Ascarids 2

Question 1

What are some of the physical features associated with Parascaris equorum?

Answer 1

• 3 lips
• NO cervical alae
• NO male bursa
• Large/stout
• Off-white

Question 2

What are some characteristics of Parascaris equorum eggs?

Answer 2

• Rust brown
• Pitted shell
• Round / ellipsoidal
• Sticky
• Albuminous surface

Question 3

1. What are the modes of transmission of Parascaris equorum?
2. What are its means of migration?

Answer 3

1. ONLY fecal-oral
2. ONLY liver-lung-tracheal-small intestine migration

Question 4

What is the pre-patent period of Parascaris equorum?

Answer 4

10 - 14 weeks

Question 5

Name 2 of the Ascarids that do NOT have hypobiotic larvae:

Answer 5

1. Parascaris equorum
2. Toxascaris leonina

(NO transplacental transmission)

(NO transmammary transmission)

Question 6

If this is a liver of a horse, what parasite is responsible?

Answer 6

Parascaris equorum

Question 7

How might a horse present with a Parascarius equorum larva infection of the lungs?

Answer 7

• Pneumonia
• Cough
• Fever
• Increased respiration rate
• White to green nasal discharge

Question 8

How might a horse present with a Parascaris equorum infection of the small intestine with adults worms?

Answer 8

• Pot belly
• Poor growth
• Diarrha / constipation
• Rough hair coat
• Colic

Question 9

1. If you had a foal infected with this, what might you treat with?
2. What should be your protocol?

Answer 9

1. Benzimidazoles
2. Treat at 2-3 months of age, treat at weaning (6 months of age) treat at 9-12 months of age (for strongyles)

Question 10

1. When a foal has a heavy infection with Parascaris equorum, how would you recommend treating?
2. Why?
3. Which antihelmintics would you NOT recommend?

Answer 10

1. Benzimidazoles
2. Benzimidazoles have a slower kill, whereas macrocyclic lactones and nicotinic agonists causes paralysis and could lead to obstruction of the bowel.
3. Do NOT use ivermectins, pyrantel, or piperazine,

Question 11

How long after passing through with the feces do Parascaris egges become infective?

Answer 11

10 days

Question 12

1. Which Ascarids are NOT infective upon passage with the feces?
2. How long before their eggs are infective?

Answer 12

1. Parascarius equorum, Toxascaris leonina, & Ascaris suum
2. 10 days for Parascaris equorum / 6 - 10 days for Toxascaris leonina / ?

Question 13

What are the physical features of Ascaris suum?

Answer 13

• NO alae
• 3 lips

Question 14

1. This is an egg of what?
2. What animal species houses this parasite?
3. What are some specific characteristics of the egg?

Answer 14

1. Ascaris suum
2. Pig
3. Egg characteristics:
   
   1. Thick shell
   2. Rough outer covering with projections
   3. Single cell inside
   4. Rust brown
   5. STICKY!