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Seminars in Immunopathology Jun 2020Schistosomiasis (bilharzia) is a neglected tropical disease caused by trematode worms of the genus Schistosoma. The transmission cycle involves human (or other... (Review)
Review
Schistosomiasis (bilharzia) is a neglected tropical disease caused by trematode worms of the genus Schistosoma. The transmission cycle involves human (or other mammalian) water contact with surface water contaminated by faeces or urine, as well as specific freshwater snails acting as intermediate hosts. The main disease-causing species are S. haematobium, S. mansoni and S. japonicum. According to the World Health Organisation, over 250 million people are infected worldwide, leading to considerable morbidity and the estimated loss of 1.9 million disability-adjusted life years (DALYs), a likely underestimated figure. Schistosomiasis is characterised by focal epidemiology and an over-dispersed population distribution, with higher infection rates in children. Complex immune mechanisms lead to the slow acquisition of immune resistance, but innate factors also play a part. Acute schistosomiasis, a feverish syndrome, is most evident in travellers following a primary infection. Chronic schistosomiasis affects mainly individuals with long-standing infections residing in poor rural areas. Immunopathological reactions against schistosome eggs trapped in host tissues lead to inflammatory and obstructive disease in the urinary system (S. haematobium) or intestinal disease, hepatosplenic inflammation and liver fibrosis (S. mansoni and S. japonicum). An effective drug-praziquantel-is available for treatment but, despite intensive efforts, no schistosomiasis vaccines have yet been accepted for public use. In this review, we briefly introduce the schistosome parasites and the immunopathogenic manifestations resulting from schistosomiasis. We then explore aspects of the immunology and host-parasite interplay in schistosome infections paying special attention to the current status of schistosomiasis vaccine development highlighting the advancement of a new controlled human challenge infection model for testing schistosomiasis vaccines.
Topics: Animals; Anthelmintics; Child; Humans; Schistosoma haematobium; Schistosoma mansoni; Schistosomiasis; Vaccines
PubMed: 32076812
DOI: 10.1007/s00281-020-00789-x -
IDCases 2023
PubMed: 36593891
DOI: 10.1016/j.idcr.2022.e01672 -
Frontiers in Medicine 2019
PubMed: 30968025
DOI: 10.3389/fmed.2019.00055 -
Current Research in Parasitology &... 2022Female genital schistosomiasis (FGS) is the gynaecological presentation of infection, resulting from egg deposition in the female genital tract. Despite the fact that... (Review)
Review
Female genital schistosomiasis (FGS) is the gynaecological presentation of infection, resulting from egg deposition in the female genital tract. Despite the fact that this condition has been reported in the early days of the discovery of in Egypt, its existence has been grossly neglected, causing many women in schistosomiasis-endemic areas to go through a preventable, debilitating, and stigmatizing presentation of FGS. To prevent this, increasing awareness of FGS is necessary for all, especially healthcare providers, to improve the diagnosis, management, and treatment. As proposed by the FAST package project, several healthcare professionals with different specializations are expected to be involved in the management of FGS. It is therefore important that basic updated knowledge on the parasitology of the disease be acquired by healthcare professionals. This review provides basic information necessary to improve the knowledge of FGS among healthcare professionals in areas endemic to schistosomiasis. Armed with these basic details, healthcare professionals can improve their confidence in the management and treatment of FGS, contributing significantly to the control and prevention of FGS in endemic areas.
PubMed: 35719849
DOI: 10.1016/j.crpvbd.2022.100093 -
Parasites & Vectors Sep 2016Schistosomiasis, caused mainly by S. mansoni, S. haematobium and S. japonicum, continues to be a serious tropical disease and public health problem resulting in an... (Review)
Review
Schistosomiasis, caused mainly by S. mansoni, S. haematobium and S. japonicum, continues to be a serious tropical disease and public health problem resulting in an unacceptably high level of morbidity in countries where it is endemic. Praziquantel, the only drug currently available for treatment, is unable to kill developing schistosomes, it does not prevent re-infection and its continued extensive use may result in the future emergence of drug-resistant parasites. This scenario provides impetus for the development and deployment of anti-schistosome vaccines to be used as part of an integrated approach for the prevention, control and eventual elimination of schistosomiasis. This review considers the present status of candidate vaccines for schistosomiasis, and provides some insight on future vaccine discovery and design.
Topics: Drug Discovery; Humans; Schistosomiasis; Vaccines
PubMed: 27716365
DOI: 10.1186/s13071-016-1799-4 -
Scientific Reports Mar 2023Schistosomiasis is a major neglected tropical disease targeted for elimination as a public health issue by 2030, however there is an urgent need for more sensitive and...
Schistosomiasis is a major neglected tropical disease targeted for elimination as a public health issue by 2030, however there is an urgent need for more sensitive and specific diagnostic tests suitable to resource-limited settings. Here we developed CATSH, a CRISPR-assisted diagnostic test for Schistosoma haematobium, utilising recombinase polymerase amplification, Cas12a-targeted cleavage and portable real-time fluorescence detection. CATSH showed high analytical sensitivity, consistent detection of a single parasitic egg and specificity for urogenital Schistosoma species. Thanks to a novel CRISPR-compatible sample preparation developed using simulated urine samples containing parasitic eggs, CATSH had a sample-to-result within 2 h. The components of CATSH can be lyophilised, reducing cold chain dependence and widening access to lower and middle-income countries. This work presents a new application of CRISPR diagnostics for highly sensitive and specific detection of parasitic pathogens in remote areas and could have a significant impact on the elimination of neglected tropical diseases.
Topics: Animals; Schistosoma haematobium; Schistosomiasis haematobia; Sensitivity and Specificity; Neglected Diseases; Eggs
PubMed: 36973334
DOI: 10.1038/s41598-023-31238-y -
The American Journal of Tropical... May 2019Schistosomiasis is traditionally classified into an acute and a chronic phase, although a precise temporal distinction between the two phases has not been established....
Schistosomiasis is traditionally classified into an acute and a chronic phase, although a precise temporal distinction between the two phases has not been established. Lung involvement can be observed in both phases. We previously reported seven cases of pulmonary lesions due to chronic schistosomiasis in African immigrants. All cases were documented with CT scans and demonstrated complete resolution after treatment with praziquantel. Moreover, another case showed spontaneous disappearance of the nodule before treatment with praziquantel. These findings are similar to those observed in the acute phase of schistosomiasis, with well-defined or ground glass nodules that resolve spontaneously. According to these findings, we postulate the presence of an "intermediate" phase of schistosomiasis involving the lungs that can be defined as an "early chronic phase," and presents analogies to the acute phase. We also hypothesize that in the "early chronic phase," the female worms transit through the lungs where they may lay eggs. These passages not only cause transient, but also radiologically visible alterations. The pathophysiology of lung lesions in the late chronic phase is probably different: the adult worms settled in the mesenteric plexuses produce eggs for years. The eggs repeatedly migrate to the perialveolar capillary beds via portal-caval shunting. Thus, in this case it is the eggs and not the adult worms that reach the lungs in a scattered way. Based on our findings, we suggest the alternative hypothesis that the pulmonary involvement is a phase of the natural evolution of the infection, both from and .
Topics: Animals; Anthelmintics; Female; Humans; Lung; Lung Diseases, Parasitic; Male; Praziquantel; Schistosoma haematobium; Schistosoma mansoni; Schistosomiasis; Schistosomiasis haematobia; Schistosomiasis mansoni; Tomography, X-Ray Computed
PubMed: 30810105
DOI: 10.4269/ajtmh.18-0576 -
PLoS Neglected Tropical Diseases Apr 2020Schistosomes are parasitic blood flukes that infect >200 million people around the world. Free-swimming larval stages penetrate the skin, invade a blood vessel, and... (Review)
Review
Schistosomes are parasitic blood flukes that infect >200 million people around the world. Free-swimming larval stages penetrate the skin, invade a blood vessel, and migrate through the heart and lungs to the vasculature of the liver, where maturation and mating occurs. From here, the parasite couples migrate to their preferred egg laying sites. Here, we compare and contrast what is known about the migration patterns within the definitive host of the three major species of human schistosome: Schistosoma mansoni, S. japonicum, and S. haematobium. We conclude that intravascular schistosomes are inexorable colonizers whose migration and egg laying strategy is profligate; all three species (and their eggs) can be found throughout the mesenteric venules, the rectal venous plexus, and, to a greater or lesser extent, the urogenital venous plexuses. In addition, it is common for parasite eggs to be deposited in locations that lack easy access to the exterior, further demonstrating the relentless exploratory nature of these intravascular worms.
Topics: Animals; Blood Vessels; Humans; Life Cycle Stages; Locomotion; Schistosoma haematobium; Schistosoma japonicum; Schistosoma mansoni; Schistosomiasis haematobia; Schistosomiasis japonica; Schistosomiasis mansoni
PubMed: 32240157
DOI: 10.1371/journal.pntd.0007951 -
The Journal of Infectious Diseases Mar 2015Approximately 200,000,000 people have schistosomiasis (schistosome infection). Among the schistosomes, Schistosoma haematobium is responsible for the most infections,... (Review)
Review
Approximately 200,000,000 people have schistosomiasis (schistosome infection). Among the schistosomes, Schistosoma haematobium is responsible for the most infections, which are present in 110 million people globally, mostly in sub-Saharan Africa. This pathogen causes an astonishing breadth of sequelae: hematuria, anemia, dysuria, stunting, uremia, bladder cancer, urosepsis, and human immunodeficiency virus coinfection. Refined estimates of the impact of schistosomiasis on quality of life suggest that it rivals malaria. Despite S. haematobium's importance, relevant research has lagged. Here, we review advances that will deepen knowledge of S. haematobium. Three sets of breakthroughs will accelerate discoveries in the pathogenesis of urogenital schistosomiasis (UGS): (1) comparative genomics, (2) the development of functional genomic tools, and (3) the use of animal models to explore S. haematobium-host interactions. Comparative genomics for S. haematobium is feasible, given the sequencing of multiple schistosome genomes. Features of the S. haematobium genome that are conserved among platyhelminth species and others that are unique to S. haematobium may provide novel diagnostic and drug targets for UGS. Although there are technical hurdles, the integrated use of these approaches can elucidate host-pathogen interactions during this infection and can inform the development of techniques for investigating schistosomes in their human and snail hosts and the development of therapeutics and vaccines for the control of UGS.
Topics: Animals; Disease Models, Animal; Genes, Helminth; Genomics; Humans; Molecular Sequence Annotation; Schistosoma haematobium; Schistosomiasis haematobia
PubMed: 25240172
DOI: 10.1093/infdis/jiu527