2.4. Roundworms Flashcards
Haemorrhage in lung as a result of lung migration of Ascaris suum but respiratory symptoms are rare for this infection
Ascaris suum
Huge size —> absorb lots of nutrients —> slower growth of pig
3 labia of roundworm (not possible to distinguish species by morphology but by the host!)
Egg of Ascaris suum
Outer part of the egg can come off
Very durable! Almost impossible to get rid of parasite once it’s on the farm. Resistant to most disinfectants, can survive many years
Egg of Ascaris suum
Outer part of the egg can come off
Flotation test. Dense solution
Life cycle of Ascaris suum
Prepatent period for Ascaris suum
45-60 days
If animals are treated within this period -> no eggs are shed
Sows are often washed to decrease the chance of infecting the piglets through fecal material
Roundworm infection of the horse -> Parascaris equorum
Mainly lungs are damaged -> haemorrhagic inflammation
Mainly in foals
Host: horse
Roundworm of the horse -> Parascaris equorum
Adult worms can reach 20-40 cm in length
Host: horse
Roundworm of the horse -> Parascaris equorum
Adult worms can reach 20-40 cm in length
3 labia of the roundworm
If host is horse —> Parascaris equorum
If host is pig —> Ascaris suum
From horse
Parascaris equorum
Is there correlation between number of eggs and number of adult worms in case of PArascaris equorum?
No, because 1 adult worm can lay up to 200.000 eggs per day
In case of Strongylus there is correlation between these two
What is special about Toxocara life cycle ?
Adult worms can develop only in young animals (calves in case of Toxocara vitulorum)
Worms produce acids that make meat of calves smell
In what animals can Toxocara vitulorum eggs be found?
In feces of young calves (<4 months)
If adult cow eats contaminated grass, it gets infected with L3 larva -> in cows it will migrate to mammary gland and be dormant there —> in case of pregnancy these worms will “activate” because of hormones —> will infect calves through milk
In case of bulls worms will stay dormant and no further infection will happen
Eggs of Toxocara vitulorum - rough surface
Life cycle of Toxocara species of carnivores
zoonotic (T. canis, T. cati)
In adult animals worms will be dormant but in the young animals will be “ascaroid-type” life cycle (intestines - liver - lung - intestines)
Paratenic hosts exist also (rodents, birds)
Can transplacental transmission happen in case of Toxocara canis ?
YES! Newborn puppies can be born already infected!
Transmammary (lactogenic) transmission also happens
Is Toxocara canis zoonotic?
YES. Usually asymptomatic. But if larva gets into the eye/CNS/liver, then disease can be very serious but it’s not very common
Toxocara canis - cuticular wings
Toxocara canis - cuticular wings
Toxocara canis - no copulatory bursa but papillae
Differences between life cycles of Toxocara canis and Toxocara cati
Toxocara cati adult worms are not dormant in the body of the adult cat but living in the intestines and produce eggs!!
Toxocara cati - egg is a bit more oval than in Toxocara canis but main thing that it’s Toxocara
Difference in morphology of different Toxocara species adult worms
- Cuticular wings
- Different shape of Oesophagostomum
Toxocara cati
Toxocara leonina eggs - no grooves and holes on the surface of the egg
Host: poultry
Ascaridia
Host: poultry
Ascaridia
Ascaridia galli
(can be confused with Heterakis gallinarum but they have preanal sucker!)
Ascaridia or Heterakis egg
Paratenic hosts of Ascaridia
Life cycle of Heterakis gallinarum
Heterakis gallinarum - males have spicules of different size and cuticular wings around the tail
Heterakis gallinarum - males have spicules of different sizes + cuticular wings on the tail
Heterakis gallinarum egg
But it’s very difficult to distinguish from Ascaridia egg so in midterm we should say that’s it’s one of the two
