Exam I - Dipylidium caninum

Question 1

What is the common name for Dipylidium caninum?

Answer 1

Common tapeworm, cucumber tapeworm, flea tapeworm, etc…

Question 2

To which taxonomic order does Dipylidium caninum belong?

Answer 2

Cyclophylidea

Question 3

To which taxonomic class does Dipylidium caninum belong?

Answer 3

Cestoda

Question 4

What is/are the final host(s) for Dipylidium caninum?

Answer 4

dogs, cats, and occasionally humans

Question 5

What is/are the intermediate host(s) for Dipylidium caninum?

Answer 5

the flea- (Ctenocephalides felis/canis) and the louse - (Trichodectes canis)

Question 6

What is the maximum length for a Dipylidium caninum adult?

Answer 6

~ 50 cm

Question 7

Describe the appearance of the Dipylidium caninum adult

Answer 7

Maximum length is 50 cm. Proglottid easily recognized, being elongate, like a large rice grain when dry and cucumber seeds when still fresh.

Each proglottid has 2 sets of reproductive organs with bilateral genital pores.

Question 8

Describe the appearance of the Dipylidium caninum egg

Answer 8

Egg packets (230 x 170 um) contain 10-20 eggs (each 35-40 um)

Remember Dipylidium caninum because the eggs are fucking huge!

Question 9

Is the Dipylidium caninum life cycle direct or indirect?

Answer 9

Indirect.

Question 10

Describe the life cycle of Dipylidium caninum

Answer 10

• Newly passed segments are active, and can crawl about the tail region of the animal. The oncospheres are contained in egg packets or capsules, each with about 20 eggs.
• These are expelled by the active segment or released by active disintegration.
• After ingestion by the intermediate host, the oncospheres travel to the abdominal cavity and develop into cystercercoids.
• All stages of the louse can ingest the oncospheres, but the adult flea with its mouthparts adapted for piercing cannot do so and infection is only acquired during the larval stage, which has chewing mouthparts.
• Development in the louse takes 30 days. Development in the flea takes several months. The final host is infected by ingestion of the flea or louse containing the cystercercoids.
• PPP is 21 days.

Question 11

What is/are the site(s) of infection for Dipylidium caninum?

Answer 11

Adult tapeworms in small intestine. Larval stage (cystercercoid) in flea and louse.

Question 12

The larval stage of Dipylidium caninum is called:

Answer 12

cystercercoid

Question 13

Describe the pathogenesis associated with Dipylidium caninum

Answer 13

Adults are largely non-pathogenic

Question 14

Describe some clinical signs associated with Dipylidium caninum

Answer 14

Dogs may scoot or rub their anus along the floor