What types of worms can affect cats?

The most common intestinal worms that cats get are called roundworms and tapeworms. Roundworms resemble white pieces of string and can be up to 5- 15 cm long. They tend to coil up like a spring. Roundworms are rarely seen because they stay in the intestines. If roundworms are passed in faeces or vomited up, it usually means that there are huge numbers of worms present in the intestines. Roundworms can produce up to 200 000 eggs per day which are excreted in the faeces. There are two different types, Toxocara cati and Toxascaris leonina.

Tapeworms are long flat worms made up of many small segments and grow to a length of 50 cm. Tapeworms constantly shed segments filled with eggs that can often be seen in faeces, or in the hair around the anus, resembling small grains of rice. The most common types of tapeworm that infect cats are called Dipylidium caninum and Taenia taeniaeformis. Hookworms, heartworm and lungworm can occur in cats with less frequency than roundworms and tapeworms. Heartworm and hookworms are more of a concern for those pets travelling overseas.

How do cats get worms?

Worm eggs or larvae are passed in faeces, and taken up either by licking and grooming as well as ingesting small prey or infected faeces, so outdoor and hunting cats will always have more worms than indoor cats. Eggs or larvae can survive on the ground for weeks or months therefore cats just wandering in the garden can pick up worms from contaminated soil. Some worm eggs are sticky and can adhere to the pet’s coat or humans and then be transferred to the cat.

Some worms require an ‘intermediate host’ (another species of animal) that they live in for part of their lifecycle. When a cat eats this intermediate host, they can become infected. In the case of tape worms, such intermediate hosts can be fleas (Dipylidium) or small rodents (Taenia).

Toxocara cati is also passed through the milk of the queen (mother) to her kittens. Whenever a queen is infected with roundworm some immature forms of the roundworm (larvae) remain dormant in certain tissues in the body. This causes no harm to the queen but when she gives birth the larvae migrate to the mammary glands and are excreted in the milk. This is a very common route of infection and we can therefore assume that most kittens will be infected with the roundworm Toxocara cati.

Cats become infected with lungworm by eating slugs and snails containing the infected larvae and become infected with heartworm by a bite from an infected mosquito.

What are the clinical signs of worms in cats?

Most often no clinical signs are evident especially in adult cats. As only small microscopic eggs are passed in the faeces, owners will only know if their cat is infested if there is a heavy infestation resulting in clinical signs, or if tapeworm segments are visible in the faeces or around the anus. Severe worm infestations can cause severe clinical signs and may be dangerous for kittens. Kittens can present with a pot belly, failure to gain weight, vomiting, diarrhoea, anaemia, rectal prolapse and death.

Cats of any age with heavy worm burdens can show weight loss, poor coat quality, vomiting, diarrhoea, respiratory problems, anal irritation and occasionally problems in other organs.

Can humans get worms from pets?

Unfortunately some types of worms can also infect humans especially children, the elderly, and people who are immuno-compromised. Although uncommon, severe health problems including digestive disorders, anaemia, blindness and brain problems are possible in infected humans. Children are more susceptible to infection given their propensity to play in, and sometimes eat, contaminated soil. Children that accidently swallow a cat flea can develop cat tapeworm.


What can be done to treat and prevent worm problems?

The best way to prevent worm related health problems in cats and the family is regular worming of your cats and removal of cat faeces.

At Frontier Veterinary Services we recommend that kittens are wormed at 2, 5, 8 and 12 weeks of age, and then monthly until they are 6 months old. The mother should be wormed at the same time as the kittens until they are weaned. Adult cats should be wormed every three months. Hunting cats or cats with close contact to small children or immuno-compromised adults can be wormed every six weeks. Steps advised by your vet to control any associated flea problems should accompany worm prevention.