Other parasites of horses Flashcards
What are nematodes of horses?
*Parascaris equorum
*Oxyuris equi
*Dictyocaulus arnfieldi
What are ectoparasites of horses?
*Lice
*Chorioptes
*Bots - gastrophilus
*Sweet itch - culicoides
What are tapeworms of horses?
*Anoplocephala perfoliata
*A. magna
*Paranplocephala mamillana
What are trematodes of horses?
*Fasciola hepatica
What is the intermediate host of Horse tapeworms?
*Oribatid mite
What is the metacestode stage found in the oribatid mite?
Cysticercoid
What are identifying characteristics of Anoplocephala perfoliata
*Lappets behind each of four suckers
Where are tapeworms found in horses?
Ileo-caecal junction
What is the life cycle of Anoplocephala perfoliata?
- Infected mite ingested by horse
- 2 months post-ingestion = adult tapeworm at ileo-caecal junction
- Proglottids passed in faeces, disintegrate and eggs released
- Oribatid mites ingest eggs = cysticercoid
What do Anoplocephala perfoliata eggs look like?
*Eggs = D-shaped
*50-80um
What can tapeworms cause in horses?
*Spasmodic colic
*Intussuseption
*Ileal impaction
*Rupture
What is the head of a tapeworm called?
Scolex
What are clinical signs of tapeworms in horses?
*Ulceration + pathological change in intestine
*Unthriftiness
*Enteritis
*Colic
When do tapeworm infections peak?
Autumn / Winter
How are tapeworms diagnosed?
*Eggs in faeces
*ELISA to detect antigen
*EquiSal saliva test
How would you treat tapeworm?
*Double dose of Pyrantel
*Praziquantel
What are general features of ascarid nematodes in horses?
- Females lay huge numbers of eggs
- Eggs are highly resistant
- L2 larvae develop in the egg
- L2 in egg is the infective stage
- Direct life cycle
*Hepato-tracheal migration
What can migrating larvae cause? What do adult ascarid worms do?
*Migrating larvae = stimulate inflammatory response
*Adults = compete for nutrients in intestines
*Adult worms can cause mechanical blockage due to size
**NO damage to mucosa
What is the life cycle of Parascaris equorum?
- Eggs in faeces - develop on ground - temp dependent (4wks)
- Egg (L2) eaten by horse
- L2 migrates to liver, lung (L2-L3)
- L4 / L5 coughed up and swallowed in SI
PPP = 12weeks
What does parascaris equorum infection cause?
*Affects foals
*Transient cough
*Poor weight gain
*Unthrifty
How does ascarid infection spread? How is this prevented?
*Foal to foal - adults immune
*Anthelmintic tx
What is Oxyuris equi also known as? Where is it found?
Horse Pinworm - Large intestine
What are features of oxyuris equi?
*Adults have pointed tails
*1-10cm
*Eggs = 80um + oval - more pointed ends than strongyle
What is the life cycle of oxyuris equi?
1.Female lays eggs on peri-anal skin - eggs fall to ground
2. Develop to L3 in egg on ground
3. Ingested by horse - larvae develop in mucosal crypts in large intestine
4. Adults in lumen of large intestines
PPP = 5 months
What are clinical signs of oxyuris equi infection?
*Pruritus
*Excoriation of tail (damage to skin)
How is oxyuris equi infection diagnosed?
*Eggs on peri-anal area
*Sellotape / scotchtape test
