Worm eggs are shed by dogs and cats in their faeces and so worms can be picked up from contaminated soil. Some worms are transmitted to our pets via other species such as slugs, snails, sheep etc.(This is called an Indirect life cycle).
Some immature worms (larvae) migrate through body tissues causing damage to the organs such as the liver.
Worms from dogs and cats can affect people who don’t have a good immune system. This would include the elderly, diabetics, people with HIV-infection, patients undergoing chemotherapy or who have had organ transplantation or who are having treatment for autoimmune diseases. Also pregnant women, babies, toddlers and the mentally handicapped have a higher risk of picking up worms from pets.
People working with animals such as farmers, kennel workers, hunters and other animal health professionals would also be more exposed to worms and consequently at a higher risk.
Roundworms are the most common worm in dogs and cats and can look like spaghetti due to their shape. They are found in either the intestines, the airways or the around the heart of their hosts.
Zoonotic (ie. this worm can affect humans): causing sight impairment, abdominal pain, liver and lung damage or affecting the brain, nerves or muscles. This is often occurs in younger children 2-7 years.
No signs and symptoms are visible with a light infection.
This parasite has a direct lifecycle (ie. only dogs carrying and transferring the parasites). Dogs become infected from eating a worm egg which has been passed in the faeces of the same or another dog. These microscopic eggs are invisible to the naked eye and can live in the environment for 2-3 years, thus remaining a health risk long after dog faeces have disintegrated.
Infection can also occur:
The vast majority of puppies carry this infection at birth and have egg-laying worms in their small intestine by three weeks of age. Infection also occurs in older dogs. Foxes can also be incidental hosts.
Zoonotic (ie. this worm can affect humans)
No signs and symptoms are visible.
Dogs and cats are infected by eating worm eggs passed in the stool of a dog or cat carrying worms or by eating prey containing larvae. Adult worms are large and found in the small intestine.
Dogs are infected with this hookworm when they eat fully developed larvae, possibly as they eat grass. The larvae can also penetrate skin causing dermatitis and inflamed skin. The adult worms are found in the small intestine and cause protein to be lost in the faeces.
Adult whipworms live in the large intestine with the worm's narrow front end embedded in the intestinal wall. A few worms are well tolerated but a heavy infection can result in bloody diarrhoea.
Zoonotic (ie. this worm can affect humans): it is capable of causing sight impairment and a variety of other symptoms in affected humans. (See Toxocara canis).
No signs and symptoms are visible with a light infection.
Direct lifecycle with cats infected from eating a worm egg in the environment which has been passed in the faeces of the same or another cat. These microscopic eggs are invisible to the naked eye and can live in the environment for at least a year, thus remaining a health risk long after cat faeces have disintegrated. Infection can also occur:
No signs and symptoms with a light infection
This hookworm uncommon in the UK, but is capable of causing severe disease. Infection can occur through the cat eating larvae from the environment. The adult worms in the intestine feeds off blood and some blood may pass in the faeces which typically turns faeces a blackish colour.
Tapeworms have a two host life cycle. Adult tapeworms live in the intestine of the final host (e.g. dog) and the immature stage of the tapeworm (usually a cyst) lives in another species of animal (e.g. sheep, fleas, rabbits or mice). The dog ingests the cyst by eating an infected part, or the whole of the other animal containing the cyst.
Zoonotic (ie. this worm can affect humans): but does not cause serious harm
Signs and symptoms: Dogs do not appear to be affected by the infection although the tapeworm segments around the anus of a dog are unsightly.
The immature tapeworm occurs in fleas and lice. Dogs are infected when they groom and ingest infected fleas or lice. There needs to be control of the fleas to control Dipylidium infection.
Dogs are infected when they eat infected prey (e.g. rabbits) or have access to carcasses or uncooked meat. Treatment will eliminate the adult tapeworms but infection may recur if the dog has future access to prey or uncooked meat.
Zoonotic (ie. this worm can affect humans): causes Hydatid Disease in humans
No signs and symptoms initially.
Dogs are infected when they gain access to offal from sheep carrying hydatid cysts. Humans can be infected if they accidentally eat eggs passed by the adult tapeworms living in the dog's intestine. This is an important zoonosis. N.B. People holidaying in affected areas may not be aware of the risk of this tapeworm (especially important in Wales and the Hebrides). Veterinary advice is recommended if people are living or holidaying in high Echinococcus granulosus risk areas.
Zoonotic (ie. this worm can affect humans): causes alveolar echinococcosis in humans
No signs and symptoms
(Found in Continental Europe, also found in foxes). Dogs are infected when they eat small rodents carrying the immature tapeworm. Dogs are unaffected by the infection. If a human accidentally eats an egg passed by the tapeworms present in a dog or fox faeces, severe disease can result. N.B. People from the UK holidaying with their pet in Echinococcus multilocularis affected areas need to be aware of the risk of this tapeworm and consider worming their pet more frequently (at least monthly) and check that the product they are using is effective against this worm. Important for the pet passport scheme.
Zoonotic (ie. this worm can affect humans):
Signs and symptoms: Cats appear visually unaffected by the infection although the tapeworm segments around the anus of a cat are unsightly.
The immature tapeworm occurs in fleas and lice. Cats are infected when they groom and ingest infected fleas or lice. It is important to control the fleas and then you will control the Dipylidium infection.
Cats are infected when they eat infected prey (mice). Treatment will eliminate the adult tapeworms but infection may recur if the cat continues to hunt.
Lungworm is the common name for the parasitic worm Angiostrongylus vasorum which infects dogs. It is so called because it lives near the heart and in the blood vessels supplying the lungs. This parasite is also known as 'French Heartworm'. There are also other types of lungworms but none of these are referred to as the Lungworm:
This lungworm has been in the news recently as it has infected dogs from many parts of England, Wales and now Scotland. Infected dogs may show a variety of signs but most commonly abnormal bleeding patterns and respiratory signs such as coughing are seen. Dogs acquire the infection when they eat a slug or snail that carry the larvae. Adult worms develop in the arteries leading to the heart after about 5 weeks. These worms lay eggs that travel through the animal's lungs and hatch allowing the young larvae to be coughed up and swallowed.
Heartworm is the common name for the parasitic worm Dirofilaria immitis which infects cats and dogs. It is so called because it lives in the pulmonary artery of the heart.
Controlling Worm infestations
Feed pets with commercial diets or cooked food to prevent raw meat-transmitted parasite infection or use a raw food supplier that pretreats and freezes the food to avoid parasites from being transmitted. Hunting should be deterred where possible and dogs and cats should not be allowed access to carcasses or placentae. Fresh drinking water should also always be provided.
There may also be a risk of infection to indoor house cats, as pet owners can bring contaminated soil and worm eggs into the home without realising. This means that cats can then become infected in what may be perceived as a safe environment.
Often, pets become infected by picking up worm eggs and larvae from the soil, ingesting faecal matter, hunting rodents and by feeding or scavenging from raw meat or carcasses. Dogs and cats can become infected at any age. Puppies can become infected while in the mother's womb if the mother is already infected and both puppies and kittens can become infected through their mother's milk.
If you have any queries about your pet’s health please contact us. Our Preventative Health Care Plan (the VIP plan) will provide worming to protect you and your pet.