Human Schistosoma Research Articles

Human Contamination and Schistosome Infection Intensity in Bulinid and Planorbid Snail Vectors in Kadawa Irrigation Area, Kano State, Nigeria

Objectives of the Study: An Epidemiological Research, a cross-sectional study, was conducted to determine the magnitude of human contamination of irrigation canal perimeter as it relates to the prevalence and intensity of schistosome cercarial infection in snail vectors.
 Place and Duration of Study: The study was conducted along water canal located within an irrigation area, Kano River Project Phase I, Kadawa, between January and June, 2012.
 Methodology: The study area was categorized into Zone of Heavy Contamination (ZHC), Zone of Light Contamination (ZLC) and Zone of Free Contamination (ZFC) based on the density of faecal lumps observed along the canal perimeter using 1 m2 quadrat sampling technique. Snail vectors of schistosomiasis were collected from these zones, identified and subjected to cercarial shedding. Brevifurcate apharyngeate cercariae were identified as schistosome cercariae.
 Results: Of the 827 snails collected 28.54% shed schistosome cercariae. The breakdown of infection prevalence was 31.37%, 27.69% and 26.26% for ZHC, ZLC and ZFC respectively. Three snail species recovered in the study area, Bulinus globosus, B. rohlfsi and Biomphalaria pfeifferi had infection intensity of 8.6, 5.67 and 3.94 respectively, with total mean intensity of 4.67. A Chi-squared analysis did not show any significant difference in infection prevalence in the three zones (χ2cal. 0.025, χ22, 0.05 = 5.99). However, infection intensity was significantly different in the three zones and among the three snail species using analysis of variance (P<0.05).
 Conclusion: Human environmental contamination with faeces and urine around irrigation canals remains the source of infection to snail hosts and then to humans. It is presumed that contact control through avoidance of defaecation in the open and building of pit latrines near water contact points along irrigation canals will be effective means of drawing a barrier to infection with schistosomes in the study area.

Lipid Topography in Schistosoma mansoni Cryosections, Revealed by Microembedding and High-Resolution Atmospheric-Pressure Matrix-Assisted Laser Desorption/Ionization (MALDI) Mass Spectrometry Imaging.

Schistosomes are parasitic platyhelminthes that cause schistosomiasis, which is a life-threatening infectious disease for humans in the tropics and subtropics worldwide. Within the human host, female and male schistosomes develop and pair as a prerequisite for egg production. Part of the eggs get lodged in organs such as the gut, spleen, and liver, where they cause severe inflammatory processes, including liver fibrosis, which is one of the most serious pathological symptoms. High-resolution atmospheric-pressure scanning microprobe matrix-assisted laser desorption/ionization (AP-SMALDI) mass spectrometry imaging (MSI) has been used as a powerful tool to investigate adult schistosomes at the topographic molecular level. An MSI-compatible protocol was developed, covering critical sample preparation steps and focusing on obtaining artifact-free, longitudinal cryosections. Planar, consecutive sections were prepared from ∼400 μm thick S. mansoni worm couples, comparing several microembedding approaches. High-resolution MSI at both, 10 and 5 μm lateral resolution unraveled anatomical structures and differential abundances of glycerophospholipids and saccharides in females and males. In addition, glycerophospholipids occurred differentially abundant in worm tissues of the female, such as the gut, which is essential for nutrient uptake and subsequent metabolism. Fragment ions of isobaric phospholipids were investigated by on-tissue MS2 imaging experiments, unambiguously showing isomer-specific ion signals. This study provides a solid basis for investigating schistosome parasites in chemical detail at the whole-worm level by MSI.

Influence of physicochemical parameters on the spatial distribution of snail species that are intermediate hosts of human schistosomes in the Senegal River Delta.

The objective of this work was to identify possible correlations between physicochemical parameters (water temperature, water flow velocity, electrical conductivity, dissolved oxygen, salinity, pH, nitrates, and phosphates) and the spatial distribution in the Senegal River delta of snail species that are intermediate hosts of human schistosomes. Eight water points (ME1 to ME4, NE1 and NE2, TA1 and TA2) were selected in the villages of Menguègne Boye, Ndellé Boye, and Thilla for biweekly monitoring of these snails and the physicochemical parameters of the water. The results show that the spatial distribution of the snail populations is related to pH, dissolved oxygen (mg/l), conductivity, temperature (̊C), and water flow velocity (m/s).

The diverse echinostomes from East Africa: With a focus on species that use Biomphalaria and Bulinus as intermediate hosts

Echinostomes are a diverse group of digenetic trematodes that are globally distributed. The diversity of echinostomes in Africa remains largely unknown, particularly in analyses using molecular markers. Therefore, we were interested in the composition and host usage patterns of African echinostomes, especially those that also use schistosome transmitting snails as intermediate hosts. We collected adults and larval stages of echinostomes from 19 different localities in East Africa (1 locality in Uganda and 18 in Kenya). In this study we provide locality information, host use, museum vouchers, and genetic data for two loci (28S and nad1) from 98 samples of echinostomes from East Africa. Combining morphological features, host use information, and phylogenetic analyses we found 17 clades of echinostomes in East Africa. Four clades were found to use more than one genus of freshwater snails as their first intermediate hosts. We also determined at least partial life cycles (2 of the 3) of four clades using molecular markers. Of the 17 clades, 13 use Biomphalaria or Bulinus as a first intermediate host. The overlap in host usage creates opportunities for competition, including against human schistosomes. Thus, our study can be used as a foundation for future studies to ascertain the interactions between schistosomes and echinostomes in their respective intermediate hosts.

Biological activity of artemisinin-naphthoquine phosphate on Schistosoma haematobium stages and the vector Bulinus truncatus.

Schistosoma haematobium infection is a major public health problem in most of Africa and the Middle East and praziquantel remains the only drug used for schistosomiasis control, therefore emergence of drug resistance is unavoidable. The antimalarial artemisinin-naphthoquine phosphate combination (co-ArNp) was recently documented to have promising effects on Schistosoma mansoni and its snail host. We conducted this in vitro study to assess the bioactivity of co-ArNp on S. haematobium and its snail vector Bulinus truncatus. Treatment of S. haematobium worms with 1 μg/ml co-ArNp for 24 h reduced worm motility, while 20 μg/ml resulted in 25-100% mortality of adult flukes within 48-72 h. Incubation of S. haematobium miracidia and cercariae with the molluscicidal co-ArNp (50% lethal concentration 7.5 μg/ml) killed all the free larval stages within 40 and 15 min, respectively. Also, exposure of B. truncatus adult snails to 20 ppm of the combined regimen caused a mortality rate of 100% within 24 h. Co-ArNp therapy has also shown encouraging activity against the other major human schistosome, S. haematobium, as well as its vector.

Gene Expression Differences in Host Response to Schistosoma haematobium Infection.

Schistosome worms infect over 200 million people worldwide. They live in the host's bloodstream and alter host immunity. Epidemiological data suggest that males and females have different responses to schistosome infection, but the effect of sex on systemic response is undetermined. Our objective was to characterize differences in peripheral blood transcriptional profiles in people with or without active Schistosoma haematobium infection and to determine whether this signature differs between males and females. mRNA was isolated using poly(A) selection and sequenced on an Illumina Hi-Seq4000 platform. Transcripts were aligned to the human hg19 reference genome and counted with the HTSeq package. Genes were compared for differential expression using DESeq2. Ingenuity Pathway Analysis (IPA) was used to identify gene networks altered in the presence of S. haematobium We enrolled 33 participants from villages in rural Tanzania where S. haematobium is endemic. After correction for multiple comparisons, we observed 383 differentially expressed genes between those with or without S. haematobium infection when sex was included as a covariate. Heat-mapping of the genes with >1.5-fold differences in gene expression revealed clustering by S. haematobium infection status. The top networks included development, cell death and survival, cell signaling, and immunologic disease pathways. We observed a distinct whole blood transcriptional profile, as well as differences in men and women, with S. haematobium infection. Additional studies are needed to determine the clinical effects of these divergent responses. Attention to sex-based differences should be included in studies of human schistosome infection.

A Spatiotemporal Analysis of Schistosomiasis in Hunan Province, China.

Based on annual parasitological data recently collected at county and village levels, this article presents a multiscale spatiotemporal analysis of transmission risk of schistosomiasis japonica in Hunan Province during 2001 to 2015 in a geographic information system environment. The study shows that the incidence and prevalence rate of human Schistosoma japonicum infection in Hunan Province decreased after 2001. A spatial autocorrelation analysis reveals the existence of spatial clusters of human Schistosoma japonicum infection and a growing tendency of spatial clustering over time. The identification of high-risk areas (hot spots) helps find areas of priority for future implementation of control strategies. The research demonstrates the importance of spatial scale in public health studies.

DNA Diagnostics for Schistosomiasis Control.

Despite extensive efforts over the last few decades, the global disease burden of schistosomiasis still remains unacceptably high. This could partly be attributed to the lack of accurate diagnostic tools for detecting human and animal schistosome infections in endemic areas. In low transmission and low prevalence areas where schistosomiasis elimination is targeted, case detection requires a test that is highly sensitive. Diagnostic tests with low sensitivity will miss individuals with low infection intensity and these will continue to contribute to transmission, thereby interfering with the efficacy of the control measures operating. Of the many diagnostic approaches undertaken to date, the detection of schistosome DNA using DNA amplification techniques including polymerase chain reaction (PCR) provide valuable adjuncts to more conventional microscopic and serological methods, due their accuracy, high sensitivity, and the capacity to detect early pre-patent infections. Furthermore, DNA-based methods represent important screening tools, particularly in those endemic areas with ongoing control where infection prevalence and intensity have been reduced to very low levels. Here we review the role of DNA diagnostics in the path towards the control and elimination of schistosomiasis.

Immune Dysfunction and Coinfection with Human Immunodeficiency Virus and Schistosoma japonicum in Yi People.

Objective To explore the association between infections with HIV and Schistosoma japonicum, and to determine the influences of the HIV-S. japonicum coinfections on the immune system of Yi people. Methods A block design study was conducted in a Yi county in southwestern China, one of the endemic areas of both HIV/AIDS and S. japonicum in China. All participants were screened for HIV antibodies and S. japonicum antibodies (SjAb) and were classified into four groups: HIV(+)/S. japonicum(−), HIV(−)/S. japonicum (+), HIV(+)/S. japonicum(+), and HIV(−)/S. japonicum(−). Results There were significant differences among the four groups in both CD4+ T lymphocytes and CD8+ T lymphocytes, but no significant difference in CD3+ T lymphocytes. Both the CD4+ T lymphocyte counts and the ratio of CD4+/CD8+ were lower in HIV-infected people compared with those uninfected. People infected with S. japonicum had increased CD4+ T lymphocyte counts but reduced CD8+ T lymphocyte counts. Similarly, the ratio of CD4+/CD8+ was higher in S. japonicum-infected people compared with those uninfected. People coinfected with HIV and S. japonicum had lower CD4+ T lymphocyte counts, lower ratio of CD4+/CD8+, and higher CD8+ T lymphocyte counts compared with those infected with HIV only or S. japonicum only. People infected with HIV only and those coinfected with HIV and S. japonicum had a higher level of IFN-γ compared with people with no infection. There were no significant differences between people infected with HIV only and with S. japonicum only in the levels of IFN-γ and IL-10. Conclusions People coinfected with HIV and S. japonicum might have a suppressed immune function because of a decrease in CD4+ T lymphocyte counts, a lowered ratio of CD4+/CD8+, and an increase in CD8+ T lymphocyte counts. Coinfection with HIV and S. japonicum would alter the level of IFN-γ in plasma.

Metabolite profiling for biomarkers in Schistosoma haematobium infection and associated bladder pathologies.

BackgroundMetabolic fingerprinting analysis can offer insights into underlying reactions in a biological system; hence it is crucial to the understanding of disease pathogenesis and could provide useful tools for discovering biomarkers. We sought to examine the urine and plasma metabolome in individuals affected by urogenital schistosomiasis and its associated-bladder pathologies.MethodologyBlood and midstream urine were obtained from volunteers who matched our inclusion criteria among residents from Eggua, southwestern Nigeria. Samples were screened by urinalysis, microscopy, PCR and ultrasonography, and categorised as advanced (urogenital schistosomiasis associated-bladder pathologies), infection-only (urogenital schistosomiasis alone) and controls (no infection and no pathology). Metabolites were extracted and data acquired with ultra high-performance liquid chromatography coupled with Thermo Q-Exactive orbitrap HRMS. Data was analysed with MetaboAnalyst, Workflow4Metabolomics, HMDB, LipidMaps and other bioinformatics tools, with univariate and multivariate statistics for metabolite selection.Principal findingsThere were low levels of host sex steroids, and high levels of several benzenoids, catechols and lipids (including ganglioside, phosphatidylcholine and phosphatidylethanolamine), in infection-only and advanced cases (FDR<0.05, VIP>2, delta>2.0). Metabolites involved in biochemical pathways related to chorismate production were abundant in controls, while those related to choline and sphingolipid metabolism were upregulated in advanced cases (FDR<0.05). Some of these human host and Schistosoma haematobium molecules, including catechol estrogens, were good markers to distinguish infection-only and advanced cases.ConclusionsAltered glycerophospholipid and sphingolipid metabolism could be key factors promoting the development of bladder pathologies and tumours during urogenital schistosomiasis.

The Essential Ectoenzyme SmNPP5 from the Human Intravascular Parasite Schistosoma mansoni is an ADPase and a Potent Inhibitor of Platelet Aggregation.

Schistosomes are intravascular parasitic platyhelminthes infecting > 200 million people globally and causing a debilitating disease, schistosomiasis. Despite the relatively large size of the adult worms and their disruption of blood flow, surprisingly, they do not appear to provoke thrombus formation around them in vivo. We hypothesize that proteins expressed at the host-parasite interface are key to this ability. Here, we functionally express an ectonucleotide pyrophosphatase/phosphodiesterase homologue, SmNPP5, that is expressed at the tegumental surface of intravascular Schistosoma mansoni. We report that SmNPP5, a known virulence factor for the worms, is a type one glycoprotein that cleaves the artificial substrate p-Nph-5'-TMP in a reaction that requires cations and at an optimal pH of 9. Using immunolocalization and enzyme activity measurements, we confirm that SmNPP5 is exclusively expressed at the host interactive surface of all intravascular life stages. SmNPP5 inhibits platelet aggregation in a dose-dependent manner, as measured by multiple electrode aggregometry (MEA) using whole blood. Inhibition is apparent when either collagen or adenosine diphosphate (ADP) is used as agonist but is lost following heat treatment of SmNPP5. Unlike its mammalian homologue, NPP5, the schistosome protein cleaves ADP and with a Km of 246 ± 34 µM. In sum, SmNPP5 is expressed in the intravascular environment where it can degrade ADP and act as an anticoagulant. In this manner, the protein likely helps limit blood clot formation around the worms in vivo to permit the parasites free movement within the vasculature.

RETRACTED: Diversity and Compatibility of Human Schistosomes and Their Intermediate Snail Hosts

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal) This article has been retracted at the request of the authors: Benjamin Sanogo, Dongjuan Yuan, Xin Zeng, Yanhua Zhang, and Zhongdao Wu. Our article reviews the evolution, geography, diversity, genetics and host-compatibility of human schistosomes and their hosts. It has come to our attention that readers have found some of the content in the article to be confusing or misleading. As authors, we have tried our best to share our scientific discovery and understanding faithfully, but we also agree that scientific reports should stand up to doubt and discussion. After serious consideration, to avoid confusion in the Schistosoma research community, we are retracting the Review. We apologize to the community for any inconvenience we have caused.

The effectiveness of water treatment processes against schistosome cercariae: A systematic review.

BackgroundSchistosomiasis is one of the most disabling neglected tropical diseases, ranking second in terms of years lived with disability. While treatment with the drug praziquantel can have immediate beneficial effects, reinfection can occur rapidly if people are in contact with cercaria-infested water. Water treatment for schistosomiasis control seeks to eliminate viable cercariae from water, thereby providing safe alternative water supplies for recreational and domestic activities including laundry and bathing. This provision may reduce contact with infested water, which is crucial for reducing reinfection following chemotherapy and cutting schistosome transmission.MethodologyA qualitative systematic review was carried out to summarize the existing knowledge on the effectiveness of water treatment in removing or inactivating human schistosome cercariae. Four online databases were searched. Studies were screened and categorized into five water treatment processes: storage, heating, chlorination, filtration, and ultraviolet (UV) disinfection.ConclusionsAll five water treatment methods can remove or inactivate cercariae in water, and hence produce cercaria-free water. However, reliable design guidelines for treating water do not exist as there are insufficient data. Overall, the review found that cercariae are inactivated when storing water for 10–72 hours (depending on temperature), or with chlorination values of 3–30 mg-min/l. UV fluences between 3–60 mJ/cm2 may significantly damage or kill cercariae, and sand filters with 0.18–0.35 mm grain size have been shown to remove cercariae. This systematic review identified 67 studies about water treatment and schistosomiasis published in the past 106 years. It highlights the many factors that influence the results of water treatment experiments, which include different water quality conditions and methods for measuring key parameters. Variation in these factors limit comparability, and therefore currently available information is insufficient for providing complete water treatment design recommendations.

Role of environmental parameters on the density of intermediate host snails of human schistosoma during the year in the commune of Richard-Toll, Senegal

The implementation and expansion of development projects (dams and irrigation schemes) in the Senegal River valley have led to a significant proliferation of snails. We conducted a one-year (2014) study project, monitoring their density in the commune of Richard Toll, to assess the role of environmental parameters on mollusc population dynamics. Four species involved in the transmission of human schistosomiasis were found: Bulinus globosus, B. truncatus, B. senegalensis, and Biomphalaria pfeifferi. Among the intermediate hosts, B. truncatus is the most abundant species, followed by B. globosus. Snail density depends on the nature of the water point but also on environmental parameters such as vegetation. This study showed that vegetation, water level (flood), and flow velocity influence the dynamics of the snail populations that are intermediate hosts of human schistosomes.

Bioenergetic theory predicts infection dynamics of human schistosomes in intermediate host snails across ecological gradients.

Epidemiological dynamics depend on the traits of hosts and parasites, but hosts and parasites are heterogeneous entities that exist in dynamic environments. Resource availability is a particularly dynamic and potent environmental driver of within-host infection dynamics (temporal patterns of growth, reproduction, parasite production and survival). We developed, parameterised and validated a model for resource-explicit infection dynamics by incorporating a parasitism module into dynamic energy budget theory. The model mechanistically explained the dynamic multivariate responses of the human parasite Schistosoma mansoni and its intermediate host snail to variation in resources and host density. At the population level, feedbacks mediated by resource competition could create a unimodal relationship between snail density and human risk of exposure to schistosomes. Consequently, weak snail control could backfire if reductions in snail density release remaining hosts from resource competition. If resource competition is strong and relevant to schistosome production in nature, it could inform control strategies.

Agrochemicals increase risk of human schistosomiasis by supporting higher densities of intermediate hosts

Schistosomiasis is a snail-borne parasitic disease that ranks among the most important water-based diseases of humans in developing countries. Increased prevalence and spread of human schistosomiasis to non-endemic areas has been consistently linked with water resource management related to agricultural expansion. However, the role of agrochemical pollution in human schistosome transmission remains unexplored, despite strong evidence of agrochemicals increasing snail-borne diseases of wildlife and a projected 2- to 5-fold increase in global agrochemical use by 2050. Using a field mesocosm experiment, we show that environmentally relevant concentrations of fertilizer, a herbicide, and an insecticide, individually and as mixtures, increase densities of schistosome-infected snails by increasing the algae snails eat and decreasing densities of snail predators. Epidemiological models indicate that these agrochemical effects can increase transmission of schistosomes. Identifying agricultural practices or agrochemicals that minimize disease risk will be critical to meeting growing food demands while improving human wellbeing.

Recent Examination for Assessing Epidemiological Status of Schistosoma Mansoni in Plaine Orety, Urban Area of Libreville, Gabon, Central Africa

Schistosoma mansoni epidemiology is very uncertain in Gabon despite its wide distribution in Sub-Saharan African whereas knowledge of schistosomiasis endemicity setting has important implications for the national policy controls. To date only two cases of S. mansoni were diagnosed by the Department of Parasitology-Mycology (DPM), Libreville-Gabon between 1995 and 2009 and both came from Plaine Orety, an urban area of Libreville. As the result of this finding a survey that we report results here was conducted to determine the epidemiological status of S. mansoni in this site. Parasitological and malacological surveys were conducted prospectively from January to May 2012. Parasitological survey included people living in Plaine Orety (Libreville) area at least three months and aged from two years upwards. Stool examination was performed using Kato-Katz technique and malacological investigations were conducted in all the streams of this area for the same period to identify the intermediate snail host of S. mansoni. A total of 495 people were examined, of them 4 cases (0.81%) were identified positive to S. mansoni with no significant influence of sex or age group (p>0.05). Infected peoples said they never went out of the country but stayed in other regions of the country, i.e. Kango, Ovan, Lambarene, Port-Gentil, Bitam and Fougamou. No intermediate snail host of human schistosomes has been identified in the whole surveyed water sites of Plaine Orety. Freshwater snails identified are: Lymnea sp, Physa sp, Melanoides sp and Indoplanorbis exustus (intermediate snail host of cattle schistosomes in India). The finding of this study illustrate existing indigenous cases of S. mansoni in Libreville (Gabon) even if local active transmission area remains to be elucidate because of the absence of intermediate snail host Biomphalaria.

Signalling pathways in schistosomes: novel targets for control interventions against schistosomiasis.

Over the last decade, there has been accumulating evidence showing that signalling pathways are involved in extensive biological and physiological processes in the human blood fluke schistosomes, playing essential roles in environmental sensing, host penetration, growth, development, maturation, embryogenesis, tissue self-renewal and survival. Owing to the likelihood of resistance developing against praziquantel, the only drug currently available that is effective against all the human schistosome species, there is an urgent requirement for an alternative treatment, arguing for continuing research into novel or repurposed anti-schistosomal drugs. An increasing number of anticancer drugs are being developed which block abnormal signalling pathways, a feature that has stimulated interest in developing novel interventions against human schistosomiasis by targeting key cell signalling components. In this review, we discuss the functional characterization of signal transduction pathways in schistosomes and consider current challenges and future perspectives in this important area of research.

Detection of duo-schistosome infection from filtered urine samples from school children in Zambia after MDA.

Schistosomiasis is one of the major Neglected Tropical Diseases (NTDs) in sub-Saharan Africa. In sub-Saharan Africa, two major human schistosome species namely Schistosoma mansoni and S. haematobium often occur sympatrically largely affecting children. Recognizing the public health impact of Schistosomiasis, the World Health Organization (WHO) is urging member states to regularly treat at least 75% and up to 100%, of all school-aged children at risk of morbidity. For control strategies based on targeted mass drug administration (MDA) to succeed it is essential to have a simple and sensitive test for monitoring the success of these interventions. Current available diagnostic tests, such as egg detection in stool by Kato-Katz (KK) for S. mansoni and detection of eggs or blood (hematuria) in urine for S. haematobium have reduced sensitivity in low intensity settings. The objective of the study was to evaluate active single or duo schistosome infections in school children following MDA using molecular diagnostics (PCR) on filtered urine samples and comparing that against traditional diagnostic tests. This cross-sectional study was conducted among 111 school children aged 7–15 years in Chongwe and Siavonga Districts in Zambia. Species-specific cell-free repeat DNA fragment were amplified from 111 filtered urine samples. Our approach detected eight times more positive cases (total 77) than by KK (9) for S. mansoni and six times more (total 72) than by hematuria (11) for S. haematobium and even more against urine filtration (77 compared to only 6). The same pattern was observed when stratified for age group and sex specific analysis with 100% sensitivity and specificity devoid of any cross amplification. In addition, 69 individuals (62%) were co-infected by both parasites. We have demonstrated a significantly higher prevalence of both species than indicated by the traditional tests and the persistent maintenance of reservoir of infection after MDA. Our approach is an effective means of detecting low intensity infection, which will enhance the effectiveness of surveillance and assess the impact of MDA control programs against schistosomiasis.

The substructure of three repetitive DNA regions of Schistosoma haematobium group species as a potential marker for species recognition and interbreeding detection

BackgroundSchistosoma haematobium is the causative agent of human urogenital schistosomiasis affecting ~112 million people in Africa and the Middle East. The parasite is transmitted by snails of the genus Bulinus, which also transmit other closely related human and animal schistosomes. The accurate discrimination of S. haematobium from species infecting animals will aid effective control and elimination programs. Previously we have shown the utility of different repetitive nuclear DNA sequences (DraI, sh73bp, and sh77bp) for the identification of S. haematobium-group species and inter-repeat sequences for discriminating S. haematobium from S. bovis.ResultsIn this current study we clarify the structural arrangement and association between the three repetitive sequences (DraI, sh73bp, and sh77bp) in both S. haematobium and S. bovis, with a unique repeat linker being found in S. haematobium (Sh64bp repeat linker) and in S. bovis (Sb30bp repeat linker). Sequence data showed that the 3′-end of the repeat linker was connected to the DraI repetitive sequence array, and at the 5′-end of the repeat linker sh73bp and sh77bp were arranged in an alternating manner. Species-specific oligonucleotides were designed targeting the species-specific repeat linkers and used in a reverse line blot (RLB) hybridization assay enabling differentiation between S. haematobium and S. bovis. The assay was used to discriminate natural infections in wild caught Bulinus globosus.ConclusionThis research enabled the characterisation of species-specific DNA regions that enabled the design of species-specific oligonucleotides that can be used to rapidly differentiate between S. haematobium and S. bovis and also have the potential to aid the detection of natural hybridization between these two species.