Nematodes- Superfamily Strongyloidea Flashcards
(15 cards)
Superfamily Strongyloidea
Families: Strongylidae, Chabertiidae, Stephanuridae, Syngamidae
Life cycle: direct, infection by L3
-some species arrest
Eggs: thin shelled, oval, avg size, cannot distinguish between spp
-Males have bursa
-well developed buccal capsule, leaf crowns, teeth
-thick body
-Dx: McMaster (for lg animals), ID L3, CS, necropsy
Large strongyles-general
- larvae migrate in organs, cause colic
- adults are bloodsuckers/plugfeeders (have mouth capsule); anemia-more pathologic
- all eggs are the same
- large intestine
- PPP: 6-11 mo
- no resistance
Cyathostomins (small strongyles)-general
- larvae damage large intestinal mucosa causing colic and diarrhea**
- synchronized emergence in spring (see most CS then)
- resistance*
- mouth capsule rectangular/square
- adults are less pathologic than large strongyle adults
- arrested development (L3, up to 2 yrs)= encyst as L3, emerge/excyst L4
- PPP: 1.5-4 mo
Strongylus vulgaris
- ID: ear shaped tooth
- PPP: 6 months (shortest)
- Adults: least pathogenic
- Larvae: most pathogenic of lg strongyles
- L4=biggest issue–> migrate in cranial mesenteric artery causing THROMBUS leading to DEATH…aberrant larvae migration
- CS: thrombo-embolus; colic…hard to detect bc larval stage is causing CS
- Dx: McMaster, necropsy–>larvae Ab test
Treatment timeline for ALL foal to yearlings
- at 2-3 mo: benzimidazole
- at 4-6 mo: treat again just before weaning
- FEC at weaning to determine if strongyles or ascarids
- at 9 and 12 mo: treat strongyles
- at 9 mo (fall): tx tapeworms
Treatment timeline for yearlings-2 yo
-treat as high shedders: 3x a year
Treatment timeline for mature horses
- determine if low or high shedder
- Low: tx 1-2x yr
- High: tx 3x yr
McMaster egg count
- Gives you eggs per gram of feces
- perform McMaster, then treat, then McMaster again 14 days later to determine resistance and efficacy of drug
- <200=low shedder
- > 500= high shedder
- assume they are small strongyles
Strongylus edentatus
- no teeth
- PPP: 11 months (longest)
- Larvae L4=in liver (portal vein) and abdominal tissues
- acute: fever, anorexia
- chronic: intermittent colic
- adults: anemia in heavy infections
Strongylus equinus
- 3 pairs of teeth, look like mountains, horses ride on mountains and on tracks
- PPP: 9 months
- Larvae L4=in liver, don’t go through portal vein, travel freely and cause hemorrhagic tracts
- adults: anemia in heavy infections
Cyathostomins (small strongyles)
L3 enter mucosa of LI and encyst, molt to L4, excyst (10x bigger than L3)
-PPP: 1.5-4 mo (shorter than large)
-CS: d+, wt loss, colic, edema (mostly associated with L4 emergence, not adults)
-Seasonality: North= larvae arrest in winter, emerge in spring (infected in fall)
South= larvae encyst in summer, emerge in rainy season
-Path: synchronized emergence of L4, protein loss
-Dx: McMaster, L3 differs from lg strongyle L3…eggs in foal feces means coprophagia–> need lots of emerging L4 for CS; too young to have reproducing strongyles. would need to eat a lot of L3 on day it was born to have d+ from small strongyles
-Tx: diff plans/dosing schedules for larval stages, arrested stages and adults
-inadequate tx from previous grazing szn–> severe CS come next spring
*don’t overstock, horses forces to eat poop area and results in lg infections of L3
**Mare is cause of infection for the foal…each horse has its own supply of encysted larvae to become next season’s adults
Oesophogostomum spp.
-nodular/pimply worm
Hosts: cattle, sheep, goats, pigs
PPP: 3-8 wks
-found in warmer climates
Adults: in LI, large, white, 1-3cm
Larvae: L4 nodules in lg (mostly) and sm intestine, low motility of L3
* localized immune rxn after molting from L3 to L4 creates nodule around worm
-heavier the exposure=more nodules=worse CS (worse in older)–> each exposure causes larger nodules
CS: anorexia, d+ (CS before eggs in feces bc caused bu immature stages
*pigs: anorexia, poor sow syndrome together w Hyostrongylus
Dx: fecal float (no eggs in acute, eggs in chronic)
PPR: contributes to exposure (increase egg output to ensure survival)
Chabertia ovina
large mouthed bowel worm
Hosts: mostly sheep, goats, infrequently cattle
Infection: LI
-plug feeders–> cause ulceration and hemorrhaging
CS: d+, anemia, wt loss
-CS prior to eggs in feces bc caused by immature stages
-cross between Oesoph and lg strongyle
Stephanurus dentatus
Host: pig, IH earthworm
***adults in kidney. big worm
typical strongylid egg
Dx: fecal float
Syngamus trachea
Gapeworm (gasping for air)
Hosts: game birds, PH earthworm (hard to control bc earthworms live 8 yrs infecting the land)
-males and females in permanent copulation forming a Y
Adults: red, female larger
Eggs: large w double operculum
CS: asphyxia, mucus in trachea suffocates–> weak –> emaciated
**do not swab trachea!! fecal float works
