Stongyloidea - dog/cat

Question 21

What is the superfamily of hookworms? What is the genus and some common spp?

Answer 21

1. Superfamily Strongyloidea
2. Genus Ancylostoma and Uncinaria

• A. caninum (dog)
• A. braziliense (dog, cat)
• A. tubaeforme (cat)
• Uncinaria Stenocephala (dog, cat, fox)

Question 22

What are some general characteristics of Ancylostoma spp (hookworms)?

Answer 22

• Direct LC
• L3 infective
• ALD possible
• SI predilection site
• Direct ingestion, percutaneous, and transmammary routes
• NO transplacental route
• 1-3cm long, stout, hooked head
• Zoonotic

Question 23

Describe the LC of Ancylostoma caninum.

Answer 23

• Adult in SI produces eggs
• Eggs develop in environment to sheathed L3 (retained L2 cuticle)

1. Ingestion

• crosses bucal mucosa and travels to lungs (can arrest in tissue as L3 after travel from lungs)
• development to L4 and travel through bronchi/trachea
• coughed and swallowed to SI
• *****can go straight to SI, if it doesn’t cross bucal mucosa

1. Percutaneous

• crosses epithelium and travels to lungs (can arrest in tissue as L3 after travel from lungs)
• development to L4 and travel through bronchi/trachea
• coughed and swallowed to SI
• Development of adults in SI

Question 24

Why is the transmammary route of infection in Anylostoma spp so important in pups?

Answer 24

• They are voracious blood feeders
• Bitch can infect 3 consecutive litters
• Acute hemorrhagic anemia can result in pup (chronic hem. anemia in bitch/older animals)

Question 25

What are some methods of control of Ancylostoma caninum infection?

Answer 25

• Anthelmintics - benzimidazoles, ivermectin/moxidectin
• There is some evidence for pyrantel resistance
• High dose fenbendazole in pregnant bitch
• Make sure bedding is clean and dry - earth or grass runs support survival of L3’s
• Possible vax in the making

Question 26

How would the proposed vax work against Ancylostoma spp?

Answer 26

• Isolate antigens (enzymes) from the membrane of the hookworm gut and use to vax
• Antibody response is generated in the host
• When subsequent hooks feed, they ingest the antibody
• The antibody neutralizes/inhibits enzymes in the hooks.
• If they can’t feed, they can’t live

Question 27

What are some general characteristics of Ancylostoma braziliense?

Answer 27

• Infects cats and dogs
• Non-blood sucking
• Causes protein-losing enteropathy
• Zoonotic
• cutaneous larva migrans in man

Question 28

What are some general characteristics of Uncinaria stenocephala?

Answer 28

• Infects foxes (“northern hookworm”)
• oral route
• No percutaneous or transmammary route (still no transplacental like previous hooks)
• Sheathed L3 is infective
• No migration, directly to SI
• PPP 14-21 days
• Not a voracious blood-sucker
• Causes protein-losing enteropathy
• Can enter via skin (percutaneous) but dies; however, it can cause a hypersensitivity response (pedal dermatitis)

Question 29

How can Ancylostoma and Uncinaria adults be distinguished?

Answer 29

• The morphology of their heads
  
  • Ancylostoma have teeth
  • Uncinaria have cutting plates