Schistosomiasis

Pediatric
Schistosomiasis
(Bilharzia)
Prof. Dr. Saad S Al Ani
Senior Pediatric Consultant
Head of Pediatric Department
Khorfakkan Hospital
Sharjah , UAE
saad.alani@moh.gov.ae

Introduction
• Schistosomiasis is a parasitic disease
caused by flukes (trematodes) of the
genus Schistosoma
• After malaria and intestinal
helminthiasis, schistosomiasis is the
third most devastating tropical disease
in the world
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Pediatric Schistosomiasis
2
http://www.who.int/mediacentre/factsheets/fs115/en/

Introduction (Cont.)
• Schistosomiasis is a major source of
morbidity and mortality for
developing countries in Africa, South
America, the Caribbean, the Middle
East, and Asia
• Most human schistosomiasis is
caused by S haematobium, S mansoni,
and S japonicum.
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• Schistosomiasis is due to immunologic
reactions to Schistosoma eggs trapped in
tissues
• Antigens released from the egg stimulate
a granulomatous reaction involving T
cells, macrophages, and eosinophils that
results in clinical disease
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Schistosoma haematobium
Adult female
Adult male
http://www.medicine.cmu.ac.th/dept/parasite/trematodes/SchAd.htm
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Schistosoma mansoni
Adult male & female
http://www.medicine.cmu.ac.th/dept/parasite/trematodes/SchAd.htm
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Schistosoma japonicum
Male and female adult worms
http://ruby.fgcu.edu/courses/davidb/50249/web/sm202.htm
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• Symptoms and signs depend on the
number and location of eggs trapped in
the tissues
• Eggs can end up in the skin, brain,
muscle, adrenal glands, and eyes
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Corachan M. Schistosomiasis and international travel. Clin Infect Dis. 2002 Aug 15.
35(4):446-50

Eggs from the three species
of schistosoma
Eggs from the three species of schistosoma that cause disease in humans. From left to right:
Schistosoma mansoni, Schistosoma haematobium, Schistosoma japonicum
https://www.yourgenome.org/facts/what-is-schistosomiasis
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Schistosoma haematobium.
Egg in urine
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Eggs of S. Hematobium
Eggs of S. haematobium surrounded by intense infiltrates of eosinophils in bladder tissue.
https://en.wikipedia.org/wiki/Schistosoma_haematobium
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Schistosoma mansoni. Egg
in feces
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Schistosoma japonicum. Egg
in fecal smear
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• The different species of Schistosoma
have different types of snails serving as
their intermediate hosts
• Biomphalaria for S mansoni
• Oncomelania for S japonicum
• Bulinus for S haematobium
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Leder K, Weller P. Epidemiology; pathogenesis; and clinical features of
schistosomiasis. UpToDate. April 24, 2009. 1-9.
Academic Journals
Wikipedia
Wikipedia

Pathophysiology
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• Is a systemic, serum sickness-like illness
that develops after several weeks in some,
but not most, individuals with new
schistosomal infections
• It may correspond to the first cycle of
egg deposition and is associated with
marked peripheral eosinophilia and
circulating immune complexes.
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Acute schistosomiasis
(Katayama syndrome)

• Most common with S japonicum and
S mansoni infections
• Most likely to occur in heavily infected
individuals after primary infection.
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(Katayama syndrome)(cont.)

• Symptoms usually resolve over several
weeks, but the syndrome can be fatal
• Early treatment with cidal drugs may
exacerbate this syndrome and necessitate
concomitant glucocorticoid therapy.
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• A history of the patient’s contact with
fresh water, such as through swimming,
boating, rafting, or water skiing, should
be obtained
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• Mild, maculopapular skin lesions may
develop in acute infection within hours
after exposure to cercariae.
• Significant dermatitis is rare with the
major human schistosomal pathogens,
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• abortive human infection with
schistosomal species that rely on other
primary hosts may cause marked
dermatitis or swimmer's itch.
• This self-limited process may recur more
intensely with subsequent exposures to
the same species.
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Chronic schistosomiasis
• Far more common than the acute form of
the infection
• Results from:
 Egg-induced immune response
 Granuloma formation
 Associated fibrotic changes
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Chronic schistosomiasis (Cont.)
• Schistosomal eggs are highly
immunogenic and induce vigorous
circulating and local immune responses
(Cercarial and adult worms are minimally immunogenic)
• Egg retention and granuloma formation
in the bowel wall (usually S mansoni or S
japonicum) may cause bloody diarrhea,
cramping, and, eventually, inflammatory
colonic polyposis
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• Chronic intestinal schistosomiasis can
present with:
Acute complications of appendicitis
Perforation
Bleeding
long after travel-related (or endemic)
exposure
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Terada T. Schistosomal appendicitis: incidence in Japan and a case report. World J Gastroenterol.
2009 Apr 7. 15(13):1648-9

• Heavy infestations are more likely to
produce hepatic disease.
• Pulmonary granulomatosis and fibrosis
can lead to pulmonary hypertension and
frank Cor pulmonale with a high
mortality rate
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• Egg retention and granuloma formation
in the urinary tract (S haematobium) can
lead to:
 Hematuria
 Dysuria
 Bladder polyps and ulcers
 Obstructive uropathies.
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Nmorsi O, Ukwandu N, Egwungenya O, Obhiemi N. Evaluation of CD4(+)/CD8(+) status and
urinary tract infections associated with urinary schistosomiasis among some rural Nigerians. Afr
Health Sci. 2005 Jun. 5(2):126-30

• S haematobium infection is also
associated with an increased rate of
bladder cancer, usually squamous cell
rather than transitional cell.
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27
Nmorsi O, Ukwandu N, Egwungenya O, Obhiemi N. Evaluation of CD4(+)/CD8(+) status and
urinary tract infections associated with urinary schistosomiasis among some rural Nigerians. Afr
Health Sci. 2005 Jun. 5(2):126-30

• Ectopic egg deposition can lead to
additional clinical syndromes, including
involvement of:
14/10/2018
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Coutinho HM, Acosta LP, Wu HW, et al. Th2 cytokines are associated with persistent
hepatic fibrosis in human Schistosoma japonicum infection. J Infect Dis. 2007 Jan 15.
195(2):288-95.
 skin  adrenal glands
 lungs  Genitalia
 Brain  eyes
 muscles

• CNS involvement can result in:
 Transverse myelitis (best described for S
haematobium and S mansoni)
and/or
 Cerebral disease (most common with S
japonicum infection).
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195(2):288-95.

• Local tissue invasion of eggs :
 brings about the release of toxins and
enzymes
 provokes a TH-2–mediated immune
response
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195(2):288-95.

Etiology
• Two major forms of schistosomiasis exist:
 Intestinal
 Urogenital
• These are caused by 5 main species
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5 main species
species Geographical distribution
Intestinal
schistosomiasis
Schistosoma mansoni
(mesenteric venules of the colon)
Africa, the Middle East, the
Caribbean, and South America
Schistosoma japonicum
(mesenteric venules of the small
intestine)
Asia only: China, Indonesia,
the Philippines, and Thailand
Schistosoma mekongi
(mesenteric venules of the small
intestine)
Several districts of Cambodia
and the Lao People’s
Democratic Republic. 200-km
area of Mekong river basin;
now extending toward
northern provinces
Schistosoma intercalatum
(mesenteric venules of the colon) and
related S guineensis
Rain forest areas of Central
and West Africa
Urogenital
schistosomiasis
Schistosoma haematobium
(vesical venous plexus)
Africa, the Middle East, India,
and Turkey
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Life cycle
• Human beings become infected with
schistosomiasis when larval forms of the
parasite, released by freshwater snails,
penetrate their skin during contact with
infested water.
• In the body, the larvae develop into adult
schistosomes
• Adult worms live in the blood vessels,
where the females release eggs
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Life cycle (Cont.)
• Some of the eggs are passed out of the body in
the feces or urine to continue the parasite life
cycle
• Others become trapped in body tissues,
causing an immune reaction and progressive
damage to organs.
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Life cycle of the 3 common
species of Schistosoma
CDC
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Life cycle of Schistosoma haematobium
https://commons.wikimedia.org/w/index.php?curid=64760447
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Epidemiology
• Globally, schistosomiasis is a major
source of morbidity and mortality
• Acute and chronic schistosomiasis
infections are not common in the United
States
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Epidemiology (Cont.)
• Urinary schistosomiasis caused by S
haematobium affects
countries in Africa and the eastern
Mediterranean
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Epidemiology(Cont.)
• Intestinal schistosomiasis caused by S mansoni
occurs in
nations, including:
 Caribbean countries
 Eastern Mediterranean countries
 South American countries
 Most countries in Africa.
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John R, Ezekiel M, Philbert C, Andrew A. Schistosomiasis transmission at high altitude crater lakes in
western Uganda. BMC Infect Dis. 2008 Aug 11. 8:110.

• Other Schistosoma species that can cause
intestinal symptoms and diseases include
S intercalatum, S japonicum, and S
mekongi.
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oS intercalatum is found in
countries within the rain forests of
central Africa.
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oS japonicum is endemic in
countries in the western Pacific region
(i.e., China, Philippines, Indonesia,
Thailand).
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oS mekongi infection occurs in the
Mekong River area of Southeast Asia
(i.e., Kampuchea, Laos, Thailand).
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• >207 million people in at least
countries have active schistosomal infection
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have disease symptoms, including organ-
specific complaints and problems related to
chronic anemia and malnutrition from the
infection
• >20 million are severely ill
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Diagnosing Schistosomiasis
• The criterion standard is microscopic
egg detection in urine or feces
• Polymerase chain reaction (PCR) testing
and assays for certain schistosomal
cytokines or biomarkers are currently
being studied
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https://emedicine.medscape.com/article/788867-overview#a2

(Cont.)
• Important laboratory findings include:
(1) Eosinophilia
and
(2) Hematuria and proteinuria,
which is associated with urinary
schistosomiasis.
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https://emedicine.medscape.com/article/788867-overview#a2

• The Helmintex test can detect egg
burdens below one per gram in patients
with intestinal schistosomiasis
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https://www.medscape.com/viewarticle
(Cont.)

Management of Schistosomiasis
complications
• Management of hepatosplenic, GI, urinary,
cardiopulmonary, and central nervous system
(CNS) complications are summarized as
follows:
 Volume depletion secondary to diarrhea -
Rarely severe, and is treated with
intravenous or oral volume replacement;
 Minor lower GI bleeding and chronic
anemia may be present but rarely require
transfusion
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complications (Cont.)
 Portal hypertension with hematemesis -
Treatment with fluid resuscitation,
transfusion, endoscopic therapy, or surgery
may be required
 Urinary obstruction - May require stenting
or other drainage procedures
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 Salmonella (or other gut source) sepsis -
May require antibiotics and fluids
 Pulmonary hypertension and cor
pulmonale - May require oxygen, diuresis,
antiarrhythmics, or other interventions
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 Cerebral infection - May require seizure
control or management of intracranial
pressure
 Transverse myelitis - May require steroids
and supportive care as well as
antihelminthic therapy
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• During acute infections, antihelminthic
treatment may at first exacerbate symptoms as
a result of increased antigen release, usually
requiring corticosteroid support.
• Treatment may produce a Loeffler-like
syndrome in cases of heavy infestation, which
may require pulmonary support.
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Treatment of schistosomiasis
• Praziquantel remains the drug of choice for
treating all species of schistosomes
• Typical dosages:
 for S haematobium, S intercalatum, and S
mansoni :
20 mg/kg orally twice daily on day 1
 S japonicum and S mekongi.
20 mg/kg orally 3 times daily on day 1
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(Cont.)
• Cure rates range from 65-90% after a single
treatment.
• Egg excretion is reduced by more than 90% in
persons not cured
• Patients should be monitored during therapy
for any seizures or other neurologic
consequences of dying cysticerci.
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Praziquantel
• Schistosomiasis
<4 years: Safety and efficacy not
established
≥4 years: 20 mg/kg PO TID for 1 day
(at intervals 4-6 hr)
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https://reference.medscape.com/drug/biltricide-praziquantel-

(Cont.)
• Corticosteroid therapy
Reduce inflammation and mitigate
reactions that develop in response to
killing the parasites
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(Cont.)
• Maturing schistosomes are less
susceptible to chemotherapy than adult
worms; therefore, a second course of
therapy should be given several weeks
after the first.
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(Cont.)
• Oxamniquine has been used for
treatment of S mansoni infections with
equally good results
• Metrifonate is effective only against
urinary schistosomes; it requires 3 doses
administered 2 weeks apart
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https://emedicine.medscape.com/article/999469-treatment#d8

(Cont.)
• Artemether
 Can kill schistosomula during the first
3 weeks of infection
 Effective for prophylaxis in areas of
high endemicity
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(Cont.)
• Used as an antimalarial, artemether is
also active against schistosome parasites
(mainly schistosomula).
• Trials involving the combination of
artemether and praziquantel show
beneficial effect.
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(Cont.)
• Surgery may be necessary in severe or chronic
schistosomiasis.
• Procedures that may be indicated include the
following:
 Resection of bladder and colonic polyps
 Correction of obstructive uropathy
 Partial colectomy for GI polyposis and fibrosis
 Placement of a distal spleno-renal shunt for
reversal of portal hypertension
 Resection of cerebral cortical granulomas after
failure of chemotherapy
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(Cont.)
Consultations may be indicated with the following
specialists:
• Infectious diseases specialist
• Gastroenterologist
• General surgeon
• Nephrologist
• Neurologist
• Neurosurgeon
• Urologist
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References
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• http://www.who.int/mediacentre/factsheets/fs115/en
• http://www.medicine.cmu.ac.th/dept/parasite/trematodes/SchAd.htm
• http://www.medicine.cmu.ac.th/dept/parasite/trematodes/SchAd.htm
• http://ruby.fgcu.edu/courses/davidb/50249/web/sm202.htm
• Leder K, Weller P. Epidemiology; pathogenesis; and clinical features of schistosomiasis. UpToDate. April
24, 2009. 1-9.
• Terada T. Schistosomal appendicitis: incidence in Japan and a case report. World J Gastroenterol. 2009
Apr 7. 15(13):1648-9
• Nmorsi O, Ukwandu N, Egwungenya O, Obhiemi N. Evaluation of CD4(+)/CD8(+) status and urinary tract
infections associated with urinary schistosomiasis among some rural Nigerians. Afr Health Sci. 2005 Jun.
5(2):126-30
• Coutinho HM, Acosta LP, Wu HW, et al. Th2 cytokines are associated with persistent hepatic fibrosis in
human Schistosoma japonicum infection. J Infect Dis. 2007 Jan 15. 195(2):288-95.
• https://commons.wikimedia.org/w/index.php?curid=64760447
• John R, Ezekiel M, Philbert C, Andrew A. Schistosomiasis transmission at high altitude crater lakes in western Uganda. BMC
Infect Dis. 2008 Aug 11. 8:110.
• https://emedicine.medscape.com/article/788867-overview#a2
• https://www.medscape.com/viewarticle
• https://reference.medscape.com/drug/biltricide-praziquantel-
• https://emedicine.medscape.com/article/999469-treatment#d8

Thank you
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65

Schistosomiasis

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