Cestodes Quiz: Tapeworms Anatomy and Life Cycle

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Questions and Answers

What distinguishes Cyclophyllidean tapeworms from Cotyloda tapeworms?

Cyclophyllidean tapeworms have two intermediate hosts, while Cotyloda have one.

Cyclophyllidean tapeworms can either be armed or unarmed, while Cotyloda are always unarmed. (correct)

Cyclophyllidean tapeworms are always zoonotic, whereas Cotyloda are not.

Cyclophyllidean tapeworms have centrally located genital pores, while Cotyloda have laterally located genital pores.

What is the primary method of attachment for adult cestodes in the host's intestine?

Through proglottids

By intestinal secretions

Via suckers only

By hooks located in the scolex (correct)

What is the significance of the life cycle of cestodes requiring an intermediate host?

It allows for the tapeworm to reproduce directly in the host.

It is necessary for the maturation of the ova. (correct)

It enables direct transmission between hosts.

It aids in the digestion process of the host.

Which of the following statements about cestode anatomy is true?

The scolex acts as a holdfast, attaching at the anterior end. Signup and view all the answers

What feature does Dipylidium caninum specifically possess?

It has armed scolex with hooklets. Signup and view all the answers

Which of the following is characteristic of Cotyloda tapeworms?

They have centrally located genital pores. Signup and view all the answers

What is the maximum potential length of Diphyllobothrium latum?

30 ft Signup and view all the answers

Which of the following statements about the ovum in cestodes is correct?

Ova are shed in feces and infective to the intermediate host upon passage. Signup and view all the answers

Which medication is effective for treating cestode infections?

Praziquantel Signup and view all the answers

What is the primary economic concern related to hydatid cysts in livestock?

Condemnation of carcasses by inspectors Signup and view all the answers

Which is NOT a recommended prevention method for zoonotic cestodes in humans?

Feeding pets raw fish Signup and view all the answers

What is a cysticercus?

A larval stage infective to the definitive host Signup and view all the answers

Which term describes the chain of proglottids in a tapeworm?

Strobila Signup and view all the answers

What is the defining feature of Cyclophyllidean tapeworms?

Armed and unarmed scolex Signup and view all the answers

Which larval stage is specifically referred to as hexacanth embryo?

Oncosphere Signup and view all the answers

What is the primary intermediate host for Taenia pisiformis?

Rabbit Signup and view all the answers

What is the prepatent period for Echinococcus granulosus?

4 to 8 weeks Signup and view all the answers

Which of the following hosts is affected by Taenia hydatigena?

Sheep Signup and view all the answers

Echinococcus multilocularis causes which disease in its intermediate hosts?

Alveolar hydatidosis Signup and view all the answers

How long is the prepatent period for Taenia taeniaeformis?

4 to 6 weeks Signup and view all the answers

What type of larva does Echinococcus spp. produce in their intermediate hosts?

Hydatid cyst Signup and view all the answers

Which species has a life cycle involving cats as the definitive host?

Taenia taeniaeformis Signup and view all the answers

In Echinococcus granulosis, what organ is NOT typically associated with hydatid cysts?

Pancreas Signup and view all the answers

Which statement is true regarding the lifecycle completion for Echinococcus spp.?

Requires the consumption of the intermediate host by the definitive host Signup and view all the answers

What type of infestations are typical for cats allowed to hunt concerning Taenia taeniaeformis?

Recurrent infestations Signup and view all the answers

What is necessary for the diagnosis of Taenia spp. infections?

Identification of adult worms Signup and view all the answers

Which animal is not typically implicated as a definitive host for Diphyllobothrium latum?

Copepods Signup and view all the answers

What contributes to the zoonotic potential of Spirometra spp.?

Ingestion of the second intermediate host Signup and view all the answers

What is a common clinical sign observed in pets infected with cestodes?

Proglottids around the rectum Signup and view all the answers

How can Dipylidium ova be distinguished from Echinococcus ova?

By size and shape Signup and view all the answers

What should humans avoid doing to reduce transmission risk of Echinococcus spp.?

All of the above Signup and view all the answers

What is a unique feature of mature proglottids of Spirometra spp.?

Separation along the longitudinal axis Signup and view all the answers

What precaution should be taken to prevent Hydatid cyst formation in humans from Echinococcus spp.?

Practicing good hygiene after dog feces contact Signup and view all the answers

What initial intermediate host is required for both Diphyllobothrium latum and Spirometra spp.?

Copepods Signup and view all the answers

What is the prepatent period for Diphyllobothrium latum infections?

6 weeks Signup and view all the answers

What is a distinguishing feature of proglottids?

They are hermaphroditic and contain both male and female reproductive organs. Signup and view all the answers

What is the correct sequence of larval stages in the lifecycle of tapeworms?

Oncosphere → 1st Stage Larva → 2nd Stage Larva Signup and view all the answers

What additional treatment is necessary when treating for Dipylidium caninum?

Treat for fleas simultaneously. Signup and view all the answers

What structure is formed in the intermediate host by Dipylidium caninum?

Cysticercoid Signup and view all the answers

What happens to the bladderworm upon ingestion by the definitive host?

The bladder is digested away, and the scolex attaches to the gut wall. Signup and view all the answers

Which statement is true about Taenia spp. compared to Dipylidium caninum?

Taenia spp. have single pores in their proglottids. Signup and view all the answers

What do the ova of Taenia spp. contain before being ingested by an intermediate host?

1st stage larva (oncosphere or hexacanth embryo). Signup and view all the answers

What is a characteristic of the proglottids in Dipylidium caninum observed by clients?

They have a double pore at the lateral midpoint. Signup and view all the answers

What is the prepatent period for Dipylidium caninum?

4 weeks Signup and view all the answers

Which stage of the larval tapeworm is infective to the definitive host?

2nd Stage Larva Signup and view all the answers

Study Notes

Cestodes: The Tapeworms

Cestodes are flatworms lacking a body cavity
Their life cycles are always indirect
Cyclophyllidean cestodes (true tapeworms) have scolices with suckers and potentially hooklets, and genital pores are on the proglottids. They usually require one intermediate host (IH) and are often zoonotic.
Cotyloda cestodes (pseudo tapeworms) have bothria (slit-like attachment organs) and genital pores centrally located on the proglottids. They require two IHs and are typically zoonotic.
Examples of Cyclophyllidean cestodes: Dipylidium caninum, Taenia spp. ( T. pisiformis, T. hydatigena, T. ovis, T. taeniaeformis), and Echinococcus spp. (E. granulosis, E. multilocularis).
Examples of Cotyloda cestodes: Diphyllobothrium latum and Spirometra spp.

Cestode Life Cycle and Anatomy

Cestodes have an indirect life cycle requiring an intermediate host (IH) and a definitive host (DH).
Adults attach to the small intestine mucosa of the DH
Proglottids containing ova are released in feces, becoming infective to the IH
The IH ingests these ova. The ova mature within the IH.
The DH ingests the IH, completing the life cycle
Adult cestodes lack digestive organs and absorb nutrients via a tegument. They have a scolex for attachment and proglottids, each containing reproductive organs. Their body size varies greatly.

Cestode Anatomy

Scolex: The head of the cestode, used for attachment to the intestinal wall. It has suckers and/or hooks.
Proglottids: Repeating segments of the cestode's body, containing reproductive organs. Mature proglottids are gravid, containing numerous eggs.
Ova: Eggs that are released with proglottids, infectious in the IH.

Specific Cestode Examples

Dipylidium caninum: Flea tapeworm, zoonotic, dogs, cats, humans, IH: flea
Taenia spp.: Common tapeworms, varying species with different IHs.
- T. pisiformis: Dog IH, grazining rabbits
- T. hydatigena: Dog, IH rabbits
- T. ovis: Dog, IH sheep
- T. taeniaeformis: Cat, IH mice
Echinococcus spp.: Zoonotic; cysts may cause disease.
- Echinococcus granulosis: hydatid cysts, IH sheep/others, humans
- Echinococcus multilocularis: alveolar hydatid cysts, IH rodents, humans
Diphyllobothrium latum: Long tapeworm, zoonotic, several IHs
Spirometra spp.: Zoonotic tapeworm, varies according to IH

Diagnosis and Treatment

Diagnosis may involve examination of proglottids in feces or identification of ova.
Treatment typically requires anthelmintic drugs, such as praziquantel or epsiprantel.

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Description

Test your knowledge on cestodes, the fascinating tapeworms that lack a body cavity. This quiz covers their anatomy, life cycles, and distinguishing features, including Cyclophyllidean and Cotyloda types. Delve into the details of their indirect life cycle and examples of each type.