18. Horse GI Nematodes Flashcards
What is the ecology/epidemiology of parascaris
primarily in foals <6mo of age
occasionally present in adult horses, often aged - in study, 50% of foals shedding vs 3% of mares
world wide distribution
pastured and stabled animals
eggs very resistant and stick and lots
What is the life cycle of parascaris equorum?
PPP ~10-12wks
Adults in small intestine > eggs w/ morula in feces > egg L1-L3 > ingested >hepato-tracheal migration
at least 3wks in enviro
what is unique about the parascaris equorum egg?
has a thick, sticky, rough shell with a protein coat
What is strongyloides westeri?
equine threadworm, females parastic,
What is the ecology/epidemiology of strongyloides westeri?
primarily patent in foals <6mo age
worldwide distribution
warm humid climates
pastured and stabled animals w/s suboptimal enviro hygiene
eggs not particularly resistant
vertical transmission (transmammary) - larvae shed in milk for up to 8 wks
What is the life cycle of strongyloides westeri?
yg horses, PPP 10-14 days
Larvated eggs in feces (L1-L3 homogonic cycle) > ingested OR L4 (heterogonic cyle) > free-living adult males and females and continue cycle > once ingested semi-tacheal M or tracheal MWh
What is strongyloidies in older horses
PPP 10-14d, same as young horses basically
Larvated eggs > L1 (rhabditiform) > L2 >L3(filariform) ingested and has somatic, tracheal or semi-tracheal migration. larvae int issues can be passed in colostrum and milk as L3
What is the pathogenesis of strongyloides
cutaneous lesions possible, resp signs, diarrhea in yg (as young as 2wks)
if known problem, treat maker just before foaling to prevent vertical transmission and foals at about 1wk of age
What is strongylus vulgaris (bloodworm), edentatus, equinus
migratory large strongyles
virtually eradicated worldwide due to modern anthemintic, worms are pasture transmitted
What is the life cycle of strongylus vulgaris
PPP ~6mo
Eggs with morula > L1-L3 (ensheathed and infective L3) > ingestion > mesenteric artery M > adults in small intestine
What is the life cycle of strongylus edentatus
PPP ~1yr
Eggs w/ morula > L1-L3(L3 infective) > liver/mesentery migration > adults
What is the lifecycle of strongylus equinus?
PPP ~1 yr
Egg w/ morula > L1-L3 (L3 infective) > liver/pancreas migration > adults in small intestine
How do we dx strongylus eggs?
Just strongyle type eggs in fecal float
What are the large intestinal nematodes of horses?
cyathostomins = small strongyles
Most abundant and diverse equine nematodes > at least 60 known species, pasture transmitted
What is the life cycle of cyathostomes?
PPP 2-3 mo
Eggs w/ morula > L1-L3 (L3 infective) > Mucosal migration > adults
Inhibited or hypobiotic(hibernating), L3/L4
