Interrupting The Cycle Of Worms In Dogs

Worms in dogs, although normally not serious, are one of those little problems that seem to come back a lot, particularly for puppies. This is because of the way their lifecycle works. Given that worms in dogs can cause health problems in both dogs and humans, owners have a responsibility to interrupt the cycle and try to keep it broken.

The roundworm is the most common type of dog worm we see in the UK because most puppies are born infected. In puppies this infestation causes swollen bellies and may delay growth whilst in humans it may rarely cause blindness.

Like all types of worms in dogs, the life cycle of the dog roundworm (the Toxocara Canis) is not complex and can be controlled with care and patience. The cycle begins when a female puppy is infected from her own mother, either in the womb or as a pup through the mother’s milk. Then, in the infected puppy, some worm larvae will migrate through the intestine wall, into the bloodstream and into muscles where they will form cysts which cannot be destroyed. If she later becomes pregnant, the larvae will be activated and will move back into the bloodstream to infect any unborn puppies, completing the cycle.

In young puppies, not all the worm larvae will form the cysts mentioned above. Rather, some will stay in the intestine and become adults. After feeding on the part-digested contents of the intestine and reaching maturity, the adult worm releases eggs which are passed with the dog’s faeces. Once in the environment, the eggs become a risk to other dogs and people. The risk of infection for people does not arise from handling puppies, but from touching soil which has been contaminated by puppies’ faeces.

That is the cycle and in order to interrupt it, dog owners should give worming treatment to adult dogs every three months. Because of puppies’ predisposition to this type of worms in dogs, they should be treated every two weeks between the ages of two and twelve weeks and once a month thereafter until they are six months old. Worms in dogs do pose a danger to public health, so even though the risk is relatively small, picking up after dogs and promoting hand hygiene in the whole family is vital to break the cycle and reduce risk.