There are many different species of worm parasites that can infect our canine friends. Some are completely harmless, some may cause human illness and some can cause life-threatening disease.

Roundworm – Toxocara canis, Toxocara cati, Toxascaris leonina

All puppies in the are born carriers of roundworm, and 15% of adult cats and dogs are thought to harbour an infection, mostly without any outward signs.
Toxocara is of concern because humans can be accidentally infected. The eggs are sticky and adhere to the dog’s coat especially in the area around the bottom.

About 25% of dogs may be carrying Toxocara eggs on their coat at any one time. As many as 200 eggs have been found per gram of hair in this area. Infection is by these eggs being ingested by children. Toxocara can cause blindness in children when the eggs hatch into larvae and travel to the back of the eye.


  1. Puppies should be wormed at 2, 5, 8 and 10 weeks of age.
  2. Bitches should be wormed at 3 weeks post-whelping and at weaning.
  3. Consider the use of Panacur liquid in pregnant bitches from 40 days of pregnancy for a 25 day treatment period. This reduces worm burdens in the puppies by 98%
  4. Worm all adult dogs with a prescription (vet only) wormer 4 x a year.


Dipylidium caninum is the most commonly found tapeworm. It can infect cats, dogs, and people. The flea carries the parasite and animals are infected with the tapeworm when they ingest fleas during grooming. Dipylidium is not a health risk although they are unpleasant.

Taenia multiceps can infect cats when they eat rodents, and dogs if they eat the carcases of infected sheep , cows, or rabbits. It is not a health risk.

Echinococcus granulosus is found only in central Wales and the Hebrides. In Europe, it is found in most Mediterranean countries. It is caught by dogs and foxes when they eat infected sheep. Echinococcus multilocularis is found in cats, dogs and foxes, from rodents.

It is not thought to be a risk in the UK, but is widespread in various parts of Europe. Indeed, under the Pet Travel Scheme (PETS), it is a mandatory requirement that all cats and dogs travelling to mainland Europe are wormed against this parasite prior to their return to the UK. Echinococcus tapeworm can cause cysts in humans which can lead to liver failure, or spread elsewhere in the body, requiring surgical removal.


Worm all cats and dogs 4 x a year and when tapeworms are seen.

Hookworm – Ancylostoma caninum in dogs and Ancylostoma tubaeforme in cats

Hookworm are rare in the UK and present a low risk to cats, dogs or people. However, they are far more common on the continent, and the risk of infection is higher.

Eggs are shed into the environment by infected animals, where they develop into larvae which can burrow through the skin of dogs, cats, and humans. The risk to human health in the UK is low. A light infection in a pet will be symptomless. A heavy infection can cause anaemia.


De-worming your dog/cat is the best way to prevent a rash caused by hookworm.



Trichuris vulgaris are rare in the UK and common on the continent. They do not cause problems in cats or humans but in large numbers may cause diarrhoea in dogs.


Although whipworms are the most difficult to eliminate among the families of dog worms, there is effective treatment available.

Whipworm is most effectively treated with fenbendazole (panacur), but febantel can also be used. Prescription medications are usually more effective. The treatment lasts for up to 5 days and is repeated after 3 weeks


Dirofilaria immitusis present in parts of Europe, and can pose a serious health threat to pets. These worms live in the heart and arteries of infected animals.

As they develop, they release tiny larvae into the animal’s bloodstream. These are ‘swallowed’ by mosquitoes as they feed on the infected animal. When the mosquitoes feed on another animal, they pass the infection on. Man is not an ideal host for this parasite, so the risk of developing serious illness as a result of exposure to this parasite is low.

However, if a dog or cat suffers a heartworm infection in the heart or lungs, surgical treatment or drugs may be required to remove them, if the animal is to be saved. Either carry a large element of risk, and a high failure rate.


All dogs travelling in affected areas should be given a monthly preventative treatment whenever average day:night temperatures exceed 57’F.


Lungworm problem are increasingly being recognised in dogs. This may be due to climatic factors and an increase in the fox population.

Crenosoma vulpis – the fox lungworm. Commonly infects young dogs after exposure to infection via the intermediate hosts – commonly slugs and snails, and fox faeces. This lungworm causes a persistent hacking cough that may be mistaken for kennel cough. It does not cause serious or life-threatening disease.

Angiostrongylus vasorum – the French Heartworm. May infect dogs after contact with slugs, snails or frogs. It commonly causes similar signs to the fox lungworm but may also cause severe breathing difficulties, collapse, blood clotting problems and acute neurological disease. Deaths occur.

It is not easy to protect a dog with bizarre tastes in alfresco dining from the risk of picking up the parasite. Regular worming is a must but ordinary over the counter wormers may not be It appears that this infection is on the increase, especially in the fox population, and in certain areas such as Surrey. As they say on Crime watch ‘don’t have nightmares ‘but do be aware and watchful and if worried seek veterinary advice.