Strongyloidea - sheep

Question 1

Name some genera of the Strongyloidea superfamily that affect sheep.

Where are their respective sites of infection?

Answer 1

• Bunostomum - SI
• Oesophagostomum - LI
• Chabertia - LI

Question 2

What are some general characteristics of Bunostomum trigonocephalum?

Answer 2

• Hookworm (blood sucker)
• SI predilection site
• Typical hookworm life cycle (L3 infective, oral route or percutaneous route, pulmonary migration if percutaneous (different than other hooks that might show migration via bucal mucosa), PPP 1-2 months)

Question 3

Name some nematodes of the sheep LI?

Answer 3

• Chabertia
• Oesophagostomum

Question 4

What is unique about the buccal capsule of Chabertia ovina?

Answer 4

• It is very large
• Dz is important in winter rainfall areas of Australia and S. Africa
• Low levels of infection
• Contributes to PGE

Question 5

What are some general features of the life cycle of Chabertia ovina?

Answer 5

• Direct
• L3 infective
• PPP ~6 weeks
• EL4 possible
• maturation from L3 to L4 in SI or LI mucosa
• Immature adults in cecum
• Adults in colon
• Migration from SI or LI mucosa to Cecum, then migration either to tissue as EL4 or to colon

Question 6

What is the pathogenesis of Chabertia ovina?

Is a FEC helpful in dx?

Answer 6

• Both L3’s and Adults cause pathogenesis
• Feed by ingesting large plugs of mucosa
• Local hemorrhage and loss of protein through damaged mucosa
• FEC often low because much of the pathogenic effects are during the PPP
• Worms may be expelled during the diarrheal phase which aid in dx