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.
Toxocara canis
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:
- Through eating raw meat or prey containing worm larvae
- Across the placenta to unborn puppies and in the milk to suckling puppies.
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.
Toxascaris leonina
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.
Uncinaria stenocephala
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.
Trichuris vulpis
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.
Toxocara cati
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:
- Through eating uncooked meat or prey containing worm larvae
- In milk to suckling kittens. This is a common infection of kittens and occurs in older cats as well.
Ancylostoma tubaeforme
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.