A Guide to the Worms in Dogs Cycle
worms in dogs seem to be one of those dog health care problems that return. This is because their lifecycle is designed to be hard to break. 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. It often causes puppies’ bellies to swell and may delay their growth, whilst in humans the worm larvae can cause blindness, although this is rare.
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. In the event of pregnancy in later life, the larvae will be reactivated and will move through the blood to infect the puppies.
In young puppies, some of the larvae will not form the above mentioned cysts. Instead, some will remain in the intestine and grow into adults. Once mature, after feeding on the partly digested food in the intestine, the adult worm releases eggs which are passed from the dog with the faeces. Once in the environment, the eggs become a risk to other dogs and people. Touching contaminated soil or sand rather than touching puppies is what poses the infection risk to people.
That is how the cycle works and to break it, owners must treat adult dogs for worms every three months. Puppies, being much more likely to be infested should be wormed every fortnight from the age of two weeks to twelve months, then monthly until the age of six months. However small and rare, worms in dogs can cause problems for human health, so dog owners must take responsibility for picking up after their dogs and encouraging good hand hygiene in the family, in order to break the cycle and reduce the risk.
