Genomic evidence of contemporary hybridization between Schistosoma species.

Hybridization between different species of parasites is increasingly being recognised as a major public and veterinary health concern at the interface of infectious diseases biology, evolution, epidemiology and ultimately control. Recent research has revealed that viable hybrids and introgressed lineages between Schistosoma spp. are prevalent across Africa and beyond, including those with zoonotic potential. However, it remains unclear whether these hybrid lineages represent recent hybridization events, suggesting hybridization is ongoing, and/or whether they represent introgressed lineages derived from ancient hybridization events. In human schistosomiasis, investigation is hampered by the inaccessibility of adult-stage worms due to their intravascular location, an issue which can be circumvented by post-mortem of livestock at abattoirs for Schistosoma spp. of known zoonotic potential. To characterise the composition of naturally-occurring schistosome hybrids, we performed whole-genome sequencing of 21 natural livestock infective schistosome isolates. To facilitate this, we also assembled a de novo chromosomal-scale draft assembly of Schistosoma curassoni. Genomic analyses identified isolates of S. bovis, S. curassoni and hybrids between the two species, all of which were early generation hybrids with multiple generations found within the same host. These results show that hybridization is an ongoing process within natural populations with the potential to further challenge elimination efforts against schistosomiasis.

Systematic map of recent evidence on reproductive performance of cattle in Africa.

Good cattle reproductive performance is essential for livestock productivity. Farmers are highly dependent on the success of productive outputs to support their livelihoods. In low- and middle-income countries (LMICs), however, optimal reproduction of cows and bulls is comparatively less well defined, with information on key reproductive parameters and reproductive management often not available. The aim of this study was to collate and synthesise the recent published evidence on cattle reproductive performance in selected sub-Saharan countries.Systematic mapping methodology was used, with searches conducted for both cow and bull reproductive performance in Eritrea, Ethiopia, Kenya, Nigeria, Somalia, South Sudan, Sudan, Tanzania and Uganda, for the period 2012-2022, in English language. Search returns were screened for relevance at title and abstract, and full-text levels, based on the research question criteria.A substantial number of studies were identified for cows (n = 133), but only very few for bulls (n = 11). A large proportion of reported studies have been conducted in Ethiopia, with relatively few from the other countries, and most studies published between 2014 and 2016, and in 2021. Certain reproductive parameters received more attention than others; calving interval was reported in 86 studies, while culling due to infertility was reported in eight studies.The study highlights where research is being conducted in this area, and importantly where there is a gap, in particular on bull reproductive performance. While there were a range of values reported for cow reproductive parameters, the values were reasonable, indicating that it is possible to have good reproductive performance in LMICs. The synthesis of studies in the map should help to inform farmers and their advisors, at farm and national levels.

Diverging patterns of introgression from Schistosoma bovis across S. haematobium African lineages.

Hybridization is a fascinating evolutionary phenomenon that raises the question of how species maintain their integrity. Inter-species hybridization occurs between certain Schistosoma species that can cause important public health and veterinary issues. In particular hybrids between Schistosoma haematobium and S. bovis associated with humans and animals respectively are frequently identified in Africa. Recent genomic evidence indicates that some S. haematobium populations show signatures of genomic introgression from S. bovis. Here, we conducted a genomic comparative study and investigated the genomic relationships between S. haematobium, S. bovis and their hybrids using 19 isolates originating from a wide geographical range over Africa, including samples initially classified as S. haematobium (n = 11), S. bovis (n = 6) and S. haematobium x S. bovis hybrids (n = 2). Based on a whole genomic sequencing approach, we developed 56,181 SNPs that allowed a clear differentiation of S. bovis isolates from a genomic cluster including all S. haematobium isolates and a natural S. haematobium-bovis hybrid. All the isolates from the S. haematobium cluster except the isolate from Madagascar harbored signatures of genomic introgression from S. bovis. Isolates from Corsica, Mali and Egypt harbored the S. bovis-like Invadolysin gene, an introgressed tract that has been previously detected in some introgressed S. haematobium populations from Niger. Together our results highlight the fact that introgression from S. bovis is widespread across S. haematobium and that the observed introgression is unidirectional.

Genomic analysis of a parasite invasion: Colonization of the Americas by the blood fluke Schistosoma mansoni.

Schistosoma mansoni, a snail-borne, blood fluke that infects humans, was introduced into the Americas from Africa during the Trans-Atlantic slave trade. As this parasite shows strong specificity to the snail intermediate host, we expected that adaptation to South American Biomphalaria spp. snails would result in population bottlenecks and strong signatures of selection. We scored 475,081 single nucleotide variants in 143 S. mansoni from the Americas (Brazil, Guadeloupe and Puerto Rico) and Africa (Cameroon, Niger, Senegal, Tanzania, and Uganda), and used these data to ask: (i) Was there a population bottleneck during colonization? (ii) Can we identify signatures of selection associated with colonization? (iii) What were the source populations for colonizing parasites? We found a 2.4- to 2.9-fold reduction in diversity and much slower decay in linkage disequilibrium (LD) in parasites from East to West Africa. However, we observed similar nuclear diversity and LD in West Africa and Brazil, suggesting no strong bottlenecks and limited barriers to colonization. We identified five genome regions showing selection in the Americas, compared with three in West Africa and none in East Africa, which we speculate may reflect adaptation during colonization. Finally, we infer that unsampled populations from central African regions between Benin and Angola, with contributions from Niger, are probably the major source(s) for Brazilian S. mansoni. The absence of a bottleneck suggests that this is a rare case of a serendipitous invasion, where S. mansoni parasites were pre-adapted to the Americas and able to establish with relative ease.

Precision mapping of snail habitat provides a powerful indicator of human schistosomiasis transmission.

Recently, the World Health Organization recognized that efforts to interrupt schistosomiasis transmission through mass drug administration have been ineffective in some regions; one of their new recommended strategies for global schistosomiasis control emphasizes targeting the freshwater snails that transmit schistosome parasites. We sought to identify robust indicators that would enable precision targeting of these snails. At the site of the world's largest recorded schistosomiasis epidemic-the Lower Senegal River Basin in Senegal-intensive sampling revealed positive relationships between intermediate host snails (abundance, density, and prevalence) and human urogenital schistosomiasis reinfection (prevalence and intensity in schoolchildren after drug administration). However, we also found that snail distributions were so patchy in space and time that obtaining useful data required effort that exceeds what is feasible in standard monitoring and control campaigns. Instead, we identified several environmental proxies that were more effective than snail variables for predicting human infection: the area covered by suitable snail habitat (i.e., floating, nonemergent vegetation), the percent cover by suitable snail habitat, and size of the water contact area. Unlike snail surveys, which require hundreds of person-hours per site to conduct, habitat coverage and site area can be quickly estimated with drone or satellite imagery. This, in turn, makes possible large-scale, high-resolution estimation of human urogenital schistosomiasis risk to support targeting of both mass drug administration and snail control efforts.

Ancient Hybridization and Adaptive Introgression of an Invadolysin Gene in Schistosome Parasites.

Introgression among parasite species has the potential to transfer traits of biomedical importance across species boundaries. The parasitic blood fluke Schistosoma haematobium causes urogenital schistosomiasis in humans across sub-Saharan Africa. Hybridization with other schistosome species is assumed to occur commonly, because genetic crosses between S. haematobium and livestock schistosomes, including S. bovis, can be staged in the laboratory, and sequencing of mtDNA and rDNA amplified from microscopic miracidia larvae frequently reveals markers from different species. However, the frequency, direction, age, and genomic consequences of hybridization are unknown. We hatched miracidia from eggs and sequenced the exomes from 96 individual S. haematobium miracidia from infected patients from Niger and the Zanzibar archipelago. These data revealed no evidence for contemporary hybridization between S. bovis and S. haematobium in our samples. However, all Nigerien S. haematobium genomes sampled show hybrid ancestry, with 3.3-8.2% of their nuclear genomes derived from S. bovis, providing evidence of an ancient introgression event that occurred at least 108-613 generations ago. Some S. bovis-derived alleles have spread to high frequency or reached fixation and show strong signatures of directional selection; the strongest signal spans a single gene in the invadolysin gene family (Chr. 4). Our results suggest that S. bovis/S. haematobium hybridization occurs rarely but demonstrate profound consequences of ancient introgression from a livestock parasite into the genome of S. haematobium, the most prevalent schistosome species infecting humans.

Genetic diversity of Biomphalaria pfeifferi, the intermediate host of Schistosoma mansoni in Shamva district, Zimbabwe: role on intestinal schistosomiasis transmission.

The fresh water snail Biomphalaria pfeifferi is the intermediate host for Schistosoma mansoni, which causes human intestinal schistosomiasis in Zimbabwe. Despite the medical importance of this intermediate host, there are no current data on its molecular characterization in Zimbabwe. In 2016, human water contact sites were identified in four communities in Madziwa area, Shamva district, Zimbabwe. The survey sites were recorded and mapped using a global positioning system. A 655 bp region of the mitochondrial cytochrome oxidase subunit I gene was amplified in 70 B. pfeifferi snails. The sequence data were analysed to determine the relationships between the individual snails, their inter, intra population diversity and structure. Overall, four unique cox1 haplotypes, with a haplotype diversity of 0.608, were identified in the snails. One haplotype spanned across most of the sites. There was no clear geographical clustering of haplotypes. The mean diversity among the haplotypes was very low (0.009), while the net divergence among the collection sites ranged from 0.000 to 0.026. The diversity within and between the sites was 0.017 and 0.012 respectively. This data advances our knowledge of the understanding of the population structure of B. pfeifferi in Madziwa area, Zimbabwe, with the high occurrence of one haplotype indicating the possibility of a recent bottleneck followed by population expansion. The population genetic structure of B. pfeifferi snails described here has provided an opportunity to investigate the contribution of snail genetics to variation in disease burden; and development of control strategies that exploit genetic differences in susceptibility to parasites.

Analytical and Clinical Assessment of a Portable, Isothermal Recombinase Polymerase Amplification (RPA) Assay for the Molecular Diagnosis of Urogenital Schistosomiasis.

Accurate diagnosis of urogenital schistosomiasis is crucial for disease surveillance and control. Routine diagnostic methods, however, lack sensitivity when assessing patients with low levels of infection still able to maintain pathogen transmission. Therefore, there is a need for highly sensitive diagnostic tools that can be used at the point-of-care in endemic areas. Recombinase polymerase amplification (RPA) is a rapid and sensitive diagnostic tool that has been used to diagnose several pathogens at the point-of-care. Here, the analytical performance of a previously developed RPA assay (RT-ShDra1-RPA) targeting the Schistosoma haematobium Dra1 genomic region was assessed using commercially synthesised S. haematobium Dra1 copies and laboratory-prepared samples spiked with S. haematobium eggs. Clinical performance was also assessed by comparing diagnostic outcomes with that of a reference diagnostic standard, urine-egg microscopy. The RT-ShDra1-RPA was able to detect 1 × 101 copies of commercially synthesised Dra1 DNA as well as one S. haematobium egg within laboratory-spiked ddH2O samples. When compared with urine-egg microscopy, the overall sensitivity and specificity of the RT-ShDra1-RPA assay was 93.7% (±88.7-96.9) and 100% (±69.1-100), respectively. Positive and negative predictive values were 100% (±97.5-100) and 50% (±27.2-72.8), respectively. The RT-ShDra1-RPA therefore shows promise as a rapid and highly sensitive diagnostic tool able to diagnose urogenital schistosomiasis at the point-of-care.

Development of a Molecular Snail Xenomonitoring Assay to Detect Schistosoma haematobium and Schistosoma bovis Infections in their Bulinus Snail Hosts.

Schistosomiasis, a neglected tropical disease of medical and veterinary importance, transmitted through specific freshwater snail intermediate hosts, is targeted for elimination in several endemic regions in sub-Saharan Africa. Multi-disciplinary methods are required for both human and environmental diagnostics to certify schistosomiasis elimination when eventually reached. Molecular xenomonitoring protocols, a DNA-based detection method for screening disease vectors, have been developed and trialed for parasites transmitted by hematophagous insects, such as filarial worms and trypanosomes, yet few have been extensively trialed or proven reliable for the intermediate host snails transmitting schistosomes. Here, previously published universal and Schistosoma-specific internal transcribed spacer (ITS) rDNA primers were adapted into a triplex PCR primer assay that allowed for simple, robust, and rapid detection of Schistosoma haematobium and Schistosoma bovis in Bulinus snails. We showed this two-step protocol could sensitively detect DNA of a single larval schistosome from experimentally infected snails and demonstrate its functionality for detecting S. haematobium infections in wild-caught snails from Zanzibar. Such surveillance tools are a necessity for succeeding in and certifying the 2030 control and elimination goals set by the World Health Organization.

Occurrence of Schistosoma bovis on Pemba Island, Zanzibar: implications for urogenital schistosomiasis transmission monitoring.

The causative agent of urogenital schistosomiasis, Schistosoma haematobium, was thought to be the only schistosome species transmitted through Bulinus snails on Unguja and Pemba Island (Zanzibar, United Republic of Tanzania). For insights into the environmental risk of S. haematobium transmission on Pemba Island, malacological surveys collecting Bulinus globosus and B. nasutus, two closely related potential intermediate hosts of S. haematobium were conducted across the island in November 2016. Of 1317 B. globosus/B. nasutus collected, seven B. globosus, identified through sequencing a DNA region of the mitochondrial cytochrome oxidase subunit 1 (cox1), were observed with patent infections assumed to be S. haematobium. However, when the collected cercariae were identified through sequencing a region of the cox1 and the nuclear internal transcribed spacer (ITS1 + 2), schistosomes from five of these B. globosus collected from a single locality were in fact S. bovis. The identified presence of S. bovis raises concerns for animal health on Pemba, and complicates future transmission monitoring of S. haematobium. These results show the pertinence for not only sensitive, but also species-specific markers to be used when identifying cercariae during transmission monitoring, and also provide the first molecular confirmation for B. globosus transmitting S. bovis in East Africa.

Whole genome amplification and exome sequencing of archived schistosome miracidia.

Adult schistosomes live in the blood vessels and cannot easily be sampled from humans, so archived miracidia larvae hatched from eggs expelled in feces or urine are commonly used for population genetic studies. Large collections of archived miracidia on FTA cards are now available through the Schistosomiasis Collection at the Natural History Museum (SCAN). Here we describe protocols for whole genome amplification of Schistosoma mansoni and Schistosome haematobium miracidia from these cards, as well as real time PCR quantification of amplified schistosome DNA. We used microgram quantities of DNA obtained for exome capture and sequencing of single miracidia, generating dense polymorphism data across the exome. These methods will facilitate the transition from population genetics, using limited numbers of markers to population genomics using genome-wide marker information, maximising the value of collections such as SCAN.

Interrupting seasonal transmission of Schistosoma haematobium and control of soil-transmitted helminthiasis in northern and central Côte d'Ivoire: a SCORE study protocol.

BACKGROUND: To achieve a world free of schistosomiasis, the objective is to scale up control and elimination efforts in all endemic countries. Where interruption of transmission is considered feasible, countries are encouraged to implement a comprehensive intervention package, including preventive chemotherapy, information, education and communication (IEC), water, sanitation and hygiene (WASH), and snail control. In northern and central Côte d'Ivoire, transmission of Schistosoma haematobium is seasonal and elimination might be achieved. In a cluster-randomised trial, we will assess different treatment schemes to interrupt S. haematobium transmission and control soil-transmitted helminthiasis over a 3-year period. We will compare the impact of (i) arm A: annual mass drug administration (MDA) with praziquantel and albendazole before the peak schistosomiasis transmission season; (ii) arm B: annual MDA after the peak schistosomiasis transmission season; (iii) arm C: two yearly treatments before and after peak schistosomiasis transmission; and (iv) arm D: annual MDA before peak schistosomiasis transmission, coupled with chemical snail control using niclosamide. METHODS/DESIGN: The prevalence and intensity of S. haematobium and soil-transmitted helminth infections will be assessed using urine filtration and Kato-Katz thick smears, respectively, in six administrative regions in northern and central parts of Côte d'Ivoire. Once a year, urine and stool samples will be collected and examined from 50 children aged 5-8 years, 100 children aged 9-12 years and 50 adults aged 20-55 years in each of 60 selected villages. Changes in S. haematobium and soil-transmitted helminth prevalence and intensity will be assessed between years and stratified by intervention arm. In the 15 villages randomly assigned to intervention arm D, intermediate host snails will be collected three times per year, before niclosamide is applied to the selected freshwater bodies. The snail abundance and infection rates over time will allow drawing inference on the force of transmission. DISCUSSION: This cluster-randomised intervention trial will elucidate whether in an area with seasonal transmission, the four different treatment schemes can interrupt S. haematobium transmission and control soil-transmitted helminthiasis. Lessons learned will help to guide schistosomiasis control and elimination programmes elsewhere in Africa. TRIAL REGISTRATION: ISRCTN ISRCTN10926858 . Registered 21 December 2016. Retrospectively registered.

Diagnostics for schistosomiasis in Africa and Arabia: a review of present options in control and future needs for elimination.

Within the World Health Organization 2012-2020 roadmap for control and elimination of schistosomiasis, the scale-up of mass drug administration with praziquantel is set to change the epidemiological landscape across Africa and Arabia. Central in measuring progress is renewed emphasis upon diagnostics which operate at individual, community and environmental levels by assessing reductions in disease, infections and parasite transmission. However, a fundamental tension is revealed between levels for present diagnostic tools, and methods applied in control settings are not necessarily adequate for application in elimination scenarios. Indeed navigating the transition from control to elimination needs careful consideration and planning. In the present context of control, we review current options for diagnosis of schistosomiasis at different levels, highlighting several strengths and weaknesses therein. Future challenges in elimination are raised and we propose that more cost-effective diagnostics and clinical staging algorithms are needed. Using the Kingdom of Saudi Arabia as a contemporary example, embedding new diagnostic methods within the primary care health system is discussed with reference to both urogenital and intestinal schistosomiasis.

Estimating the cost of young stock mortality in livestock systems-An application to sheep farming in Ethiopia.

Introduction: In sub-Saharan Africa, pre-weaning young stock mortality (YSM) is in the order of 20 to 30% across most livestock species and production systems. High YSM has significant economic implications for livestock keepers, but few studies provide estimates of the "cost of YSM." This study explores a bio-economic herd modeling approach to estimate the "cost of YSM" at farming/livestock system level. Methods: The static zero-growth version of DYNMOD was used to calculate the annual physical and monetary output of a sheep flock consisting of 100 breeding females at different levels of lamb mortality. Production parameter values and prices were taken from recently published research. Calculations were carried out for values of lamb mortality decreasing from 30% to 0% in 5% intervals, with 20% representing the "baseline" YSM. Calculations were repeated for a "high" fertility scenario (100% vs. 59% parturition rate) to gauge the sensitivity of the cost of YSM to another parameter determining flock productivity. Results: The relation of revenue per head and YSM is close to linear over the range of analyzed YSM with 1% decrease in YSM resulting in an increase in revenue per animal of approximately 1%. At the higher fertility rate, the absolute cost of YSM to sheep farmers is higher while the relative increase in revenue per animal resulting from YSM reduction is lower. The estimated difference in revenue of the 100-ewe flock between the 20% and 0% lamb mortality scenarios (at baseline fertility) amounts to approximately USD 90 per additionally surviving lamb, which is far above its market value. Discussion: Reduced lamb mortality ultimately impacts flock revenue through increased sales of "mature" animals, which embody the value of a lamb plus the revenue/profit from raising it to marketable age/weight. The modeling results suggest that foregone profit is an important component of the systemic "cost of YSM." Consequently, expected profit per animal, in addition to its current market value, is essential for estimating the absolute cost of YSM at farming system level.

Re-assessing thermal response of schistosomiasis transmission risk: evidence for a higher thermal optimum than previously predicted.

The geographical range of schistosomiasis is affected by the ecology of schistosome parasites and their obligate host snails, including their response to temperature. Previous models predicted schistosomiasis' thermal optimum at 21.7 °C, which is not compatible with the temperature in sub-Saharan Africa (SSA) regions where schistosomiasis is hyperendemic. We performed an extensive literature search for empirical data on the effect of temperature on physiological and epidemiological parameters regulating the free-living stages of S. mansoni and S. haematobium and their obligate host snails, i.e., Biomphalaria spp. and Bulinus spp., respectively. We derived nonlinear thermal responses fitted on these data to parameterize a mechanistic, process-based model of schistosomiasis. We then re-cast the basic reproduction number and the prevalence of schistosome infection as functions of temperature. We found that the thermal optima for transmission of S. mansoni and S. haematobium range between 23.1-27.3 °C and 23.6-27.9 °C (95 % CI) respectively. We also found that the thermal optimum shifts toward higher temperatures as the human water contact rate increases with temperature. Our findings align with an extensive dataset of schistosomiasis prevalence in SSA. The refined nonlinear thermal-response model developed here suggests a more suitable current climate and a greater risk of increased transmission with future warming for more than half of the schistosomiasis suitable regions with mean annual temperature below the thermal optimum.

Re-assessing thermal response of schistosomiasis transmission risk: Evidence for a higher thermal optimum than previously predicted.

The geographical range of schistosomiasis is affected by the ecology of schistosome parasites and their obligate host snails, including their response to temperature. Previous models predicted schistosomiasis' thermal optimum at 21.7°C, which is not compatible with the temperature in sub-Saharan Africa (SSA) regions where schistosomiasis is hyperendemic. We performed an extensive literature search for empirical data on the effect of temperature on physiological and epidemiological parameters regulating the free-living stages of S. mansoni and S. haematobium and their obligate host snails, i.e., Biomphalaria spp. and Bulinus spp., respectively. We derived nonlinear thermal responses fitted on these data to parameterize a mechanistic, process-based model of schistosomiasis. We then re-cast the basic reproduction number and the prevalence of schistosome infection as functions of temperature. We found that the thermal optima for transmission of S. mansoni and S. haematobium range between 23.1-27.3°C and 23.6-27.9°C (95% CI) respectively. We also found that the thermal optimum shifts toward higher temperatures as the human water contact rate increases with temperature. Our findings align with an extensive dataset of schistosomiasis prevalence in SSA. The refined nonlinear thermal-response model developed here suggests a more suitable current climate and a greater risk of increased transmission with future warming for more than half of the schistosomiasis suitable regions with mean annual temperature below the thermal optimum.

Integrating HIV Pre-Exposure Prophylaxis (PrEP) Education During Medical Residency: Training Outcomes and Suggestions for Learning Effectiveness.

Human immunodeficiency virus (HIV) infection is now preventable with pre-exposure prophylaxis (PrEP) drugs, however, barriers to PrEP implementation include primary-care physician (PCP) knowledge-gap and lack of comfort prescribing and managing PrEP. We hypothesized that integrating HIV-PrEP education during medical-residency would help address these problems and developed a 40-minute case-based lecture focused on the 2021 United States Preventative Services Taskforce (USPSTF) oral HIV-PrEP guidelines and integrated this into our residency's core curriculum. We analyzed data from physician-trainees who voluntarily completed a pre- and post-lecture survey measuring HIV-PrEP "knowledge" and "self-assessed readiness to independently initiate and manage PrEP." Independent group analysis was completed via the Mann-Whitney U and Pearson Chi-square 2-sided test with P-value <0.05 deemed significant. Of the total of 189 residents invited to the lecture, 130 (69%) completed the pre-survey while 107 (57%) completed the post-survey. Per knowledge-assessment: the median number of correctly answered questions rose from a pre-lecture baseline of 4/9 (44%) to 8/9 (89%) following the education intervention (P < .001). When asked about comfort initiating and managing HIV-PrEP on their own, 7/130 (5.4%) responded in agreement pre-lecture, but this rose to 55/107 (51.4%) post-lecture (P < .001). Our study revealed PrEP training during residency was effective per stated objectives and may be an important tool to increase PrEP delivery/uptake to achieve the target goals for the National HIV/AIDS Strategy.

Interventions to reduce camel and small ruminant young stock morbidity and mortality in Ethiopia.

Morbidity and mortality of young stock is a challenge for livestock producers globally. In Ethiopia, where camels and small ruminants (sheep and goats) are essential smallholder and pastoral livestock, young stock losses can cause severe consequences to livelihoods. This pilot study, part of a Government-led Young Stock Mortality Reduction Consortium project, was undertaken to identify and evaluate interventions to reduce young stock mortality in mixed crop-livestock and pastoral production systems in Ethiopia. Pastoralists and mixed crop-livestock farmers were enrolled by convenience sampling across four regions. Households were sampled with questionnaire surveys to establish baseline mortality risk and prevalence of diarrhoea and respiratory disease in animals younger than one year, and followed longitudinally over a one-year period, with final evaluations conducted from March to July 2020. Mortality risk and prevalence of diarrhoea and respiratory disease before and after implementation were compared using Poisson regression models including household as random effect. Prior to intervention, median camel mortality, prevalence of diarrhoea, and respiratory disease across production systems in the different households was 0.4, 0.44 and 0.2, respectively. This compared to median pastoralist small ruminant mortality risk and prevalence of diarrhoea and respiratory disease of 0.45, 0.32 and 0.18, respectively. Post-intervention, median camel mortality, prevalence of diarrhoea and respiratory disease dropped to 0.1, 0.08 and 0. Similarly, more than half of the small ruminant households reported no mortality, and no cases of diarrhoea or respiratory disease. In camels, rate ratios of mortality risk, prevalence of diarrhoea, and respiratory disease post-intervention compared to the baseline were 0.41, 0.41 and 0.37. In small ruminants, rate ratios were 0.33, 0.35 and 0.46. All reductions were statistically significant (p < 0.01). Generally, pastoralists experienced higher mortality and disease prevalence compared to mixed crop-livestock smallholders, and the effect of intervention was slightly higher in pastoralist households. The pilot study findings demonstrated highly significant reductions in mortality and risk of diarrhoea and respiratory disease post-interventions. However, not all households benefitted from the interventions, with a few households reporting increased mortality and morbidity. Many households had very few animals which made it challenging to measure impact and the study was conducted over a single year, without a control group, so between year effects could not be accounted for in the reductions observed. These findings should contribute to improved livestock productivity in Ethiopia.

The long road to schistosomiasis elimination in Zanzibar: A systematic review covering 100 years of research, interventions and control milestones.

Zanzibar is among the few places in sub-Saharan Africa where interruption of Schistosoma transmission seems an achievable goal. Our systematic review identifies and discusses milestones in schistosomiasis research, control and elimination efforts in Zanzibar over the past 100 years. The search in online databases, libraries, and the World Health Organization Archives revealed 153 records published between May 1928 and August 2022. The content of records was summarised to highlight the pivotal work leading towards urogenital schistosomiasis elimination and remaining research gaps. The greatest achievement following 100 years of schistosomiasis interventions and research is undoubtedly the improved health of Zanzibaris, exemplified by the reduction in Schistosoma haematobium prevalence from>50% historically down to<5% in 2020, and the absence of severe morbidities. Experiences from Zanzibar have contributed to global schistosomiasis guidelines, whilst also revealing challenges that impede progression towards elimination. Challenges include: transmission heterogeneity requiring micro-targeting of interventions, post-treatment recrudescence of infections in transmission hotspots, biological complexity of intermediate host snails, emergence of livestock Schistosoma species complicating surveillance whilst creating the risk for interspecies hybridisation, insufficient diagnostics performance for light intensity infections and female genital schistosomiasis, and a lack of acceptable sanitary alternatives to freshwater bodies. Our analysis of the past revealed that much can be achieved in the future with practical implementation of integrated interventions, alongside operational research. With continuing national and international commitments, interruption of S. haematobium transmission across both islands is within reach by 2030, signposting the future demise of urogenital schistosomiasis across other parts of sub-Saharan Africa.