1. Tapeworms are segmented parasitic worms that live attached to the intestinal mucosa of their hosts. Two main types that infect humans are Diphyllobothrium latum (fish tapeworm) and Taenia saginata (beef tapeworm). 2. D. latum has a complex life cycle involving fish and humans. Humans can become infected by eating undercooked fish containing the larval stage. In the intestine the larvae develop into adult tapeworms up to 10 meters long. 3. T. saginata infects humans through eating raw or undercooked beef containing the larval cysticerci stage. The adult tapeworm lives in the human small intestine and releases eggs

1. TAPE WORMS CESTODES
CLASS: Cestoidea
ORDER: Pseudophyllidea
Cyclophyllidea

2. GENERAL CHARACTERS
• Segmented
• Tape-like
• Compressed dorso-ventrally
• Few mm---several metres
• Live attached to mucosa in SI: absorb food
• DISEASE : DIPHYLLOBOTHRIASIS

3. ADULT WORM
• Scolex: organ of attachment only. No nutrition
• Muscular organ
• No suckers
• Pair of longitudnal grooves: bothria
• Rostellum: apical protrusion; present/absent
• hooks+/-
• NECK: behind scolex
• body generates

4. strobilia
• Body: no GIT. nutrients absorbed by integument
• Chain of segments
Types:
• immature…...... near neck; undifferentiated
• mature……… ….. larger; hermaphrodite
female/male reproductive systems
• Gravid: furthest away:
atrophied primary genitalia
uterus full of eggs

5. EGG
• Ovoid
• Operculated
• embryo formed later on: six –hooks;
hexacanth; called oncosphere
• Two coverings of embryo
• 1. embryophore
• 2. outer thin egg shell

7. Life cycle
• 2 hosts needed (except H nana; one host)
• Definite Host: MAN
• (except E granulosis; dog is definite host, man
intermediate)
• Intermediate host: mammals, fish ,arthropods
• one or two; harbor larvae

8. PATHOGENICITY
• ingestion:
• egg or larvae in food, water, fish, meat
• No damage to host except mechanical
obstruction in heavy infection; diarrhea, loss
of appetite, vitamin deficiency
• Cysts/ larvae in vital tissues pose risk like
brain, liver, lungs

9. LAB DIAGNOSIS
• Faeces: eggs, proglottidis
• Extra-intestinal: biopsy, serology, radio-image
Prevention:
• Avoid : raw food, contaminated water
• Protect community: safe disposal of human
faeces
• Avoid: animal contact

10. DIPHYLUOBOTHRIAM LATUM
• FISH TAPE-WORM
• Endemic: Northern hemisphere. Europe, Russia,
Japan, tropical Africa, Americas; Asia; not India,
Habitat:
• SI: jejnum or ileum of man
• Dog, cat, fox & fish eating animals
• Size: longest tape worm; 10 metres length
• 3000 or > proglottids

11. MORPHOLOGY….contd
• colour; IVORY
• Scolex: almond-shaped; spoon shaped
length; 2-3mm & 1mm width
• Grooves: 2 slit-like grooves with lateral lips
• No rostellum/hooklets
• Neck: thin, unsegmented,
several times head length

12. D LATUM

13. STROBILIA
• 3000 segments
• Mature: 10-20 mm……broad
2-4 mm…… long
• Eggs: periodic discharge via uterine pore
• Upto 1 million eggs daily in lumen of SI in
immature stage; mature in 1-2 weeks
• Terminal proglottids : hence empty
• Terminal segments dry, break-up and discharge in
faeces

14. EGG; not infective to man
• Yellow-brown; Oval; elliptical
• 70um length* 45um breadth
• Mass of granulated yolk cells surrounding an
undeveloped ovum
• Shell; thin, smooth
• Contains immature embryo
• Inconspicuous operculum at one end
• Small knob at other end
• Saturated solu. of common salt : does not float

15. D Latum egg

17. TRANSMISSION
• Ingestion of infective larvae ie plerocercoid
In raw /insufficiently cooked fish as trout,
perch, pike
• larvae attach to wall of SI; in 2-4 weeks
develop into a mature tape worm
• EGGS are laid in lumen of intestine and passed
in feces; eggs are operculated & immature
• Fresh water: eggs hatch in 1-2 weeks

19. CORACIDIA: released ; spherical, ciliated
embryos with 3 pairs of hooklets
• CRUSTACEANS: ingest these
• Genus Cyclops/ Diaptomus
PROCERCOIDS: elongated larval forms develop in
few weeks
• FISH: eat the crustaceans and procercoids
develop into
PLEROCERCOIDS: these migrate to muscle &CT of
fish

20. Stages of D latum

21. LARVAL STAGE
• First: coracidium; in water
• Second: procercoid; in cyclops : & Diaptomus
In first intermediate host
• third stage: plerocercoid; develops in fresh-water
fish; second intermediate host
• Plerocercoid larvae: or SPARGANUM
• white, tape-like
• 10mm*2mm
• Fully developed: head with sucking grooves

22. LIFE CYCLE…contd
• completed by definite host eating fish
• Definite host: live for years
• human
• Animals: dog, cat, bear, fox, leapords
SYMPTOMS
GIT, weight loss, weakness, toxin-related
B 12deficiency: if in jejunum: megaloblastic
anaemia

23. ADULT DIPHYLOBOTHRIUM

24. PROGLOTTIDES

25. PROGLOTTIDES

26. PREVENTION
• FISH: Avoid raw fish intake esp. Smoked/
pickled
Kill pleros in fish by brine saturation,
freeze -10 C for 24-48 hrs
Prevent feeding dogs by fish offals
Latrine provision: eggs do not reach waters
• Maintains endemic state
• HEALTH EDUCATION

27. LABORATORY DIAGNOSIS
Faeces
• Eggs: 70-45um,oval,yellow with operculum
Yolk, ovum. Do not float in saturated saline
• Segments of worms
• Rare as disintegrate in intestine
• Shrunken, empty of eggs
• Undamaged mature segments 10-20 mm *3-
7mm with central pore.

28. ECHINOCOCCUS GRANULOSUS
• DOG TAPE WORM
• MAN ; Echinococcosis
• hydatid disease/hydatidosis
• FAMILY: Taeniidiae of Cyclophyllidiae
• DISTRIBUTION: world-wide
• Sheep, dogs, humans
• dogs/wild carnivores; livestock
• Africa; east, north, south, India, Mediterranian,
Mid-east, south America, Australia

29. TRANSMISSION
ZOONOSIS:
• Food/ hands contaminated with dog feces
• Intermediate host:
Sheep, cattle, pigs, camel
• Egg ingestion: by intermediate host
• Embryos: released in duodenum
• Penetrate intestinal wall and enter blood
vessels to liver, lungs, other organs

30. HYDATID CYSTS
• EMBRYOS develop to hydatid cyst
• Proto-scoleces develop in it
• Infected animal tissue of sheep eaten by dog, fox,
wolves
• In dog or definite host:
Scoleces evaginate, attach to SI wall, grow worm
Mature worm: 9mm long; 3-4 segments
Scolex: 4 suckers; crown of 2 rows of hooks

31. HYDATID CYST

32. EGGS
• Produced & released by detached gravid last
segment on rupture
• Highly resistant eggs; survive long
• d/d: taenia
• MAN: dead end host as not eaten by animals;
occasionally feed on human remains
• Eggs: ingested….embryos freed in SI, enter BV
to blood….liver, lungs, bones , joints

33. HYDATID CYST
• EMBRYOS embed in tissues
• Few days….sac-like structures
• Few months/years…..hydatid cyst
HYDATID CYST
1.Outer thick laminated cyst wall
2.Inner thin , nucleated germinal layer
3. Brood capsules from inner wall
4.Germinal layer detached, will form daugter cysts

38. • Brood capsules: break off & sink down
through cyst fluid.
• Hydatid sand:
• Freed brood capsules
• Individual protoscolece
• Host response: fibrosis, calcification

42. Clinical features
FATE:
• Rupture of cyst: anaphylactic shock
• Cysts: grow for short time, die, calcify.
SITE & SIZE:
• Liver: 60% right lobe of liver
• Lungs: pulmonary symptoms;
sputum: blood, cyst fluid
Bone: pain on expansion; fracture
Rare: brain, kidney, spleen

43. PREVENTION
• Personal hygiene: hand wash after pet
handling
• Animal handling care: pets, herdsmen
• De-worming of dogs regularly
• Stray dogs: eliminate
• Uncooked offal/ meat : not fed to dogs
• Dog entry banned in slaughter houses
• Inspection of caracases

44. LAB DIAGNOSIS
• Clinical
• Ultra-sound
• Serum: anti bodies
• Surgical removal of cyst: do not puncture
examine for brood capsules, protoscoleces
• HISTOLOGY
PAS: laminated membrane
ZN: hooks of protoscoleces

45. Cyst fluid
• Let settle by gravity
• Centrifuge
• Deposit….make slide
• Protoscolex: colour-less, round/oval
• invagination, hooks

46. D/D Hepatoma
• Serum
• Glyco-proteins
• Amino-transferases
• Other LFTs
• Normal in Hydatid but increased in hepatoma
• ESR: marked increase in hepatoma
• moderate in hydatid

47. CASONI’S TEST
• Intra-dermal
• No standardization of Ag, technique,
interpretation
• Non specific
• False positive

48. SEROLOGICAL DIAGNOSIS
• SITE DEPENDANT:
• Liver: more sensitive than lung
• False negative:
• Calcified cyst
• Circulating immune complexes
• Indirect heme-agglutination test

49. ECHINOCOCCUS MULTILOCCULARIS
• Multi-locular OR Alveolar hydatid disease
• Canada, Alaska, USSR, Europe
• Definite host:
• Fox, wolves
• Inter-mediate: rodents, voles
• Man: accidental intermed host; ingest eggs
• LIVER: invasive, spreads like malignant tumor,
cavities, & necrosis; no capsule like hydatid
• FATAL; usually

50. FAMILY TAENIIDIAE
• Taeniasis
• Human definite host
• Taenia saginata
• Taenia solium
• Taenia asiatica
DISTRIBUTION
World-wide; mass travel; Africa, America, Asia
inadequate sewage disposal
Cattle, beef-eating
Camel: Morocco, Egypt

51. Life cycle
• T saginata:
• Transmission: eating raw, inadequately cooked
beef, meat with cysticercus larvae
• After digestion, the head is freed & attaches
to the wall of SI by its suckers.
• Segments (proglottides)are added from neck
downwards in 2-3 months. Long tape-worm
with gravid segment at tail end also found.

52. LIFE CYCLE OF TAENIAS

53. Life cycle taenias

54. MATURE WORM
• Length: 4-10 metre
• Segments: 2000
• Scolex: cubical, 2mm across, 4 suckers
• Single worm usually; multiple rare
• Fully developed gravid segments become
detached, rupture to release eggs in feces
• Gravid segments may travel to peri-anal area
to discharge eggs

55. • Eggs have to reach grazing sites to access cattle.
• Segments may migrate to lands, disintegrate &
release eggs…mature/immature
• Mature eggs survive for months on lands.
• Each segment has 80,000 eggs
• After ingestion by cows, embryos are released by
eggs, pass intestinal wall, enter BV to reach
muscles where they grow to cysticerci larvae:
survive for months; calcify
• Embryos lose hooklets in muscle

58. Taenia solium

60. T saginata

62. TAENIA SCOLEX

63. TAENIAS EGG

64. CLINICAL FEATURES
• Abdominal pain
• Intestinal disturbances
• Loss of apetite
• Migrating segments: appendicitis, choleangitis,
• Pruritis ani
PREVENTION:
Avoid eating raw meat
Cysticerci larvae: Cook at 56 C, freeze 3 weeks
Meat inspection

65. Latrines: provision
Feces: containment, kill eggs/segments
do not use as fertilizer in pastures
Treat infected personel
Health education

66. LAB DIAGNOSIS
• Segment: passed singly; expelled on T/M
• recovered from clothing/feces
• Eggs: round/oval
• 33-43 um in diameter
• yolk cells
• embryo with hooklets: Acid fast
Embryophore: thick, brown, radially striated
Clear membrane/ egg shell: surrounds egg.
lost on segment disintegration

67. SEGMENTS
• White & Opaque
• Movement: move by muscle contraction;
• keep in closed container;
• use forceps for handling
• Wash with water, let soak if dry.
• Press bet. two slides & hold with tape/ band
• Immerse in formol saline for10 min to kill eggs
• Look in light for uterus, branching. Mature
imp

68. GRAVID SEGMENT
• White, opaque
• 20mm*6mm(longer than T solium)
• 13 side branches of main stem (T solium less)
SCOLEX
Small; 2mm
4 suckers
No hooks( d/d T solium)

69. TAENIA SOLIUM
• Less widely distributed
• Africa, China, India, Central America, Pakistan
• Human feces reach pigs, pork eaten
raw/under-cooked
• Tape worm: 2-3 metres length
• segments: 800-1000
• Scolex: round, 1mm
• 4 suckers, crown of hooks on two rows

70. infection
• One
• Multiple
• Both taenias
• 30,000-50,000 eggs
• Pigs ingest viable eggs, infective cystecerci in
muscles, embryonic hooklets lost

71. T solium
• Human host by food, contaminated fingers.
• Gravid segments regurgitated in stomach
• Cystecerci deposited in muscles, s/c tissue,
brain, sc, eyes
• Brain: epilepsy
• X rays: calcified cysts