SchistosomiasisVirginia, Giselle, & NickBIOL 065: Pneumonia & FluThursday, April 19, 2012

Schistosoma literally means “Split Body” in Greek

Facts & Figures

• A “Neglected Tropical Disease” (NTD)o Centers for Disease Control and Preventiono World Health Organization

• 207 Million infections worldwide

• Prevalent in 76 countries

• Causes 22,000 deaths per year

History

• First recorded in 1850 BC in Egypto Scrolls contain writings of treatment and

symptomso Mummified bodies contain eggs in kidneyso 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 – 1915o 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

• Schistosomes are not specific to the humans and other mammals they infect

• Living near bodies of freshwater with a high population of snails

• Specific Lifestyleso Men whose work requires that they wade in

contaminated lakes and riverso Women who use contaminated fresh water

sources to wash clothes and disheso Children who play in contaminated streams

and ponds

The stage of the worm that swims in freshwater and infects humans

Organism

• Genus: Schistosomao 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 Parasiteo Alternatively reproduces sexually and asexually

within a suitable host

Lifecycle of Blood Fluke

• 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

• Eggs:o Most often pass through the

body with few symptoms

o Growth impairment

o Paralysis

o Death

• 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

o Anemia

o Malnutrition

o Hypertension

o Fibrosis

o Calcification

Diagnosis & Treatment

• 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

• Avoidance of contaminated bodies of watero Includes stagnant water where breeding of

parasites and bacteria can occur easiest

• Eradication of snails that cause schistosomiasiso 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

"On my honor, I have neither given nor received unauthorized aid on this assignment"

- Virginia Davis, Nick Dillon, & Giselle Montgomery

Honor Code