1. Introduction of Cestodes (Tapeworms)
Phylum Platyhelminthes
Class Cestoda
Order Pseudophyllidea
Order Cyclophyllidea

2. Morphology
Flat, segmented body with various length (several mm ~ several meters)
3 regions of worm body:
Scolex: suckers, hooklets, grooves
Neck: germinal portion
Strobila: immature, mature, gravid proglottids (segments)

3. Monoecious (each segment): reproductive system highly developed
Digestive system degenerated
All species are parasitic

4. Tapeworms

5. Taenia solium Taenia saginata
链状带绦虫
Pork tapeworm / Hook tapeworm
猪肉绦虫/有钩绦虫
Taenia saginata
肥胖带绦虫
Beef tapeworm / Hookless tapeworm
牛肉绦虫/无钩绦虫

6. Morphology T.saginata T.solium Size 4-8 m 2-4 m Scolex 4 suckers
rostellum & hooklets
Mature proglottid
Ovary
2 lobes
3 lobes
Testes
Gravid proglottid:
Uterine branches
15-30
7-12

7. Taenia spp. (saginata and solium), adult worm: the chain of proglottides is called the strobila, and may be composed of over proglottides. T.saginata may measure 9 m, whereas T.solium may reach 6 m
Taenia spp. adult worm
The chain of proglottids is called the strobila, and may be composed of over proglottids. T.saginata may measure 9 m, whereas T.solium may reach 6 m.

8. The beef tapeworm (Living specimen)来源
The beef tapeworm (Living specimen)

9. The scolex of T. solium hooklets rostullum suckers
The scolex of T. solium (show here) has four suckers and an armed-rostellum. The scolex of T. saginata looks similar but lacks hooks. These two species can be differentiated by counting the number of uterine branches in the proglottids; T. solium has between 7 to 13 per side, while T. saginata has 15 to 20. 来源
The scolex of T. solium

10. The scolex of T. saginata
Taenia saginata
Adult-scolex 来源
The scolex of T. saginata

11. Taenia saginata, fresh specimen.
Note : Four suckers, no rostellum 来源
Taenia saginata, fresh specimen

12. Gravid proglottid of T. solium
Gravid proglottid, India ink technique.
Taenia solium
Note : Less than 14 lateral uterine branches (one side). 来源
Gravid proglottid of T. solium

13. Gravid proglottid of T. saginata
Taenia saginata
Gravid proglottid , India ink technique.
Note : More than 14 lateral uterine branches (one side). 来源
Gravid proglottid of T. saginata

14. Larva Cysticercus bovis Cysticercus cellulosae
Ovoid, cystic, size = a bean
Invaginated scolex and neck

15. T.solium: cysticercus cellulosae with invaginated scolex来源
Courtesy of Dr. Dan Steriu.  Head of Parasitology Laboratory,  Cantacuzino Institute Spl. Independentei.  103 sect. 5 Bucuresti , Romania.
T.solium: cysticercus cellulosae with invaginated scolex

16. Egg Indistinguishable in two species Ovoid < Ascarid egg
Radically striated embryophore
Content: hexocanth embryo (oncosphere: 6 hooklets)

17. Can not differentiate T. saginata from T. solium
Wet mount.
Note : Brown, striated embryophore.
Can not differentiate T. saginata from T. solium 来源
Taenia spp. egg
Can not differentiate T. saginata from T. solium

18. Taenia spp. egg Wet mount. Note : Brown, striated embryophore.
Can not differentiate T. saginata from T. solium 来源
Taenia spp. egg

19. Life Cycle Definitive host Discharged stage
Human being; No reservoir host
Discharged stage
Eggs or gravid proglottids in feces

20. Life cycle of Taenia saginata
Life cycle of Taenia saginata Humans are the only definitive hosts for Taenia saginata.  The adult tapeworms (length: usually 5 m or less, but up to 25 m) reside in the small intestine, where they attach by their scolex.  They produce proglottids (each worm has 1,000 to 2,000 proglottids), which mature, become gravid, detach from the tapeworm, and migrate to the anus or are passed in the stool (approximately 6 per day).  The eggs contained in the gravid proglottids (80,000 to 100,000 eggs per proglottid) are released after the proglottid becomes free and are passed with the feces.  The eggs can survive for months to years in the environment.  Cattle and other herbivores become infected by ingesting vegetation contaminated with eggs (or proglottids).  In the animal's intestine, the eggs release the oncosphere, which evaginates, invades the intestinal wall and migrates to the striated muscles, where its develops into a cysticercus.  The cysticercus can survive for several years in the animal. Humans become infected by ingesting raw or undercooked infected meat.  In the human intestine, the cysticercus develops over 2 months into an adult tapeworm, which can survive for more than 30 years.
Life cycle of Taenia saginata

21. Life cycle of Taenia solium
Life cycle of Taenia solium The life cycle of Taenia solium is similar to that of T. saginata.  The adults (length 2 to 7 m; less than 1,000 proglottids, which are less active than in T. saginata, and each with 50,000 eggs; longevity up to 25 years) develop not only in humans but also some other animal species (monkeys, hamsters).  The cysticercus develops not only in striated muscle, but also in the brain, liver, and other tissues of pigs and other animals, including humans.  Humans develop taeniasis when they ingest undercooked pork meat containing cysticerci.  They develop cysticercosis by ingesting T. solium eggs, either by ingestion of fecally contaminated food, or by autoinfection.  In the latter case, a human infected with adult T. solium ingests eggs produced by that tapeworm, either through fecal contamination or, more arguably, from proglottids carried into the stomach by reverse peristalsis.
Life cycle of Taenia solium

22. Tissue(brain, eye, skin etc.)
T.saginata
T.solium
D.H
Human
I.H
Cattle
Swine
Habitation
Small intestine
Tissue(brain, eye, skin etc.)
Infective stage
Cysticercus bovis
Cysticercus
Cellulosae
Egg
Disease
Taeniasis
Cysticercosis

23. Pathogenesis
Taeniasis ( Infected by eating cysticerus; Pathogenic factor: adult worm)
Deprivation of nutrition
Disfunction of the intestine: vomiting or diarrhea
Allergic reactions
Appendicitis
Obstructions of the intestine

24. Cysticercosis (Intrinsic or extrinsic auto-infection; Cross infection due to T.solium egg only; Pathogenic factor: cysticercus cellulosae)
Symptoms vary with site & intensity of infection
Clinical aspects: headache, dizziness, epilepsy, blurred vision, subcutaneous nodule etc

25. Diagnosis Taeniasis Cysticercosis
Anal swab: to find egg at perianal region
Fecal exam: to find segment (species identification)
Cysticercosis
Biopsy (subcutaneous nodule)
X-ray/CT/MRI: cerebral cysticercosis
Ophthalmoscopy: ophthalmic cysticercosis

26. Epidemiology Distribution Cosmopolitan
In china: mainly in minority regions

27. Epidemic factors
Egg or gravid proglottid contamination of grass and soil
Method of raising domestic animals
Unhygienic dinning habit of eating raw or undercooked meat

28. Control Treatment Scientific cattle and pig raising
Paziquantel
Areca nut + pumpkin seed+ purge
Scientific cattle and pig raising
Avoid to consume raw meat
Meat inspection

29. Echinococcus granulosus
细粒棘球绦虫/包生绦虫

30. Morphology Adult worm Egg 3-6 mm long with 4 segments
Scolex & cervical portion (2 rows of hooklets and 4 suckers)
Immature, mature, gravid segments
Egg
Similar to the Taenia egg

31. Adult of Echinococcus granulosus来源
Adult of Echinococcus granulosus

32. Hydatid cyst Round & cystic Cyst wall: laminated layer, germinal layer
Contents: cystic fluid, brood capsules, protoscolex, daughter & grand daughter cyst, (hydatic sand)

33. Hydatid sand
The protoscoleces generally settle down at the bottom of the cyst and are known as hydatid sand.

34. Protoscoleces with double row hooklets and calcareous corpuscles
Protoscolices with double row hooklets and calcareous corpuscles. 来源
Protoscoleces with double row hooklets and calcareous corpuscles

35. Protoscolices with double row hooklets and calcareous corpuscles.来源
Protoscoleces

36. "Hydatid sand".  Fluid aspirated from a hydatid cyst will show multiple protoscolices (size approximately 100 µm), each of which has typical hooklets.  The protoscolices are normally invaginated (left), and evaginate (middle, then right) when put in saline.  Image contributed by Georgia Division of Public Health. 来源
Hydatid sand

37. Life Cycle Adult worm Larva (hydatid cyst)
In the small intestine of the dog and other carnivores
Larva (hydatid cyst)
In the tissue of human being, sheep, horse, pig, etc.

38. The adult Echinococcus granulosus (3 to 6 mm long) 1
The adult Echinococcus granulosus (3 to 6 mm long) 1.resides in the small bowel of the definitive hosts, dogs or other canids.  Gravid proglottids release eggs 2. that are passed in the feces.  After ingestion by a suitable intermediate host (under natural conditions: sheep, goat, swine, cattle, horses, camel), the egg hatches in the small bowel and releases an oncosphere 3. that penetrates the intestinal wall and migrates through the circulatory system into various organs, especially the liver and lungs.  In these organs, the oncosphere develops into a cyst 4. that enlarges gradually, producing protoscolices and daughter cysts that fill the cyst interior.  The definitive host becomes infected by ingesting the cyst-containing organs of the infected intermediate host.  After ingestion, the protoscolices 5. evaginate, attach to the intestinal mucosa 6. , and develop into adult stages 1. in 32 to 80 days.  The same life cycle occurs with E. multilocularis (1.2 to 3.7 mm), with the following differences: the definitive hosts are foxes, and to a lesser extent dogs, cats, coyotes and wolves; the intermediate host are small rodents; and larval growth (in the liver) remains indefinitely in the proliferative stage, resulting in invasion of the surrounding tissues.  With E. vogeli (up to 5.6 mm long), the definitive hosts are bush dogs and dogs; the intermediate hosts are rodents; and the larval stage (in the liver, lungs and other organs) develops both externally and internally, resulting in multiple vesicles.  E. oligarthrus (up to 2.9 mm long) has a life cycle that involves wild felids as definitive hosts and rodents as intermediate hosts.  Humans become infected by ingesting eggs 2. , with resulting release of oncospheres 3. in the intestine and the development of cysts in various organs. 来源

39. Infective stage: egg
Infective route: mouth
Location: liver, lung, brain, eye, kidney, muscles, bone and heart
Zoonotic parasite

40. Pathogenesis ‘Echinicoccosis’, ‘Hydatidosis’
Depend on the location and the number of hydatid cysts
Pressure: liver, pulmonary, etc
Allergy: anaphylactic shock
Regeneration: secondary infection

41. Epidemiology Distribution Forest type (human are seldom involved)
Wolf-moose/reindeer
Dingo-wallaby
Animal raising type (human are involved)
Dog-sheep/cattle/pig

42. Endemic factors High resistant egg
Intimate contact between dog, animals and man in local district
Contamination of the feces by infected dogs
Improper the viscera disposition

43. Diagnosis Physical (hepatic hypertrophy)
History of residence in endemic area
X-ray/Ultrasonography
Immunological means
Biopsy and puncture are forbidden unless during operation

44. Treatment and Control Surgical removal of the cyst
Long-term Mebendazole therapy
40 mg/kg/day × 1-6 months
Personal protection
Reasonable disposition of the viscera from infected animals
Treatment of sheep dogs periodically

45. 来源 http://www.cdfound.to.it/html/echi1.htm