Worms

What types of worms affect cats?

Roundworms and tapeworms are the most common types of worms that affect cats. Both types live in the intestinal tract. Worms can be difficult to diagnose since the cat may not show any symptoms of having worms and may be in (otherwise) very good health, However, left unchecked, the worms will continue to multiply and will cause vomiting or diarrhoea, weight loss, and impact on the animal's ability to thrive. In kittens, a distended abdomen will often mean that it is full of worms.

We are lucky in that, in the UK, treatment to prevent worms is routine and inexpensive. Worms are easily prevented and generally speaking most cases of worms, if caught early on, can be successfully treated. In other, less developed, parts of the world many, many animals still die from worms because they do not receive the medicine that we take for granted over here.

Roundworms

These are the most common of the two types of intestinal worms in cats. There are two different types:

• Toxocara cati
• Toxascaris leonina

Both types of roundworms can be transmitted as follows:

• When a cat eats an infected rodent (which would have become infected by ingesting roundworm eggs)
• When a cat eats the infected faeces of another cat (the eggs are passed in the cat's faeces)

In addition to the above methods of transmission, the Toxocara cati roundworm can also be passed onto kittens by their mother. A queen that is infected with roundworms can retain some dormant roundworm larvae in muscle tissues in her body. Whilst this will not adversely affect the queen, the larvae may end up migrating either:

• across the placenta during pregnancy, infecting the unborn kittens. This can be very dangerous - a kitten born with lots of worms inside it will be incredibly sick and may even die.
• to the mammary glands when she gives birth. These will then be excreted in her milk.

These methods of transmission are extremely common and, as such, it is often assumed that all kittens will be infected with Toxocara cati roundworms.

Roundworms are pale pink/white in colour and look like a very fine coiled rope. Roundworms are often visible in an infected animal's faeces or vomit (the eggs will most likely be too tiny to see).

Tapeworms

One of the most common types of tapeworm to infect cats is Dipylidium caninum. This tapeworm is transmitted to cats by fleas as follows: eggs from the tapeworm (which look like grains of rice) are to be found in an infected cat's faeces and also in the hair around the cat's anus. Immature fleas (larvae) will ingest these eggs. The tapeworm can then be spread to another cat if it ingests an infected flea whilst grooming. Because of this, it follows that if a cat has fleas, it is likely to have this type of tapeworm, and vice versa.

Another common type of tapeworm is Taenia taeniaformis and this worm is transmitted to cats as follows: rats, mice, voles and other rodents will ingest the eggs; the worms will then be transmitted to a cat if it eats an infected rodent. It therefore follows that cats that hunt may come into contact with this type of worm.

Unlike roundworms, cats are never born with tapeworms.

Tapeworms look like long strips and are made up of flat segments. These segments fill with eggs and then break off and are excreted in the faeces. These segments can visibly be seen twitching; you might see them on the skin around the cat's anus or in its faeces.

When should my cat be wormed?

Kittens should be wormed regularly because roundworms are very commonly passed onto them and because their immune systems are not as strong as those of adult cats. Kittens are usually first wormed (using a drug for roundworms) at only a few weeks old and then every 2 weeks up to approximately 16 weeks old.

Since tapeworms tend only to be a problem for adult cats, they can need treating for both roundworms and tapeworms. How often (and for which worms) your cat should be wormed will depend on things like whether it hunts and whether it is treated regularly for fleas (because fleas become infected when they bite an infected cat).

Anti-flea treatments are the most effective way to prevent and stop tapeworms; only worm against tapeworms if you suspect that your cat is infected with one.

Most vets will recommend that adult cats should be wormed against roundworms every 2-6 months (regardless of whether or not you suspect that your cat has roundworms).

PLEASE NOTE: Pregnant queens and kittens should only be wormed under the supervision of your vet.

Where do I get worming treatment?

You can purchase worming treatments from supermarkets as well as from pet shops and veterinary surgeries. Worming treatments come in many forms: tablets, liquids, cream, granules, injections and spot-on treatments. There is a vast multitude of products on the market but not all of them are very effective. Additionally, some products treat both roundworms and tapeworms; some only one or the other. Ask your vet which type is most appropriate for your cat and which brands he/she recommends.

Some products will not be suitable for pregnant queens or for kittens - please choose carefully.

Can humans become infected?

Yes it is possible but not common. By both worming and treated your cat for fleas regularly, the risk will be minimal. Tapeworm infections in humans are rare. Roundworm infections are less uncommon; roundworm eggs cause an infection called toxocara. This usually infects children who may pick up infective stages of the parasite on their hands when playing outside. This infection can cause eye damage and, in the extreme, blindness. This is because the larvae travel through the body and can get lodged behind the retina. This can be prevented by ensuring that children's hands are washed thoroughly before they eat and that you wash your hands thoroughly after cleaning out your cat's litter tray.