Lecture 3 Flashcards
What kind of life cycle to ascarids typically have?
Direct
What are the primary hosts of Toxocara cati?
Wild and domestic felids
What is the most common method of infection with T. cati in wild felids and feral cats?
Ingestion of paratenic (transport) hosts
Rodents, birds, chickens, earthworms, ruminants, etc.
Identify this species and describe how to differentiate it from another closely-related ascarid.
Toxocara cati
Note the broad, arrow-shaped cervical alae, which are much more distinct than those found in T. canis.
How would you tell the difference between the eggs of T. cati and T. canis?
T. cati eggs are very similar to those of T. canis, but are smaller.
How many modes of infection are possible with T. cati?
3
Ingestion of larvated eggs (fecal-oral)
Ingestion of paratenic host
Lactogenic
(Recall that T. canis can also move trans-placentally)
True or false:
After ingestion of a paratenic host with T. cati or after lactogenic transmission, it is possible for adults to develop directly in the host intestine instead of undergoing migration.
TRUE
Where do T. cati eggs hatch after being swallowed by the host?
Duodenum
(stomach in T. canis)
How long does it take for freshly-laid T. cati eggs to become infectious?
2-6 weeks
How long does it take for freshly-swallowed T. cati eggs to hatch and migrate to the lungs?
~4 days
True or false:
T. cati chooses whether to perform tracheal migration or somatic migration based on the host’s age, just like T. canis.
FALSE
In T. cati, tracheal migration predominates regardless of age.
This is why trans-placental infection is not a concern for this parasite.
What is the pre-patent period of T. cati?
8 weeks
True or False:
You would expect to see a lot of hypobiotic larvae in an adult cat with a T. cati infection
FALSE
Recall that T. cati does not usually undergo the Liver/Lung/Somatic migration.
True or False:
In the case of lactogenic transmission with T. cati, the pre-patent period is often reduced.
TRUE
In lactogenic transmission, the larvae will often directly develop in the small intestine without undergoing migration.
This can shorten the pre-patent period to as short as 3 weeks.
In the case of lactogenic transmission with T. cati, when are hypobiotic larvae re-activated in female cats?
Late pregnancy to early lactation
If a cat is infected with T. cati during gestation, where will the larvae end up?
Most will go directly for lactogenic transmission.
Would you expect there to be a lot of hypobiotic larvae in non-feline hosts infected with T. cati?
Yes
In paratenic hosts, the Liver/Lung/Somatic pathway predominates, resulting in hypobiotic larvae spread throughout the body.
What would you expect the minimum pre-patent period to be in the case of a cat that ingests a paratenic host infected with T. cati larvae?
3 weeks
The pre-patent period can be reduced from 8 weeks because many larvae will not migrate, but will develop directly in the small intestine.
Which animal serves as an important reservoir for T. cati infections?
Rodents
Important paratenic hosts.
How long do adult T. cati worms survive in feline hosts?
4 to 7 months
How long does it take for freshly laid T. cati eggs to become infective?
2 weeks or more.
List some clinical signs associated with Toxocara infections in cats and dogs.
Potbelly
Ill thrift, emaciation (poor doer)
Potentially sneezing/coughing
Vomiting +/- mucoid diarrhea
Kittens and adult cats are often asymptomatic
Which drugs could you use to treat T. cati infections?
The BIG THREE plus Emodepside
Note that there are fewer anthelmintic drugs approved for cats than there are for dogs.
What is the proper deworming regimen for a kitten infected with T. cati?
Every 2 weeks until 3-4 months old.
