1. Echinococcus granulosus

2. Echinococcus granulosus
ADULT MORPHOLOGY - small tapeworm mm long
consists of scolex, neck, immature proglottid, mature proglottid, and gravid proglottid

3. Echinococcus granulosus
Hydatid disease
Cosmopolitan
Mediterranean countries
Russian federation
China
North and East Africa
Australia
South America
North America: Deep South and Far West

6. Carnivore
Humans
Herbivore

7. 10-30 scolices per brood capsule

8. Pathogenesis Hydatid cyst Slow growth Asymptomatic for years
Up to 20 years (unless in nervous system)
Pathology depends on
Location
Size
How many

9. Pathogenesis Crowds host tissues Destroys tissues-replaces with cyst
Grows continuously
15 quarts of fluid
Millions of scolices
Rupture of the cyst fatal
Anaphylactic shock hydatid fluid (death)
In most herbivores, cysts do not keep growing

10. Unilocular hydatid cyst in the lung
Note pressure effects exerted by cyst that crowds and destroys lung tissue

11. Hydatid Cyst

12. Diagnosis
Physical imaging
MRI
CT scan
Ultrasound
X-ray
Serodiagnosis

13. Hydatid Cyst of Echinococcus granulosus

14. Treatment Surgery Recurrence Mebendazole
Preoperative chemotherapy-albendazole
Protoscolicidal compounds
Ethanol
Saline
Formalin
Recurrence
50%
Undetected cysts
Inadequate removal
Mebendazole
48% of cysts

16. Epidemiology How do people get infected?
How do eggs get into environment?
How do we ingest them?

17. Epidemiology Human-Dog Herbivores: Sheep, goats, camels, rabbit
Sheep raising areas
Offal

18. Epidemiology
Human-Dog contact

19. Epidemiology
Human-wildlife contact

20. Echinococcus granulosus

21. Complex Echinococcus granulosus comprises multiple species
Life cycle patterns
Host specificity
Development Rate
Antigenicity
Transmission dynamics
Chemotherapeutic drug response
Pathology

22. Control
Sheep vaccine successful

23. Echinococcus multilocularis

24. Life Cycle of Echinococcus multilocularis
1. Adult tapeworm occurs in intestine of foxes.
Dogs, cats, and coyotes can also serve as definitive hosts.
Adult is small mm long

25. Echinococcus multilocularis
Alveolar hydatid cyst in a mouse - cyst metastasizes from the liver to fill the body cavity

26. Alveolar Hydatid Cyst

27. Echinococcus multilocularis
Liver
Cyst multilocular hydatid
External budding
Extend processes throughout tissues
Cirrhosis of liver
Thinner membrane
Metastasis
Advanced cases

28. Echinococcus multilocularis
Not easily operable
timing
Chemotherapy
Praziquantel can increase growth
Mebendazole and albendazole given throughout the life of the patient.
retards growth
Not easily treatable

29. Echinococcus multilocularis
Fox tapeworm
Europe, Asia, Americas, New Zealand

30. Echinococcus multilocularis
This species has recently been reported in the upper Midwest (North and South Dakota, Minnesota, Iowa, Nebraska, southern Wisconsin, and Indiana). Recently identified in Illinois, Ohio and Missouri.

32. Epidemiology Increasing in Europe
Up to 1980’s only in France, Switzerland, Germany, and Austria
Spreading throughout Europe.

33. Epidemiology Increase in fox infection Increase in human infection
Still rare
Switzerland and Germany
Antirabies vaccines
Increased fox abundance
Movement of foxes
Encroachment on urban areas
Contact with domestic dogs

35. Hymenolepis

36. Hymenolepis Hymenolepis diminuta Hymenolepis nana Rare in humans 90 cm
Model tapeworm
Hymenolepis nana
“Dwarf tapeworm” 40 mm long
Common in humans
97.3% children in Moscow
1% children in SE US
Cysticercoid

37. Hymenolepis nana D A 1 B 2 3 4 C

38. Pathogenesis and Treatment
Similar to Adult species of Taenia
Praziquantel

39. Dipylidium caninum

40. Dipylidium caninum Most common tapeworm of dogs Cats, humans
2 sets of reproductive organs

41. Gravid proglottids shed
Dog eats flea
Infective stage?

43. Diagnostics

44. Pathogenesis and Treatment
Similar to Adult species of Taenia
Praziquantel