Lecture 7 2/2/24 Flashcards
What are the general characteristics of the Strongylida superfamily Metastrongyloidea?
-aka lungworms
-males with caudal copulatory bursa
-small buccal cavity
-leave definitive host as larvae in most cases
-usually live in lungs
-mostly indirect life cycles
-migratory in DH
How can Metastrongyloidea be diagnosed?
-zinc sulfate fecal flotation
-Baermann test (alive, moving larvae only)
What are the characteristics of Dictyocaulus spp.?
-actually a Trichostrongyle
-aka large lungworm
-live in airway passages
-DH is cattle, sheep, goats, horses, herbivores
-no IH
-females 50-100 mm
-males 23-80 mm
-L1 300-600 um
-PPP of 3-8 weeks
How do Dictyocaulus spp. utilize Pilobolus fungus?
-the fungus will be found on the grass/soil
-larvae will migrate onto fungus
-when sporangium cap explodes off, larvae spread
Which Dictyocaulus spp. infects cattle?
D. viviparus
Which Dictyocaulus spp. infects sheep and goats?
D. filaria
Which Dictyocaulus spp. infects equids?
D. arnfieldi
What is important about the various Dictyocaulus spp.?
there is no cross-infection between different DHs
What are the clinical signs of D. viviparus in cattle?
-coughing
-moderate to severe dyspnea
-loud breath sounds
-fever
What are the characteristics of Muellerius spp.?
-aka hair lungworm
-IH is snails and slugs
-DH is sheep and goats
-male 11-14 mm
-female 19-23 mm
-L1 250-300 um
-PPP of 6 weeks
How can Muellerius spp. be identified?
kinked tail with dorsal spine
Where are Muellerius spp. found in the lungs?
deeply embedded in lung parenchyma or in reactive nodules
What are the characteristics of Parelaphostrongylus tenuis?
-aka meningeal worm - not a lungworm
-IH is snails and slugs
-DH is white tailed deer
-abnormal hosts include sheep, goats, alpacas, llamas, horses, cattle, moose
-males and females 6-15 cm
-L1 300-400 um
-L1 with dorsal spine on kinked tail
-PPP of 3 months
What are the characteristics of Parelaphostrongylus diagnosis/treatment/prevention?
-larvae only shed in white tail deer feces; cannot be used to diagnose abnormal hosts
-cerebrospinal fluid eosinophilia suggestive of infection in abnormal hosts
-can find worms in brain/spinal cord post-mortem
-treatment only effective before neurologic signs
-want to keep deer/snails out of pasture
What are the characteristics of Aelurostrongylus spp.?
-aka feline lungworm
-IH is snails and slugs
-paratenic hosts are amphibians, birds, reptiles, rodents
-DH is cats
-males 4-6 mm
-females 9-10 mm
-L1 350-400 um
-PPP of 6 weeks
How can Aelurostrongylus spp. be recognized?
-adults in pulmonary artery and lung parenchyma
-male with reduced bursa, stubby rays, stout spicules
-vulva close to female tail
-eggs scattered in lung; pass as larvae with wavy tail/spine
Which larval stage is infectious in Aelurostrongylus spp.?
L3
How can Aelurostrongylus spp. be diagnosed?
-larvae in feces
-tracheal wash
-radiographs
What are the clinical signs of Aelurostrongylus spp.?
-can be subclinical
-mild infection: coughing and anorexia
-severe infection: cough, dyspnea, polypnea, death
What is the pathogenesis of Aelurostrongylus spp.?
-damage lung tissue
-incite inflammatory reaction
-hypertrophy/hyperplasia of smooth muscle in arteries/bronchioles/alveolar ducts
-fibrosis and mineralization of bronchioles
What are the characteristics of Filaroides osleri and Filaroides hirthi?
-aka dog lungworms
-no IH
-unknown if PH involved
-DH is dogs
-males 4-7 mm
-females 8-12 mm
-L1 is 325-378 um
Where do adult Filaroides osleri live?
nodules at the tracheal bifurcation
Which larval stage is infectious in Filaroides spp.?
L1 (only species)
What are the clinical signs of Filaroides osleri?
-dry cough when exercising
-laryngeal or tracheal massage does not elicit cough
-obstruction of air flow once nodules are enlarged enough
Where are adult Filaroides hirthi found?
lung parenchyma: alveoli and bronchioles
Which dogs often experience Filaroides hirthi?
research beagle colonies
How does Filaroides hirthi get to the lungs?
hepatic-portal system and mesenteric lymph system
What is Filaroides hirthi hyperinfection?
reinvasion by the larvae passed in the feces in dogs that are immunocompromised
What are the clinical signs of Filaroides hirthi?
-nonproductive cough
-dyspnea
-exercise intolerance
What types of lesions can be seen in the lungs with Filaroides hirthi?
-small foci of granulomatous reaction
-tumor-like lesions
What are the characteristics of Metastrongylus spp.?
-aka swine lungworm
-IH is earthworms
-DH is swine
-males 11-26 mm
-females 28-60 mm
-eggs 45-57 x 38-41 um
-only lungworm that passes eggs instead of larvae in feces
-PPP of 3-4 weeks
What are the characteristics of the Metastrongylus spp. lifecycle?
-eggs coughed up and swallowed
-eggs passed in feces contain L1 larva
-earthworm eats eggs
-larva develops to L3 in earthworm
-earthworm eaten by pig
-larvae penetrate pig intestinal wall and enter the lymphatic system to go to heart/lungs
-adults reside in bronchi/bronchioles
What disease state is seen with Metastrongylus spp. infection?
pneumonia and parasitic bronchitis
How can Metastrongylus spp. be identified?
-females have vulva at posterior end
-elongated and thin
-female uterus contains larvated eggs
-male with two thin elongated spicules
-male with reduced bursa and stubby rays
-found in pulmonary air passages
What are the characteristics of Rhabditoidea?
-facultative parasites
-most species are free living
-small, thin shelled, larvated eggs
-rhabditiform esophagus in free living adults
What are the characteristics of Rhabditis/Pelodera spp.?
-facultative parasite
-accidental hosts include dogs, pigs, cattle, rodents, horses, people
-adults 1-1.5 mm
-free-living nematode
-produces folliculitis exposed animals
-larvae found in skin scraping or biopsy
What are the characteristics of Strongyloides spp.?
-aka intestinal threadworm
-DH is mammals, birds, reptiles
-adult female 2-9 mm
-produces eggs without male: males are not parasitic
-eggs 50x30 um
What is unique about the Strongyloides spp. lifecycle?
-L3 stage will choose between being parasitic or free-living
-dependent on environment and whether or not it is suitable for non-parasitic life
What are the characteristics of Strongyloides stercoralis?
-DH is dogs and humans
-PPP of 2-3 weeks
-larvae become sequestered in tissues
-animals infected through milk or auto-infection
-often asymptomatic
-can cause diarrhea and lung disease
What are the characteristics of Strongyloides westeri?
-causes foal heat diarrhea
-foals infected through transmammary transmission
-develop adults and diarrhea 5-10 days after infection
What are the characteristics of Strongyloides ransomi?
-seen in pigs
-causes mortality in up to 50% of infected piglets
-causes anorexia, diarrhea, dysentery
-clinical signs and mortality before eggs shed
What are the characteristics of Strongyloides papillosus?
-seen in ruminants
-can erode intestinal mucosa and cause death
-causes anorexia, diarrhea, anemia
-penetrating larvae cause lesions on feet
