Cestodes ( Tapeworms)

What are the basic identifiers of cestodes ?

• long

• dorsoventrally flattened

• lack a body cavity

Define metacestode?

The infective stage in cestodes

• larval stage of a cestode that develops in the intermediate host and then is infective to the definitive host

what are the body regions of cestodes?

• scolex

• neck

• strobila

Order Cyclophillidea

• _____ = body wall

• absorbs nutrients

• no mouth present

• most live in ______

• tegument

• small intestine

Cyclophyllidean genral life cycle

• ______ life cycle

• final host sheds segments (proglottids) or eggs

• swallowed by intermediate host → travels via _____ to predilection site where_____ develops

• intermediate host (with metacestode) is eaten → ______ in final host

• indirect

• blood …… metacestode

• new infection

Echinococcus spp.

E. granulosus

• Definitive host :

• intermediate host :

• metacestode stage in ________

• dogs, canids

• ruminant

• hydatid cyst

  • thick walled

  • expansive (compressive growth

Echinococcus spp.

E. multilocularis

• Definitive host :

• intermediate host :

• metacestode stage in ________

• cats, dogs, foxes

• rodent

• alveolar cyst

  • multiocular

  • invasive ( tumor-life growth )

Echinococcus spp.

• ____ life cycle

• ____ can become accidental intermediate hosts

• indirect

• humans

Taenia spp. of dog

• _____ life cycle

• definitive host : ______

• intermediate host : _______

• transmission : ______

• adults in ________

• indirect life cycle

• dogs

• rabbits, rodents, livestock carcasses

• small intestine of dog

  • cause little harm

Hydatigera (taenia) taeniaeformis

• _____ life cycle

• definitive host : ______

• intermediate host : _______

• transmission : ______

• adults in ________

• indirect

• cats

• rodents

• ingestion of IH

• small intestine of the cat

  • cause little harm

Taeniasis in humans

• _____ life cycle

• metacestode stage is _____ in undercooked meat

• indirect

• cysticercus

Taeniasis in humans

taenia saginata

Unarmed beef tapeworm

Taeniasis in humans

taenia saginata

• definitive host :

• intermediate host:

• transmission :

• human

• cattle

• ingestion of cysticercus

Taeniasis in humans

taenia solium

armed pork tapeworm

Taeniasis in humans

taenia solium

• definitive host :

• intermediate host:

• transmission :

• human

• pig

• ingestion of cysticercus OR ingestion of infected egg

Diphylidium caninum

Flea or sesame seed tapeworm

Dipylidium caninum

• life cycle :

• definitive host :

• intermediate host:

• transmission :

• indirect

• dog, cat

• flea

• ingestion of cysticercoid in flea

Diphylidium caninum

• common in _____

• dry up and look like ________

• seen on _______

Zoonotic

• dogs and cats

• sesame seeds

• rectum, fur, feces, environment

Anoplcephala spp

equine tapeworm

Anoplocephala spp.

• life cycle :

• definitive host :

• intermediate host:

• transmission :

• indirect

• horse

• pasture mite

• ingestion of cysticercoid in mite

Anoplocephala spp.

• affects the ________

stomach, intestines, cecum

Moniezia spp.

ruminant tapeworm

Moniezia spp.

• life cycle :

• definitive host :

• intermediate host:

• transmission :

• indirect

• cattle sheep, goats

• pasture mite

• ingestion of cysticercoid in mite

Diphyllobothrium latum

broad fish tapeworm

Diphyllobothrium latum

• life cycle :

• definitive host :

• intermediate host:

• transmission :

• indirect

• fish-eating mammals

• copepod (1st) , fish (2nd)

• ingestion of plerocercoid in fish

Diphyllobothrium latum in Dogs, Cats, Humans

• infective larval stage in ______

• adults in _______

• animals usually _____

• humans ____________

• tissue of fish

• small intestine

• subclinical

• asymptomatic or non-specific GI symptoms

Spirometra spp.

zipper tapeworm

Spirometra spp.

• life cycle :

• definitive host :

• intermediate host:

• transmission :

• indirect

• dogs, cats (humans accidentally)

• copepod (1st), amphibian/reptile/small mammal (2nd)

• ingestion of plerocercoid in tissue of second IH