1. The Biology of Schistosomiasis
By: Tricia Stone, Marielle Remillard & Tracy Wright

2. Schistosomes macroscopic parasite from the genus Schistosoma
characterized by significant sexual dimorphism
Schistosoma=split body

3. Types of Schistosomes Three species affect humans:
1.) S. mansoni: large intestine
2.) S. japonicum: small intestine
3.) S. haematobium: urinary bladder

4. intermediate fresh water snail host
Life Cycle
intermediate fresh water snail host
miracidia
feces and urine

5. Intermediate Snail Hosts
S. mansoni: Biomphalaria (Africa)
S. haematobium: Bulinus (Africa)
S. japonicum: Oncomelania (Asia)
Biomphalaria
Bulinus
Oncomelania

6. intermediate fresh water snail host
Life Cycle
intermediate fresh water snail host
cercariae

7. Life Cycle in the Human
YUMMY!!
cercariae
human host
human host

8. Life Cycle in the Human
schistosomulum
human host

9. Life Cycle in the Human
schistosomulum
human host
adult schistosome

10. excreted in the feces and urine
Life Cycle in the Human
eggs
excreted in the feces and urine
adult schistosome

11. Life Cycle

12. Stage 1: Migratory Phase
moves through the body to target tissue
begins with penetration through egg production
often symptomless
possible rash and itchy skin
some upper respiratory complications (i.e. cough)

13. Stage 2: Acute Phase 4-10 weeks after infection
begins with egg production
Symptoms:
- fever
- headache
- diarrhea
- fatigue
- nonspecific abdominal pain

14. Stage 3: Chronic Phase prolonged infection (up to 10 years) symptoms:
- cirrhosis of the liver
- kidney damage
- bleeding of upper bowel
- urinary bladder damage
- enlargement of liver and spleen

15. “Slippery Little Suckers Aren’t They…” ~ Julia Roberts (Pretty Woman)
Innate Immunity
penetration of skin
Specific Immunity
adults take on host antigens

16. Incidence

17. Risk Factors 200 million infected globally
20 million with chronic schistosomiasis
600 million at risk
-extreme poverty
-lack of public health facilities
-unsanitary conditions
-unawareness among the people

18. Prevention
avoid swimming in fresh water in countries where schistosomiasis is prevalent.
drink clean water
scrape body down after accidental exposure
water-resistant creams
Snail Control

19. Diagnosis and Treatment
blood tests
examination of stool and urine samples to detect eggs
Treatment
Drugs
Praziquantel - effective in the treatment of all forms of schistosomiasis, with virtually no side effects *
Oxamniquine - used exclusively to treat intestinal schistosomiasis in Africa and South America *
Metrifonate - effective for the treatment of urinary schistosomiasis
Vaccination
Research efforts are directed at finding a vaccine, but no success
*obtained from W.H.O.

20. Interested in More???

21. Questions??????