Nearly all puppies are infected with the roundworm, Toxacara canis.
They can be infected in 2 ways.
1 Whilst still in the womb due to infection across the placenta = Pre-natal infection;
2 From the mothers milk in the first few weeks of life.
Toxacara has a very complex life cycle. When a dog swallows an egg, it hatches in the intestine into a larva, which then migrates through the blood to the liver and the lungs, the larvae are then coughed up, and swallowed to end up back in the intestine. They then produce eggs which pass out in the faeces.

This is why puppies often cough or vomit up worms, as well as sometimes passing them in their faeces.
These eggs are not only infectious to dogs, but also to humans, especially children. The eggs hatch, and migrate through our bodies. As we are not the host, the larvae remain in their migrated sites, which in children include the eyes.
The only way this can be prevented is to regularly worm your dog, (and safely dispose of any dog faeces found), and limit dogs in areas where children play.

If your puppy has a large worm burden it often has a pot belly, it doesn’t thrive very well, and may have diarrhoea.
All pups should be wormed with a suitable worming produce at 2 wks of age,then at 5 wks, and before leaving the breeders. They should then be wormed at 8wks and 12wks  this helps eliminate Pre – natal infection and to eliminate any infection acquired from the milk of the mum, or from an increase of faecal egg output by the mum.

After this your dog should be treated monthly until 6mths old with a broad spectrum wormer.

Worming adult dogs

When and what to worm adult dogs, depends on what they are being exposed to.

The main worms they come into contact with are as follows :-


All dogs should be wormed every 3 months for roundworms, mainly to help prevent the transmission of the worms to children where they can cause severe eye injury and Blindness.

Tape worm

Dogs should be wormed twice a year for routine tapeworm prevention.
Dogs with a high risk tapeworm infection need to be wormed every 6 weeks.
A Dog is considered high risk if it is fed a raw meat diet, or has access to carcasses or raw offal, or spends a lot of time in Wales and walks where there are sheep. (NOTE the sheep tapeworm is highly contagious to man, infection can cause liver and neurological problems) You also need to remember that your dog can also infect sheep with the tapeworm

This is a worm that is becoming more common especially in the Southwest of England. It can cause a number of
symptoms, the most serious being clotting problems leading to bleeding and heart failure. The worm is passed to dogs by eating slugs which contain the young worms.