Equine Parasites Exam II Flashcards
What are the pathogenesis and lesions associated with adult infection of Draschia megastoma and Habronema spp?
Gastritis
Nodules or tumors
What are the pathogenesis and lesions that can occur in a Draschia megastoma and Habronema spp larval infection?
1) Cutaneous habronemiasis and Cutaneous draschiasis
2) Ulceration
3) Granular conjunctivitis
4) Nodules in the lungs
What are the clinical signs of adult and larval infections of Drascia megastoma and Habronema spp?
Adults cause gastritis.
Larvae cause “summer sores” (cutaneous habronemiasis)
What is another name for cutaneous habronemiasis?
“Summer sores”
Why are fecal examinations for Habronema spp and Draschia megastoma not good diagnostic tools?
Because the eggs are thin-walled and collapse with a loss of buoyancy in routine fecal examinations.
What is the infective stage for Habronema spp and Draschia megastoma?
How does it get into host?
L3 is the infective stage.
Fly larvae eat the hatched L1 in dung, L1 to L2, fly larvae pupates, L2to L3, adult fly transmits L3 to host by depositing larvae on lips, eyes, wounds, or fly itself may be ingested by host.
What is the infective stage for Parascaris equorum?
The L2 in egg is the infective stage.
Describe the life cycle of Parascaris equorum.
PPP is 10-12 weeks. It has a direct life cycle and is ingested (per os). No transmammary or transplacental transmission.
Where is the site of infection for Parascaris equorum?
The small intestine.
Describe the pathogenesis and lesions of Parascaris equorum.
1) Perforation through wall of small intestine, liver, and lungs. Hepatic tracheal migration.
2) Intestinal obstruction. Obstruction can occur with immature populations.
3) Unthriftiness or production losses.
What are some clinical signs that present with a Parascaris equorum infection?
Coughing during migratory phase.
Unthriftiness in heavy to moderate infections in young animals.
What three ways are Strongyloides westeri transmitted?
Per os and percutaneously, by the heterogonic phase.
And transmammary, by the 4th day.
What is the site of infection for the larvae of Strongyloides westeri?
For the adults?
The larvae infect somatic tissues (arrested).
The adults infect the small intestines.
What are the clinical signs and pathogenesis of larval Strongyloides westeri infection?
Of adult infection?
Skin penetration by larval migration causes erythematous reaction.
Infection in skin can cause urticaria.
Adults can cause diarrhea.
What is the diagnostic tool for Strongyloides westeri and when can we expect to see the eggs in the young horse?
Fecal flotation methods.
Expect to see eggs in horses < 5 months old. Suspect eggs seen in an older horse are likely Strongyle eggs.
What is the common name for Strongyloides westeri?
Threadworm
What is the scientific name for the large pinworm?
Oxyuris equi.
Where is the site of infection for the Oxyuris equi?
The large intestine (dorsal colon)
What is the infective stage for Oxyuris equi?
L3 larvae in egg.
Where do gravid Oxyuris females lay their eggs?
They travel out of the anus and lay eggs around the perineum in a gelatinous substance.
What are the clinical signs and pathogenesis of a Oxyuris infection?
Pruritus and peri-anal irritation (from eggs and gelatinous substance)
What can be used to diagnose a Oxyuris infection?
Note broken hair at tail head
Adhesive tape method or perianal scrapings to diagnose infection.
The following describes which worm species:
Direct life cycle (PPP 4-5 months)
L3 in egg (oval with flat side) is infective
Little immunity development
Adhesive tape method
Can become issue especially in barns/stables
Peri-anal irritation (from gelatinous substance)
Broken hair at tail head
This is the Oxyuris equi. The large pinworm.