T1 - Schistosomiasis

Question 1

• caused by parasitic flatworms that belong to the genus Schistosoma
• blood flukes

Answer 1

Schistosomiasis

Question 2

Three main Schistosoma species that affect humans

Answer 2

1. S. japonicum
2. S. mansoni
3. S. haematobium

Question 3

Schistosoma species that affect animals

Answer 3

1. S. japonicum
2. S. mekongi
3. S. malayensis

Question 4

Life cycle pattern

Answer 4

1. Eggs shed from infected humans to freshwater
2. Eggs hatch and release miracidia
3. Miracidia penetrate snail tissue
4. Sporocysts develop in snail
5. Free-swimming cercariae released from snail into water
6. Cercariae penetrate skin
7. Cercariae lose tails during penetration and become schistosomulae
8. Circulation
9. Migration to portal blood in liver and maturation into adults
10. Paired adults migrate to: Mesenteric venules of bowel/rectum and Venous plexus of bladder

Question 5

Schistosoma found in mesenteric venules of bowel/rectum

Answer 5

1. S. mansoni
2. S. japonicum
3. S. mekongi

Question 6

Schistosoma found in venous plexus of bladder

Answer 6

1. S. mansoni
2. S. haematobium

Question 7

mode of transmission

Answer 7

direct contact with contaminated freshwater

Question 8

pathogenesis

Answer 8

1. acute pathogenecity
2. chronic pathogenecity

Question 9

acute pathogenecity

Answer 9

1. Cercariae penetration -> temporary urticarial rash
2. Schistosomulae migration -> hypersensitivity
3. Migration and positioning of adult worms -> abdominal pain

Question 10

chronic pathogenecity

Answer 10

1. Intestinal egg deposition -> inflammatory reaction -> fibrosis
2. Hepatic/Hepatosplenic egg deposition -> granulomatous reaction -> splenomegaly/hepatomegaly -> fibrosis

Question 11

Symptoms:
intestinal schistosomiasis

Answer 11

• abdominal pain
• bloody diarrhea
• liver/spleen enlargement

Question 12

Symptoms:
urogenital schistosomiasis

Answer 12

• dysuria (painful urination)
• hematuria (blood in urine)
• potential complications like bladder cancer

Question 13

Diagnosis of Schistosoma

Answer 13

1. Urine or stool samples
2. Blood test
3. Serological test

Question 14

Geographical distribution of Schistosoma

Answer 14

1. Africa
2. Brazil, Surinam, and Venezuela (South America)
3. Dominican Republic, Guadeloupe, Martinique
4. Southern part China
5. Southeast Asia
6. Corsica

Question 15

people at risk of schistosoma

Answer 15

1. Children
2. Fisherman
3. Farmers
4. Exposed in contaminated water

Question 16

treatment for schistosomiasis

Answer 16

1. praziquantel
2. oxamniquine

Question 17

prevention for schistosoma

Answer 17

avoid bathing, swimming, wading, or other contact with freshwater in disease-endemic countries