RVT- Endoparasites of horses Flashcards
Where is Parascaris equorum found in its host and what are the clinical signs of infection?
Small intestine
Young horses- Potbelly, unthrifty appearance, intermittent colic, coughing due to migration of larvae into lungs, constipation or diarrhea.
Adults - usually none
What is the mode of infection for Parascaris equorum?
Ingestion of infective ova on pastures and stalls.
Eggs are ‘sticky’
Larvae migrate to liver and lungs and are coughed up and swallowed
How is Parascaris equorum diagnosed?
Standard vial or centrifugal flotation
How is Parascaris equorum treated?
Pasture management
Steam cleaning in stables
Fenbendazole
Resistant to moxidectin and ivermectins
What are ways to protect young horses from Parascaris equorum infection?
Keep on cleanest pasture away from other aged horses
Deworm at 6-8 weeks of age and continue deworming every 6-8 weeks for 1st year of life.
What is another name for Cyathostomes?
Small strongyles
Where are small strongyles found in horses?
Large intestine and cecum
What are the clinical signs of strongyle infection?
Unthrifty appearance Poor performance Intermittent colic Possible diarrhea Clinical signs esp seen in horses under 2 years of age
Why are strongyle infections increasingly important?
No dewormers(except moxidectin) are affective against encysted larvae: also adept at building resistance to anthelminthics
What is hypobiosis?
Arrested development of larvae stages. This occurs in strongyle infections to facilitate survival of eggs to when environmental conditions are good. In Ontario this would be in late fall or early winter.
How is Cyathostomes diagnosed?
Centrifugal fecal flotation
Baermann technique
How is Cyathostomes treated?
Moxidectin for adults and encysted larvae
selective treatment
Resistance to pyrantel pamoate and fenbendazole in some areas
What do the eggs of small strongyles look like?
Thin-walled morulated egg with 8-16 cell morula.
90 x 50 um
Which of the strongyle species is the most dangerous?
Large strongyles as they are destructive feeders that migrate through various organs causing significant damage.
Small strongyles, esp in adults pale in comparison
Which species of strongyle migrates through the cranial mesentary artery affecting the blood supply to the intestines?
Strongylus vulgaris
What are the 2 stages to the lifecycle of the large strongyle?
Free-living stage
Parasitic stage
What are the clinical signs of large strongyle infection?
Most clinical signs associated with larval migration
Colic, anemia, weight loss, hind limb lameness, death
Ulcers
Strongyle eggs found in a fecal flotation are likely associated with what species of strongyle?
Cyathostomins ( small strongyle) as most Large strongyles have been eradicated in Ontario and other parts of North America
What methods are used to diagnose Large strongyle infection?
Fecal flotation for eggs
Baermann technique for larvae
How is Large strongyle infection treated?
Larvae - Ivermectin, moxidectin
Adults- Ivermectin, moxidectin, fenbendazole
Pasture management
What is another name for ‘pinworm’ in horses?
Oxyuris equi
Where is Oxyuris equi found in the horse?
Colon, cecum and anus
What are the clinical signs of pinworm infection?
Tail rubbing
Pruritus of perianal region
Is pinworm infection typically seen in young or old horses?
Over 18 months
