Parasitology - Lecture 21 (Horse Parasites) Flashcards
When consideirn horse parasites, lets start with those affiliated with the stomach, therfore discuss Gastrophilus spp
Gatsrophilus spp –> The horse bot fly:
- bots are the larvak stage of the bot fly
-
WHat is sigificant about Habronema/Drachia
- Adult nematode is nonpatjopgenic in the stomach
- More importantly –> clinical importance is that ic can cause cutaneous habronemiasis –> aberrant larval infection, due to fly laying eggs in open wounds
Discuss the basics of Habronema/Draschia
Habronema/Draschia:
Mucosa vectorse horse stomach worms –> Draschia and Habronema
Adult flies infected with these nematodes –> larvae are deposited on horse when fly feeds —> either 1) horse ingests worm larva; worm completes its life cycle (all is well) OR. 2) worm larva deposited on conjunctiva or wound; dead end for larvae and damage to host (all is NOT well)
Discuss Habronema/Draschia in terms of summer sores:
Summer sores:
- **Draschia/Habronema larvae ** migrate in wound as lkong as as it is moist
- Pruritis/inflamatory reaction to migrating larva > non heakling sore
- If in the eye, larvae will cause conjucntivitis, somerimes leading to ulceration
- L3 in skin wound - most important stage; intensely pruritic
- Adult in stomach –> minor importance
Diagnosis: hard
Treatments:
- oral ivermectin, moxidectin
- Larva are hard to kill –> cuytaneous lesions are often removed surgically
Discuss Trichostrongylus axei
- Can also infect ruminants
- Can cause gastrtitis, mostkly asymptomatic
Diagnosis: produces strongyle eggs
Many other horse strongyle eggs complicate fecal diagnosis
Treat,ent: macrocyclic lactones, benzimadoles, pyrantel
As a review, what are the different horse stomach parasites
- Bots
- Habronema/Draschia
- Trichostrongylus
Now lets discuss horse small intestine parasites
Parascaris equorum - horse ascarid
- Most common parasiite in YOUNG horses
- High reproductive capacity
- Enviornemtnally resiatnt eggs
- Young horsesacquire some immunity with exposure
Discuss the Parscaris equorum life cycle
- Laravted egg ingested orally –> L3 hatches in intestine –> migrates to liver –> lung (L3, L4) –> trachea –> coughed up and swallowed –> small intestine (L4, adult) –> unembryonated egg
PPP is about 10 weeks
No in utero or transmammary transmission
Discuss Parascaris pathology
- most severe in young horses
- liver –> possible fibrosdis –> not ocmmonly noticed
- **Lungs –> inflammation; secondary infectiond ** due to larval migration
- ## **Intestine: ** undernourishment; colic; heavy loads –> occluded lumen (severe colic, bile duct migration, rare perforation and pertonitis
Discuss the diagnosis of Parascaris
- Eggs on fecal float –> 90 um in diameter with an akbumin coat
- ## Adults in manure after dewomring
Discuss prevention ansd control for Parscaris
- clip and clean up areas where young horses are mainatined
- Clean the stalls
- Clean mare’s udders and teats before foaling
Treatment: 2 months old –> fenbendazole, piperazine, ivermectin, moxidectin,pyrantel 4 months old –> fenbendazole
Discuss Strongyloides westeri
- Inestinal threadworm
- Small intestine
- ife cycle: free living and parasitic life cycles
Transmission:
- Transmammary
- Skin –> ground
- Oral –> ground
PPP 1-2 weeks
Most important in foals: Less significance than S. ransomi in pigs
For strongyloides westeri, discuss the treatment and prevention
Treatment –> ivermectin
Prevention: Treat mares at foaling with ivermectin
For parasites of horses, discuss which ones belong in the stomach and which ones belong in the smnall intestine
Stomach:
Gasterophilus spp —> bots cause gastric myiasis
Habronema?Draschia – (L3 - Cutanous Habronemiasis)
Trichostrongylus axei
Small intestine:
Parascaris equorum
Strongyloides
