Exam II - Oxyuris equi

Question 1

What is the common name for Oxyuris equi?

Answer 1

large pinworm

Question 2

What is/are the host(s) for Oxyuris equi?

Answer 2

all equids

Question 3

Describe the appearance of Oxyuris equi adults

Answer 3

Long, white, pointed tail, up to 10 cm. Normally only females are seen

Question 4

Describe the appearance of Oxyuris equi eggs

Answer 4

Eggs are 85 x 40 um, single operculum and flatter on one side

Question 5

What is the PPP for Oxyuris equi?

Answer 5

4-5 months

Question 6

Describe the life cycle for Oxyuris equi

Answer 6

• Adults live in dorsal colon
• females migrate through anus to lay eggs around the perineum
• Eggs develop to contain L₃ (infective stage) and are ingested with food & water
• L₃ live in crypts of dorsal colon
• Develop to L₄ and adults in dorsal colon
• PPP is 4-5 months

Question 7

What is the infective stage of Oxyuris equi?

Answer 7

Egg with L₃

Question 8

What is/are the site(s) of infection for Oxyuris equi?

Answer 8

large intestine

Question 9

Describe any pathogenesis and/or clinical signs associated with Oxyuris equi

Answer 9

Peri-Anal Irritation leads to pruritus (itching)

Question 10

How would you diagnose Oxyuris equi?

Answer 10

• Broken hair at tailhead (from rubbing against fences)
• perianal scraping for eggs
• scotch tape method

Question 11

What are some treatment & prevention options for Oxyuris equi?

Answer 11

MCLs, but resistance is suspected