Schistosomiasis: Difference between revisions
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Schistosomiasis | {{SI}} | ||
[[File:Schistosomiasis itch.jpeg| | {{Infobox medical condition | ||
| name = Schistosomiasis | |||
| image = [[File:Schistosomiasis_in_a_child_2.jpg|250px]] | |||
| caption = A child with [[schistosomiasis]] showing [[abdominal distension]] | |||
| field = [[Infectious disease]] | |||
| synonyms = Bilharzia, snail fever | |||
| symptoms = [[Abdominal pain]], [[diarrhea]], [[bloody stool]], [[hematuria]] | |||
| complications = [[Liver damage]], [[kidney failure]], [[infertility]], [[bladder cancer]] | |||
| onset = Weeks to months after exposure | |||
| duration = Chronic | |||
| causes = [[Parasitic worms]] of the genus ''[[Schistosoma]]'' | |||
| risks = [[Swimming]] or [[wading]] in [[contaminated water]] | |||
| diagnosis = [[Urine]] or [[stool examination]], [[antibody tests]] | |||
| prevention = [[Avoidance of contaminated water]], [[improved sanitation]], [[mass drug administration]] | |||
| treatment = [[Praziquantel]] | |||
| frequency = 236.6 million people worldwide (2019) | |||
| deaths = 200,000 deaths annually | |||
}} | |||
[[File:Cercarial dermatitis lower legs.jpg|left|thumb|Cercarial dermatitis lower legs]] | |||
[[File:Schistosomiasis itch.jpeg|Schistosomiasis itch|thumb]] | |||
[[File:Caput medusae.jpg|thumb|Caput medusae]] | |||
[[File:Schistosomiaisis Bladder Calcifications.png|thumb|Schistosomiasis Bladder Calcifications]] | |||
== Other names == | == Other names == | ||
Schistosomiasis, also known as bilharzia, is a disease caused by parasitic worms. | Schistosomiasis, also known as bilharzia, is a disease caused by parasitic worms. | ||
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== Clinical features == | == Clinical features == | ||
Although the worms that cause schistosomiasis are not found in the United States, people are infected worldwide. | Although the worms that cause schistosomiasis are not found in the United States, people are infected worldwide. | ||
In terms of impact this disease is second only to malaria as the most devastating parasitic disease. | In terms of impact this disease is second only to malaria as the most devastating parasitic disease. | ||
Schistosomiasis is considered one of the neglected tropical diseases (NTDs). | Schistosomiasis is considered one of the neglected tropical diseases (NTDs). | ||
The parasites that cause schistosomiasis live in certain types of freshwater snails. | The parasites that cause schistosomiasis live in certain types of freshwater snails. | ||
The infectious form of the parasite, known as cercariae, emerge from the snail into the water. | The infectious form of the parasite, known as cercariae, emerge from the snail into the water. | ||
You can become infected when your skin comes in contact with contaminated freshwater. | You can become infected when your skin comes in contact with contaminated freshwater. | ||
Most human infections are caused by ''Schistosoma mansoni, S. haematobium'', or ''S. japonicum''. | Most human infections are caused by ''Schistosoma mansoni, S. haematobium'', or ''S. japonicum''.]] | ||
[[File:S mansoni eggT.jpg|alt=S mansoni egg|thumb|'''S mansoni egg''']] | [[File:S mansoni eggT.jpg|left|thumb|alt=S mansoni egg|left|thumb|'''S mansoni egg''']] | ||
== Diagnosis == | == Diagnosis == | ||
* Examination of stool and/or urine for ova is the primary method of diagnosis for suspected schistosome infections. | * Examination of stool and/or urine for ova is the primary method of diagnosis for suspected schistosome infections. | ||
* The choice of sample to diagnose schistosomiasis depends on the species of parasite likely causing the infection. | * The choice of sample to diagnose schistosomiasis depends on the species of parasite likely causing the infection. | ||
* Adult stages of ''S. mansoni'', ''S. japonicum'', ''S. mekongi'', and ''S. intercalatum'' reside in the mesenteric venous plexus of infected hosts and eggs are shed in feces; | * Adult stages of ''S. mansoni'', ''S. japonicum'', ''S. mekongi'', and ''S. intercalatum'' reside in the mesenteric venous plexus of infected hosts and eggs are shed in feces; | ||
* ''S. haematobium'' adult worms are found in the venous plexus of the lower urinary tract and eggs are shed in urine. | * ''S. haematobium'' adult worms are found in the venous plexus of the lower urinary tract and eggs are shed in urine.]] | ||
[[File:Schistosomiasis Life Cycle.png|alt=Schistosomiasis Life Cycle|thumb|'''Schistosomiasis Life Cycle''']] | [[File:Schistosomiasis Life Cycle.png|thumb|alt=Schistosomiasis Life Cycle|left|thumb|'''Schistosomiasis Life Cycle''']] | ||
=== Travel and other history === | === Travel and other history === | ||
Careful review of travel and residence history is critical for determining whether infection is likely and which species may be causing infection. | Careful review of travel and residence history is critical for determining whether infection is likely and which species may be causing infection. | ||
=== Serological tests === | === Serological tests === | ||
* Serologic testing for antischistosomal antibody is indicated for diagnosis of travelers or immigrants from endemic areas who have not been treated appropriately for schistosomiasis in the past. | * Serologic testing for antischistosomal antibody is indicated for diagnosis of travelers or immigrants from endemic areas who have not been treated appropriately for schistosomiasis in the past. | ||
* Commonly used serologic tests detect antibody to the adult worm. | * Commonly used serologic tests detect antibody to the adult worm. | ||
* For new infections, the serum sample tested should be collected at least 6 to 8 weeks after likely infection, to allow for full development of the parasite and antibody to the adult stage. | * For new infections, the serum sample tested should be collected at least 6 to 8 weeks after likely infection, to allow for full development of the parasite and antibody to the adult stage. | ||
* Serologic testing may not be appropriate for determination of active infection in patients who have been repeatedly infected and treated in the past because specific antibody can persist despite cure. | * Serologic testing may not be appropriate for determination of active infection in patients who have been repeatedly infected and treated in the past because specific antibody can persist despite cure. | ||
* In these patients, serologic testing cannot distinguish resolved infection from active infection. | * In these patients, serologic testing cannot distinguish resolved infection from active infection. | ||
* An antigen test has been developed that can detect active infection based on the presence of schistosomal antigen, but this test is not commercially available in the United States and at this time is undergoing field evaluations for accurate diagnosis of low-intensity infections. | * An antigen test has been developed that can detect active infection based on the presence of schistosomal antigen, but this test is not commercially available in the United States and at this time is undergoing field evaluations for accurate diagnosis of low-intensity infections.]] | ||
[[File:Schistosomiasis haematobia.jpg|alt=Schistosomiasis haematobia|thumb|Schistosomiasis haematobia]] | [[File:Schistosomiasis haematobia.jpg|left|thumb|alt=Schistosomiasis haematobia|left|thumb|Schistosomiasis haematobia]] | ||
== Incubation == | == Incubation == | ||
* The incubation period for patients with acute schistosomiasis is usually 14-84 days; however, many people are asymptomatic and have subclinical disease during both acute and chronic stages of infection. | * The incubation period for patients with acute schistosomiasis is usually 14-84 days; however, many people are asymptomatic and have subclinical disease during both acute and chronic stages of infection. | ||
* Persons with acute infection (also known as Katayama syndrome) may present with rash, fever, headache, myalgia, and respiratory symptoms. Often eosinophilia is present with hepato- and/or splenomegaly. | * Persons with acute infection (also known as Katayama syndrome) may present with rash, fever, headache, myalgia, and respiratory symptoms. Often eosinophilia is present with hepato- and/or splenomegaly. | ||
==== DPDx Resources ==== | ==== DPDx Resources ==== | ||
* DPDx: Schistosomiasis | * DPDx: Schistosomiasis | ||
* Specimen collection: Stool | * Specimen collection: Stool | ||
* Specimen collection: Urine | * Specimen collection: Urine | ||
== Pathophysiology == | == Pathophysiology == | ||
Clinical manifestations of chronic disease result from host immune responses to schistosome eggs. | Clinical manifestations of chronic disease result from host immune responses to schistosome eggs.]] | ||
== Treatment == | == Treatment == | ||
* Infections with all major ''Schistosoma'' species can be treated with praziquantel. | * Infections with all major ''Schistosoma'' species can be treated with praziquantel. | ||
* The timing of treatment is important since praziquantel is most effective against the adult worm and requires the presence of a mature antibody response to the parasite. | * The timing of treatment is important since praziquantel is most effective against the adult worm and requires the presence of a mature antibody response to the parasite. | ||
* For travelers, treatment should be at least 6-8 weeks after last exposure to potentially contaminated freshwater. | * For travelers, treatment should be at least 6-8 weeks after last exposure to potentially contaminated freshwater. | ||
* <br /> | * <br /> | ||
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* There is a lack of safety trial data for the use of praziquantel in children less than 4 years of age or pregnant women. | * There is a lack of safety trial data for the use of praziquantel in children less than 4 years of age or pregnant women. | ||
* WHO reports that there is growing evidence that infected children as young as 1 year old can be effectively treated with praziquantel without serious side effects; however, the drug is commonly available in the form of large, hard-to-swallow pills, which puts young children at risk for choking and other difficulties swallowing the drug. | * WHO reports that there is growing evidence that infected children as young as 1 year old can be effectively treated with praziquantel without serious side effects; however, the drug is commonly available in the form of large, hard-to-swallow pills, which puts young children at risk for choking and other difficulties swallowing the drug. | ||
==Additional images== | |||
<gallery> | |||
File:Trematode lifecycle stages.png|Trematode lifecycle stages | |||
File:Medical Civic Action Program in Shinile Woreda, Ethiopia, 2010 (5119873865).jpg|Medical Civic Action Program in Shinile Woreda, Ethiopia, 2010 | |||
</gallery> | |||
{{stub}} | {{stub}} | ||
{{Helminthiases|state=collapsed}} | {{Helminthiases|state=collapsed}} | ||
| Line 81: | Line 100: | ||
[[Category:Hepatology]] | [[Category:Hepatology]] | ||
[[Category:Neglected tropical diseases]] | [[Category:Neglected tropical diseases]] | ||
[[Category:Infectious causes of cancer]] | [[Category:Infectious causes of cancer]]]] | ||
Latest revision as of 23:31, 26 April 2025
Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD's medical weight loss NYC, sleep center NYC
Philadelphia medical weight loss and Philadelphia sleep clinics
| Schistosomiasis | |
|---|---|
| File:Schistosomiasis in a child 2.jpg | |
| Synonyms | Bilharzia, snail fever |
| Pronounce | N/A |
| Specialty | N/A |
| Symptoms | Abdominal pain, diarrhea, bloody stool, hematuria |
| Complications | Liver damage, kidney failure, infertility, bladder cancer |
| Onset | Weeks to months after exposure |
| Duration | Chronic |
| Types | N/A |
| Causes | Parasitic worms of the genus Schistosoma |
| Risks | Swimming or wading in contaminated water |
| Diagnosis | Urine or stool examination, antibody tests |
| Differential diagnosis | N/A |
| Prevention | Avoidance of contaminated water, improved sanitation, mass drug administration |
| Treatment | Praziquantel |
| Medication | N/A |
| Prognosis | N/A |
| Frequency | 236.6 million people worldwide (2019) |
| Deaths | 200,000 deaths annually |
Other names[edit]
Schistosomiasis, also known as bilharzia, is a disease caused by parasitic worms.
Clinical features[edit]
Although the worms that cause schistosomiasis are not found in the United States, people are infected worldwide. In terms of impact this disease is second only to malaria as the most devastating parasitic disease. Schistosomiasis is considered one of the neglected tropical diseases (NTDs). The parasites that cause schistosomiasis live in certain types of freshwater snails. The infectious form of the parasite, known as cercariae, emerge from the snail into the water. You can become infected when your skin comes in contact with contaminated freshwater. Most human infections are caused by Schistosoma mansoni, S. haematobium, or S. japonicum.]]
Diagnosis[edit]
- Examination of stool and/or urine for ova is the primary method of diagnosis for suspected schistosome infections.
- The choice of sample to diagnose schistosomiasis depends on the species of parasite likely causing the infection.
- Adult stages of S. mansoni, S. japonicum, S. mekongi, and S. intercalatum reside in the mesenteric venous plexus of infected hosts and eggs are shed in feces;
- S. haematobium adult worms are found in the venous plexus of the lower urinary tract and eggs are shed in urine.]]
Travel and other history[edit]
Careful review of travel and residence history is critical for determining whether infection is likely and which species may be causing infection.
Serological tests[edit]
- Serologic testing for antischistosomal antibody is indicated for diagnosis of travelers or immigrants from endemic areas who have not been treated appropriately for schistosomiasis in the past.
- Commonly used serologic tests detect antibody to the adult worm.
- For new infections, the serum sample tested should be collected at least 6 to 8 weeks after likely infection, to allow for full development of the parasite and antibody to the adult stage.
- Serologic testing may not be appropriate for determination of active infection in patients who have been repeatedly infected and treated in the past because specific antibody can persist despite cure.
- In these patients, serologic testing cannot distinguish resolved infection from active infection.
- An antigen test has been developed that can detect active infection based on the presence of schistosomal antigen, but this test is not commercially available in the United States and at this time is undergoing field evaluations for accurate diagnosis of low-intensity infections.]]
Incubation[edit]
- The incubation period for patients with acute schistosomiasis is usually 14-84 days; however, many people are asymptomatic and have subclinical disease during both acute and chronic stages of infection.
- Persons with acute infection (also known as Katayama syndrome) may present with rash, fever, headache, myalgia, and respiratory symptoms. Often eosinophilia is present with hepato- and/or splenomegaly.
DPDx Resources[edit]
- DPDx: Schistosomiasis
- Specimen collection: Stool
- Specimen collection: Urine
Pathophysiology[edit]
Clinical manifestations of chronic disease result from host immune responses to schistosome eggs.]]
Treatment[edit]
- Infections with all major Schistosoma species can be treated with praziquantel.
- The timing of treatment is important since praziquantel is most effective against the adult worm and requires the presence of a mature antibody response to the parasite.
- For travelers, treatment should be at least 6-8 weeks after last exposure to potentially contaminated freshwater.
| Schistosoma species infection | Praziquantel dose and Duration |
|---|---|
| Schistosoma mansoni, S. haematobium, S. intercalatum | 40 mg/kg per day orally in two divided doses for one day |
| S. japonicum, S. mekongi | 60 mg/kg per day orally in three divided doses for one day |
Safety[edit]
- There is a lack of safety trial data for the use of praziquantel in children less than 4 years of age or pregnant women.
- WHO reports that there is growing evidence that infected children as young as 1 year old can be effectively treated with praziquantel without serious side effects; however, the drug is commonly available in the form of large, hard-to-swallow pills, which puts young children at risk for choking and other difficulties swallowing the drug.
Additional images[edit]
-
Trematode lifecycle stages
-
Medical Civic Action Program in Shinile Woreda, Ethiopia, 2010
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| Parasitic disease caused by helminthiases | ||||
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