Tapeworm infection: taeniasis
What is taeniasis?
Taeniasis is infection caused by a particular tapeworm species. These may include Taenia saginata, T. solium, and T. asiatica.
How do you contract taeniasis?
Taeniasis occurs when an individual ingests contaminated, undercooked or raw meat, usually beef (T. saginata) or pork (T. solium and T. asiatica).
What are the symptoms of taeniasis?
Most individuals with tapeworm infections are asymptomatic. However, tapeworms can cause gastrointestinal symptoms such as abdominal pain, weight loss, poor appetite, and upset stomach. Sometimes, individuals with taeniasis can see tapeworm segments (called proglottids) being passed through the anus and in the stool.
Taeniasis can lead to urticaria, an itchy rash of wheals and hives.
How long can a tapeworm become?
- The T. saginata tapeworm is usually less than 5 metres but can become 25 metres in length.
- T. solium can mature to lengths of 2 to 7 metres.
How do tapeworms spread?
Humans with taeniasis pass eggs or proglottids in the stool. Cattle or pigs become infected with these eggs or proglottids when ingesting contaminated vegetation. The tapeworm eggs hatch and migrate to the muscles of infected pigs or cattle. They develop into cysticerci. Humans then become infected by ingesting poorly cooked beef or pork containing these cysticerci.
Tapeworm infection is maintained by poor food preparation practices, as well as the continuous infection of pigs and cattle by feeding on vegetation contaminated by tapeworm eggs.
What is cysticercosis?
Cysticercosis is caused by ingestion of T. solium eggs. The larval stage of the tapeworm can penetrate the intestinal wall and affect a variety of organ systems. Subcutanous nodules affect about half of patients with cysticercosis.
Involvement of the central nervous system, eyes and skeletal muscle can also occur.
How is taeniasis confirmed?
Taeniasis is diagnosed by finding taenia eggs when examining the stool under the microscope. Taenia eggs can be detected 2 to 3 months following infection. The proglottids can also be seen and may indicate a species-specific diagnosis.
Biopsy of a subcutaneous nodule or radiological imaging may detect the cysts of cysticercosis
How is taeniasis treated?
Taeniasis is treated with praziquantel. The dose may vary depending on the particular type of tapeworm infection. This drug works by affecting the parasite's structure and leads to paralysis of the tapeworm so that the human body can clear the infection. If praziquantel is not available, niclosamide is a suitable alternative.
Cysticercosis may be treated with antihelminthics such as praziquantel and albendazole. Treatment can result in inflammatory reactions so requires caution and consideration of use of systemic corticosteroids and anticonvulsants.
- Intestinal Tapeworms ‐ UpToDate
- Cysticercosis ‐ UpToDate
- Parasites – Taeniasis – Centers of Disease Control and Prevention (CDC)
- Cysticercosis – Fitzpatrick’s Dermatology in General Medicine
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