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Taeniasis in humans is a parasitic infection caused by the tapeworm species Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), and Taenia asiatica (Asian tapeworm). Humans can become infected with these tapeworms by eating raw or undercooked beef (T. saginata) or pork (T. solium and T. asiatica). People with taeniasis typically have mild gastrointestinal symptoms or may be asymptomatic.
Humans become infected by eating raw or undercooked infected beef or pork. Once ingested, cysticerci attach to the small intestine and develop into adult tapeworms over the course of 2 months. The adult tapeworms produce proglottids that mature, detach, and migrate to the anus and are then passed in the feces.
T. saginata tapeworms are usually 4-12 m in length, but can grow to be 25 m; the adult tapeworms produce 1,000 to 2,000 proglottids/ worm and may produce up to 100,000 eggs per worm.
T. solium (pork) tapeworms are smaller, 2-8 m in length, produce an average of 1,000 proglottids/worm, and may produce 50,000 eggs per worm.
T. asiatica tapeworms range in size from 4-8 m, produce 700 proglottids/worm and may produce 80,000 eggs per proglottid.
More on: DPDx: Taeniasis
Disease
Because of the large size of T. saginata tapeworms, T. saginata taeniasis is more frequently symptomatic compared to T. solium or T. asiatica taeniasis. Typical symptoms of taeniasis include mild epigastric discomfort, nausea, flatulence, diarrhea, or hunger pains. In some instances, passage of tapeworm segments is perceptible.
The most visible symptom of taeniasis is the active passing of proglottids through the anus and in the feces. In rare cases, proglottids may become lodged in the appendiceal lumen, or bile or pancreatic ducts.
Diagnosis
Microscopic identification of eggs and proglottids in feces is diagnostic for taeniasis; however, eggs and proglottids are not released into the feces until approximately 2 to 3 months after the adult tapeworm is established in the upper jejunum. Repeated examination and concentration techniques will increase the likelihood of detecting light infections. Examination of 3 stool samples collected on different days is recommended to increase the sensitivity of microscopic methods. Eggs of Taenia spp. cannot be differentiated; a species determination may be possible if mature, gravid proglottids (or, more rarely, examination of the scolex) are present.
Recently developed coproantigen and molecular assays are more sensitive than stool examination, but these assays are not yet available outside of the research laboratory. Serologic methods, which are available only in research settings, may be used to identify T. solium tapeworm carriers.
Household contacts of neurocysticercosis cases should be evaluated for taeniasis to reduce the risk of cysticercosis.
More on: Taeniasis
Treatment
Praziquantel is the medication most often used to treat active taeniasis, given at 5-10 mg/kg orally once for adults and 5-10 mg/kg orally once for children. Available evidence suggests that using 10mg/kg once orally may have a higher rate of cure than the 5mg/kg dose. Niclosamide is an alternative, given at 2 g orally once for adults and 50 mg/kg orally once for children. Albendazole, given as 400mg daily for three days, may be used as another option for the treatment of taeniasis, although this is based on studies treating small numbers of infected individuals with T. solium or T. saginata. Stools may be collected for 3 days after treatment to search for proglottids or scolices for species identification if necessary. Stools should be re-examined for Taenia eggs 1 and 3 months after treatment to be sure the infection is cleared.
Both praziquantel and albendazole should be used cautiously in patients suspected to have cysticercosis. There are case reports of seizures that may have been temporally associated with treatment.
Oral praziquantel is available for human use in the United States.
Niclosamide is NOT available for human use in the United States.
Oral albendazole is available for human use in the United States.
Praziquantel and albendazole are not approved by the U.S. Food and Drug Administration for the treatment of taeniasis.
Praziquantel
Niclosamide
Albendazole
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- Efficacy of Single-Dose and Triple-Dose Albendazole and Mebendazole against Soil-Transmitted Helminths and Taenia spp.: A Randomized Controlled Trialpdf icon
- Albendazole: a review of anthelmintic efficacy and safety in humanspdf icon
- Controlling Taenia solium and soil transmitted helminths in a northernLao PDR village: Impact of a triple dose albendazole regimepdf icon
- Albendazole treatment in human taeniasispdf icon
- Systematic review of the effectiveness of selected drugs for preventive chemotherapy for Taenia solium taeniasispdf icon
- Assessing the impact of a joint human-porcine intervention packagefor Taenia solium control: Results of a pilot study from northern Lao PDRpdf icon
- Infection rate with Taenia solium taeniasis. pdf icon
- Side-effects reported in studies found through supplementary searching of treatment with albendazole, niclosamide or praziquantel of other parasitespdf icon
- Strategies used to diagnose Taenia solium taeniasispdf icon