posted by admin on Jun 2
There are many types of roundworms that could infect mammals; but the 2 most common types found in domestic cats are:
Toxicara felis:
Kittens can be infected after birth by their mothers milk. Towards the end of her pregnancy, hormones trigger any dormant larvae in her muscles to pass into the mammary glands. These larvae migrate through the milk glands and straight into the stomachs of the newborn kittens.
Once ingested, these larvae grow inside the kitten and can become adult worms while the kitten is still young - obviously they will use the nutrition from the milk instead of the kitten itself.
The kittens can also ingest futher larvae from infective eggs in the environment (on their bedding, etc) or more commonly, through the bitches milk until they are weaned.
Kittens with a heavy burden of worms will have their growth stunted, and very likely have distended, swollen bellies and will often vomit and have diarrhoea. Severe infections of worms have been known to totally block the intestines.
However, kittens should have naturally expelled all their adult worms by 7 months of age. Any eggs or larvae ingested after this time won’t become adult worms in the gut, but will pass through the intestine wall into the body of the kitten (now an adult cat) and settle as their resting state (as cysts) in the muscle tissues.
Any eggs that were ‘passed’ by these kittens or the queen onto the ground or bedding, usually in faeces, have very protective cases and can survive outside for up to 2 years waiting to be eaten or licked up by an animal or human (not washing their hands before eating).
If these eggs are ingested by any animal other than a dog (their specific host) they will not become adult worms in the body - it is host specific to only cats.
However instead, they will travel through the body to the muscle tissue and remain temporarily inactive in a ‘cyst’. This animal (or person) then becomes their temporary host as the worm larvae are hoping that one day, when this ‘animal’ dies, it will be eaten by a cat (or other animal that is then eaten by a cat) and they can complete their lifecycle.
Basically this worms job is to live in the female cats muscle tissue until she becomes pregnant so it can infect her kittens.
Toxicara leonina:
This roundworm will infect both cats and dogs as part of it’s life cycle, but it is not a zoonosis - it has not been known to pass to humans in it’s live state.
There is no infection before birth from the mother to her unborn young, or through the mothers milk - infection is commonly seen in young adolescent animals as they begin to explore their enviroment and ingest eggs or temporary hosts containing inactive larvae (i.e; a cat eating an infected mouse or beetle, or a dog eating undercooked offal and game).
There are normally no outward clinical signs of light or heavy infestation with this worm, as they are well tolerated by both cats and dogs, so you wouldn’t know that your pet even had them!
A good a reason as any to regularly worm your cats!!!