Infestation with a parasite that lives and grows in the intestine. There are two kinds, the common tapeworm which occurs throughout the world and the armed tapeworm, which occurs in the tropics and subtropics. Tapeworms live in the small intestine of man, where they feed on liquid food. They can grow to be very long (up to 10 metres) and are long-lived (13 years). Man is usually infested with one or more worms. The tapeworm has a head with four suckers (scoleces, 1-2 mm long), and the armed tapeworm also has a crown of barbed hooks. A thin neck connects the head to the body, which consists of hundreds (700-1,000) of segments. A fully-grown segment is 2-3 cm long and has male and female reproductive organs (hermaphrodite). When mature a segment contains about 80,000 eggs, and ten such segments are discharged with their eggs each day. The segments remain mobile for several hours, and as they crawl they release their eggs. The eggs are found in faeces, and can be seen moving there, and around the anus. Man, cattle and pigs can be intermediate hosts. The larva emerges from the egg after it has established itself in the intestine of the intermediate host and develops into a bladder worm. Man can be infested by eating raw or undercooked meat from infested cattle or pigs, and even by handling beef (the eggs of Taenia saginata stick to the hands). The outer covering of the bladder worm dissolves in the stomach and the head attaches itself to the small intestine. Tapeworm infestation leads to anal itching caused by the segments crawling around the anus. Increased appetite, weight loss, abdominal pain and irregular defecation can result from infestation, but usually there are no symptoms. Short-term treatment with drugs is usually effective. Infection can be prevented by checking meat for the presence of bladder worms. Infection can also be prevented by not eating raw meat, cooking meat thoroughly or by keeping it in a freezer for some time.