1. Echinococcus granulosus (细粒棘球绦虫)

2. GENERAL INTRODUCTION Worldwide distribution Extra-intestinal tapeworm
Small tapeworm
Laval infection of E. granulosus may cause serious clinical disease ---hydatidosis/ hydatid disease

3. Morphology Only 2-8 mm long Usually comprises of-
Scolex: with four suckers and 2 circular rows of hooks
neck
immature proglottid
mature proglottid
gravid proglottid
The eggs of E. granulosus and Teania spp. are indistinguishable

4. Hydatid Cyst: Round & cystic Wall – cuticle layer, germinal layer
Contents
cystic fluid, brood capsules, protoscolex, daughter & grand daughter cysts (hydatid sands)

5. Hydatid cyst Brood capsule Cuticle layer Germinal layer Daughter cyst
Granddaugher cyst
Protoscolex
Brood capsule
Brood capsule

6. Hydatid cyst

7. Daughter cysts

8. protoscolex

9. Life cycle

10. Definitive host: dog & other canine
Intermediate host: sheep, cattle, camel & human
Infective stage: egg (gravid proglottid)
Sites of hydatid: liver, lungs, abdominal cavity, spleen, kidneys, heart, bones, central nervous system etc
Man is a dead end host

11. Adult worms in intestine of dog

12. Pathogenesis Cause Hydatid Disease (Hydatidosis)
Sites of hydatid cyst: liver, lungs, abdominal cavity, spleen, kidney, heart, bones, brain etc
Analysis of 15,289 cases in Xinjiang,China
Liver 69.97%
Lung 19.3%
Abdominal cavity 3%

13. Clinical menifestations
Depends on the size, the location and the number of cyst.
Pressure –by tremendous size of the cyst. results in disfunction of liver, lung or nervous system
Allergy -due to rupture of cyst, may cause severe allergic reaction
Regeneration – due to rupture of cyst, intracystic protoscolex or germinal layer may be transplanted and result in multiple secondary infection
Secondary regeneration 5.3%
Toxicosis by secretion of worm

15. Surgical removal of the cysts

18. Diagnosis History of contacting with sheep & dogs
Clinical symptoms of a slow-growing tumor accompanied by eosinophilia are suggestive
Parasitological examination for finding scolexes, brood capsules & daughter cysts
Cysts in organs or calcified cysts can be visualized using x-rays, CT & B-ultrasound examination
Biopsy are forbidden unless during operation

19. Serological examination for specific Ab or Cag.
Intradermal (Casoni) test with hydatid fluid is useful.
Antibodies against hydatid fluid antigens have been detected in a sizable population of infected individuals by ELISA or indirect hemagglutination test.

20. CT, brain
B-ultrasound, liver
CT, liver
X-ray, lung

21. Man's arm showing positive skin test for hydatid disease

22. Epidemiology
World distribution. South America (Argentina, Brazil, Uruguay etc ),North America (American, Canada etc) Europe(Iceland, Russia, France, Spain etc), Africa (Kenya, Libya, Egypt, Tunisia etc ).

23. Endemic Factors Contamination of the feces by infected dogs
Intimate contact between dog, herbivorous animal and man in local district
Traveling to endemic areas & importing from endemic areas

24. Control and treatment
Regular treatment of infected dogs to reduce worm load.
Prevention of dogs from eating infected offals of domestic animals(sheep,etc) in the endemic areas.
Health education and strict personal hygiene.
Avoidance of unnecessary contact with infected dogs.
Surgery is still remains the mainstay of the treatment of hydatid disease.
Albendazole have proved to be effective against hydatid cyst(for median or small size cysts).

25. Summary T. solium T. saginata E. granulosus
Proglottides only 3
Rostellum present absent present
Hooks absent
Uterine branches unregularly branched
Definitive host human human dog/wolf
Intermediate host pig/human cattle sheep/human
Infective stage egg/cysticercus cysticercus egg