This document provides up-to-date guidance on laboratory studies as well as smallscale (semi-field) and large-scale field trials to assess the efficacy and determine field
application rates of new molluscicide products for control of schistosomiasis.
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Disease: Infection is widespread in poor communities, 221 million people affected worldwide...
Affected Populations: Women, Children...
Prevention and Control: WHO recommends praziquantel for treatment of all forms of schistosomiasis...
Lesson on schistosomiasis (bilharziasis): Causes, Symptoms and Treatment. Schistosomiasis is caused by parasitic blood flukes from the genus schistosoma. Schistosoma cercariae penetrate human skin and enter the bloodstream of the infected individual, where the parasites enter the portal vein. Schist...osoma parasites also enter the mesenteric and bladder circulations, where they release eggs. Symptoms of schistosomiasis are related to the location of the parasites, the parasite burden and the amount of eggs produced. Systems affected in schistosomiasis include the hepatic, splenic, genitourinary, pulmonary, and nervous systems.
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DNA studies of Egyptian mummies shows evidence of the existence of Schistosomiasis about 5000 years ago. Schistosomiasis is increasing in prevalence, affecting nearly 10% of the world’s population and ranking second only to malaria as a cause of morbidity & mortality.
Schistosoma haematobium are... found in tropical Africa & part of southwest Asia.
Schistosoma mansoni are found in tropical Africa, part of southwest Asia, south America & Caribbean islands.
Schistosoma japonicum are found in parts of Japan, China, Philippines, India & part of southeast Asia.
Blood flukes are known as schistosomes because of the "split body" on the ventral side of the male, in which the female is held during insemination and egg laying.
Man is the definite host harbouring adult parasites, and fresh water snails are intermediate hosts.
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Species of the genus Schistosoma are digenetic trematodes and the causative agents of the Neglected Tropical Disease (NTD) schistosomiasis; a parasitic disease that ranks second only to malaria in terms of socioeconomic impacts. Over 220 million people worldwide are currently infected, 90% of whom l...ive in sub-Saharan Africa (SSA), with an estimated annual mortality of at least 200,000. Infection in humans, as well as alternative mammalian definitive hosts, occurs in contaminated freshwater environments via cercariae shed from specific snail intermediate hosts. Early acute morbidity can occur following cutaneous penetration, sometimes leading to an urticarial rash known as swimmers itch or cercarial dermatitis.
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Schistosomiasis, also known as Bilharzia, is an infection caused by a parasitic worm that lives in fresh water in subtropical and tropical regions. Schistosomiasis is second only to malaria as the most devastating parasitic disease. The parasites that cause schistosomiasis live in certain types of f...reshwater snails. The infectious form, known as cercariae, emerge from the snail and then contaminate the water. People become infected when their skin comes into contact with the contaminated freshwater. Most human infections are caused by Schistosoma mansoni, Schistosoma haematobium, or Schistosoma japonicum.
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Schistosomiasis, also known as bilharzia, is an infection caused by a parasitic worm that lives in fresh water in subtropical and tropical regions.
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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Female Genital Schistosomiasis (FGS) is a gynaecological disease caused by Schistosoma haematobium, a parasitic worm that is acquired by skin contact with freshwater contaminated by schistosome cerceriae. Communities in which the infection is most endemic have limited access to clean water and healt...hcare services. Up to 150 million adolescent girls and women are estimated to be at risk of FGS and about 16–56 milion womens are living with FGS, with the majority of these in sub-Saharan Africa. The variability of these estimates points to the fact that this neglected tropical disease is not well studied and frequently not prioritized by local, regional, and global health policy makers.
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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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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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Website last accessed on 31.03.2023
Preventive chemotherapy with praziquantel (PZQ) is the cornerstone of schistosomiasis control. However, a single dose of PZQ (40 mg/kg) does not cure all infections. Repeated doses of PZQ at short intervals might increase efficacy in terms of cure rate (CR) and intensity reduction rate (IRR). Here, ...we determined the efficacy of a single versus four repeated treatments with PZQ on Schistosoma mansoni infection in school-aged children from Côte d'Ivoire, using two different diagnostic tests.
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La schistosomiase est une parasitose aiguë et chronique provoquée par des vers (trématodes) du genre Schistosoma. Au moins 249 millions de personnes ont eu besoin d’un traitement préventif en 2012. Le traitement préventif, qui doit être répété sur plusieurs années, permettra de réduire ...et de prévenir la morbidité.
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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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