Parasit - Lab Quiz 10-2

drraythe's version from 2015-05-13 13:29

Suborder Strongylida

Oesophagostomum dentatum (nodular worm)

Question Answer
DHSwine (cattle, sheep, goats, pigs)
What kinda egg?Oviparous (unembryonated)
Describe the LC of Oesophagostomum dentatumUnembryonated egg in feces → Ingestion of L3 larvae → nodule formation in/on intestinal wall → L4 emerge from nodules → adults in large intestine
What might the nodule formation be accompanied by?May be accompanied w/ catarrhal enteritis & stunted growth
What happens w/ intestine after L4 emerge from nodules to be adults?Nodules later ceasate & calcify → interferes w/ intestinal motility
CS of an O. dentatum infxn?Thin sow syndrome → small litter size
Grower pigs → poor growth rates
Condemnation of intestines at slaughter
What is the clinical dz associated w/?Assoc. w/ host immune rxn to L3 larvae in nodule NOT to the adult in intestinal lumen. no eggs in feces/ non-patent infxn
How do you dx O. dentatum?You might see unembryonated eggs in feces (probably not thou) but clinical dz assoc w/ non-patent infxn, so diagnosis dependent on interpretation of CS or postmortem findings
RememberLooks like esophagus teeth. Is nodular in intestine. (What? I guess you could say the eso looks like an intestine & it's all "chewed up by a pig" w/ bumps all over it)

Stephanurus dentatus/ kidney worm

Question Answer
Where do you find adults of S. dentatus?Large worm found in cysts in perirenal fat & pelvis of the kidney
Where do you find larvae of S. dentatus?Liver
What does the adult worm look like?Mottled appearance
Where do you find eggs of S. dentatus?Urine
How do larvae infect DH?Ingest L3, ingest PH (earthworm), penetrate skin, OR in-utero infxn possible (transplacental)
What is the primary pathology of S. dentatus?During larval migration in the liver – 4-9 mo....liver gets "milk spots" & the liver is condemed at slaughter
Why might a pig w/ S. dentatus be paralyzed in the posterior?Aberrant Larvae migrating in spinal cord
What environment facilitates pigs getting S. dentatus?Pigs on dirt get this worm – not those raised on concrete!
LC?Eggs in URINE → L3 develops in enviro → Pig can eat L3, L3 penetrates skin, xplacental infxn or L3 gets into earthworm & pig eats worm → Larvae migrate in liver for 4-9mo → Migrate to kidney to lay eggs & encyst
RememberSteph's teeth have bit many things-- kidney, liver, spine...she has a DIRTy mouth, esp bc she likes to drink pee (shes versatility gross, like her LC) but her skin is milkyspot white

Syngamus trachea “Gapeworm”

Question Answer
DHBirds only
What do the adults look like?In permanent copula, so in Y-shape
Where do adult Gapeworms live?Trachea of birds
How would you describe the eggs?Bioperculate/bipolar plugs
Describe the lifecycle of the GapewormEither direct ingestion of egg, L3 OR eat earthworm w/ L3 → gut → migration to lungs → trachea
What are the CS of a Syngamus trachea/Gapeworm infxn?Dyspnea, suffocation, death. Gaping- open mouth breathing, extended neck
Dx?Tracheal swabs


Ostertagia ostertagi

Question Answer
Ostertagia ostertagi aka? Is indistinguishable with who? Who is suseptable?‘Brown or Western Stomach Worm’ Indistinguishable w/ Teladorsagia circumcinta. Most important nematode in cattle – calves/yearlings are most susceptible. (Teladorsagia circumcinta is more in sheep/goats)
Describe Ostertagia ostertagi Adults?Thin, red-brown. Males are bursate with 2 spicules
What do Ostertagia ostertagi eggs look like?
What is the Ostertagia ostertagi LC?Direct, non-migratory. L3 is infective
Eggs in feces hatch, L3 ingested → penetrate gastric glands, molt to L4 → emerge onto mucosal surface, mature to adults. L3 are cold resistant & can undergo hypobiosis
Special thing to remember about Ostertagia ostertagi larval stages?L3s are cold resistant & can undergo hypobiosis
Where does Ostertagia/Teladorsagia cause dz?Abomasum/ True Stomach
What are the 2 dzs of Ostertagia/Teladorsagia?Type I: Summer ostertagiosis (late spring-early fall)
Type II: Winter ostertagiosis (late winter-early spring)
What is Type I ostertagiosis? When does it happen? What will you see?‘Summer ostertagiosis’ (late spring-early fall)
Targets are weanling calves in 1st grazing season
Emerging immature adults & feeding of adult worms cause profuse, bright green diarrhea, rapid wt loss, anorexia. See many eggs & adults in feces. ↓ Mortality
What is Type II ostertagiosis? When does it happen? What will you see?‘Winter ostertagiosis’ (late winter-early spring)
Targets are yearling calves entering 2nd grazing season
Rapid maturation & emergence of hypobiotic larvae cause similar CS, but few eggs/adults in feces. CS: Anemia, hypoproteinemia, emaciation. ↑ Mortality


Question Answer
Haemonchus is most important in which animals?Sheep (& cattle)
What are the characteristics of Haemonchus? Males/Females?Blood sucker of abomasum; Adults have small buccal capsule w/ lancet to pierce mucosa and suck blood; Females have a characteristic barber pole effect due to uterus/ovaries winding around blood filled gut
Haemonchus LC?Direct, non-migratory. Eggs in feces (L1-L3) → L3 ingested, penetrate gastric epithelium of abomasum → L4 → immature adult → re-emerge, mature to adult
Hypobiosis important as L3s are NOT very cold resistant, but they can over-winter or over-summer
Pathology of Haemonchus infxn? Who is susceptible?All ages susceptible. You will see a ‘peri-parturient rise’ = ewes at lambing causing rapid pasture contamination. Path = Acute/chronic Blood loss
Acute haemonchosis – 10,000 or more worms present. Anemia, black tarry feces (no Diarrhea), bottle jaw, anorexia, wool loss, weakness
Chronic haemonchosis – (most common) 100-1000 worms – assoc with low prevalence, low xmission. Little or no anemia
Whats Refugia?Proportion of worm population that is not selected by drug treatment (worm in untreated animal, stage of worms unaffected by drug treatment, eggs and larvae on pasture at time of treatment). Selective rather than whole herd treatment. Decrease development of resistance by diluting eggs produced by few resistant worms with eggs that did not receive treatment/ sensitive
Dx?FAMACHA or eggs in feces
What is FAMACHA?A selective treatment approach, uses scale to measure anemia in sheep & goats to determine Tx instead of whole herd Tx. Does not use fecal egg count! Delays development of resistance in a wild gene pool (refugia) → the larger the refugia, slower evolution of resistance. Tx only those animals that require it → bottle jaw or anemia. If you Tx & move to a clean pasture, the only worms left are resistant & now you’ve contaminated pasture w/ a pure resistant strain!