Schistosomiasis
Virginia, Giselle, & Nick
BIOL 065: Pneumonia & Flu
Thursday, April 19, 2012
Schistosoma literally means “Split Body” in Greek
Facts & Figures
• A “Neglected Tropical Disease” (NTD)
o Centers for Disease Control and Prevention
o World Health Organization
• 207 Million infections worldwide
• Prevalent in 76 countries
• Causes 22,000 deaths per year
History
• First recorded in 1850 BC in Egypt
o Scrolls contain writings of treatment and symptoms
o Mummified bodies contain eggs in kidneys
o Spread to China by 200 BC
• Theodore Bilharz – 1851
o First discovered the parasite in human tissue and
eggs in excrement
• Lt. Col. Robert Thomson Leiper – 1915
o First documented lifecycle and mode of transmission
• Africa is the most prominent location of the
parasite and infection in the current era
The schistosome is capable of infecting humans
through direct contact with intact skin
Risk Factors
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Schistosomes are not specific to the humans
and other mammals they infect
Living near bodies of freshwater with a high
population of snails
Specific Lifestyles
Men whose work requires that they wade in
contaminated lakes and rivers
o Women who use contaminated fresh water sources
to wash clothes and dishes
o Children who play in contaminated streams and
ponds
o
The stage of the worm that swims in freshwater and infects humans
Organism
• Genus: Schistosoma
o 3 widespread species cause infection
 S. haematobium, S. japonicum, & S. mansoni
o 2 more localized species cause infection
 S. intercalatum & S. mekongi
o Additional species cause infection in other animals
but rarely in humans
• Digenetic Parasite
o Alternatively reproduces sexually and asexually
within a suitable host
Lifecycle of Blood Fluke
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Parasitic worms penetrate skin and infect
human host
Parasites reside in blood vessels surrounding
intestines or bladder where they release
eggs into feces or urine
Cycle continues once eggs enter rivers and
streams due to poor sanitation control
Once in river, worms complete their
lifecycle within freshwater snails
Monsters Inside Me: http://www.youtube.com/watch?v=VnlYUe57Lr0
The female worm resides in the groove of the male worm once inside of
the mammal’s body for maturation and reproduction
Symptoms
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Eggs:
o Most often pass through the body
with few symptoms
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o
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Growth impairment
Paralysis
Death
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Adult worms:
o Rash
o Abdominal pain
o Slight cough
o Diarrhea
o Chills
o Fever
o Eosinophilia
o Enlargement of lymph nodes,
spleen and liver
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o
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Anemia
Malnutrition
Hypertension
Fibrosis
Calcification
Diagnosis & Treatment
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Diagnosis:
o The most important factor in diagnosis is collecting the
patient history for the case.
o The most common definitive diagnosis tool is the microscopic
identification of schistosoma eggs in stool or urine.
 Smears can be for stool or urine depending on the kind of
schistosomiasis.
o Pelvic x-rays and tissue biopsies may also be used to
diagnosis.
Treatment:
o Medication
 Praziquantel in single oral doses based on patient
This drug is only effective on the adult worms not
eggs
•
The 3 types of schistosoma eggs and as they would be seen in a
microscopic biopsy examination of infected human tissue
Prevention
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Avoidance of contaminated bodies of water
o Includes stagnant water where breeding of parasites
and bacteria can occur easiest
Eradication of snails that cause schistosomiasis
o Can be achieved through the use of
 Carnivorous crayfish
 Molluscicides
Treating drinking water with chemicals such as iodine
and boiling it to remove harmful agents
Should you still come into contact one can dry
themselves vigorously with a towel to prevent the
parasite from penetrating the skin
References (from Research Paper)
Ahmed, S. H. (2011, October 28). Schistosomiasis. In Drugs, Diseases & Procedures. Retrieved April 1, 2012, from Medscape
Reference website: http://emedicine.medscape.com/article/228392-overview#a0101
Brightman, C. (2011, September/October). Schistosomiasis. Travel Health, 38-42.
Brown, M. (2011). Schistosomiasis. Clinical Medicine, 11(5), 479-82.
Crawford, D. H. (2007). Microbes jump species. In Deadly Companions (pp. 69-73). New York, USA: Oxford University Press, Inc.
Schistosomiasis [Fact Sheet]. (2012, January). Retrieved April 1, 2012, from World Health Organization website:
http://www.who.int/mediacentre/factsheets/fs115/en/index.html
Schistosomiasis FAQs. (2010, November 2). Parasites - Schistosomiasis. Retrieved April 1, 2012, from Centers for Disease
Control and Prevention website: http://www.cdc.gov/parasites/schistosomiasis/gen_info/faqs.html
Honor Code
"On my honor, I have neither given nor received
unauthorized aid on this assignment"
- Virginia Davis, Nick Dillon, & Giselle Montgomery