Lungworms Flashcards
What are the 3 primary lungworms of ruminants?
Dictyocaulus
- Protostrongylus*
- Muellerius*
Dictyocaulus spp. is typically found in what climate?
Moist, temperate climates.
Tends to be found around the tropics.
Name the primary hosts for these species:
- Dictyocaulus viviparous*
- Dictyocaulus filaria*
- Dictyocaulus arnfieldi*
-
D. viviparous
- cattle, bison, camelids, wild ruminants
-
D. filaria
- sheep, goats, wild ruminants
-
D. arnfieldi
- donkey, horse
Is Dictyocaulus viviparous in fact viviparous?
(The answer…may surprise you)
Lol Nope.
D. viviparous is, in fact, ovoviviparous.
Recall that this means eggs are laid containing and L1 larva.
How would you describe these lips (other than sensuous)?
Pair of tri-lobe lips.
This is characteristic of Dictyocaulus adults.
What characteristic can you use to know that you are looking at a Dictyocaulus spp. larva?
Brown food granules in intestine.
Where do adult Dictyocaulus live?
Bronchi and bronchioles
Lay eggs, which are coughed up, swallowed, and passed in the feces.
Describe the larval migration of L3 Dictyocaulus once swallowed.
Gut, lymphatics, thoracic duct, blood, heart, lung, pulmonary capillaries, alveoli, bronchioles and bronchi.
So, like, if Dictyocaulus adults live in the lungs, how do the eggs get into the feces?
Eggs are coughed up, swallowed, and passed in the feces.
List the prepatent periods of each of the Dictyocaulus species.
-
D. viviparous
- 4-10 weeks
-
D. filariae
- 4-6 weeks in goats, 8 weeks in sheep
-
D. arnfieldi
- 4-5 weeks
What do larval Dictyocaulus feed on?
Trick question!
The larvae do not feed, but rely on stored food granules in the gut.
In what scientists are calling “rad” and “totally awesome,” Dictyocaulus larvae rely on this fungal species for dispersion.
Pilobolus
True or False:
The penetration phase with Dictyocaulus tends to be asymptomatic.
True
This phase involves L3 migration from the gut to the lungs via the lymphatics, then the blood stream.
What kind of exudate would you expect to find in the bronchioles of an animal infected with Dictyocaulus during the prepatent phase?
Eosinophilic exudate
What kind of pathology would you expect to see during the patent phase of a Dictyocaulus infection?
- Adults in the upper airway result in severe bronchitis and epithelial damage.
- Airways blocked by worms.
- Frothy mucus + cellular exudate.
- Emphysema and consolidation of lobules.
- Secondary infection, pneumonia.
These worms were found in the lung of a cow. What species do you suspect?
Dictyocaulus spp.
Whenever you see a mass of worms in the bronchi of a ruminant, you should think Dictyocaulus.
Because this is a cow, the species is probably Dictyocaulus viviparous
Wow look, cytology! And things are happening on it!
Dictyocaulus worms in bronchi. Note the inflammatory exudation and cellular infiltration.
These are lungs. But not normal lungs! What’s going on?
Interstitial emphysema.
In this case, this is parasitic bronchitis caused by infection with adult Dictyocaulus worms.
What happens in the post-patent phase of Dictyocaulus infections?
Worms are usually expelled due to the massive immune response.
Worms may not be completely expelled in the case of very large infections.
Some animals may have impaired pulmonary function even after expelling the worms.
When are Dictyocaulus infections most common?
Usually occur in the fall (Sept - Oct)
L3 larvae tend to prefer cool, wet weather
What factors affect the severity of Dictyocaulus infections?
Number of parasites
Size and location of parasites
Host response to parasites
What age of animals tend to be most affected by Dictyocaulus infections?
Calves and yearlings
(especially when exposed to a new pasture)
How can you diagnose Dictyocaulus infections?
Clinical signs (however, these are non-specific)
L1 in fresh feces (Baerman method)
Adult worms detected in necropsy
Why is it important to have a fresh fecal sample when trying to detect Dictyocaulus larvae?
You are most likely to find L1 Dictyocaulus larvae in the feces. However, if the animal happens to have a strongyle infection and you let the fecal sample sit for too long, the strongyle eggs may hatch and release their larvae. You may then mistake these larvae for Dictyocaulus.
GET FRESH POO!
What is the name of this test, and what is it used for?
Baerman test. Used to collect motile larvae from a FRESH fecal sample.
Editor’s note: this test REALLY looks like a poop martini.
What species is this?
L1 larva of Dictyocaulus viviparous. Note the food granules and rounded head.
What species is this?
L1 larva of Dictyocaulus filaria. Note the cephalic button and blunt tail.