What are worms?
Worms are internal parasites - that is, they live inside your pet rather than on its coat like fleas or ticks. Most of them live in the intestinal tract, where they feed on nutrients as they pass through the dog's body, although some types live in other organs.
Worms can affect your pet's health, and in rare cases they can spread to humans. If you suspect your dog has worms, you should consult a vet or one of Pets at Home's specialist flea and worm advisors for more guidance.
How can your dog get worms?
Worms spread in different ways depending on the type. They often get into your dog's body when it eats eggs from the ground, although they can be transferred to puppies from the mother. External parasites can also transmit worms to your dog.
Dogs can ingest worm eggs from what they eat; sometimes when they come into contact with infected faeces or dirt, from drinking contaminated water or when they pick up wild animals in their mouths. Ingestion is one of the most common ways for dogs to get worms.
From their mother
Roundworm eggs can form cysts in adult dogs that lie dormant until the dog becomes pregnant, at which point they become active and infect the puppies. The mother's milk can also pass a roundworm infection to puppies.
From parasites and insects
Tapeworm eggs can live in fleas. If your dog swallows fleas when it grooms, it may contract a tapeworm infection when the flea moves to the gut. Beetles and other small insects may also carry worm eggs that cause infections when they are eaten.