Swine ascariosis

Question 1

Size of ascaris suum

Answer 1

male: 15-30 cm
femlae: 20-40cm

Question 2

What is the size classification of Ascaridida?

Answer 2

Medium – large

Question 3

Describe the morphology of Ascaridida.

Answer 3

White, spindle shaped, without buccal capsule, three well-developed lips, cervical alae on anterior end

Question 4

What is the reproductive feature of male Ascaridida?

Answer 4

2 spicules posterior, without bursa, sometimes with small lateral alae

Question 5

What type of life cycle do Ascaridida have?

Answer 5

Direct

Question 6

What is the shape and shell characteristic of Ascaridida eggs?

Answer 6

Oval, subspherical and thick shelled

Question 7

How is Ascaridida transmitted?

Answer 7

Orally, lactogenic, transplacental or eating PH

Question 8

What are the four main types of development in Ascaridida?

Answer 8

• Ascaroid type
• Toxocaroid type
• Ascaridoid type
• Anisakoid type

Question 9

Describe the Ascaroid type development.

Answer 9

Entero-hepato-pulmonary migration of larva after hatching in SI

Question 10

What is the life cycle progression of Ascaroid type?

Answer 10

SI (hatch) - liver - lungs - pharynx - oesophagus - SI (maturate)

Question 11

Which species are examples of Ascaroid type?

Answer 11

• Ascaris spp.
• Parascaris equorum

Question 12

Describe the Toxocaroid type development.

Answer 12

Somatic migration and arrested development of larvae

Question 13

What is the life cycle progression of Toxocaroid type?

Answer 13

SI (hatch) - liver - lungs - Greater circulation - brain, muscle, heart

Question 14

What can Toxocaroid larvae become?

Answer 14

Hypobiotic (dormant) larvae

Question 15

Which species are examples of Toxocaroid type?

Answer 15

Toxocara spp.

Question 16

Describe the Ascaridoid type development.

Answer 16

Histotropic phase confined to mucosa of SI (NO migration!)

Question 17

What follows the histotropic phase in Ascaridoid type development?

Answer 17

Re-entering of larvae into lumen - Develop to adult stage

Question 18

Which species are examples of Ascaridoid type?

Answer 18

• Ascaridia spp.
• Toxascaris leonina
• Heterakis spp.

Question 19

Describe the Anisakoid type development.

Answer 19

Indirect life cycle with IH = Crustaceans, FH = marine mammals, PH = Fish, squids

Question 20

Which species are examples of Anisakoid type?

Answer 20

Anisakis spp.

Question 21

What is the definitive host (FH) for Ascaris suum?

Answer 21

Pig – SI

Question 22

What is the paratenic host (PH) for Ascaris suum?

Answer 22

Earthworm

Question 23

Describe the eggs of Ascaris suum.

Answer 23

Medium, spherical, 3 thick shells, rough surface, unembryonated, dark brown

Question 24

What is the life cycle of Ascaris suum?

Answer 24

Unembryonated eggs passed in faeces – develop into infective L3 within the egg (2-4 weeks) - Eggs/PH ingested – L3 hatch in SI – penetration of intestinal wall to veins of cecum and colon – Hepato-Pulmonary migration to lungs – migrate to pharynx, swallowed to SI – moult to L5 and mature to adults

Question 25

What is the prepatent period for Ascaris suum?

Answer 25

6-8 weeks

Question 26

What pathogenesis occurs due to Ascaris suum larvae?

Answer 26

Damage in the organs they migrate, causing inflammatory reactions, intralobular destruction, hemorrhages ## Footnote followed by infiltration of esosinophils and collagen production - **milk spots on liver**

Question 27

What is a consequence of Ascaris suum migration in the liver?

Answer 27

Milk spots on liver due to eosinophil infiltration and collagen production

Question 28

How many eggs can female Ascaris produce daily?

Answer 28

2 million eggs daily

Question 29

What conditions can Ascaris suum eggs survive?

Answer 29

Resistant to freezing and drying – can survive up to five years under most farm environments

Question 30

What factors can destroy Ascaris suum eggs?

Answer 30

Exposure to sunlight and prolonged drying

Question 31

What treatments are available for Ascaris suum?

Answer 31

* Levamisole * Benzimidazoles

Question 32

What is a control method for Ascaris suum?

Answer 32

Deworming program

Question 33

What methods are used for diagnosis of Ascaris suum?

Answer 33

* Necropsy * Coprological examination (fertilized, unfertilized, decorticated eggs)

Question 34

What is the geographical distribution of Ascaris suum?

Answer 34

Worldwide