Oxyuris equi (1)

Question 1

What are the hosts?

Answer 1

All equid species

Question 2

Describe adults

Answer 2

Long

White

Pointed tail

Largest of pinworms - adults up to 10 cm long

Esophageal bulb and a tapered tail

Normally only female ever seen

Adult lives in colon

Question 3

Describe egg

Answer 3

85 x 40 micro m

Single operculum

Flatter on one side

Asymmetical eggs embryonate rapidly, typically seen as larvated

Question 4

Explain the life cycle

Answer 4

Adults live in dorsal colon

Female migrates through anus

Lays eggs around perineum - Deposit eggs and gelatinous substance

Gelatinous substance irritates skin - Animal rubs against walls
depositing eggs everywhere

L1 to L3 develop inside egg - egg is long lasting

Egg with L3 ingested with food and water

L3 to Adult in dorsal colon

PPP: 4-5 months

Egg with L3 - infective

Question 5

What is the site of infection?

Answer 5

Large intestine

Question 6

Describe the Pathogenesis

Answer 6

Gelatinous substance irritates skin leading to pruritis

Perinatal irritation

Broken hair at base of tail

Question 7

How do you diagnose?

Answer 7

Adhesive tape method

Perianal scrapings

Used to find eggs - eggs are not in feces

Question 8

How do you treat and prevent?

Answer 8

Reinfection common because eggs distributed thoroughly by horse rubbing

Available

Important to thoroughly clean environment as that is the cause of reinfection

Question 9

What is the common name?

Answer 9

Large pinworm