Schistosomiasis, also known as bilharzia, is a disease caused by parasitic worms that require two hosts: humans and certain species of snails. There are two forms of the disease, namely, intestinal schistosomiasis, caused by Schistosoma mansoni and S. japonicum, and urogenital schistosomiasis, cause...d by S. haematobium. There are less common schistosome species in some parts of the world, e.g. S. mekongi and S. intercalatum. Schistosomiasis ranks second only to malaria as the most common parasitic disease worldwide.
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Schistosomiasis, commonly known as bilharzia, is an acute and chronic tropical disease caused by trematodes of the genus Schistosoma. The schistosome parasite is transmitted through a snail intermediate host with the human being the definitive host. Worldwide, schistosomiasis continues to cause a pu...blic health problem with 779 million people exposed to the infection. The disease is present in 78 countries and endemic in 52 of those countries where an estimated 90% of people need treatment. Schistosomiasis has been successfully controlled in many countries but its burden remains high in Africa, particularly in sub-Saharan countries.
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Schistosomiasis, which is the second most important parasitic infection after malaria in terms of its socioeconomic impact, is responsible for the loss of an estimated 4.5 million disability-adjusted life years (DALYs) worldwide. Schistosomiasis, including both intestinal and urinary forms of the di...sease, occurs in 78 countries across the globe. An estimated 240 million people are infected, with more than 779 million living at risk globally. The majority of those infected and those at risk for infection live in low-income countries, and approximately 80% of the morbidity occurs in impoverished communities and households in sub-Saharan Africa. Within Uganda, 91 of the 134 districts are endemic for intestinal schistosomiasis caused by Schistosoma mansoni, and the eastern region, especially along Lake Victoria, has one of the highest S. mansoni burdens worldwide. Schistosoma haematobium is only endemic in the five districts of the Lango region in northern Uganda.
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The sub-Saharan African region, carries 90% of the over 250 million cases of schistosomiasis occurring worldwide. In this region, after Nigeria, Tanzania is second country having the highest cases of schistosomiasis and approximately 51.5%0 of the Tanzanian population is either exposed or live in ar...eas with high risk of exposure. The country is endemic to both Schistosoma mansoni and Schistosoma haematobium, these infections are common in communities characterised with limited access to water, sanitation, hygienic practices and health services. Schistosoma mansoni infection is associated with hepatosplenic disease characterised with hepatomegaly, splenomegaly, progressive periportal fibrosis (PPF) which can lead to portal hypertension and its related sequelae, mainly ascites, liver surface irregularities, oesophageal varices and haematemesis. The main consequences of S. haematobium infection are haematuria, dysuria, nutritional deficiencies, urinary bladder lesions, hydronephrosis, urinary bladder squamous cell carcinoma and in children, growth retardation. Preventive chemotherapy using mass drug administration (MDA) of praziquantel targeting primary school aged children is the main strategy for controlling schistosomiasis in Tanzania.
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Schistosomiasis is a neglected tropical disease of global medical and veterinary importance. As efforts to eliminate schistosomiasis as a public health problem and interrupt transmission gather momentum, the potential zoonotic risk posed by livestock Schistosoma species via viable hybridisation in s...ub-Saharan Africa have been largely overlooked. We aimed to investigate the prevalence, distribution, and multi-host, multiparasite transmission cycle of Haematobium group schistosomiasis in Senegal, West Africa.
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Schistosomiasis is a prevalent parasitic, neglected tropical disease (NTD) affecting over 220 million people globally, especially in sub-Saharan Africa (SSA). The pathology of this disease in terms of intestinal, liver and urinary presentations is well-known, yet its chronic effect on host genitalia... is often ignored or overlooked. Male genital schistosomiasis (MGS) is a gender-specific manifestation of urogenital schistosomiasis (UGS), associated with the presence of Schistosoma haematobium eggs and related pathologies in genitalia of men inhabiting or visiting endemic areas in SSA. Despite the first reported by Madden, the epidemiology, diagnostic testing and case management of MGS are not well-described owing to limited research and diminishing focus over several decades.
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HIV-1 infection disproportionately affects women in sub-Saharan Africa, where areas of high HIV-1 prevalence and Schistosoma haematobium endemicity largely overlap. Female genital schistosomiasis (FGS), caused most frequently by S. haematobium egg deposition in the genital tract, has been associated... with prevalent HIV-1 infection in cross-sectional studies. The presence of S. haematobium eggs in genital tissue is also associated with vascularization and the accumulation of CD4+ lymphocytes and macrophages, making the granuloma-associated environment a potential contributor to HIV-1 vulnerability. In addition to modulation of the local cervicovaginal environment, FGS has also been associated with a higher frequency of systemic CD4 T-cells expressing the chemokine receptor CCR5. Tissue-entrapped eggs are also associated with clinically visible FGS-associated manifestations in the cervicovaginal mucosa. FGS lesions may breach the intact cervicovaginal immune barrier and are hypothesized to provide an entry point for HIV-1 infection. However, the underlying mechanism for potential HIV-1 vulnerability in FGS has not been fully characterized and requires further investigation.
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Schistosomiasis is an acute and chronic parasitic disease caused by blood flukes (trematode
worms) of the genus Schistosoma. At least 249 million people required preventive treatment in
2012. Preventive treatment, which should be repeated over a number of years, will reduce and
prevent morbidity.
Schistosomiasis is a chronic parasitic infection caused by worms. It is most common in rural and impoverished populations. In the Americas, the parasite species is Schistosoma mansoni, which is associated with intestinal schistosomiasis. The main risk factor for infection is exposure through househo...ld, work, or recreational activities in fresh water contaminated with faeces from infected humans.
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Schistosomiasis is an acute and chronic parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma. Estimates show that at least 251.4 million people required preventive treatment in 2021. Preventive treatment, which should be repeated over a number of years, will reduce and... prevent morbidity. Schistosomiasis transmission has been reported from 78 countries. However, preventive chemotherapy for schistosomiasis, where people and communities are targeted for large-scale treatment, is only required in 51 endemic countries with moderate-to-high transmission.
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Schistosomiases are acute or chronic visceral parasitic diseases due to 5 species of trematodes (schistosomes). The three main species infecting humans are Schistosoma haematobium, Schistosoma mansoni and Schistosoma japonicum. Schistosoma mekongi and Schistosoma intercalatum have a more limited dis...tribution.
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Human schistosomiasis, a parasitic and often chronic illness, is one of the major neglected tropical diseases worldwide. It is estimated that 240 million people suffer from schistosomiasis, with more than 200000 fatalities recorded each year. Schistosomiasis is caused by an infection of the blood fl...uke Schistosoma and is transmitted to humans through direct contact with infected water.
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Schistosomiasis is a helminthic infection and one of the neglected tropical diseases (NTDs). It is caused by blood flukes of the genus Schistosoma. It is an important public health problem, particularly in poverty-stricken areas, especially those within the tropics and subtropics. It is estimated th...at at least 236 million people worldwide are infected, 90% of them in sub-Saharan Africa, and that this disease causes approximately 300,000 deaths annually. The clinical manifestations are varied and affect practically all organs. There are substantial differences in the clinical presentation, depending on the phase and clinical form of schistosomiasis in which it occurs. Schistosomiasis can remain undiagnosed for a long period of time, with secondary clinical lesion. Here, we review the clinical profile of schistosomiasis. This information may aid in the development of more efficacious treatments and improved disease prognosis.
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Goal and objectives of the guideline
The goal of this guideline is to provide evidence-based recommendations to countries in their efforts to accomplish schistosomiasis morbidity control and elimination as a public health problem, and to move towards interruption of transmission.
The recommendatio...ns contained herein will help countries to implement national schistosomiasis control and elimination programmes and support efforts to verify the interruption of transmission.
The specific objectives are to provide guidance on:
prevalence thresholds, target age groups and frequency of preventive chemotherapy for schistosomiasis;
establishment of water, sanitation and hygiene (WASH) and snail control activities to support control and elimination of schistosomiasis;
use of diagnostic tests in humans in low transmission areas and for moving to, and evaluating the interruption of transmission of schistosomiasis;
tools for the assessment of Schistosoma spp. infection in snail hosts; and
diagnostic tests for the assessment of schistosomiasis infection in animal reservoirs of infection
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Schistosomiasis is an infectious disease caused by helminth parasites of the genus Schistosoma. Worldwide, an estimated 250 million people are infected with these parasites with the majority of cases occurring in sub-Saharan Africa. Within Asia, three species of Schistosoma cause disease. Schistosom...a japonicum is the most prevalent, followed by S. mekongi and S. malayensis. All three species are zoonotic, which causes concern for their control, as successful elimination not only requires management of the human definitive host, but also the animal reservoir hosts. With regard to Asian schistosomiasis, most of the published research has focused on S. japonicum with comparatively little attention paid to S. mekongi and even less focus on S. malayensis. In this review, we examine the three Asian schistosomes and their current status in their endemic countries: Cambodia, Lao People’s Democratic Republic, Myanmar, and Thailand (S. mekongi); Malaysia (S. malayensis); and Indonesia, People’s Republic of China, and the Philippines (S. japonicum). Prospects for control that could potentially lead to elimination are highlighted as these can inform researchers and disease control managers in other schistosomiasis-endemic areas, particularly in Africa and the Americas.
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La schistosomiase est une parasitose aiguë et chronique provoquée par des vers (trématodes) du genre Schistosoma. Selon les estimations, au moins 251,4 millions de personnes avaient besoin d’un traitement préventif en 2021. Le traitement préventif, qui devrait être renouvelé pendant un cert...ain nombre d’années, permettra de réduire et de prévenir la morbidité. La transmission de la schistosomiase est avérée dans 78 pays. Cependant, la chimioprophylaxie de la maladie, dont le but est de traiter à grande échelle les populations et les communautés, n’est nécessaire que dans 51 pays d’endémie où la transmission est de modérée à forte.
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Schistosomiasis is widely recognized as a disease that is socially determined. An
understanding of the social and behavioural factors linked to disease transmission and
control should play a vital role in designing policies and strategies for schistosomiasis
prevention and control. To this must b...e added the awareness that schistosomiasis is
also a disease of poverty. It still survives in poverty-stricken, remote areas where there
is little or no safe water or sanitation, and health care is scarce or non-existent. For
a variety of complex reasons, many of which are addressed in this book, the disease
is particularly prevalent in sub-Saharan Africa, and persists in certain areas of rural
China. This concern for human behaviour in an environment of poverty echoes the
concerns of the new research priority for “diseases of poverty” identified by the
Special Programme for Research & Training in Tropical Diseases.
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In 2014, an estimated 40 million women of reproductive age were infected with Schistosoma haematobium, S. japonicum and/or S. mansoni. In both 2003 and 2006, the World Health Organization (WHO) recommended that all schistosome-infected pregnant and breastfeeding women be offered treatment, with praz...iquantel, either individually or during treatment campaigns. In 2006, WHO also stated the need for randomized controlled trials to assess the safety and efficacy of such treatment. Some countries have yet to follow the recommendation on treatment and many programme managers and pregnant women in other countries remain reluctant to follow the recommended approach.
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Schistosomiasis and soil-transmitted helminths (STH) infections are major public health problems. We aimed to study the 6-mo impact of mass drug administration with praziquantel and albendazole on urinary schistosomiasis and STH.We examined children (aged 2–15 y) from one hamlet, who provided urin...e and faeces samples at baseline (n=197), 1 mo (n=102) and 6 mo (n=92); 67 completed the protocol.At baseline, 47/67 (70.1%) children presented Schistosoma haematobium (75.8% in the baseline total sample) and 12/67 (17.9%) with STH (30.5% in the initial sample, p=0.010). Among the children, 47.3% had heavy Schistosoma haematobium infection. The most frequent STH was Trichuris trichiura in 9.0%. We also found Hymenolepis nana (13.2%) and Plasmodium falciparum (9.1%) infections and anaemia (82.1%). One mo after chemotherapy there was a significant (p=0.013) reduction of Schistosoma haematobium prevalence (23.5%) and a high egg reduction rate (86.9%). Considering the sample of 67 children, the mean egg concentration was 498 at baseline, 65 at 1 mo and 252 at 6 mo (p<0.05). We also observed a reduction in STH infections, 50% in Ascaris lumbricoides, 33.3% in T. trichiura and 50% in hookworms. At 6 mo, the prevalence of Schistosoma haematobium (76.1%) was similar to the baseline and the STH reduction was not significant.Longitudinal studies have reported many losses in these settings, but we were able to show that mass drug administration for control of schistosomiasis and STH present low effectiveness, that reinfections occur rapidly and that stand alone anthelmintic therapy is not a sustainable choice.
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Human schistosomiasis is caused mainly by 3 schistosome species: Schistosoma haematobium, S. mansoni and S. japonicum. S. guineensis, S. intercalatum and S. mekongi have a highly localized distribution in Central Africa and along the Mekong River in South-East Asia, respectively. Soil-transmitted h...elminthiases (STH) are infections caused by 4 parasite species: Ascaris lumbricoides, Trichuris trichiura, Ancylostoma duodenale and Necator americanus. The 2 latter species are indistinguishable microscopically and are usually reported together as “hookworms”. Schistosomiasis and STH are neglected tropical diseases (NTDs) and are transmitted mainly in areas with poor access to clean water and sanitation. The presence of an intermediate snail host in water is essential to allow Schistosoma to complete their life cycle. Schistosomiasis and STH can cause significant morbidity, including anaemia, nutritional disturbances and, in the case of schistosomiasis, granuloma, organ pathology and cancer, and an increased risk of acquisition of HIV. In women, urogenital schistosomiasis may cause vaginal bleeding, pain during sexual intercourse and nodules in the vulva, now described as female genital schistosomiasis. Groups at risk for STH and schistosomiasis are those in need of micronutrients: preschool-aged children (pre-SAC, 1–4 years of age), school-aged children (SAC, 5–14 years), women of reproductive age (WRA) and, in addition for schistosomiasis adult and entire communities in high-risk areas.
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