It isn't always easy to tell if your cat has worms, unless the cat has a heavy infestation thus making the symptoms more obvious. It has been estimated that "6 out of 10 cats in the UK have worms at any one time". A good way to remember which type of worm is which is that roundworms look like spaghetti and tapeworms resemble grains of rice. Both of these can be picked up from the cat's prey, rodents and birds for example. Roundworms are passed from cat to cat via eggs and larvae in their faeces. These eggs and larvae can live in the soil for months or even years. The cat picks them up on it's coat and paws and then ingests them while grooming - thus infecting the cat, and so the cycle goes on. Worming treatments for your cat must be carried out on a regular basis to prevent reinfestation.
The symptoms will range from none to vomiting, diarrhoea, pot-bellied appearance, dehydration, weight loss and loss of condition.
Toxocara cati is a white roundworm which most frequently infects young kittens, being passed via the mother's milk. Pregnant cats should be treated for worms while pregnant and while feeding her kittens, also the kittens should be treated every few weeks in their own right. The adult roundworms live in the small intestine where they lay eggs which are then shed into the environment via the cat's faeces. Cats can also become infected from their prey which have ingested these eggs. There is a slight risk to humans from toxocara cati, acquired by accidental ingestion of these roundworms, mainly from dogs and possibly from cats. This disease is called visceral larval migrans, the roundworm larvae travel around the body and may settle in the eye and, in some cases, cause impairment of vision.
Toxascaris leonina is also a white roundworm, very similar to Toxocara cati, but much less common. Infection of this roundworm occurs when cats ingest the eggs, which then hatch in the intestine, and develop into the adult worms. Cats can ingest these eggs from their prey. This type of roundworm is not passed from the mother to her kittens from her milk, it is unlikely to be seen in cats under 6 months of age.
Diplidium caninum is a segmented tapeworm which lives in the cats small intestine. Each segment of the worm contains maturing eggs. These segments, when passed from the cat, resemble grains of rice, you may even notice them around the cats anus, on the cats coat or bedding. These segments can cause anal irritation and excessive licking of this area.
Tapeworms are spread by the ingestion of fleas. The flea larvae swallows the eggs from the tapeworm segment, these eggs mature as the flea matures, making the adult flea infectious to the cat. When the cat ingests the flea, the tapeworm larvae are released into the small intestine and so the cycle goes on again. To treat this tapeworm you will also need to carry out flea treatment to help prevent reinfestation. The symptoms of this type of tapeworm infection can be, in severe cases, abdominal pain and an increase in food. Tapeworms can infect humans so cats should be wormed regularly and a flea control programme carried out.
Taenia taeniaeformis is also a segmented tapeworm, it is larger and less common than Dipylidium caninum. They have nothing to do with fleas, they are transmitted from infected rats, mice and voles to the cat. The adult tapeworm lives in the cats intestine, and the segments containing the maturing eggs are passed in the faeces. The same worming treatment can be used as for dipylidium caninum. These types of tapeworms do not transmit to humans.
Aelurostrongylus abstrusus is a small worm that lives in the air passages of the lungs. There would be no outward sign that your cat had this worm unless it was heavily infested, then the cat would be coughing. Again this worm does not transmit to humans.
Toxoplasma gondii is a small parasite of cats that lives in the cells lining the intestines. It uses other mammals as hosts, for example humans and dogs. This parasite invades the muscle tissue and forms cysts in host animals. Cats can get this parasite if they eat infected meat which is raw or undercooked or by eating the infected muscles, containing these cysts, of their prey. Once infected the eggs from this parasite are passed out in the cats faeces. These eggs become infectious and other animals can become infected if they eat them. The cat will show no signs that it has this parasite unless it has a severe infection. The signs of a severe infection are high temperature, vomiting, diarrhoea, pneumonia and heart and liver disease. This infection can be transmitted to humans, it can be very serious in pregnant women, the baby can be affected. To minimise the risk of this infection to humans gloves should be used when cleaning out cat litter trays, these trays should be cleaned out on a daily basis, and be cautious when handling raw meat.