Equine Parasites

Question 1

Large Strongyles

Answer 1

Significant cause of intestinal disease in horses
* results in colic, diarrhea, and / or chronic weight loss
* adults live in cecum and colon of those infected
* migrate through host tissue during development - causes damage to organs

Question 2

Large Strongyle
Family

Answer 2

Strongylus
* vulgaris
* edentatus
* equinus

Question 3

Strongylus vulgaris

Answer 3

• Most commonly associated with clinical signs of disease
• Penetrate submucosal arteries. along endothelium to cecal and colic arteries, to base of cranial mesenteric artery - get back to intestin via arteries
• Cause thrombosis, inflammation, and necrosis of intestine

Question 4

Strongylus edentatus

Answer 4

• Invade gut vall, penetrate blood vessels and travel to liver via hepatic portal vein - return to large intestine via mesentery
• Migration may cause observable clincal signs

Question 5

Strongylus equinus

Answer 5

• Leave intestine and go to liver; then back to large intestine
• Migration may cause observable clinical signs

Question 6

Anoplocephala perfoliata

Answer 6

Also known as equine tapeworm
* may not be a common cause of colic
* live in ileocecal junction - lacerates mucosa
* associated with intussesceptions - unsure if cause or not

Question 7

Parascaris equorum

Answer 7

Also known as roundworms or ascarids
* not significant in adults, but causes disease in foals
* results in ill thrift and poor weight gain
* intestinal impaction with large worm numbers
* not a “lung worm”, but larvae migrate through lungs in foals - respiratory disease signs

Question 8

Cyathostomes

Answer 8

Small Strongyles
* cause severe diarrhea, weight loss, hypoproteinemia, and possible death in adults
* seen in late winter or spring

Question 9

Dictyocaulus arnfieldi

Answer 9

Also known as the equine lung worm
* respiratory parasite
* commonly seen in donkeys - rarely produce clinical signs (carriers?)
* horses can get thru contact with donkeys or their pasture - bronchial inflammation and chronic cough
* worm can grow up to 16 cm long