If your cat has tapeworms you may see the tapeworm segments (containing eggs) around the tail or anal area. They look a little bit like grains of rice. They are white to yellowish in colour and may wriggle and move. After they have been shed they will eventually dry and shrivel up. Sometimes if your cat has a very heavy infestation of tapeworms then it may show signs of weight loss or general malaise. Occasionally these worms may cause vomiting or diarrhoea; large segments of the tapeworm could be vomited up. Cats with tapeworms may also show signs of anal irritation since the tapeworm segments can cause itchiness and irritation as they emerge. The cat with tapeworms will therefore groom and nibble around its tail and bottom quite frequently. There are several different species of tapeworm which may infect our pets.
The tapeworm which is most common in both dogs and cats is called Dipylidium caninum. It lives in the small intestine and regularly sheds segments which are about 5-8mm long. These segments are passed from the anus of the cat and may be noticed around the tail area. The segments will usually fall from the cat eventually and they will then shed their eggs into the carpet or cracks in the floorboards where flea larvae will become infected. When the infected flea larvae (which is the intermediate host) develops into an adult flea it will find a host such as a cat to complete its own life-cycle. Since the infected flea is likely to irritate the cat and be eaten during normal grooming activities the worm will be passed on to its final host - your cat! The life-cycle of this worm takes about three weeks, so it is roughly in line with the length of its intermediate host's life-cycle. If your cat has a flea problem then it will almost certainly have these tapeworms too! If you want to get rid of these worms you must control the fleas. See the article on fleas for advice.
Cats may catch the tapeworms Taenia pisiformis and Taenia taeniaeformis from small prey mammals such as rabbits, mice and rats. If your cat is a hunter then it is likely to be infected with these tapeworms from time to time. Exposure to these worms is dependent upon your cat's lifestyle. Indoor cats will probably never catch these tapeworms while regular outdoor hunters may be frequently infected. The segments of these tapeworms are easily noticed since they can be about 1 cm in length.
The most worrying of the tapeworms which may infect your cat in the UK is Echinococcus granulosa. This tapeworm is small so it would probably not be noticed in the same way that other species would be. The life cycle of this parasite is around 5 weeks and it is a problem because it can infect humans as well as other animals. Humans together with pigs, sheep, cattle and deer are intermediate hosts for this tapeworm. The final hosts include cats and dogs as well as some wild carnivores. It is a problem for humans because in the intermediate hosts these worms form cysts (called hydatid cysts) these cysts are formed in vital organs such as the liver or lungs and can cause organ failure and even death. In rural areas, especially where sheep are present these worms may be a particular problem since the cats may eat parts of infected sheep carcasses and catch these parasites. It is very important that owners of cats are aware of this zoonotic disease and treat their cats for worms regularly. This is particularly important if your cat hunts, scavenges or receives any raw meat as part of its diet. In the UK this problem is not as widespread as in Europe where the tapeworm Echinococcus multilocularis is present.
Cats should ideally be wormed every three months with a reliable product such as Drontal or Droncit for tapeworms. If your cat is a regular hunter or has fleas then it may be necessary to worm more frequently.