View source for Medicine:Schistosomiasis

{{short description|Human disease caused by parasitic worms called schistosomes}}
{{Infobox medical condition (new)
| name            = Schistosomiasis
| synonyms        = Bilharzia, snail fever, Katayama fever<ref name=NHS2011>{{cite web | title=Schistosomiasis (bilharzia) | url=http://www.nhs.uk/Conditions/schistosomiasis/Pages/Introduction.aspx | work=NHS Choices | access-date=15 March 2014 | date=17 December 2011 | url-status=live | archive-url=https://web.archive.org/web/20140315131919/http://www.nhs.uk/Conditions/schistosomiasis/Pages/Introduction.aspx | archive-date=15 March 2014 }}</ref><ref name=PatientInfo>{{cite web | title=Schistosomiasis | url=http://www.patient.info/doctor/schistosomiasis-pro | website=Patient.info | access-date=11 June 2014 | date=2 December 2013 | url-status=live | archive-url=https://web.archive.org/web/20150626231520/http://patient.info/doctor/schistosomiasis-pro | archive-date=26 June 2015}}</ref>
| image           = Schistosomiasis in a child 2.jpg
| image_size      = 250px
| caption         = 11-year-old boy with [[Medicine:Ascites|abdominal fluid]] and [[Medicine:Portal hypertension|portal hypertension]] due to schistosomiasis (Agusan del Sur, Philippines)
| field           = [[Medicine:Infectious disease (medical specialty)|Infectious disease]]
| pronounce       = {{IPAc-en|ˌ|ʃ|ɪ|s|t|ə|s|ə|ˈ|m|aɪ|ə|s|ᵻ|s|,_|-|t|oʊ|-|,_|-|s|oʊ|-}}{{refn|{{cite web | url=https://www.oxforddictionaries.com/definition/english/schistosomiasis | archive-url=https://web.archive.org/web/20140716220332/http://www.oxforddictionaries.com/definition/english/schistosomiasis | url-status=dead | archive-date=July 16, 2014 | title=schistosomiasis - definition of schistosomiasis in English from the Oxford dictionary | publisher=OxfordDictionaries.com | access-date=20 January 2016}} }}{{refn|{{MerriamWebsterDictionary|schistosomiasis}}}}
| symptoms        = [[Medicine:Abdominal pain|Abdominal pain]], [[Medicine:Diarrhea|diarrhea]], bloody stool, [[Medicine:Hematuria|blood in the urine]]<ref name=WHO2014/>
| complications   = Liver damage, [[Medicine:Kidney failure|kidney failure]], [[Medicine:Infertility|infertility]], [[Medicine:Bladder cancer|bladder cancer]]<ref name=WHO2014/>
| onset           =
| duration        =
| causes          = Schistosomes from freshwater snails<ref name=WHO2014/>
| risks           =
| diagnosis       = Finding eggs of the parasite in urine or stool, [[Biology:Antibodies|antibodies]] in blood<ref name=WHO2014/>
| differential    =
| prevention      = Access to clean water<ref name=WHO2014/>
| treatment       =
| medication      = [[Chemistry:Praziquantel|Praziquantel]]<ref name=WHO2014/>
| prognosis       =
| frequency       = 252 million (2015)<ref name=GBD2015Pre>{{cite journal | vauthors = Vos T, Allen C, Arora M, Barber RM, Bhutta ZA, Brown A, etal | collaboration = GBD 2015 Mortality and Causes of Death Collaborators | title = Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015 | journal = Lancet | volume = 388 | issue = 10053 | pages = 1545–1602 | date = October 2016 | pmid = 27733282 | pmc = 5055577 | doi = 10.1016/S0140-6736(16)31678-6 }}</ref>
| deaths          = 4,400–200,000<ref name=The2013/><ref name=GBD2015De/>
}}

<!-- Definition and symptoms -->
'''Schistosomiasis''', also known as '''snail fever''', '''bilharzia''', and '''Katayama fever''',<ref name=NHS2011/><ref name=PatientInfo/><ref>{{cite journal | vauthors = Colley DG, Bustinduy AL, Secor WE, King CH | title = Human schistosomiasis | journal = Lancet | volume = 383 | issue = 9936 | pages = 2253–64 | date = June 2014 | pmid = 24698483 | pmc = 4672382 | doi = 10.1016/s0140-6736(13)61949-2 }}</ref> is a [[Medicine:Helminthiasis|disease]] caused by [[Earth:Parasitism|parasitic]] [[Biology:Flatworm|flatworm]]s called schistosomes.<ref name=WHO2014/> The urinary tract or the intestines may be infected.<ref name=WHO2014/> Symptoms include [[Medicine:Abdominal pain|abdominal pain]], [[Medicine:Diarrhea|diarrhea]], bloody stool, or [[Medicine:Hematuria|blood in the urine]].<ref name=WHO2014/> Those who have been infected for a [[Medicine:Chronic condition|long time]] may experience liver damage, [[Medicine:Kidney failure|kidney failure]], [[Medicine:Infertility|infertility]], or [[Medicine:Bladder cancer|bladder cancer]].<ref name=WHO2014/> In children, it may cause [[Medicine:Failure to thrive|poor growth]] and [[Medicine:Learning disability|learning difficulty]].<ref name=WHO2014>{{cite web | title=Schistosomiasis Fact sheet N°115 | url=https://www.who.int/mediacentre/factsheets/fs115/en | publisher=World Health Organization | access-date=15 March 2014 | date=3 February 2014 | url-status=dead | archive-url=https://web.archive.org/web/20140312203924/http://www.who.int/mediacentre/factsheets/fs115/en/ | archive-date=12 March 2014}}</ref>

<!-- Cause -->
The disease is spread by contact with [[Earth:Fresh water|fresh water]] contaminated with the parasites.<ref name=WHO2014/> These parasites are released from infected [[Biology:Freshwater snail|freshwater snail]]s.<ref name=WHO2014/> The disease is especially common among children in developing countries, as they are more likely to play in contaminated water.<ref name=WHO2014/> Schistosomiasis is also common among women, who can have greater exposure through daily chores that involve water like washing clothes and fetching water.<ref>{{cite journal |last1=Trienekens |first1=Suzan C. M. |last2=Faust |first2=Christina L. |last3=Meginnis |first3=Keila |last4=Pickering |first4=Lucy |last5=Ericsson |first5=Olivia |last6=Nankasi |first6=Andrina |last7=Moses |first7=Arinaitwe |last8=Tukahebwa |first8=Edridah M. |last9=Lamberton |first9=Poppy H. L. |date=2020-05-13 |title=Impacts of host gender on Schistosoma mansoni risk in rural Uganda—A mixed-methods approach |journal=PLOS Neglected Tropical Diseases |language=en |volume=14 |issue=5 |pages=e0008266 |doi=10.1371/journal.pntd.0008266 |issn=1935-2735 |pmc=7219705 |pmid=32401770 |doi-access=free }}</ref> Other high-risk groups include farmers, fishermen, and people using unclean water during daily living.<ref name=WHO2014/> It belongs to the group of [[Medicine:Helminthiasis|helminth infections]].<ref>{{cite web | title=Chapter 3 Infectious Diseases Related To Travel | url=http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-3-infectious-diseases-related-to-travel/schistosomiasis | publisher=cdc.gov | access-date=30 November 2014 | date=1 August 2013 | url-status=live | archive-url=https://web.archive.org/web/20150402165447/http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-3-infectious-diseases-related-to-travel/schistosomiasis | archive-date=2 April 2015}}</ref> Diagnosis is by finding eggs of the parasite in a person's urine or stool.<ref name=WHO2014/> It can also be confirmed by finding [[Biology:Antibodies|antibodies]] against the disease in the blood.<ref name=WHO2014/>

<!-- Prevention and Treatment -->
Methods of preventing the disease include improving access to clean water and reducing the number of snails.<ref name=WHO2014/> In areas where the disease is common, the medication [[Chemistry:Praziquantel|praziquantel]] may be given once a year to the entire group.<ref name=WHO2014/> This is done to decrease the number of people infected, and consequently, the spread of the disease.<ref name=WHO2014/> Praziquantel is also the treatment recommended by the [[Organization:World Health Organization|World Health Organization]] for those who are known to be infected.<ref name=WHO2014/>

<!-- Epidemiology -->
Schistosomiasis affected about 236.6 million people worldwide in 2019.<ref name="WHO-2021">{{cite web|date=2021-05-18|title=Schistosomiasis|url=https://www.who.int/news-room/fact-sheets/detail/schistosomiasis|access-date=2021-06-05|website=www.who.int|language=en}}</ref> An estimated 4,400 to 200,000 people die from it each year.<ref name=The2013>{{cite journal | vauthors = Thétiot-Laurent SA, Boissier J, Robert A, Meunier B | title = Schistosomiasis chemotherapy | journal = Angewandte Chemie | volume = 52 | issue = 31 | pages = 7936–56 | date = July 2013 | pmid = 23813602 | doi = 10.1002/anie.201208390 }}</ref><ref name=GBD2015De>{{cite journal | vauthors = Vos T, Allen C, Arora M, Barber RM, Bhutta ZA, Brown A, etal | collaboration = GBD 2015 Mortality and Causes of Death Collaborators | title = Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980-2015: a systematic analysis for the Global Burden of Disease Study 2015 | journal = Lancet | volume = 388 | issue = 10053 | pages = 1459–1544 | date = October 2016 | pmid = 27733281 | pmc = 5388903 | doi = 10.1016/s0140-6736(16)31012-1 }}</ref> The disease is most commonly found in Africa, Asia, and South America.<ref name=WHO2014/> Around 700 million people, in more than 70 countries, live in areas where the disease is common.<ref name=The2013/><ref>{{cite web | title=Schistosomiasis A major public health problem | url=https://www.who.int/schistosomiasis/en | publisher=World Health Organization | access-date=15 March 2014 | url-status=live | archive-url=https://web.archive.org/web/20140405213018/http://www.who.int/schistosomiasis/en/ | archive-date=5 April 2014}}</ref> In tropical countries, schistosomiasis is second only to [[Medicine:Malaria|malaria]] among parasitic diseases with the greatest economic impact.<ref name="SCP">{{cite web | author=The Carter Center | title=Schistosomiasis Control Program | url=http://www.cartercenter.org/health/schistosomiasis/index.html | access-date=17 July 2008 | url-status=live | archive-url=https://web.archive.org/web/20080720091015/http://cartercenter.org/health/schistosomiasis/index.html | archive-date=20 July 2008}}</ref> Schistosomiasis is listed as a neglected tropical disease.<ref>{{cite web | title=Neglected Tropical Diseases | url=https://www.cdc.gov/globalhealth/ntd/diseases/index.html | publisher=cdc.gov | access-date=28 November 2014 | date=6 June 2011 | url-status=live | archive-url=https://web.archive.org/web/20141204084219/http://www.cdc.gov/globalhealth/ntd/diseases/index.html | archive-date=4 December 2014}}</ref>

==Signs and symptoms==
[[File:Cercarial dermatitis lower legs.jpg|thumb|Cercarial dermatitis can present as an itchy, red, maculopapular rash (flat and raised lesions) at the sites of cercarial penetration.]]
[[File:Schistosomiasis itch.jpeg|thumb|upright=1.3|Skin blisters on the forearm, created by the entrance of ''Schistosoma'' parasites]]

Many individuals do not experience symptoms. If symptoms do appear, they usually take 4–6 weeks from the time of infection. The first symptom of the disease may be a general feeling of illness. Within 12 hours of infection, an individual may complain of a tingling sensation or light rash, commonly referred to as "[[Medicine:Swimmer's itch|swimmer's itch]]", due to irritation at the point of entrance. The rash that may develop can mimic [[Medicine:Scabies|scabies]] and other types of rashes. Other symptoms can occur 2–10 weeks later and can include [[Medicine:Fever|fever]], aching, a cough, [[Medicine:Diarrhea|diarrhea]], chills, or gland enlargement. These symptoms can also be related to avian schistosomiasis, which does not cause any further symptoms in humans.<ref name="Schistosoma/Schistosomiasis">{{cite web |url=https://www.lecturio.com/concepts/schistosoma-schistosomiasis/| title=Schistosoma/Schistosomiasis|website=The Lecturio Medical Concept Library |access-date= 2 July 2021}}</ref>{{Request quotation|date=July 2021|reason=The source does not seem to mention "avian" or "bird".}}

The manifestations of schistosomal infection vary over time as the cercariae, and later adult worms and their eggs, migrate through the body.<ref name="Gryseels-2006">{{cite journal|vauthors=Gryseels B, Polman K, Clerinx J, Kestens L|date=September 2006|title=Human schistosomiasis|journal=Lancet|volume=368|issue=9541|pages=1106–18|doi=10.1016/s0140-6736(06)69440-3|pmid=16997665|s2cid=999943}}</ref> If eggs migrate to the brain or spinal cord, seizures, paralysis, or spinal-cord inflammation are possible.<ref>{{cite web | url=https://www.cdc.gov/parasites/schistosomiasis/disease.html | title=Parasites - Schistosomiasis, Disease | website=www.cdc.gov | access-date=4 December 2016 | url-status=live | archive-url=https://web.archive.org/web/20161202195524/http://www.cdc.gov/parasites/schistosomiasis/disease.html | archive-date=2 December 2016}}</ref>

===Acute Infection===
Manifestation of acute infection from schistosoma include cercarial dermatitis (hours to days) and acute schistosomiasis (2–8 weeks).{{citation needed|date=January 2023}}

====Cercarial dermatitis====
The first potential reaction is an itchy, [[Medicine:Maculopapular rash|maculopapular]] rash that results from cercariae penetrating the skin within the first 12 hours to days of cercarial skin penetration.<ref name="Elsevier-2020" /> The first time a non-sensitized person is exposed, the rashes are usually mild with an associated prickling sensation that quickly disappear on its own since this is a type of hypersensitivity reaction.<ref name="Elsevier-2020" /> In sensitized people who have previously been infected, the rash can develop into itchy, red, raised lesions (papules) with some turning into fluid-filled lesions (vesicles).<ref name="Elsevier-2020" /> Previous infections with cercariae causes a faster developing and worse presentation of dermatitis due to the stronger immune response.<ref>{{cite web|date=2019-05-13|title=CDC - DPDx - Cercarial Dermatitis|url=https://www.cdc.gov/dpdx/cercarialdermatitis/index.html|access-date=2021-11-01|website=www.cdc.gov|language=en-us}}</ref> The round bumps are usually one to three centimeters across.<ref name="Gray-2011">{{cite journal | vauthors = Gray DJ, Ross AG, Li YS, McManus DP | title = Diagnosis and management of schistosomiasis | journal = BMJ | volume = 342 | pages = d2651 | date = May 2011 | pmid = 21586478 | pmc = 3230106 | doi = 10.1136/bmj.d2651 }}</ref> Because people living in affected areas have often been repeatedly exposed, acute reactions are more common in tourists and migrants.<ref>{{cite journal | vauthors = Bottieau E, Clerinx J, de Vega MR, Van den Enden E, Colebunders R, Van Esbroeck M, Vervoort T, Van Gompel A, Van den Ende J | title = Imported Katayama fever: clinical and biological features at presentation and during treatment | journal = The Journal of Infection | volume = 52 | issue = 5 | pages = 339–45 | date = May 2006 | pmid = 16169593 | doi = 10.1016/j.jinf.2005.07.022 }}</ref> The rash can occur between the first few hours and a week after exposure, and they normally resolve on their own in around 7–10 days.<ref name="Gray-2011"/><ref name="Elsevier-2020" /> For human schistosomiasis, a similar type of [[Medicine:Dermatitis|dermatitis]] called "swimmer's itch" can also be caused by cercariae from animal trematodes that often infect birds.<ref name="Gryseels-2006"/><ref name="Elsevier-2020" /><ref name="Ross-2002">{{cite journal | vauthors = Ross AG, Bartley PB, Sleigh AC, Olds GR, Li Y, Williams GM, McManus DP | title = Schistosomiasis | journal = The New England Journal of Medicine | volume = 346 | issue = 16 | pages = 1212–20 | date = April 2002 | pmid = 11961151 | doi = 10.1056/NEJMra012396 | url = http://espace.library.uq.edu.au/view/UQ:64149/UQ64149_OA.pdf }}</ref> Cercarial dermatitis is not contagious and can not be transmitted from person-to-person.<ref name="CDC FAQ-2020" />

Symptoms may include:
* Flat, red rash<ref name="Elsevier-2020" />
* Small red, raised pimples<ref name="CDC FAQ-2020" />
* Small red blisters<ref name="CDC FAQ-2020" />
* Prickling or tingling sensation, burning, itching of the skin<ref name="CDC FAQ-2020" />

Scratching the rash can lead to secondary bacterial infection of the skin, thus it is important to refrain from scratching.<ref name="CDC FAQ-2020" /> Some common treatments for itching include corticosteroid cream, anti-itch lotion, application of cool compresses to rash, bathing in Epsom salts or baking soda, and in severe itching cases, prescription strength cream and lotions.<ref name="CDC FAQ-2020" /> Oral [[Chemistry:Antihistamine|antihistamine]]s can also help relieve the itching.<ref name="Elsevier-2020" />

====Acute schistosomiasis (Katayama fever)====
Acute schistosomiasis (Katayama fever) may occur weeks or months (around 2–8 weeks)<ref name="Rosenthal-2021">{{Citation|last=Rosenthal|first=Philip J.|title=Schistosomiasis (Bilharziasis)|date=2021|url=http://accessmedicine.mhmedical.com/content.aspx?aid=1175788717|work=Current Medical Diagnosis & Treatment 2021|editor-last=Papadakis|editor-first=Maxine A.|place=New York, NY|publisher=McGraw-Hill Education|access-date=2021-11-01|editor2-last=McPhee|editor2-first=Stephen J.|editor3-last=Rabow|editor3-first=Michael W.}}</ref> after the initial infection as a systemic reaction against migrating schistosomulae as they pass through the bloodstream through the lungs to the liver and also against the antigens of eggs.<ref name="Gryseels-2006" /> Similarly to swimmer's itch, Katayama fever is more commonly seen in people with their first infection such as migrants and tourists, and it is associated with heavy infection.<ref name="Cohen-2017" /> It is seen, however, in native residents of China infected with ''[[Biology:Schistosoma japonicum|S. japonicum]]''.<ref>{{cite journal | vauthors = Ross AG, Sleigh AC, Li Y, Davis GM, Williams GM, Jiang Z, Feng Z, McManus DP | title = Schistosomiasis in the People's Republic of China: prospects and challenges for the 21st century | journal = Clinical Microbiology Reviews | volume = 14 | issue = 2 | pages = 270–95 | date = April 2001 | pmid = 11292639 | pmc = 88974 | doi = 10.1128/CMR.14.2.270-295.2001 }}</ref> ''S. japonicum'' can cause acute schistosomiasis in chronically infected population, and it can lead to a more severe form of acute schistosomiasis.<ref name="Elsevier-2020" />

Symptoms may include:
* Dry cough with changes on chest X-ray<ref name="Rosenthal-2021" />
* Fever<ref name="Rosenthal-2021" />
* Fatigue
* [[Medicine:Myalgia|Muscle aches]]<ref name="Rosenthal-2021" />
* Headache<ref name="Rosenthal-2021" />
* Malaise<ref name="Rosenthal-2021" />
* Abdominal pain<ref name="Cohen-2017" />
* Diarrhea<ref name="Rosenthal-2021" />
* Enlargement of both the liver and the spleen<ref name="Rosenthal-2021" />
* Hives<ref name="Rosenthal-2021" />
Acute schistosomiasis usually self-resolves in 2–8 weeks in most cases.,<ref name="Rosenthal-2021" /> but a small proportion of people have persistent weight loss, diarrhea, diffuse abdominal pain, and rash.<ref name="Gryseels-2006"/>

Complications may include:

Neurological side effects may include 
* Spinal cord inflammation ([[Medicine:Transverse myelitis|transverse myelitis]]) may occur if worms or eggs travel to the spinal cord during this acute phase of infection.<ref name="Elsevier-2020" />
* Headaches 
* Disturbances of sensorium
* Hemiplegia
* Tetraplegia
* Visual impairment
* Ataxia/ speech impairment 
* Motor paralysis
Cardiac side effects may include

*Myocarditis
* Pericarditis 
* Asymptomatic myocardial ischemia

Treatment may include:
* [[Biology:Corticosteroid|Corticosteroid]] such as [[Chemistry:Prednisone|prednisone]] is used to alleviate the hypersensitivity reaction and reduce inflammation<ref name="Elsevier-2020" />
* [[Chemistry:Praziquantel|Praziquantel]] can be administered to kill the adult schistosomes to prevent chronic infection in addition to corticosteroid therapy.<ref name="Elsevier-2020" /> It is not effective to recent infection as it only targets the adult worms, but not the premature schistosomulae.<ref name="Rosenthal-2021" /> Therefore, a repeat treatment of praziquantel several weeks after initial infection may be warranted.<ref name="Rosenthal-2021" /> It is recommended to treat with praziquantel 4–6 weeks after initial exposure since it targets adult worms.<ref>{{Citation|last1=Lackey|first1=Elizabeth K.|title=Schistosomiasis|date=2021|url=http://www.ncbi.nlm.nih.gov/books/NBK554434/|work=StatPearls|place=Treasure Island (FL)|publisher=StatPearls Publishing|pmid=32119321|access-date=2021-11-02|last2=Horrall|first2=Shawn}}</ref>  For Acute Schistosomiasis(AS) Praziquantel is ineffective onn schistosomulae above 7 days and does not prevent the chronic phase of the disease. Too early of treatment can worsen symptoms of AS. In some cases, this worsening of symptoms can be life-threatening by causing encephalitis related to vasculitis, myocarditis, or pulmonary events. 
* Oxamniquine (50 mg/kg once) can be administer at the early phase of schistosomiasis. It is more effective in against schistsomulae than praziquantel but only with S.mansoni. This prevents the occurrence of chronic S.mansoni infection and egg-laying stage.
* Artemeter is an artemisin derivative efficient against schistosomulae aged 7-21 days. only reduced S.mansoni infection by 50% in exposed children 

===Chronic infection===
In long-established disease, adult worms lay eggs that can cause [[Medicine:Inflammation|inflammatory]] reactions. The eggs secrete [[Biology:Proteolysis|proteolytic]] [[Biology:Enzyme|enzyme]]s that help them migrate to the bladder and intestines to be shed. The enzymes also cause an [[Biology:Eosinophilic|eosinophilic]] inflammatory reaction when eggs get trapped in tissues or embolize to the liver, spleen, [[Medicine:Lung|lung]]s, or [[Biology:Brain|brain]].<ref name="Gryseels-2006"/> The long-term manifestations are dependent on the species of schistosome, as the adult worms of different species migrate to different areas.<ref name="Mandell-2010">{{cite book | title=Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases | url=https://archive.org/details/mandelldouglasbe00gera | url-access=limited | isbn=978-0443068393 | pages=[https://archive.org/details/mandelldouglasbe00gera/page/n3245 3216]–3226.e3 | chapter=Trematodes (Schistosomes and Liver, Intestinal, and Lung Flukes)| last1=Mandell | first1=Gerald L. | last2=Bennett | first2=John Eugene | last3=Dolin | first3=Raphael | last4=Douglas | first4=Robert Gordon | year=2010 }}</ref> Many infections are mildly symptomatic, with [[Medicine:Anemia|anemia]] and [[Medicine:Malnutrition|malnutrition]] being common in endemic areas.<ref>{{cite web | title=Schistosomiasis | url=https://www.niaid.nih.gov/topics/schistosomiasis/Pages/default.aspx | website=www.niaid.nih.gov | access-date=7 February 2016 | url-status=live | archive-url=https://web.archive.org/web/20160213101849/https://www.niaid.nih.gov/topics/schistosomiasis/Pages/default.aspx | archive-date=2016-02-13}}</ref>

====Intestinal schistosomiasis====
The worms of ''[[Biology:Schistosoma mansoni|S. mansoni]]'' and ''S. japonicum'' migrate to the veins of the gastrointestinal tract and liver.<ref name="Ross-2002" /> Eggs in the gut wall can lead to pain, [[Medicine:Hematochezia|blood in the stool]], and diarrhea (especially in children).<ref name="Ross-2002" /> Severe disease can lead to narrowing of the [[Biology:Large intestine|colon]] or [[Biology:Rectum|rectum]].<ref name="Gray-2011" />

In intestinal schistosomiasis, eggs become lodged in the intestinal wall during their migration from the mesenteric venules to the intestinal lumen, and the trapped eggs cause an immune system reaction called a [[Medicine:Granuloma|granulomatous reaction]].<ref name="Elbaz-2013">{{cite journal|last1=Elbaz|first1=Tamer|last2=Esmat|first2=Gamal|date=2013-09-01|title=Hepatic and Intestinal Schistosomiasis: Review|url=|journal=Journal of Advanced Research|language=en|volume=4|issue=5|pages=445–452|doi=10.1016/j.jare.2012.12.001|issn=2090-1232|pmc=4293886|pmid=25685451}}</ref> They mostly affect the large bowel and rectum, and involvement of the small bowel is more rare.<ref name="Elsevier-2020" /> This immune response can lead to obstruction of the colon and blood loss. The infected individual may have what appears to be a potbelly. There is a strong correlation between morbidity of intestinal schistosomiasis and the intensities of infection.<ref name="Elsevier-2020" /> In cases of light infections, symptoms may be mild and can go unrecognized.<ref name="Cohen-2017" /> The most common species to cause intestinal schistosomiasis are ''S. mansoni'' and ''S. japonicum'', however, ''[[Biology:Schistosoma mekongi|S. mekongi]]'' and ''[[Biology:Schistosoma intercalatum|S. intercalatum]]'' can also cause this disease.<ref name="Cohen-2017" />

Symptoms may include:
* Abdominal pain and discomfort<ref name="Elsevier-2020" />
* Loss of appetite<ref name="Elsevier-2020" />
* Mucous diarrhea with or without gross blood<ref name="Elsevier-2020" />
* Blood in feces that is not visibly present (fecal occult blood)<ref name="Elsevier-2020" />
* Abdominal distention<ref name="Elsevier-2020" />

Complications may include:
* [[Medicine:Polyp|Intestinal polyps]]<ref name="Elsevier-2020" />
* Intestinal ulcers<ref name="Elsevier-2020" />
* [[Medicine:Iron-deficiency anemia|Iron deficient anemia]]<ref name="Elbaz-2013"/>
* [[Medicine:Fistula|Fistula]]<ref name="Elsevier-2020" />
* [[Medicine:Stenosis|Bowel strictures (narrowing of colon or rectum)]]<ref name="Elsevier-2020" />
* Protein-losing enteropathy<ref name="Elsevier-2020" />
* Partial or complete [[Medicine:Bowel obstruction|bowel obstruction]]<ref name="Elsevier-2020" />
* [[Medicine:Appendicitis|Appendicitis]] (rare)<ref name="Elsevier-2020" />
Approximately 10-50% of people living in endemic regions of ''S. mansoni'' and ''S. japonicum'' develop intestinal schistosomiasis.<ref name="Elsevier-2020" /> ''S. mansoni'' infection epidemiologically overlaps with high HIV prevalence in Sub-Saharan Africa, where gastrointestinal schistosomiasis has been linked to increased HIV transmission.<ref name="Yegorov-2019" />

==== Hepatosplenic schistosomiasis ====
Eggs also migrate to the liver leading to fibrosis in 4 to 8% of people with chronic infection, mainly those with long-term heavy infection.<ref name="Ross-2002" />

Eggs can become lodged in the [[Biology:Liver|liver]],<ref name="Elbaz-2013" /> leading to [[Medicine:Portal hypertension|portal hypertension]], splenomegaly, the buildup of fluid in the abdomen, and potentially life-threatening dilations or swollen areas in the esophagus or gastrointestinal tract that can tear and bleed profusely ([[Medicine:Esophageal varices|esophageal varices]]). This condition can be separated into two distinct phases: inflammatory hepatic schistosomiasis (early inflammatory reaction) and chronic hepatic schistosomiasis. Most common species to cause this condition are ''S. mansoni'', ''S. japonicum'', and ''S. mekongi''.{{citation needed|date=January 2023}}

Inflammatory hepatic schistosomiasis
* This condition occurs mainly in children and adolescents due to early immune reaction to eggs trapped within the periportal and presinusoidal spaces of the liver creating numerous granulomas.<ref name="Elsevier-2020" /> Liver function is not affected, and the severity of liver and spleen enlargement is correlated to the intensity of the infection.<ref name="Elsevier-2020" /> It is characterized by an enlarged left lobe of the liver with a sharp edge and enlarged spleen with nodules.<ref name="Elsevier-2020" /> The enlargement of liver and spleen is usually mild, but in severe cases, they can enlarge to the level of the belly button and even into the pelvis.<ref name="Elsevier-2020" />

[[File:Caput medusae.jpg|thumb|Caput medusae can occur as a result of the portal hypertension caused by periportal fibrosis]]
Chronic (fibrotic) hepatic schistosomiasis
* This is a late stage liver disease that occurs mainly in young and middle-aged adults who have been chronically infected with a heavy infection and whose immune regulation of fibrosis is not functioning properly.<ref name="Elsevier-2020" /> It affects only a small proportion of people who are infected.<ref name="Elsevier-2020" /> Liver function and liver architecture are not affected unlike cirrhosis.<ref name="Elsevier-2020" /> The pathogenesis of this disease is caused by deposition of collagen and extracellular matrix proteins within the periportal space, which leads to liver portal fibrosis and enlarged fibrotic portal tracts (Symmer's pipe stem fibrosis).<ref name="Elbaz-2013" /> The periportal fibrosis physically compress the portal vein leading to [[Medicine:Portal hypertension|portal hypertension]] (increased portal venous pressure), increased pressure of the splenic vein, and subsequent enlargement of the spleen.<ref name="Elsevier-2020" /> Portal hypertension can also increase the pressure in portosystemic anastomoses (vessel connections between the portal circulation and systemic circulation) leading to esophageal varices and [[Medicine:Caput medusae|caput medusae]].<ref name="Elsevier-2020" /> These portosystemic anastomoses also allows a pathway for the eggs to travel to locations such as the lungs, spinal cord, or brain.<ref name="Elsevier-2020" /> Co-infection with hepatitis is common in regions endemic to schistosomiasis with hepatitis B or hepatitis C, and co-infection with hepatitis C is associated with more rapid liver deterioration and worse outcome.<ref name="Elbaz-2013" /> Fibrotic hepatic schistosomiasis caused by ''S. mansoni'' usually develops in around 5–15 years, while it can take less time for ''S. japonicum''.<ref name="Elsevier-2020" />
* Symptoms may include:
** [[Medicine:Esophageal varices|Esophageal varices]] (can cause life-threatening esophageal variceal bleed)<ref name="Elbaz-2013" />
** [[Medicine:Ascites|Ascites]] (end-stage)<ref name="Elbaz-2013" />
** [[Medicine:Caput medusae|Caput medusae]]<ref name="Elsevier-2020" />
** [[Medicine:Hepatosplenomegaly|Enlarged spleen and liver]]<ref name="Elsevier-2020" />
* Complications may include:
** Neuroschistosomiasis<ref name="Elsevier-2020" /> due to portosystemic anastomoses from portal hypertension
** Pulmonary Schistosomiasis<ref name="Elsevier-2020" /> due to portosystemic anastomoses from portal hypertension

==== Pulmonary schistosomiasis ====
Portal hypertension secondary to hepatosplenic schistosomiasis can cause vessel connections between the portal (liver and gut) circulation and systemic circulation to develop, which creates a pathway for the eggs and worms to travel to the lungs.<ref name="Elsevier-2020" /> The eggs can be deposited around the alveolar capillary beds and causes granulomatous inflammation of the pulmonary arterioles followed by fibrosis.<ref name="Elsevier-2020" /> This leads to high blood pressure in the pulmonary circulation system ([[Medicine:Pulmonary hypertension|pulmonary hypertension]]), increased pressure in the right heart, enlargement of the pulmonary artery and right atria, and [[Medicine:Right ventricular hypertrophy|thickening of the right ventricular wall]].<ref name="Elsevier-2020" />

Symptoms of [[Medicine:Pulmonary hypertension|pulmonary hypertension]] may include:
* Shortness of breath
* Chest pain
* Feeling tired
* Fainting during physical exertion

====Urogenital schistosomiasis====
[[File:Schistosomiaisis Bladder Calcifications.png|thumb|right|350px|Calcification of the [[Biology:Urinary bladder|bladder]] wall caused by deposition of calcium around the ''Schistosoma'' eggs on a plain X-ray image of the pelvis, in a 44-year-old sub-Saharan man, due to urinary schistosomiasis]]

The worms of ''[[Biology:Schistosoma haematobium|S. haematobium]]'' migrate to the veins around the [[Biology:Urinary bladder|bladder]] and ureters where they reproduce.<ref name="Mandell-2010" /><ref name="Santos-2021" /> ''S. haematobium'' can produce up to 3000 eggs per day, these eggs migrate from the veins to the bladder and ureter lumens, but up to 50 percent of them can become trapped in the surrounding tissues causing granulomatous inflammation, polyps formation, and ulceration of bladder, ureter, and genital tract tissues.<ref name="Elsevier-2020" /><ref name="Santos-2021" /> This can lead to [[Medicine:Hematuria|blood in the urine]] 10 to 12 weeks after infection.<ref name="Gryseels-2006" /><ref name="Gray-2011" /> Over time, [[Medicine:Fibrosis|fibrosis]] can lead to obstruction of the urinary tract, [[Medicine:Hydronephrosis|hydronephrosis]], and kidney failure.<ref name="Gryseels-2006"/><ref name="Gray-2011"/> [[Medicine:Bladder cancer|Bladder cancer]] diagnosis and mortality are generally elevated in affected areas; efforts to control schistosomiasis in [[Place:Egypt|Egypt]] have led to decreases in the bladder cancer rate.<ref name="Gray-2011"/><ref>{{cite journal | vauthors = Mostafa MH, Sheweita SA, O'Connor PJ | title = Relationship between schistosomiasis and bladder cancer | journal = Clinical Microbiology Reviews | volume = 12 | issue = 1 | pages = 97–111 | date = January 1999 | pmid = 9880476 | pmc = 88908 | doi = 10.1128/CMR.12.1.97 }}</ref> The risk of bladder cancer appears to be especially high in male smokers, perhaps due to chronic irritation of the bladder lining allowing it to be exposed to [[Biology:Carcinogen|carcinogen]]s from smoking.<ref name="Ross-2002"/><ref name="Mandell-2010"/>

In women, genitourinary disease can also include genital lesions that may lead to increased rates of [[Biology:HIV|HIV]] transmission.<ref name="Gray-2011"/><ref name="Yegorov-2019">{{cite journal | vauthors = Yegorov S, Joag V, Galiwango RM, Good SV, Okech B, Kaul R | title = Impact of Endemic Infections on HIV Susceptibility in Sub-Saharan Africa | journal = Tropical Diseases, Travel Medicine and Vaccines | volume = 5 | pages = 22 | date = 2019 | pmid = 31798936 | pmc = 6884859 | doi = 10.1186/s40794-019-0097-5 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Feldmeier H, Krantz I, Poggensee G | title = Female genital schistosomiasis: a neglected risk factor for the transmission of HIV? | journal = Transactions of the Royal Society of Tropical Medicine and Hygiene | volume = 89 | issue = 2 | pages = 237 | date = March 1995 | pmid = 7778161 | doi = 10.1016/0035-9203(95)90512-x }}</ref> If lesions involve the fallopian tubes or ovaries, it may lead to infertility.<ref name="Elsevier-2020" /> If the reproductive organs in male are affected, there could be blood in the sperm.<ref name="Elsevier-2020" />

Urinary symptoms may include:
* Blood in the urine - blood is usually seen at the end of a urine stream (most common symptom)<ref name="Elsevier-2020" /><ref name="Cohen-2017" />
* Painful urination<ref name="Elsevier-2020" />
* Increase frequency of urination<ref name="Elsevier-2020" />
* Protein in the urine<ref name="Elsevier-2020" />
* Secondary urinary tract infection<ref name="Elsevier-2020" />
* Secondary kidney infection<ref name="Elsevier-2020" />
* Calcification of the bladder wall
Genital symptoms may include:
* Inflammation and ulceration of uterine cervix, vagina, or vulva<ref name="Cohen-2017" />
* Blood in the sperm<ref name="Elsevier-2020" />
* Infertility in female<ref name="Elsevier-2020" />

Kidney function is unaffected in many cases, and the lesions are reversible with proper treatment to eliminate the worms.<ref name="Elsevier-2020" />

==== Neuroschistosomiasis ====
[[Biology:Central nervous system|Central nervous system]] lesions occur occasionally due to inflammation and granuloma development around eggs or worms that find their way to the brain or spinal cord through the circulatory system, and they can potentially develop irreversible scarring without proper treatment.<ref name="Elsevier-2020" /> Cerebral granulomatous disease may be caused by ''S. japonicum'' eggs in the brain during both the acute and chronic phase of the disease.<ref name="Cohen-2017" /> Communities in China affected by ''S. japonicum'' have rates of seizures eight times higher than baseline.<ref name="Ross-2002" /> Cerebral granulomatous infection may also be caused by ''S. mansoni''. ''In situ'' egg deposition following the anomalous migration of the adult worm, which appears to be the only mechanism by which ''Schistosoma'' can reach the central nervous system in people with schistosomiasis.<ref name="pmid23829901" /> The destructive action on the nervous tissue and the mass effect produced by a large number of eggs surrounded by multiple, large granulomas in circumscribed areas of the brain characterize the pseudotumoral form of neuroschistosomiasis and are responsible for the appearance of clinical manifestations: headache, hemiparesis, altered mental status, vertigo, visual abnormalities, seizures, and ataxia. Similarly, granulomatous lesions from ''S. mansoni'' and ''S. haematobium'' eggs in the [[Biology:Spinal cord|spinal cord]] can lead to [[Medicine:Transverse myelitis|transverse myelitis]] (inflammation of the spinal cord) with flaccid [[Medicine:Paraplegia|paraplegia]].<ref>{{cite journal|vauthors=Freitas AR, Oliveira AC, Silva LJ|date=July 2010|title=Schistosomal myeloradiculopathy in a low-prevalence area: 27 cases (14 autochthonous) in Campinas, São Paulo, Brazil|journal=Memórias do Instituto Oswaldo Cruz|volume=105|issue=4|pages=398–408|doi=10.1590/s0074-02762010000400009|pmid=20721482|doi-access=free|hdl=1807/58195|hdl-access=free}}</ref> In cases with advanced hepatosplenic and urinary schistosomiasis, the continuous embolization of eggs from the portal mesenteric system (''S. mansoni'') or portal mesenteric-pelvic system (''S. haematobium'') to the brain, results in a sparse distribution of eggs associated with scant periovular inflammatory reaction, usually with little or no clinical significance.<ref name="pmid23829901">{{cite book | vauthors = Pittella JE | title = Neuroparasitology and Tropical Neurology | chapter = Pathology of CNS parasitic infections | series = Handbook of Clinical Neurology | volume = 114 | pages = 65–88 | date = 2013 | pmid = 23829901 | doi = 10.1016/B978-0-444-53490-3.00005-4 | isbn = 9780444534903 }}</ref>

Spinal cord inflammation ([[Medicine:Transverse myelitis|transverse myelitis]]) symptoms may include:
* Paralysis of the lower extremities<ref name="Elsevier-2020" />
* Loss of bowel or urinary control<ref name="Elsevier-2020" />
* Loss of sensation below the level of the lesion<ref name="Elsevier-2020" />
* Pain below the level of the lesion<ref name="Elsevier-2020" />

Cerebral granulomatous infection symptoms may include:
* Seizures<ref name="Elsevier-2020" />
* Headaches<ref name="Elsevier-2020" />
* Motor impairment<ref name="Elsevier-2020" />
* Sensory impairment<ref name="Elsevier-2020" />
* Cerebellar symptoms<ref name="Elsevier-2020" />
** Unsteady gait
** Inability to stand or sit without support
** Uncoordinated movements
** [[Medicine:Scanning speech|Scanning speech]]
** [[Medicine:Nystagmus|Irregular eye movements]]
Corticosteroids are used to prevent permanent neurological damage from the inflammatory response to the eggs, and sometimes anticonvulsants are needed to stop the seizures.<ref name="Elsevier-2020" /> Corticosteroids are given prior to administration of praziquantel.<ref name="Elsevier-2020" />

==Transmission and life cycle==
[[File:Schistosomiasis life cycle.png|thumb|Life cycle of Schistosoma spp.]]
Infected ''Schistosoma'' individuals release eggs into water via their fecal material or urine. A collection of stool samples under a microscope will show the eggs of ''S. intercalatum'', ''S. mansori'', and ''S. japonicum''. Looking at a urine sample under a microscope would reveal the eggs of ''S. haematobium'' and rarely, the eggs of ''S. mansori.''<ref name="CDC - Schistosomiasis - Disease">{{cite web | url=https://www.cdc.gov/parasites/schistosomiasis/disease.html | title=CDC - Schistosomiasis - Disease | website=www.cdc.gov | access-date=11 November 2016 | url-status=live | archive-url=https://web.archive.org/web/20161103033352/http://www.cdc.gov/parasites/schistosomiasis/disease.html | archive-date=3 November 2016}}</ref> After [[Biology:Larva|larva]]e hatch from these eggs, the larvae infect a very specific type of freshwater snail. For example, in ''S. haematobium'' and ''S. intercalatum'' it is snails of the genus ''[[Biology:Bulinus|Bulinus]]'', in ''S. mansoni'' it is ''[[Biology:Biomphalaria|Biomphalaria]]'', and in ''S. japonicum'' it is ''[[Biology:Oncomelania|Oncomelania]]''.<ref name=CookZumla2009>{{cite book | veditors = Cook GC, Zumla AL | year=2009 | title=Manson's Tropical Diseases | url = https://archive.org/details/mansonstropicald00frcp | url-access = limited | pages=[https://archive.org/details/mansonstropicald00frcp/page/n1451 1431]–1459 | publisher=Saunders Elsevier | edition=22 | isbn=978-1-4160-4470-3 }}</ref> The schistosome larvae undergo the next phase of their lifecycles in these snails, spending their time reproducing and developing. Once this step has been completed, the parasite leaves the snail and enters the water column. The parasite can live in the water for only 48 hours without a mammalian host. Once a host has been found, the worm enters its blood vessels. For several weeks, the worm remains in the vessels, continuing its development into its adult phase. When maturity is reached, mating occurs and eggs are produced. Eggs enter the bladder/intestine and are excreted through urine and feces and the process repeats. If the eggs do not get excreted, they can become engrained in the body tissues and cause a variety of problems such as immune reactions and organ damage.<ref name="WHO-2021" /> While transmission typically occurs only in countries where the freshwater snails are native, a case in Germany was reported where a man got schistosomiasis from an infected snail in his aquarium.<ref>{{cite web|date=1 September 2020|title=Abenteuer Diagnose: Bilharziose|url=https://www.ardmediathek.de/ndr/video/visite/abenteuer-diagnose-bilharziose/ndr-fernsehen/Y3JpZDovL25kci5kZS9jNzliYzgwYi1jNTdiLTQ3ZmQtYjBmZC03NDkyODQ3OWU5Mzg/}}</ref>

Humans encounter larvae of the schistosome parasite when they enter contaminated water while bathing, playing, swimming, washing, fishing, or walking through the water.<ref name="Chitsulo 41–51">{{cite journal | vauthors = Chitsulo L, Engels D, Montresor A, Savioli L | title = The global status of schistosomiasis and its control | journal = Acta Tropica | volume = 77 | issue = 1 | pages = 41–51 | date = October 2000 | pmid = 10996119 | pmc = 5633072 | doi = 10.1016/S0001-706X(00)00122-4 }}</ref><ref>{{cite web | url=https://www.who.int/mediacentre/factsheets/fs115/en | title=Schistosomiasis | publisher=World Health Organization | language=en-GB | access-date=11 November 2016 | url-status=dead | archive-url=https://web.archive.org/web/20161119053826/http://www.who.int/mediacentre/factsheets/fs115/en/ | archive-date=November 19, 2016}}</ref><ref name="CDC - Schistosomiasis - Disease"/>
[[File:Trematode lifecycle stages.png|thumb|Lifecycle stages of a typical trematode, ''[[Biology:Schistosoma japonicum|Schistosoma japonicum]]''.]]

=== Life cycle ===
The life cycle stages:<ref name="CDC-Schistosomiasis-Biology-2019" />
# The excretion of schistosome eggs in urine or feces depending on species
# The hatching of the eggs leading to release of the free-swimming, ciliated larvae called miracidia
# Miracidia find and penetrate the snails, which are the intermediate hosts (specific species of snails is dependent on the species of schistosoma)
# Within the snails, two successive generations of [[Biology:Trematode life cycle stages|sporocysts]] occur
# Sporocysts give rise to the infective free-swimming larvae with forked tails called cercariae, and they leave the snails to enter the water
# Cercariae find the human hosts and penetrate their skin
# Upon entrance into the human hosts, cercariae lose their tails and become schistosomulae
# The schistosomulae travel to the lungs and heart via the venous circulation
# They migrate to the portal venous system of the liver where they mature into the adult form with two separate sexes
# The adult male and female are paired together, exit the liver via portal venous system, and travel to the venous systems of the intestines or bladder (species dependent) and produce eggs
## ''S. japonicum'' - superior mesenteric veins (but can also inhabit inferior mesenteric veins)
## ''S. mansoni'' - inferior mesenteric veins (but can also inhabit superior mesenteric veins)
## ''S. haematobium'' - vesicular and pelvic venous plexus of the bladder (occasionally rectal venules)
## ''S. intercalatum'' and ''S. guineensis'' - inferior mesenteric plexus (lower portion of the bowels compared to ''S. mansoni'')
Schistosomes can live an average of 3–5 years, and the eggs can survive for more than 30 years after infection.<ref name="Elsevier-2020" />

=== Other hosts ===
Schistosomiasis is also a concern of cattle husbandry<ref name="Murphy-et-al-2012">{{cite journal | last1=Murphy | first1=William L. | last2=Knutson | first2=Lloyd V. | last3=Chapman | first3=Eric G. | last4=Mc Donnell | first4=Rory J. | last5=Williams | first5=Christopher D. | last6=Foote | first6=Benjamin A. | last7=Vala | first7=Jean-Claude | title=Key Aspects of the Biology of Snail-Killing Sciomyzidae Flies | journal=Annual Review of Entomology | publisher=Annual Reviews | volume=57 | issue=1 | date=2012-01-07 | issn=0066-4170 | doi=10.1146/annurev-ento-120710-100702 | pages=425–447| pmid=22149268 }}</ref> and [[Biology:Mouse|mice]].<ref name="Campbell-2016">{{cite journal | last=Campbell | first=William C. |  title=Lessons from the History of Ivermectin and Other Antiparasitic Agents | journal=Annual Review of Animal Biosciences | publisher=Annual Reviews | volume=4 | issue=1 | date=2016-02-15 | issn=2165-8102 | doi=10.1146/annurev-animal-021815-111209 | pages=1–14| pmid=26515271 | doi-access=free }}</ref> O-methyl-threonine is weakly effective in mouse schistosomiasis but is not in use.<ref name="Campbell-2016" />

== Pathogenesis ==
The infectious stage starts when the free-swimming larval form of the schistosome, cercariae, penetrates the human skin using their suckers, proteolytic enzymes, and tail movements; the cercariae transformed into schistosomulae by losing its tail and subsequently travels to the heart and lungs through venous system until it eventually reach the liver where it will mature into the adult form.<ref name="CDC-Schistosomiasis-Biology-2019">{{cite web|date=2019-08-14|title=CDC - Schistosomiasis - Biology|url=https://www.cdc.gov/parasites/schistosomiasis/biology.html|access-date=2021-10-28|website=www.cdc.gov|language=en-us}}</ref><ref name="Elsevier-2020">{{cite book|url=https://linkinghub.elsevier.com/retrieve/pii/C2016001879X|title=Hunter's Tropical Medicine and Emerging Infectious Diseases|date=2020|publisher=Elsevier|isbn=978-0-323-55512-8|language=en|doi=10.1016/c2016-0-01879-x|s2cid=241260330}}</ref> The diseases caused by the schistomes are characterized into acute schistosomiasis and chronic schistosomiasis, and they can vary dependent on the species of schistosome.<ref name="Cohen-2017">{{Citation|last1=Cohen|first1=Jon|title=Preface to the Fourth Edition|date=2017-01-01|work=Infectious Diseases (Fourth Edition)|pages=xiv|editor-last=Cohen|editor-first=Jonathan|publisher=Elsevier|language=en|doi=10.1016/b978-0-7020-6285-8.00276-8|isbn=978-0-7020-6285-8|last2=Powderly|first2=William|last3=Opal|first3=Steven|s2cid=185460553|editor2-last=Powderly|editor2-first=William G.|editor3-last=Opal|editor3-first=Steven M.|doi-access=free}}</ref>

'''Acute infection'''
* Minutes to days after initial infection:
** [[Medicine:Swimmer's itch|Cercerial dermatitis (Swimmer's itch)]] - swimmer's itch is caused by a localized allergic reaction at the sites of skin penetration by the cercariae causing an inflammatory reaction that is characterized by itchy red pimples and blisters.<ref name="CDC FAQ-2020">{{cite web|last=Prevention|first=CDC-Centers for Disease Control and|date=2020-09-18|title=CDC - Cercarial Dermatitis - Frequently Asked Questions (FAQs)|url=https://www.cdc.gov/parasites/swimmersitch/faqs.html|access-date=2021-10-28|website=www.cdc.gov|language=en-us}}</ref>
* Few weeks to months after initial infection:
** Acute Schistosomiasis (Katayama's Fever) - the exact pathophysiology of this disease remains unknown.<ref name="Cohen-2017" /> It has been hypothesized to be caused by a systemic immune response due to immune complex formation (Type III hypersensivity) with the foreign antigens on the migratory schistosomula and the eggs, and the subsequent deposition of these complexes on various tissues leading to activation of an autoimmune response.<ref name="Elsevier-2020" /><ref name="Cohen-2017" /> Acute schistosomiasis caused by ''S. mansoni'' and ''S. haematobium'' generally affect people who have been infected for the first time such as tourists visiting endemic regions.<ref name="Elsevier-2020" /> In contrast, cases of acute schistosomiasis caused by ''S. japonicum'' can occur in reinfection to population who reside in endemic regions, and they occur in higher incidences{{verify spelling|date=September 2022|reason=''incidence'' is normally used only in the singular form, perhaps ''incidence'', ''incidents'',  or ''instances'' was intended}} and can have worse prognosis.<ref name="Elsevier-2020" /> It was proposed that the large amount of egg antigens released by ''S. japonicum'' interact with antibodies leading to the formation of high volume of immune complexes, which cause enlargement of the lymph tissues.<ref name="Elsevier-2020" /> This sequence of events can lead to clinical manifestation of fever, enlargement of spleen and liver due to fibrosis, portal hypertension, and death.<ref name="Elsevier-2020" />

'''Chronic infection'''

The clinical manifestations of chronic infection is mainly caused by immune reaction to the eggs entrapment within tissues resulting in [[Medicine:Granuloma|granuloma]] formation and chronic inflammation.<ref name="Cohen-2017" /> Adult worms live together in pairs (one male and female), sexually reproduce, and lay eggs in the veins around the intestines and bladder depending on the species, and these eggs can rupture the wall of the veins to escape to the surrounding tissues.<ref>{{cite journal|last1=Siqueira|first1=Lidiany da Paixão|last2=Fontes|first2=Danilo Augusto Ferreira|last3=Aguilera|first3=Cindy Siqueira Britto|last4=Timóteo|first4=Taysa Renata Ribeiro|last5=Ângelos|first5=Matheus Alves|last6=Silva|first6=Laysa Creusa Paes Barreto Barros|last7=de Melo|first7=Camila Gomes|last8=Rolim|first8=Larissa Araújo|last9=da Silva|first9=Rosali Maria Ferreira|last10=Neto|first10=Pedro José Rolim|date=December 2017|title=Schistosomiasis: Drugs used and treatment strategies|url=https://linkinghub.elsevier.com/retrieve/pii/S0001706X17306812|journal=Acta Tropica|language=en|volume=176|pages=179–187|doi=10.1016/j.actatropica.2017.08.002|pmid=28803725}}</ref> The eggs make their way through the tissues to the intestinal or bladder lumen with help of proteolytic enzymes, however, a large amount of eggs are unable to finish their journey and remained stuck within the tissues where they can elicit an immune response.<ref name="Cohen-2017" /> The miracidia in these eggs can then release antigens that stimulate an inflammatory immune response.<ref name="Cohen-2017" /> The miracidia within the eggs live for around 6–8 weeks before they die and stop releasing the antigens.<ref name="Cohen-2017" /> The granulomatous response is a cellular immune response mediated by CD4<sup>+</sup> T cells, neutrophils, eosinophils, lymphocytes, macrophages, and monocytes, and this chronic inflammatory response elicited by the eggs can cause fibrosis, tissue destruction, and granuloma nodules that disrupt the functions of the organs involved.<ref name="Cohen-2017" /><ref name="Santos-2021">{{cite journal|last1=Santos|first1=Lúcio Lara|last2=Santos|first2=Júlio|last3=Gouveia|first3=Maria João|last4=Bernardo|first4=Carina|last5=Lopes|first5=Carlos|last6=Rinaldi|first6=Gabriel|last7=Brindley|first7=Paul J.|last8=Costa|first8=José M. Correia da|date=January 2021|title=Urogenital Schistosomiasis—History, Pathogenesis, and Bladder Cancer|journal=Journal of Clinical Medicine|language=en|volume=10|issue=2|pages=205|doi=10.3390/jcm10020205|pmid=33429985|pmc=7826813|doi-access=free}}</ref> [[Biology:T helper cell|Th1 helper cell response]] is prominent releasing cytokines such as IFN-'''γ''' during the early phases of infection, and it transitions to [[Biology:T helper cell|Th2 response]] leading to increase in level of IgE, IL-4, and eosinophils as egg production progresses.<ref name="Elsevier-2020" /> In chronic infections, the Th2 response shifts to increasing the level of IL-10, IL-13, and IgG4, which reverses the progression of the granulomas and lead to collagen deposition at the sites of the granulomas.<ref name="Elsevier-2020" /> The specific clinical symptoms and severity of the disease this causes depends on the type of schistosome infection, duration of infection, number of eggs, and the organ at which the eggs are deposited.<ref name="Cohen-2017" /> The amount of eggs entrapped in the tissues will continue to increase if the schistosoma are not eliminated.<ref name="Cohen-2017" />

==Diagnosis==
[[File:Schistosome20043-300.jpg|thumb|right|High-powered detailed micrograph of ''Schistosoma'' parasite eggs in human bladder tissue]]
[[Image:Schistosoma japonicum (3) histopathology.JPG|thumb|''S. japonicum'' eggs in hepatic portal tract]]

===Identification of eggs in stools===

Diagnosis of infection is confirmed by the identification of eggs in stools. Eggs of ''S. mansoni'' are about 140 by 60&nbsp;µm in size and have a lateral spine. The diagnosis is improved through the use of the Kato-Katz technique, a semiquantitative stool examination technique. Other methods that can be used are enzyme-linked immunosorbent assay, circumoval precipitation test, and alkaline phosphatase immunoassay.<ref>{{cite web | url=http://www2.ttcn.ne.jp/~akky/parasite/clinic.htm | archive-url=https://web.archive.org/web/20010523203148/http://www2.ttcn.ne.jp/~akky/parasite/clinic.htm | url-status=dead | archive-date=23 May 2001 | title=Clinical Aspects | access-date=14 June 2007 | publisher=University of Tsukuba School of Medicine}}</ref>

Microscopic identification of eggs in [[Biology:Feces|stool]] or urine is the most practical method for diagnosis. Stool examination should be performed when infection with ''S. mansoni'' or ''S. japonicum'' is suspected, and urine examination should be performed if ''S. haematobium'' is suspected. Eggs can be present in the stool in infections with all ''Schistosoma'' species. The examination can be performed on a simple smear (1 to 2&nbsp;mg of fecal material). Because eggs may be passed intermittently or in small numbers, their detection is enhanced by repeated examinations or concentration procedures, or both. In addition, for field surveys and investigational purposes, the egg output can be quantified by using the Kato-Katz technique (20 to 50&nbsp;mg of fecal material) or the Ritchie technique. Eggs can be found in the urine in infections with ''S. haematobium'' (recommended time for collection: between noon and 3 PM) and with ''S. japonicum''. Quantification is possible by using filtration through a [[Engineering:Nucleopore filter|nucleopore filter]] membrane of a standard volume of urine followed by egg counts on the membrane. Tissue biopsy (rectal biopsy for all species and biopsy of the bladder for ''S. haematobium'') may demonstrate eggs when stool or urine examinations are negative.<ref name=CDC2016Diag>{{CDC | article=Schistosomiasis Infection: Laboratory Diagnosis | url=https://www.cdc.gov/dpdx/schistosomiasis/dx.html | author=Global Health - Division of Parasitic Diseases and Malaria | access-date=5 January 2016}}</ref>

Identification of microhematuria in urine using urine reagent strips is more accurate than circulating antigen tests in the identification of active schistosomiasis in endemic areas.<ref>{{cite journal | vauthors = Ochodo EA, Gopalakrishna G, Spek B, Reitsma JB, van Lieshout L, Polman K, Lamberton P, Bossuyt PM, Leeflang MM | title = Circulating antigen tests and urine reagent strips for diagnosis of active schistosomiasis in endemic areas | journal = The Cochrane Database of Systematic Reviews | issue = 3 | pages = CD009579 | date = March 2015 | volume = 2015 | pmid = 25758180 | pmc = 4455231 | doi = 10.1002/14651858.CD009579.pub2 | collaboration = Cochrane Infectious Diseases Group }}</ref>

===Antibody detection===

Antibody detection can be useful to indicate schistosome infection in people who have traveled to areas where schistosomiasis is common and in whom eggs cannot be demonstrated in fecal or urine specimens. Test sensitivity and specificity vary widely among the many tests reported for the serologic diagnosis of schistosomiasis and are dependent on both the type of antigen preparations used (crude, purified, adult worm, egg, cercarial) and the test procedure.<ref name=CDC2016Diag/>

At the U.S. Centers for Disease Control and Prevention, a combination of tests with purified adult worm antigens is used for antibody detection. All serum specimens are tested by FAST-ELISA using ''S. mansoni'' adult microsomal antigen. A positive reaction (greater than 9 units/µl serum) indicates infection with ''Schistosoma'' species. Sensitivity for ''S. mansoni'' infection is 99%, 95% for ''S. haematobium'' infection, and less than 50% for ''S. japonicum'' infection. Specificity of this assay for detecting schistosome infection is 99%. Because test sensitivity with the FAST-ELISA is reduced for species other than ''S. mansoni'', immunoblots of the species appropriate to the person's travel history are also tested to ensure detection of ''S. haematobium'' and ''S. japonicum'' infections. Immunoblots with adult worm microsomal antigens are species-specific, so a positive reaction indicates the infecting species. The presence of antibody is indicative only of schistosome infection at some time and cannot be correlated with clinical status, worm burden, egg production, or prognosis. Where a person has traveled can help determine which ''Schistosoma'' species to test for by immunoblot.<ref name=CDC2016Diag/>

In 2005, a field evaluation of a novel handheld microscope was undertaken in Uganda for the diagnosis of intestinal schistosomiasis by a team led by Russell Stothard from the Natural History Museum of London, working with the Schistosomiasis Control Initiative, London.<ref name="Stothard">{{cite journal | vauthors = Stothard JR, Kabatereine NB, Tukahebwa EM, Kazibwe F, Mathieson W, Webster JP, Fenwick A | title = Field evaluation of the Meade Readiview handheld microscope for diagnosis of intestinal schistosomiasis in Ugandan school children | journal = The American Journal of Tropical Medicine and Hygiene | volume = 73 | issue = 5 | pages = 949–55 | date = November 2005 | pmid = 16282310 | doi = 10.4269/ajtmh.2005.73.949 | url = http://www.ajtmh.org/cgi/pmidlookup?view=long&pmid=16282310 | doi-access = free }}</ref>

===Molecular diagnostics===
[[Biology:Polymerase chain reaction|Polymerase chain reaction]] (PCR) based testing is accurate and rapid.<ref name=Ut2015/> However, it is not frequently used in countries where the disease is common due to the cost of the equipment and the technical expertise required to run the tests.<ref name=Ut2015/> Using a microscope to detect eggs costs about US$0.40 per test whereas PCR is about $US 7 per test as of 2019.<ref name=Hun2019/> [[Biology:Loop-mediated isothermal amplification|Loop-mediated isothermal amplification]] are being studied as they are lower cost.<ref name=Ut2015>{{cite journal | vauthors = Utzinger J, Becker SL, van Lieshout L, van Dam GJ, Knopp S | title = New diagnostic tools in schistosomiasis | journal = Clinical Microbiology and Infection | volume = 21 | issue = 6 | pages = 529–42 | date = June 2015 | pmid = 25843503 | doi = 10.1016/j.cmi.2015.03.014 | doi-access = free }}</ref> LAMP testing is not commercially available as of 2019.<ref name=Hun2019>{{cite journal| vauthors = Mutro Nigo M, Salieb-Beugelaar GB, Battegay M, Odermatt P, Hunziker P |date=2019-12-19|title=Schistosomiasis: from established diagnostic assays to emerging micro/nanotechnology-based rapid field testing for clinical management and epidemiology |journal=Precision Nanomedicine|volume=3 |pages=439–458 |doi=10.33218/prnano3(1).191205.1 |doi-access=free}}</ref>

=== Laboratory testing ===
''S. haematobium'' screening in the community can be done by using urine dip-stick to check for hematuria, and the stool guaiac test can be used to test for blood in the stool for potential ''S. mansoni'' and ''S. japonicum'' infection.<ref name="Elsevier-2020" /> For travelers or migrants in endemic regions, [[Medicine:Complete blood count|complete blood count with differential]] can be used to identify a high level of eosinophil in the blood, which could be indicative of an acute infection.<ref name="Elsevier-2020" /> [[Medicine:Liver function tests|Liver function test]] can be ordered if hepatosplenic schistosomiasis is suspected, and a subsequent hepatitis test panel can be ordered if liver function test is abnormal.<ref name="Elsevier-2020" />

=== Tissue biopsy ===
If other diagnostic methods of schistosomiasis have failed to detect the infection, but there is still a high suspicion for schistosomiasis, tissue biopsy from the rectum, bladder, and liver can be obtained to look for schistosome eggs within the tissue samples.<ref name="Elsevier-2020" /><ref name="Cohen-2017" />

=== Imaging ===
Imaging modalities such as [[Physics:X-rays|X-rays]], [[Physics:Ultrasound|ultrasound]], [[CT scan|computed tomography (CT)]], and [[Physics:Magnetic resonance imaging|magnetic resonance imaging (MRI)]] can be utilized to evaluate for severity of schistosomiasis and damages of the infected organs.<ref name="Cimini-2021">{{cite journal|last1=Cimini|first1=Andrea|last2=Ricci|first2=Maria|last3=Gigliotti|first3=Paola Elda|last4=Pugliese|first4=Luca|last5=Chiaravalloti|first5=Agostino|last6=Danieli|first6=Roberta|last7=Schillaci|first7=Orazio|date=August 2021|title=Medical Imaging in the Diagnosis of Schistosomiasis: A Review|journal=Pathogens|language=en|volume=10|issue=8|pages=1058|doi=10.3390/pathogens10081058|pmc=8401107|pmid=34451522|doi-access=free}}</ref> For example, X-ray and CT scans of the chest can be used to detect lesions in the lungs from pulmonary schistosomiasis, and pelvic X-ray can reveal calcification of the bladder in chronic urinary schistosomiasis.<ref name="Cimini-2021" /> Ultrasound may be used to look for abnormalities in the liver and spleen in hepatosplenic schistosomiasis, and CT scan of the liver is a good tool to look for calcification in the liver associated with ''S. japonicum'' infection.<ref name="Cimini-2021" /> CT scan can also be used to assess damages from the schistosomiasis infection in the intestinal, urogenital, and central nervous system.<ref name="Cimini-2021" /> MRI is used to evaluate schistosomiasis of the central nervous system, liver, and genital.<ref name="Cimini-2021" />

[[Biology:PET-CT|PET/CT]] scan that identifies tissues with higher metabolic activity have been used to help diagnose schistosomiasis in rare cases.<ref name="Cimini-2021" /> This is due to the high level of inflammation caused by the schistosomal eggs, which increases the metabolic rate of the surrounding tissues.<ref name="Cimini-2021" />

==Prevention==
[[File:Xintan Town - on the levee - P1540385.JPG|thumb|"Schistosomes are here. People and livestock are strictly prohibited from entering the water!", a warning painted on a Yangtze levee in Honghu, Hubei, China]]
Many countries are working towards eradicating the disease. The [[Organization:World Health Organization|World Health Organization]] is promoting these efforts. In some cases, urbanization, pollution, and the consequent destruction of snail habitat have reduced exposure, with a subsequent decrease in new infections. The elimination of snail populations using molluscicides had been attempted to prevent schistosomiasis in the past, but it was an expensive process that often only reduced but did not eliminate the snail population.<ref name="Elsevier-2020" /> The drug praziquantel is used for prevention in high-risk populations living in areas where the disease is common.<ref>WHO (2013) Schistosomiasis: [https://www.who.int/iris/bitstream/10665/78074/1/9789241503174_eng.pdf Progress report 2001–2011, strategic plan 2012–2020]. Geneva: World Health Organization.</ref> The Centers for Disease Control and Prevention advises avoiding drinking or coming into contact with contaminated water in areas where schistosomiasis is common.<ref>{{cite web | title=Schistosomiasis - Prevention & Control | url=https://www.cdc.gov/parasites/schistosomiasis/prevent.html | publisher=Centers for Disease Control and Prevention | language=en-us | date=7 November 2012 | url-status=live | archive-url=https://web.archive.org/web/20170803085446/https://www.cdc.gov/parasites/schistosomiasis/prevent.html | archive-date=3 August 2017}}</ref>

A 2014 review found tentative evidence that increasing access to clean water and [[Engineering:Sanitation|sanitation]] reduces schistosome infection.<ref name="McGarveyGrimes2014">{{cite journal | vauthors = Grimes JE, Croll D, Harrison WE, Utzinger J, Freeman MC, Templeton MR | title = The relationship between water, sanitation and schistosomiasis: a systematic review and meta-analysis | journal = PLOS Neglected Tropical Diseases | volume = 8 | issue = 12 | pages = e3296 | date = December 2014 | pmid = 25474705 | pmc = 4256273 | doi = 10.1371/journal.pntd.0003296 | doi-access = free }}</ref>

Other important preventive measures include hygiene education leading to behavioral change and sanitary engineering to ensure safe water supply.<ref name="Elsevier-2020" />

=== Preventive anthelminthic administration ===
For schistosomiasis control, the World Health Organization recommends preventive anthelminthic administration , which is the treatment of an entire affected population and the periodic treatment of all groups at high risk of acquiring schistosomiasis by using [[Chemistry:Praziquantel|Praziquantel]].<ref name="WHO-2021" /> In 2019, 44.5% of people with schistosomiasis were treated globally, and 67.2% of school-aged children needing preventive chemotherapy received treatment.<ref name="WHO-2021" />

===Snails, dams, and prawns===
For many years from the 1950s onwards, vast dams and irrigation schemes were constructed, causing a massive rise in water-borne infections from schistosomiasis. The detailed specifications laid out in various United Nations documents since the 1950s could have minimized this problem. Irrigation schemes can be designed to make it hard for the snails to colonize the water and to reduce the contact with the local population.<ref>{{cite magazine | vauthors=Charnock, Anne | title=Taking Bilharziasis out of the irrigation equation | magazine=New Civil Engineer | date=7 August 1980 | quote=Bilharzia caused by poor civil engineering design due to ignorance of cause and prevention}}</ref> Even though guidelines on how to design these schemes to minimise the spread of the disease had been published years before, the designers were unaware of them.<ref>{{cite book | title=The IRG Solution — hierarchical incompetence and how to overcome it | publisher=Souvenir Press | location=London | year=1984 | page=88}}</ref> The dams appear to have reduced the population of the large migratory prawn ''[[Biology:Macrobrachium|Macrobrachium]]'', which eats the snails. After the construction of fourteen large dams, greater increases in schistosomiasis occurred in the historical habitats of native prawns than in other areas. Further, at the 1986 Diama Dam on the Senegal River, restoring prawns upstream of the dam reduced both snail density and the human schistosomiasis reinfection rate.<ref name="pmid28438916">{{cite journal | vauthors = Sokolow SH, Jones IJ, Jocque M, La D, Cords O, Knight A, Lund A, Wood CL, Lafferty KD, Hoover CM, Collender PA, Remais JV, Lopez-Carr D, Fisk J, Kuris AM, De Leo GA | title = Nearly 400 million people are at higher risk of schistosomiasis because dams block the migration of snail-eating river prawns | journal = Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences | volume = 372 | issue = 1722 | date = June 2017 | page = 20160127 | pmid = 28438916 | pmc = 5413875 | doi = 10.1098/rstb.2016.0127 }}</ref><ref>{{cite journal | vauthors = Sokolow SH, Huttinger E, Jouanard N, Hsieh MH, Lafferty KD, Kuris AM, Riveau G, Senghor S, Thiam C, N'Diaye A, Faye DS, De Leo GA | title = Reduced transmission of human schistosomiasis after restoration of a native river prawn that preys on the snail intermediate host | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 112 | issue = 31 | pages = 9650–5 | date = August 2015 | pmid = 26195752 | pmc = 4534245 | doi = 10.1073/pnas.1502651112 | bibcode = 2015PNAS..112.9650S | doi-access = free }}</ref>

===Integrated strategy in China===
In China, the national strategy for schistosomiasis control has shifted three times since it was first initiated: transmission control strategy (from mid-1950s to early 1980s), morbidity control strategy (from mid-1980s to 2003), and the "new integrated strategy" (2004 to present). The morbidity control strategy focused on synchronous chemotherapy for humans and bovines and the new strategy developed in 2004 intervenes in the transmission pathway of schistosomiasis, mainly including replacement of bovines with machines, prohibition of grazing cattle in the grasslands, improving sanitation, installation of fecal-matter containers on boats, praziquantel drug therapy, snail control, and health education. A 2018 review found that the "new integrated strategy" was highly effective to reduce the rate of ''S. japonicum'' infection in both humans and the intermediate host snails and reduced the infection risk by 3–4 times relative to the conventional strategy.<ref name="QianZhang2018">{{cite journal | vauthors = Qian C, Zhang Y, Zhang X, Yuan C, Gao Z, Yuan H, Zhong J | title = Effectiveness of the new integrated strategy to control the transmission of Schistosoma japonicum in China: a systematic review and meta-analysis | journal = Parasite | volume = 25 | pages = 54 | year = 2018 | pmid = 30444486 | pmc = 6238655 | doi = 10.1051/parasite/2018058 | url = }} {{open access}}</ref>

==Treatment==
[[File:Medical Civic Action Program in Shinile Woreda, Ethiopia, 2010 (5119873865).jpg|thumb|Ethiopian children treated for ''Schistosoma mansoni'']]

Two drugs, praziquantel and [[Chemistry:Oxamniquine|oxamniquine]], are available for the treatment of schistosomiasis.<ref>{{cite web | url=http://www.emedicine.com/med/topic2071.htm | title=eMedicine - Schistosomiasis | access-date=June 14, 2007 | publisher=eMedicine | url-status=live | archive-url=https://web.archive.org/web/20070707075024/http://www.emedicine.com/med/topic2071.htm | archive-date=July 7, 2007 }}</ref> They are considered equivalent in relation to efficacy against ''S. mansoni'' and safety.<ref>{{cite journal | vauthors = Danso-Appiah A, Olliaro PL, Donegan S, Sinclair D, Utzinger J | title = Drugs for treating Schistosoma mansoni infection | journal = The Cochrane Database of Systematic Reviews | volume = 2 | issue = 2 | pages = CD000528 | date = February 2013 | pmid = 23450530 | pmc = 6532716 | doi = 10.1002/14651858.cd000528.pub2 | url = http://archive.lstmed.ac.uk/4574/1/Cochrane_Database_2_CD000528.pdf }}</ref> Because of praziquantel's lower cost per treatment, and oxaminiquine's lack of efficacy against the urogenital form of the disease caused by ''S. haematobium'', in general praziquantel is considered the first option for treatment.<ref>{{cite web | url=https://www.who.int/tdr/news/2014/praziquantel-for-schistosomiasis/en | title=WHO TDR news item, 4th Dec 2014, Praziquantel dose confirmed for schistosomiasis | access-date=September 5, 2016 | url-status=live | archive-url=https://web.archive.org/web/20160913205716/http://www.who.int/tdr/news/2014/praziquantel-for-schistosomiasis/en/ | archive-date=September 13, 2016 }}</ref> Praziquantel can be safely used in pregnant women and young children.<ref name="Cohen-2017" /> The treatment objective is to cure the disease and to prevent the evolution of the acute to the chronic form of the disease. All cases of suspected schistosomiasis should be treated regardless of presentation because the adult parasite can live in the host for years.<ref>{{cite journal | vauthors = Brinkmann UK, Werler C, Traoré M, Doumbia S, Diarra A | title = Experiences with mass chemotherapy in the control of schistosomiasis in Mali | journal = Tropical Medicine and Parasitology | volume = 39 | issue = 2 | pages = 167–74 | date = June 1988 | pmid = 3140359 }}</ref>

Schistosomiasis is treatable by taking by mouth a single dose of the drug praziquantel annually.<ref name="STreat">{{cite web | author=The Carter Center | title=How is Schistosomiasis Treated? | url=http://www.cartercenter.org/health/schistosomiasis/treatment.html | access-date=17 July 2008 | archive-url=https://web.archive.org/web/20080225084801/http://www.cartercenter.org/health/schistosomiasis/treatment.html <!-- Bot retrieved archive --> | archive-date=25 February 2008}}</ref>

Praziquantel only eliminates the adult schistosomes, but it is not effective in killing the eggs and immature worms.<ref name="Elsevier-2020" /> Live eggs can be excreted by the infected individuals for weeks after treatment with praziquantel.<ref name="Elsevier-2020" /> The immature worms can survive and grow up to be adult schistosomes after praziquantel therapy.<ref name="Elsevier-2020" /> Thus, it is important to have repeated schistosomiasis testing of the stool and/or urine around 4–6 weeks after praziquantel therapy.<ref name="Elsevier-2020" /> Treatment of praziquantel may be repeated to ensure complete elimination of the parasite.<ref name="Elsevier-2020" />

The WHO has developed guidelines for community treatment based on the impact the disease has on children in villages in which it is common:<ref name="STreat"/>
* When a village reports more than 50 per cent of children have blood in their urine, everyone in the village receives treatment.<ref name="STreat"/>
* When 20 to 50 percent of children have bloody urine, only school-age children are treated.<ref name="STreat"/>
* When fewer than 20 percent of children have symptoms, mass treatment is not implemented.<ref name="STreat"/>

Other possible treatments include a combination of praziquantel with [[Chemistry:Metrifonate|metrifonate]], [[Chemistry:Artesunate|artesunate]], or [[Physics:Mefloquine|mefloquine]].<ref name=Cochrane2014>{{cite journal | vauthors = Kramer CV, Zhang F, Sinclair D, Olliaro PL | title = Drugs for treating urinary schistosomiasis | journal = The Cochrane Database of Systematic Reviews | volume = 2014 | issue = 8 | pages = CD000053 | date = August 2014 | pmid = 25099517 | pmc = 4447116 | doi = 10.1002/14651858.CD000053.pub3 }}</ref> A Cochrane review found tentative evidence that when used alone, metrifonate was as effective as praziquantel.<ref name=Cochrane2014/> Mefloquine, which has previously been used to treat and prevent malaria, was recognised in 2008–2009 to be effective against schistosomes.<ref name=Xiao2013>{{cite journal | vauthors = Xiao SH | s2cid = 16689743 | title = Mefloquine, a new type of compound against schistosomes and other helminthes in experimental studies | journal = Parasitology Research | volume = 112 | issue = 11 | pages = 3723–40 | date = November 2013 | pmid = 23979493 | doi = 10.1007/s00436-013-3559-0 }}</ref>

Historically, [[Chemistry:Antimony potassium tartrate|antimony potassium tartrate]] remained the treatment of choice for schistosomiasis until the development of praziquantel in the 1980s.<ref>{{cite journal |last1=Walker |first1=Mark D. |date=August 2018 |title=Etymologia: Antimony |journal=Emerg. Infect. Dis. |volume=24 |issue=8 |pages=1601|quote= citing public domain text, published by the CDC |doi= 10.3201/eid2408.et2408 |doi-access=free |pmc=6056124 }}</ref>

'''Post-treatment monitoring'''
Osteopontin (OPN)  is a promising tool for monitoring praziquantel efficacy and post-treatment fibrosis regression as (OPN) expression is modulated by ''S. mansoni'' egg antigens and its levels correlate with severity of schistosomiasis fibrosis and portal hypertension in mice and humans. Praziquantel pharmacotherapy reduces systemic OPN levels and liver collagen content in mice.<ref>{{cite journal|date=2021-01-23|title=Praziquantel pharmacotherapy reduces systemic osteopontin levels and liver collagen content in murine schistosomiasis mansoni|url=https://www.sciencedirect.com/science/article/abs/pii/S0020751921000308|journal=International Journal for Parasitology|language=en|doi=10.1016/j.ijpara.2020.11.002|issn=0020-7519|last1=Pereira|first1=Thiago A.|last2=Vaz De Melo Trindade|first2=Guilherme|last3=Trindade Santos|first3=Elisangela|last4=Pereira|first4=Fausto E.L.|last5=Souza|first5=Márcia Maria de|volume=51|issue=6|pages=437–440|pmid=33493521|s2cid=231711719}}</ref>

==Epidemiology==
[[File:WHO schistosomiasis stats 2020.png|thumb|Geographic representation of Schistosomiasis endemic countries and their preventive chemotherapy requirement status in the year of 2020 from the World Health Organization.]]
[[File:Schistosomiasis world map-Deaths per million persons-WHO2012.svg|thumb|upright=1.3|Deaths from schistosomiasis per million persons in 2012 {{Div col|small=yes|colwidth=10em}}{{legend|#b3b3b3|no data}}{{legend|#ffff20|0-1}}{{legend|#ffe820|1-2}}{{legend|#ffd820|3-4}}{{legend|#ffc020|5-13}}{{legend|#ffa020|14-15}}{{legend|#ff9a20|16-18}}{{legend|#f08015|19-21}}{{legend|#e06815|22-24}}{{legend|#d85010|25-28}}{{legend|#d02010|29-40}}{{div col end}}]]
[[File:Schistosomiasis world map - DALY - WHO2002.svg|thumb|upright=1.3|[[Disability-adjusted life year]] for schistosomiasis per 100,000&nbsp;inhabitants.{{Div col|small=yes|colwidth=10em}}
{{legend|#b3b3b3|no data}}
{{legend|#ffff65|less than 50}}
{{legend|#fff200|50–75}}
{{legend|#ffdc00|75–100}}
{{legend|#ffc600|100–150}}
{{legend|#ffb000|150–200}}
{{legend|#ff9a00|200–250}}
{{legend|#ff8400|250–300}}
{{legend|#ff6e00|300–350}}
{{legend|#ff5800|350–400}}
{{legend|#ff4200|400–450}}
{{legend|#ff2c00|450–500}}
{{legend|#cb0000|more than 500}}
{{div col end}}]]

The disease is found in tropical countries in Africa, the Caribbean, eastern South America, [[Place:Southeast Asia|Southeast Asia]], and the [[Place:Middle East|Middle East]]. ''S. mansoni'' is found in parts of South America and the Caribbean, Africa, and the Middle East; ''S. haematobium'' in Africa and the Middle East; and ''S. japonicum'' in the [[Place:Far East|Far East]]. ''S. mekongi'' and ''S. intercalatum'' are found locally in [[Place:Southeast Asia|Southeast Asia]] and central [[Place:West Africa|West Africa]], respectively.{{citation needed|date=May 2021}}

The disease is endemic in about 75 developing countries and mainly affects people living in rural agricultural and peri-urban areas.<ref>{{cite journal | vauthors = Oliveira G, Rodrigues NB, Romanha AJ, Bahia D | year=2004 | title=Genome and Genomics of Schistosomes | journal=Canadian Journal of Zoology | volume=82 | issue=2 | pages=375–90 | doi=10.1139/Z03-220 }}</ref><ref name="CDC2011"/><ref name="Chitsulo 41–51"/>
{| class="wikitable"
|+Schistosoma species and endemic regions<ref name="WHO-2021" />
!Type of infection
!Species
!Location
|-
|Intestinal
|Schistosoma mansoni
|Africa, Middle East, Caribbean, Brazil, Venezuela, Suriname
|-
|Intestinal
|Schistosoma japonicum
|China, Indonesia, Philippines
|-
|Intestinal
|Schistosoma mekongi
|Cambodia, Laos
|-
|Intestinal
|Schistosoma guineensis
|Central Africa rain forest
|-
|Intestinal
|Schistosoma intercalatum
|Central Africa rain forest
|-
|Urogenital
|Schistosoma haematobium
|Africa, Middle East, Corsica
|}

===Infection estimates===
In 2010, approximately 238&nbsp;million people were infected with schistosomiasis, 85 percent of whom live in Africa.<ref name="LancetEpi2012">{{cite journal | vauthors = Vos T, Flaxman AD, Naghavi M, Lozano R, Michaud C, Ezzati M, etal | title = Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010 | journal = Lancet | volume = 380 | issue = 9859 | pages = 2163–96 | date = December 2012 | pmid = 23245607 | pmc = 6350784 | doi = 10.1016/S0140-6736(12)61729-2 }}</ref> An earlier estimate from 2006 had put the figure at 200 million people infected.<ref>{{cite book | last1=WHO | title=Guidelines for the Safe Use of Wastewater, Excreta and Greywater, Volume 4 Excreta and Greywater Use in Agriculture. | date=2006 | publisher=World Health Organization | location=Geneva | isbn=978-9241546850 | edition=third | url=http://www.susana.org/en/resources/library/details/1004 | url-status=live | archive-url=https://web.archive.org/web/20141017235811/http://www.susana.org/en/resources/library/details/1004 | archive-date=2014-10-17 }}</ref> As of the latest WHO record, 236.6 million people were infected in 2019.<ref name="WHO-2021" /> In many of the affected areas, schistosomiasis infects a large proportion of children under 14 years of age. An estimated 600 to 700 million people worldwide are at risk from the disease because they live in countries where the organism is common.<ref name="The2013"/><ref name="CDC2011"/> In 2012, 249 million people were in need of treatment to prevent the disease.<ref>{{cite web | title=Schistosomiasis | url=https://www.who.int/mediacentre/factsheets/fs115/en | work=Fact sheet N°115 | publisher=WHO Media Centre | access-date=6 December 2014 | date=February 2014 | url-status=dead | archive-url=https://web.archive.org/web/20141206055845/http://www.who.int/mediacentre/factsheets/fs115/en/ | archive-date=6 December 2014 }}</ref> This likely makes it the most common parasitic infection with malaria second and causing about 207 million cases in 2013.<ref name="CDC2011" /><ref>{{cite web | title=Malaria | url=https://www.who.int/mediacentre/factsheets/fs094/en | work=Fact sheet N°94 | publisher=WHO Media Centre | access-date=6 December 2014 | date=March 2014 | url-status=dead | archive-url=https://web.archive.org/web/20141207045459/http://who.int/mediacentre/factsheets/fs094/en/ | archive-date=7 December 2014 }}</ref>

''S. haematobium'', the infectious agent responsible for urogenital schistosomiasis, infects over 112 million people annually in Sub-Saharan Africa alone.<ref name="Pennington-2014">Luke F. Pennington and Michael H. Hsieh (2014) [http://ebooks.benthamscience.com/book/9781608051489/ Immune Response to Parasitic Infections] {{webarchive|url=https://web.archive.org/web/20141207140442/http://ebooks.benthamscience.com/book/9781608051489/ |date=2014-12-07 }}, Bentham e books, Vol 2, pp. 93-124, {{ISBN|978-1-60805-148-9}}</ref> It is responsible for 32 million cases of dysuria, 10 million cases of [[Medicine:Hydronephrosis|hydronephrosis]], and 150,000 deaths from [[Medicine:Kidney failure|kidney failure]] annually, making ''S. haematobium'' the world's deadliest schistosome.<ref name="Pennington-2014" />

===Deaths===
Estimates regarding the number of deaths vary. Worldwide, the [[Organization:Global Burden of Disease Study|Global Burden of Disease Study]] issued in 2010 estimated 12,000 direct deaths<ref name=Loz2012>{{cite journal | vauthors = Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, etal | s2cid = 1541253 | title = Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010 | journal = Lancet | volume = 380 | issue = 9859 | pages = 2095–128 | date = December 2012 | pmid = 23245604 | doi = 10.1016/S0140-6736(12)61728-0 | pmc = 10790329 | url = https://zenodo.org/record/2557786 | hdl = 10536/DRO/DU:30050819 | hdl-access = free }}</ref> while the WHO in 2014 estimated more than 200,000 annual deaths related to schistosomiasis.<ref name="WHO2014"/><ref name="The2013"/> Another 20 million have severe consequences from the disease.<ref>{{cite journal | vauthors = Kheir MM, Eltoum IA, Saad AM, Ali MM, Baraka OZ, Homeida MM | title = Mortality due to schistosomiasis mansoni: a field study in Sudan | journal = The American Journal of Tropical Medicine and Hygiene | volume = 60 | issue = 2 | pages = 307–10 | date = February 1999 | pmid = 10072156 | doi = 10.4269/ajtmh.1999.60.307 | doi-access =  | s2cid = 34157815 }}</ref> It is the most deadly of the neglected tropical diseases.<ref name="CDC2011">{{cite web | title=Neglected Tropical Diseases | url=https://www.cdc.gov/globalhealth/ntd/diseases/schisto_burden.html | website=cdc.gov | access-date=28 November 2014 | date=6 June 2011 | url-status=live | archive-url=https://web.archive.org/web/20141208061607/http://www.cdc.gov/globalhealth/ntd/diseases/schisto_burden.html | archive-date=8 December 2014 }}</ref>

==History==
The most ancient evidence of schistosomiasis dates back to more than 6,000 years ago. Studies conducted on human skeletal remains found in northern [[Place:Syria|Syria]] (5800–4000 BC) demonstrated evidence of a terminal spined schistosome from the pelvic sediment of skeletal remains. Even though this evidence comes from the Middle East, it has been suggested that the 'cradle' of schistosomes lies in the region of the [[Place:African Great Lakes|African Great Lakes]], an area in which both the parasites and their intermediate hosts are in an active state of evolution. Subsequently, it is believed that schistosomiasis spread to Egypt as a result of the importation of monkeys and slaves during the reign of the fifth dynasty of the Pharaohs (ca. 2494–2345 BC).<ref>{{cite journal|last1=Di Bella|first1=Stefano|last2=Riccardi|first2=Niccolò|last3=Giacobbe|first3=Daniele Roberto|last4=Luzzati|first4=Roberto|date=2018-07-04|title=History of schistosomiasis (bilharziasis) in humans: from Egyptian medical papyri to molecular biology on mummies|journal=Pathogens and Global Health|language=en|volume=112|issue=5|pages=268–273|doi=10.1080/20477724.2018.1495357|issn=2047-7724|pmc=6225400|pmid=30016215}}</ref>

Schistosomiasis is known as bilharzia or bilharziosis in many countries, after German physician Theodor Bilharz, who first described the cause of urinary schistosomiasis in 1851.<ref>{{cite journal |last1=Bilharz |last2=Siebold |first2=C. Th. v.  |title=Ein Beitrag zur Helminthographia humana … |journal=Zeitschrift für wissenschaftliche Zoologie |date=1852 |volume=4 |pages=53–76 |url=https://www.biodiversitylibrary.org/item/50076#page/61/mode/1up |trans-title=A contribution to the literature on helminths [afflicting] humans … |language=de}} See: "2. Distomum Haematobium ''Bilh.''", pp. 59–62.</ref><ref name=Schisto>{{cite book | last=Jordan | first=Peter | title=Schistosomiasis | publisher=Cambridge University Press | location=Cambridge | year=1985 | isbn=978-0-521-30312-5 | page=1}}</ref>

The first physician who described the entire disease cycle was the Brazilian parasitologist Pirajá da Silva in 1908.<ref>{{cite book |last=Droz|first= Jean-Pierre |date=15 July 2015|title=Tropical Hemato-Oncology|page=vii|quote=Theodor Bilhharz (who discovered schistosomiasis in Egypt), and Pirajá da Silva (who established its life cycle)|url=https://books.google.com/books?id=g1UwCgAAQBAJ&q=Piraj%C3%A1+da+Silva+schistosomiasis+life+cycle|publisher=Springer|isbn=9783319182575}}</ref><ref>{{cite book | last=Jamieson | first=Barrie | date=2017 | title=Schistosoma: Biology, Pathology and Control | url=https://books.google.com/books?id=PUSEDgAAQBAJ&pg=PA25 | publisher=CRC Press | isbn=9781498744263}}</ref> The earliest case known of infection was discovered in 2014, belonging to a child who lived 6,200 years ago.<ref>{{cite news | first=Maria | last=Cheng| agency=Associated Press | title=Ancient parasite egg found in 6,200-year-old child skeleton gives earliest evidence of a modern disease | date=20 June 2014 | newspaper=National Post | url=http://news.nationalpost.com/2014/06/20/ancient-parasite-egg-found-in-6200-year-old-child-skeleton-gives-earliest-evidence-of-a-modern-disease/ | url-status=live | archive-url=https://archive.today/20140621014643/http://news.nationalpost.com/2014/06/20/ancient-parasite-egg-found-in-6200-year-old-child-skeleton-gives-earliest-evidence-of-a-modern-disease/ | archive-date=21 June 2014 }}</ref>

The disease was a common cause of death for Egyptians in the Greco-Roman Period.<ref>[https://www.ucalgary.ca/uofc/Others/HOM/Proceedings-2004.pdf#page=13 "Proceedings of the 13h Annual History of Medicine Days"] {{webarchive|url=https://web.archive.org/web/20121028114711/http://www.ucalgary.ca/uofc/Others/HOM/Proceedings-2004.pdf |date=2012-10-28 }}, a medical historical paper from the University of Calgary. March 2004.</ref>

In 2016, more than 200 million people needed treatment, but only 88 million people were actually treated for schistosomiasis.<ref>{{cite web | url=https://www.who.int/mediacentre/factsheets/fs115/en/ | title=Schistosomiasis | website=World Health Organization | language=en-GB | access-date=12 January 2017 | url-status=live | archive-url=https://web.archive.org/web/20170124070606/http://www.who.int/mediacentre/factsheets/fs115/en/ | archive-date=24 January 2017 }}</ref>

===Etymology===
Schistosomiasis is named for the genus of parasitic flatworm ''Schistosoma'', a term which means 'split body'. The name Bilharzia comes from Theodor Bilharz, a {{wipe|Germany}} [[Biology:Pathology|pathologist]] working in [[Place:Egypt|Egypt]] in 1851 who first discovered these worms.{{citation needed|date=May 2021}} The name Katayama disease comes from the Katayama district of Hiroshima Prefecture in {{wipe|Japan}}, where schistosomiasis was once endemic.<ref>{{cite journal |doi=10.1016/S1383-5769(03)00046-1 |title=History of Katayama disease: Schistosomiasis japonica in Katayama district, Hiroshima, Japan |date=2003 |last1=Ishii |first1=Akira |last2=Tsuji |first2=Moriyasu |last3=Tada |first3=Isao |journal=Parasitology International |volume=52 |issue=4 |pages=313–319 |pmid=14665388 }}</ref>

==Society and culture==
Schistosomiasis is endemic in Egypt, exacerbated by the country's dam and irrigation projects along the Nile. From the late 1950s through the early 1980s, infected villagers were treated with repeated injections of tartar emetic. Epidemiological evidence suggests that this campaign unintentionally contributed to the spread of [[Medicine:Hepatitis C|hepatitis C]] via unclean needles. Egypt has the world's highest hepatitis C infection rate, and the infection rates in various regions of the country closely track the timing and intensity of the anti-schistosomiasis campaign.<ref name="pmid16628669">{{cite journal | vauthors = Strickland GT | title = Liver disease in Egypt: hepatitis C superseded schistosomiasis as a result of iatrogenic and biological factors | journal = Hepatology | volume = 43 | issue = 5 | pages = 915–22 | date = May 2006 | pmid = 16628669 | doi = 10.1002/hep.21173 | s2cid = 21288399 | doi-access = free }}</ref>

From ancient times to the early 20th century, schistosomiasis' symptom of blood in the urine was seen as a [[Medicine:Male menstruation|male version of menstruation]] in Egypt and was thus viewed as a [[Religion:Rite of passage|rite of passage]] for boys.<ref>{{cite journal | first1 = Helmut | last1 = Kloos | first2 = Rosalie | last2 = David | year=2002 | journal=Human Ecology Review | volume=9 | issue=1 | url=http://www.humanecologyreview.org/pastissues/her91/91kloosdavid.pdf | title=The Paleoepidemiology of Schistosomiasis in Ancient Egypt | pages=14–25 | quote=By the early twentieth century, the Egyptian population was well aware of the widespread occurrence of haematuria to the point where the passing of blood by boys was considered as a normal and even necessary part of growing up, a form of male menstruation linked with male fertility (Girges 1934, 103). | url-status=live | archive-url=https://web.archive.org/web/20131126102437/http://www.humanecologyreview.org/pastissues/her91/91kloosdavid.pdf | archive-date=2013-11-26 }}</ref><ref>{{cite journal | last=Rutherford | first=Patricia | year=2000 | title=The Diagnosis of Schistosomiasis in Modern and Ancient Tissues by Means of Immunocytochemistry | journal=Chungara, Revista de Antropología Chilena | volume=32 | issue=1 | issn=0717-7356 | quote=The ancient Egyptians also wrote of boys becoming men when blood was seen in their urine, as this was likened to the young female's first menstruation (Despommier et al. 1995). Also, archaeological evidence such as wall reliefs, hieroglyphs, and papyri all confirm that their lifestyle encompassed activities such as bathing, fishing and playing in the Nile, and this combined with bad sanitation habits, would make almost everyone susceptible to this infection. | doi=10.4067/s0717-73562000000100021 | doi-access=free }}</ref>

Among human parasitic diseases, schistosomiasis ranks second behind malaria in terms of socio-economic and public health importance in tropical and subtropical areas.<ref>{{cite news | title=Water-related Diseases | url=https://www.who.int/water_sanitation_health/diseases/schisto/en | access-date=29 November 2015 | publisher=World Health Organization | url-status=dead | archive-url=https://web.archive.org/web/20151201221832/http://www.who.int/water_sanitation_health/diseases/schisto/en/ | archive-date=1 December 2015 }}</ref>

==Research==

A proposed vaccine against ''S. haematobium'' infection called "Bilhvax" underwent a phase 3 clinical trial among children in Senegal. The results, reported in 2018, showed that it was not effective despite provoking some immune response.<ref>{{cite journal | vauthors = Riveau G, Schacht AM, Dompnier JP, Deplanque D, Seck M, Waucquier N, Senghor S, Delcroix-Genete D, Hermann E, Idris-Khodja N, Levy-Marchal C, Capron M, Capron A | title = Safety and efficacy of the rSh28GST urinary schistosomiasis vaccine: A phase 3 randomized, controlled trial in Senegalese children | journal = PLOS Neglected Tropical Diseases | volume = 12 | issue = 12 | pages = e0006968 | date = December 2018 | pmid = 30532268 | pmc = 6300301 | doi = 10.1371/journal.pntd.0006968 | doi-access = free }}</ref> Using [[Biology:CRISPR gene editing|CRISPR gene editing technology]], researchers decreased the symptoms due to schistosomiasis in an animal model.<ref>{{cite web|url=https://www.bionity.com/en/news/158791/crispr-cas9-shown-to-limit-impact-of-certain-parasitic-diseases.html|title=CRISPR/Cas9 shown to limit impact of certain parasitic diseases|website=www.bionity.com|language=en|access-date=2019-01-18}}</ref>

Using thromboelastography, researchers at Tufts University observed that murine blood incubated by adult worms for 1 hour has a coagulation profile similar to that of patients that have hemophilia or on anti-coagulant drugs, suggesting that schistosomes could possess anti-coagulant properties.<ref>{{cite journal |last1=Da'dara |first1=Akram A. |last2=de Laforcade |first2=Armelle M. |last3=Skelly |first3=Patrick J. |date=May 2016 |title=The impact of schistosomes and schistosomiasis on murine blood coagulation and fibrinolysis as determined by thromboelastography (TEG) |journal=Journal of Thrombosis and Thrombolysis |volume=41 |issue=4 |pages=671–677 |doi=10.1007/s11239-015-1298-z |issn=1573-742X |pmc=5467217 |pmid=26573180}}</ref><ref>{{cite journal |last1=MacDonald |first1=Stephen G. |last2=Luddington |first2=Roger J. |date=October 2010 |title=Critical factors contributing to the thromboelastography trace |url=https://pubmed.ncbi.nlm.nih.gov/20978992/ |journal=Seminars in Thrombosis and Hemostasis |volume=36 |issue=7 |pages=712–722 |doi=10.1055/s-0030-1265288 |issn=1098-9064 |pmid=20978992|s2cid=10336191 }}</ref> Inhibiting schistosome activity in blood coagulation could potentially serve as a therapeutic option for schistosomiasis.

== See also ==
* [[Medicine:Angiostrongyliasis|Angiostrongyliasis]], another disease transmitted by snails

== References ==
{{Reflist}}

== External links ==
{{offline|med}}
* {{Curlie|Health/Conditions_and_Diseases/Infectious_Diseases/Parasitic/Flukes/Schistosomiasis/}}
* [http://www.aljazeera.com/programmes/lifelines/2014/04/river-hope-201442313163529194.html ''River of Hope''] — documentary about the rise of schistosomiasis along the Senegal river (video, 47 mins)
* [https://www.iamat.org/risks/schistosomiasis Schistosomiasis information for travellers from IAMAT] (International Association for Medical Assistance to Travellers)
* {{YouTube|Vsp7c2ul4jc|Why Snails Are Deadly? Explained}} by Facts in Motion

{{Medical condition classification and resources
 | DiseasesDB      =11875
|DiseasesDB_mult={{DiseasesDB2|11882}}{{DiseasesDB2|11856}}
 | ICD10           = {{ICD10|B|65||b|65}}
 | ICD9            = {{ICD9|120}}
 | OMIM            =
 | MedlinePlus     =001321
 | eMedicineSubj=article
 | eMedicineTopic=228392
 | MeshID          = D012552
|Orphanet=1247
}}
{{Helminthiases|state=collapsed}}
{{Diseases of Poverty|state=collapsed}}

[[Category:Helminthiases]]
[[Category:Zoonoses]]
[[Category:Tropical diseases]]
[[Category:Hepatology]]
[[Category:Wikipedia medicine articles ready to translate]]

{{Sourceattribution|Schistosomiasis}}