Nematodes-Superfamily Metastrongyloidea

Question 1

Superfamily Metastrongyloidea: general characteristics

Answer 1

Life cycle: mostly indirect, L3 infective stage by intermediate host (snail or slug)
Dx stage: L1 kinked or s-shaped tail (mostly); BAERMANN
CS: only in heavy infections
Infects: resp, vascular, nervous systems
-small buccal capsule

Question 2

Muellerius spp.

Answer 2

-lungworm
Hosts: FH: shoats, IH: mollusks
PPP: 6-10 weeks
Adults: embedded in lung tissue, L1 w/ s-shaped kink tail
-L1 pass in feces and penetrate foot of mollusk, develop to L3, sheep ingests mollusk, L3 migrates to lungs, develop to adults in LN and nodules in lungs
Path: lead shot nodular lesions- gritty feeling
CS: pneumonia (rare in sheep) heavy infections in goats more serious–> smaller than Dictyocaulus so don’t cause as much of an issue, can’t see as well on necropsy
Dx: Baermann
Tx: anthelminthics, hard to control bc of mollusk, can’t really ID in fecal float

Question 3

Parelaphostrongylus tenius

Answer 3

Meningeal worm
Hosts: FH: white tailed deer, IH: mollusks
Aberrant hosts: equine, sheep, goats, llamas, camels, etc.
Path: larvae invade nervous tissue, can be fatal…normally not patent –> CANNOT do fecal- parasite never reaches sexual maturity to make eggs
CS: severe neuro dz- only see in aberrant hosts
Dx: (in aberrant hosts) CS, white tailed deer in pastures
Tx: not great, if CS remain after tx often euthanize

Question 4

Metastrongylus sp.

Answer 4

pig lungworm
Hosts: FH: pig, IH: earthworm (see more in young outdoor pigs)
PPP: 4 weeks
Eggs: small eggs w/ L1, irregular exterior (rough and thick), smaller than ascarids, rougher, thicker shell than strongyloides
Adults: slender, white, 6cm, in bronchi and bronchioles
Path: lung migration causes lesions
CS: bronchitis, coughing, secondary infections, fatal (in pigs 4-6 mo
Dx: eggs w/ L1 in fecal float
Tx: anthelmintics, long-lasting exposure bc earthworms, adults usually asymptomatic
-Metacarpals although small, are rough and thick, and can knock the wind out of you

Question 5

Aelurostrongylus abstrusus

Answer 5

cat lungworm
Hosts: FH: cats, IH: snails/slugs, PH: birds/rodents/frogs (infected more from PH than IH, cats eat birds more than slugs)
-form aggregates in lung tissue, lay eggs in “nests”
infection: lung parenchyma and bronchioles
Path: low pathogenicity, higher in adult hunting cats
CS: chronic mild cough, anorexia, dyspnea, death in severe infections
Dx: L1 w/kinked tail in feces (Baermann)
Tx: prevent access to IH and PHs, anthelminthics rare, parasite used to be restricted geographically, but has been spreading–> parasite is changing

Question 6

Angiostrongylus vasorum

Answer 6

French heartworm
Hosts: FH: wild/domestic canids, mostly foxes
IH: snails/slugs
PH: birds, rodents, frogs
PPP: 28-108 days (1-4 months)
Infection: pulmonary arteries and R ventricle
CS: chronic cough, dyspnea, exercise intolerance, anorexia (chronic infections)
-chronic=more common
-acute=more fatal
-gradually progressing pulmonary dz and cardiac failure
-infects older dogs
Dx: L1 (kinked tail), Baermann, necropsy (slender, pinkish, females =barber poles)
Angio-arteries, only older dogs have heart attacks

Question 7

Filaroides (oslerus) osleri

Answer 7

Tracheal worm
Hosts: dogs and wild carnivores
PPP: 6-7 mo, infected as puppies, no CS until puppy is grown
Life cycle: DIRECT L1 INFECTIVE (kinked tail), L1 expelled in sputum or passed in feces, infect through ingestion of regurgitated stomach contents, lung tissue, or feces of infected dogs–> can be passed from moms licking pups
-young dogs, breeding facilities
Path: hemorrhagic or granular nodules in trachea and bronchi
CS: dry, nonproductive cough, resp distress, anorexia, emaciation –> light infections are asymptomatic, only see CS with heavy infections
Dx: nodules seen w bronchoscope, L1 w kinked tail in feces or sputum–> centrifugal float or w/ Baermann
Tx: persistent problem in kennels, need to go to breeder to stop issues…dont confuse w kennel cough
Larry the dog licks