The tapeworm is a long thin, flat worm (hence its name) which attaches by a sucker and/or hooks in the head to the intestine of the host. The worm has a thin neck and the rest of the body consists of detachable body segments. These contain male and female reproductive organs and as the segments mature and are pushed further down the body by the development of new young segments at the neck, many thousands of eggs are formed in each segment. Some tapeworms (eg Taenia saginata) have motile segments, which can crawl out the anus, dropping to the ground and then crawl around the ground, expelling eggs over an area. Others (eg Taenia solium) are non-motile, they are passed in the dung and remain there until they dry out, when the eggs are released.
Milk tapeworm (Moniezia, Thysaniesia)
Moniezia, the most common milk tapeworm, are small, affecting only young stock still being fed on milk. The intermediate host is a mite which lives in damp grass. The mite ingests the eggs and then is accidentally swallowed by the calf, kid or lamb. Since these young animals will start licking grass at an early age, they can be infected very early in life. It is possible for a 6 week old calf to be infected by an adult tapeworm and already passing eggs. The passed segments can be seen in the dung looking like grains of rice.
The symptoms of infection are pot-belly, dullness, poor growth and diarrhoea.
Prevention is difficult, but young animals should be kept away from areas where the mite lives, on wet grass. Calf houses should be regularly cleared and disinfected.
Treatment – Lintex, or VALBAZEN CATTLE which is effective against milk tapeworm and round worm, VALBAZEN SHEEP AND GOATS is effective against milk tapeworm, roundworm and liver fluke.
Narrow Tapeworm Aintellina
This tapeworm is not common and not harmful except in very young animals. The life-cycle, treatment and control is the same as for the milk tapeworm.
Liver Tapeworm Stilesia hepatica
Stilesia lives in the bile ducts of the liver and is usually only found at slaughter. Although huge numbers can be present, so many that the bile duct can become distended, they seem to be completely harmless to the animal. The only loss is rejection of the liver at the abattoir, for aesthetic reasons, not from danger to human health. Very little is known about its life cycle, except that wild antelope seem to be an intermediate host. No treatment can effectively penetrate the bile duct.
Measles in Cattle and Pigs Taenia solium(in pigs) Taenia saginata (in cattle)
This condition in pigs and cattle has no relationship with the disease of children. Measles in pigs and cattle is the intermediate (bladderworm) stage of a tapeworm whose primary host is man. The adult tape lives in the intestine of man and can reach a length of 5 metres, with up to 1000 segments each containing up to 100 000 eggs. The tape produces 5 – 8 ripe segments daily which leave the body via the stools. If this material reaches the animals’ environment they can ingest thousands of eggs at a time. Unborn piglets or calves can be infected in utero if their mother swallows worm eggs. The eggs hatch in the intestine of the animal and burrow into the intestinal wall. They are carried via the bloodstream until they become lodged in some part of the body, usually in muscle tissue. The larvae develop into a bladder, about the size of a pea. When the animal is slaughtered for meat, these cysts are present in muscle tissue. If the meat is under-cooked the bladderworm survives and is ingested by the human. It develops into an adult tapeworm in the intestine, and feeds on the stomach contents, causing malnutrition, lethargy and weight loss. The great danger is the possibly of the human ingesting eggs, which may travel to the brain, causing a form of epilepsy.
There is no effective treatment against measles. Control measures include the treatment of tapeworm infection in humans; proper use of toilets, so that pigs never come into contact with human waste, stringent meat inspection at slaughter and ensuring that all pork products are well cooked before consumption.
Handbook on Stock Diseases; Monnig and Veldman