49. Liver hydative disease

THEME XIII: HYDATID DISEASE

1. What is the definition of “hydatid disease”?

• Hydatid disease → is a parasitic infection caused by the larval stage of the cestode Echinococcus granulosus

2. Hydatid disease is a major health problem in endemic area. Which area is accepted as an endemic?

• Endemic area of hydatid disease is this one where cattle and sheep are raised, and dogs have access to animal offal

3. Indicate some of the endemic area of hydatid disease

• Some of the endemic area of hydatid disease are:

1. Mediterranean countries (Spain, Greece, Turkey)
2. North Africa
3. The Middle East
4. Australia
5. New Zealand
6. South America

4. There are several species of the cestode echinococcus. Which is the most common form of them?

• Echinococcus granulosus is the commonest form of the disease and has the widest geographical distribution

5. Which animals are '”Definitive hosts” of Echinococcus granulosus?

• The dogs and other canines.
• The adult form of E. granulosus lives in the small intestine of the definitive hosts

6. Which animals are 'intermediate hosts' of echinococcus granulosus?

• The sheeps and cattles are intermediate host E. granulosus

7. Definitive or intermediate hosts of Echinococcus granulosus are humans?

• Humans are intermediate hosts of E. granulosus

8. Which activities may interrupt the parasite's lifecycle of E. granulousus prevent the spread of hydatid disease?

• These activities include appropriate disposal of infected animal viscera
• Humans should be cautious with consumption of potentially contaminated fruits and vegetables in endemic areas

9. What is the structure of the adult parasite of echinococcus granulosus?

• The adult parasite → is a 5-mm tapeworm that has a

1. Pyriform head (scolex) with four suckers and numerous hooklets,
2. A short neck,
3. Only a few segments (proglottids), of which the terminal one releases the ova, 300-500 in number

10. What is the structure of the intermediate form of Echinococcus granulosus?

• The intermediate form of echinococcus granulosus → is hydatid cysts.
• This is a spherical- shaped collection of fluid (some housing innumerable scolices),
• With two true parasitic membranes (laminated and germinal)

11. What is the structure and the origin of pericystic layer of hydatid cysts?

• Surrounding the cyst is an outer layer (pericystic layer), which does not belong to the parasite but represents host parenchyma compressed into a fibrovascular layer

12. Which organ is the most commonly localization of hydatid cysts?

• Liver is the most common localization of hydatid cysts

13. Which is the second most common organ affected by hydatid cysts?