Taeniasis (Tapeworm Infection)

Definition

Taeniasis refers to tapeworm infection caused by tapeworms of the genus Taenia. Out of 30 species of Taenia, the pork tapeworm (Taenia solium) and the beef tapeworm (Taenia saginata) are the two most important human pathogens. Humans acquire taeniasis by eating raw or undercooked contaminated meat or vegetables. The adult worms live in the small intestine. Taeniasis causes very few symptoms in most people. It is diagnosed when a portion of the worm (body segment, head, and eggs) is passed out in the stool.

Causes

T. saginata and T. solium are found worldwide. Tapeworm infections with T. saginata occur upon eating contaminated raw beef. Infections due to T. solium occur when people eat raw or undercooked pork. Infected persons pass tapeworm eggs in their stool. Eggs of T. saginata are only infectious to cattle. Humans get T. saginata infection by eating raw or undercooked beef preparations infected with the larvae of T. saginata called cysticerci bovis. However, in case of T. solium, both eggs and larvae are infectious to humans. T. saginata does not transmit from person to person though T. solium may be spread in this manner.

Symptoms

In majority of the cases, people with tapeworm infections show no symptoms or very mild symptoms. People with T. saginata tapeworm infection show more symptoms than those with T. solium taeniasis. The reason is that the T. saginata tapeworm is much larger in size (about 10 meters) than the T. solium tapeworm (around 3 meters). Tapeworm infection causes digestive problems. Symptoms of taeniasis may include the following:

  • Abdominal pain
  • Upset stomach
  • Loss of appetite
  • Weight loss
  • Passing of tapeworm segments (proglottids) or eggs in the stool
  • Presence of tapeworm segments in the appendix, or the pancreatic and bile ducts (less commonly seen)
  • Fatal tissue infection called cysticercosis (in case of T. solium tapeworms)

Eggs pass out in the stool 2 to 3 months after T. saginata tapeworm infection and after 2.5 to 3.5 months with T. solium. Symptoms of cysticercosis may show weeks to years after infection. In cysticercosis, the larvae of T. solium leave the egg shells and enter the intestinal wall. The larvae then spread to different tissues like brain, heart, eyes, and spine and cause seizures, weakness, problems with heartbeat, vision or blindness.

Treatment

If taeniasis or cysticercosis do not show any symptoms, treatment is not required. If body segments of adult tapeworms pass in the stools, anthelmintic (anti-worm) drugs are given.

Medication

Anthelmintic drugs (like albendazole, niclosamide, praziquantel) are usually given to the patients. Anthelmintic drugs may cause inflammation. For this reason, patients are also given drugs called glucocorticoids (dexamethasone).

Surgery

Surgery is required only in severe cases, where Taenia segments become lodged in and block bile or pancreatic ducts or cause appendicitis. Surgery may also be required for cysticercosis.

Prevention

The following measures should be followed to prevent taeniasis:

  • Cooking beef and pork thoroughly.
  • Avoiding contamination of soil, and human and animal food with stool.
  • Avoiding the use of raw sewage as manure.

 

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