Tapeworms are a group of parasitic worms that live in the intestinal tracts of some animals. Several different species of tapeworms can infect humans. Tapeworm disease or cestodiasis occurs most commonly after eating raw or undercooked meat or fish that contains the immature form of the tapeworm. Tapeworm infections pose a serious public health problem in many less developed countries due to poor sanitation conditions. The disease is most common where livestock, such as cattle and pigs, are raised in areas where human feces are not disposed of in a sanitary manner. Another common source of human tapeworms arecertain species of freshwater fish. Tapeworm infections tend to occur more frequently in areas of the world where the people regularly eat raw or undercooked beef, pork, or fish. Persons of all ages and both sexes are susceptibleto tapeworm infection, but children are generally not exposed until they areold enough to begin eating meat or fish.
In addition to the typical infection caused by eating undercooked meat or fish, people may also be directly infected by ingesting tapeworm eggs shed by the adult worm. This type of tapeworm infection can lead to a condition referred to as cysticercosis, where the larvae continue to develop within tissues other than the intestinal tract. One of the most serious forms of this diseaseoccurs when the tapeworm larvae infect the central nervous system, a diseasereferred to as neurocysticercosis. In contrast to a typical tapeworm infection, which may not be associated with symptoms, neurocysticercosis is a seriouscondition that may cause seizures and is potentially life-threatening.
Identification of tapeworm segments or eggs in a stool sample is necessary for diagnosis of an adult tapeworm infection. In many cases, a tentative diagnosis may be made on the basis of a patient's description of short chains of tapeworm segments in their stool. Whenever possible, tapeworm segments should be carefully collected in water or salt solutions, using strict precautions toavoid contamination. Stool examination should be performed in a laboratory having experience in the diagnosis of intestinal parasites. It is recommendedthat at least three stool samples be collected on alternate days to increasethe likelihood of being able to make an accurate diagnosis. magnetic resonance imaging (MRI) may be necessary to determine the exact location of the tapeworm larvae within the body.
Effective treatment of tapeworm infections involves administering compounds that are toxic to the adult worm. Many of the early treatments were also somewhat toxic to the patient, so treatment was often quite an ordeal. Newer medications are much more easily tolerated and are highly effective in eliminatingthe parasite from the body. It is recommended that follow-up stool samples be examined at one month and three months after treatment has been completed.Treatment can be considered successful if no eggs are present in several stool samples. It should be noted that the tapeworm medications do not kill the tapeworm eggs when they kill the adult worm, so the potential for infection with eggs still exists as the dead worm segments are passed. Proper personal hygiene in individuals receiving treatment will greatly reduce this potential.
The best way to prevent infection with tapeworms is to eliminate the exposureof livestock to the tapeworm eggs by properly disposing of human feces. Thenext best strategy is to thoroughly cook or freeze all meat and fish before it is eaten to prevent consumption of live tapeworm larvae in infected samples. Larval cysts in pork and beef are killed by moderate temperatures of 150°F (65°C) or if frozen for at least 12 hours. Proper cooking of freshwater fish could also eliminate the possibility of human infection with the fishtapeworm. Freezing fresh fish for 24 hours will also kill the larval form.