Exam I - Trichuris spp.

Question 1

Trichuris spp. belong to which taxonomic superfamily?

Answer 1

Trichinelloidea

Question 2

What is the common name for Trichuris spp?

Answer 2

whipworm

Question 3

What is/are the final host(s) for Trichuris spp?

Answer 3

Dogs & cats

Question 4

What size would you expect Trichuris spp adults to be?

Answer 4

Adults are 4-6 cm long with a thick posterior end tapering rapidly to a long filamentous anterior end, hence resembling a whipworm.

Question 5

Describe the appearance of the Trichuris spp egg

Answer 5

Egg is lemon shape, yellow or brown in color, with a conspicuous plug at both ends. Size 80 X 35 um.

Question 6

What is the infective stage of Trichuris spp?

Answer 6

Infective stage is L₁ in egg

Question 7

Describe the life cycle of Trichuris spp

Answer 7

• Infective stage is L1 in egg (Eggs survive for several years under optimal conditions)
• After ingestion of infective stage, plugs are digested and the released L₁ penetrate the glands of the cecal mucosa. All 4 molts occur within these glands.
• The adults emerge to lie on the mucosal surface with their anterior ends embedded.
• Adults copulate, females lay eggs which pass in the feces.
• PPP is 6-12 wk.

Question 8

What is the PPP for Trichuris spp?

Answer 8

6 - 12 weeks

Question 9

What is the site of infection for Trichuris spp?

Answer 9

Adults in large intestine, particularly cecum.

The common name for Trichuris spp is whipworm, so the way I remember that if you get whipped, you’re going to have large welts.

Whipworm… large intestine.

Question 10

Describe the pathogenesis caused by a large number of Trichuris spp.

Answer 10

Large numbers cause a diphtheritic (”leather-like” character) inflammation of the cecal mucosa.

Question 11

What clinical signs would you expect to see associated with Trichuris spp.?

Answer 11

watery bloody diarrhea