial, involving variables associated with omics technologies, public genomic awareness and adoption tendencies for new medical technologies. However, interrelationships of the various factors and their synergy has not been sufficiently quantified. Based on a survey of 270 participants involved in the use of molecular tests (omics-based biomarkers, OBMs), this study examined how characteristics of omics biomarkers influence precision medicine implementation outcomes (ImO) through an intermediary factor, public genomic awareness (represented by User Response, UsR). A structural equation modelling (SEM) approach was applied to develop and test a 3 latent variable mediation model; each latent variable being measured by a set of indicators ranging between three and six. Mediation analysis results confirmed a partial mediation effect (an indirect effect represented as the product of paths 'a' and 'b' (a*b)) of 0.36 at 90% confidence level, CI = [0.03, 9.94]. Results from the individual mediation paths 'a' and 'b' however, showed that these effects were negative(a = -0.38, b = -0.94). Path 'a' represents the effect of characteristics of OBMs on the mediator, UsR; 'b' represents the effect of the mediator, UsR on implementation outcomes, ImO, holding OBMs constant. The results have both theoretical and practice implications for biomedical genomics research and clinical genomics, respectively. For instance, the results imply better ways have to be devised to more effectively engage the public in addressing extended family support for extended family cascade screening, especially for monogenic hereditary conditions like BRCA-related breast cancer and colorectal cancer in Lynch syndrome families. At basic biomedical research level, results suggest an integrated biomarker development pipeline, with early consideration of factors that may influence biomarker uptake. The results are also relevant at health systems level in indicating which factors should be addressed for successful

Infection status and risk factors associated with urinary schistosomiasis among school-going children in the Ndumo area of uMkhanyakude District in KwaZulu-Natal, South Africa two years post-treatment

Objectives: To assess the efficacy of praziquantel in children infected with Schistosoma haematobium over a 2-year period in the Ndumo area of uMkhanyakude District, South Africa. Methods: This cohort study enrolled 173 school-going children in September 2017 who had participated in a baseline survey conducted in 2015 in the Ndumo area. Questionnaire interviews were conducted to collect information on the risk factors related to the transmission of schistosomiasis. The filtration technique was performed to detect Schistosoma haematobium eggs in urine. Infection intensity was classified as light or heavy. The Chi-square test was used to assess the associations between variables at the 95% confidence level, and p = 0.05 was considered significant. Results: Of the 173 participants screened 2 years post-treatment, 10 were infected. Six of these were new infection cases, while four were cases of re-infection. The intensity of infection had decreased significantly (p = 0.001) at the time of the follow-up survey compared to the baseline survey. However, no significant difference was found among the risk factors for schistosomiasis 2 years later. Conclusions: The prevalence of S. haematobium had decreased significantly in the cohort at 2 years post praziquantel treatment, during a period of persistent drought in the area. Risk factors that were significantly associated with schistosomiasis at baseline were no longer significantly associated at 2 years following treatment

A systematic review and meta-analysis quantifying schistosomiasis infection burden in pre-school aged children (PreSAC) in sub-Saharan Africa for the period 2000-2020.

IntroductionFollowing the adoption of the World Health Assembly Resolution WHA 65.21 and Neglected Tropical Diseases road map 2021-2030, schistosomiasis control programmes have shifted from morbidity control to disease elimination. However, several gaps continue to be observed in the implementation of control programmes with certain age groups omitted from these campaigns increasing health inequalities and risks of reinfections to previously treated groups. We used the Inverse Variance Heterogeneity (IVhet) model to estimate the prevalence of schistosomiasis infection among preschool-aged children.MethodsWe did a systematic review of peer-reviewed literature on schistosomiasis in sub-Saharan Africa for the period January 1, 2000 to November 30, 2020. Quantitative data for cases of schistosomiasis infection were extracted, including country and region where the studies were done, year of publication and specific schistosome species observed. The IVhet model was used to estimate the pooled prevalence estimate (PPE), the heterogeneity and publication bias.ResultsWe screened 2601 articles to obtain 47 eligible studies containing quantitative data on preschool-aged children. Of the selected studies, 44.7% (n = 22) were from East Africa while the least number of studies obtained (2.1%, n = 1) was from Central Africa. 21712 subjects were screened for infection due to Schistosoma spp; 13924 for S. mansoni and 7788 for S. haematobium. The PPE for schistosomiasis among PreSAC was 19% (95% CI: 11-28). Infection due to S. mansoni (IVhet PPE: 22% (95% CI: 9-36) was higher than that due to S. haematobium (15%; 95% CI: 6-25). A Luis Furuya-Kanamori index of 1.83 indicated a lack of publication bias. High level of heterogeneity was observed (I2 > 90%) and this could not be reduced through subgroup analysis.ConclusionSchistosomiasis infection among pre-school aged children 6 years old and below is high. This indicates the importance of including this age group in treatment programmes to reduce infection prevalence and long-term morbidities associated with prolonged schistosome infection

Evaluation of the Tanzania programme on task shifting for caesarean sections

Objectives: To critically examine the AMO program in terms of history, training, career progression, deployment, staffing, main tasks in the scheme of service, reporting structures and supervision, special rewards or incentives, regulatory authorities, professional associations and affiliations and to learn lessons that could inform the ongoing Tanzania health sector system strengthening reforms.Methods: A descriptive cross-sectional survey augmented by key informant interviews was used to collect data on the Tanzania AMO programme. Data entry and analysis was through SPSS software Version 23. Thematic content analysis was done for qualitative data obtained from key informant interviews.Results: The AMO programme was established more than 5 decades ago. The AMO deficit at district hospitals ranged between 62.5% and 68.8%. The AMO training Programme remains an in-service model that had not been upgraded to degree level. The advanced diploma awarded to AMOs is yet to be recognised by the National Council of Technical Education of Tanzania. AMOs are registered under the Medical Council of Tanganyika. There are limited advancement opportunities through the AMO grade. Continuous professional development (CPD) programme is yet to be established.Conclusion: If Tanzania should address the HRH gap at primary and secondary level of care, then the AMO programme should be reviewed in the following domains; human resources development, career and professional advancement, practice regulations and recognition by the NACTE.Keywords: Task shifting; task sharing; caesarean section, assistant medical officers; associate clinicians; clinical officers; nonphysician clinician

Challenges and Opportunities Presented by Current Techniques for Detecting Schistosome Infections in Intermediate Host Snails: A Scoping Review

Schistosomiasis, a neglected tropical disease (NTD), causes morbidity and mortality in over 250 million people globally. And 700 million people are at risk of contracting it. It is caused by a parasite of the genus Schistosoma. Freshwater snails of the family Planorbidae are of public health significance as they are intermediate hosts of these highly infective flukes. Accurate diagnostic techniques to detect schistosome infections in intermediate host snails (IHS) and environmental surveillance are needed to institute measures for the interruption of transmission and eventual elimination. We carried out a systematic review of the literature to assess advantages and limitations of different diagnostic techniques for detecting schistosome infections in snails. Literature from Scopus, Web of Science, and PubMed databases from 2008 to 2020 were searched using combinations of predefined search terms with Boolean operators. The studies revealed that conventional diagnostics are widely used, although they are labor-intensive, have low specificity and sensitivity levels, and cannot detect prepatent infections. Whereas more advanced techniques such as immunological, nucleic-acid amplification, and eDNA diagnostics have high sensitivity and specificity levels, they are costly, hence, not suitable for field applications and large-scale surveys. Our review highlights the importance of designing and developing innovative diagnostics that are high in specificity and sensitivity as well as affordable and technically feasible for use in field laboratories and for large-scale surveys