Draschia megastoma/Habronema spp. (1)

Question 1

What are the final hosts?

Answer 1

All equid species

Question 2

What are the intermediate hosts?

Answer 2

Musca spp. fly

Stomoxys calcitrans

Question 3

Describe adults

Answer 3

13-25 mm

Reside in stomach

Question 4

Describe eggs

Answer 4

Thinshelled

Larvated

40-55 x 8-16 micro m

Eggs difficult to see
- Don’t float well in fecal examinations

Question 5

Explain the life cycle

Answer 5

Adult worms in stomach

Eggs excreted in feces

Eggs develop to L1

Fly larvae eat L1 larvae

L1->L2 in fly larvae

Fly larvae form pupae in soil

L2 molt to L3 in pupae

Fly hatches from pupa and carries L3 larvae

Fly may deposit larvae on lips, eyes, and wounds - Fly itself may be
ingested

L3 released as fly is ingested

Develop to adults in stomach

Question 6

What are the sites of infection?

Answer 6

Adults and larvae - in stomach

L3 in skin = “wrong place at wrong time”

Question 7

Describe the Pathogenesis

Answer 7

Larvae - granular conjunctivitis

Summer sores

Nonpathogenic

Gastritis

Nodules near Margo plicatus

Question 8

Describe Summer sores

Answer 8

Larvae laid in secretions or open wounds

When IH feeds on face, L3 deposited in wrong place

Describe cutaneous habronemiasis and cutaneous draschiasis

 - Rapid production of granulation tissue
 - Caseocalcareous nodules in granulation
 - Extreme pruritis

Question 9

How do you diagnose?

Answer 9

Recovery of eggs in feces difficult

Larvae in scraping of skin lesions

Thinshelled larvated (paperclip) eggs - difficult to recover

Question 10

How do you treat and prevent?

Answer 10

MCLs effective against L3 and adults

Fly control

Summer sores - local applications to lesions
- Cryotherapy (freezing) or surgical removal

Question 11

What is the common name?

Answer 11

Stomach nematodes