Tapeworm infection in people usually results from eating undercooked foods from infected animals. Pigs or cattle, for example, become infected when grazing in pastures or drinking contaminated water. People can also become infected by eating contaminated fish that is raw or undercooked.
The parasites mature in the animal’s intestines to pea-shaped larvae. They spread to the animal's blood and muscles. They are then transmitted to people who eat the contaminated food. This method is more common with beef or fish.
Factors that may increase the chances of a tapeworm:
Eating raw or undercooked pork, beef, or fish
Poor hygiene—not washing your hands can increase the risk of transferring tapeworm parasites by hand-to-mouth contact
Exposure to cattle or pigs, particularly in areas where human and animal feces are not properly disposed
Travel to underdeveloped countries with poor sanitary conditions
Tapeworms may be seen in vomit or stool. In some cases, tapeworm infection may not cause any symptoms. If symptoms do occur, they may include:
Centers for Disease Control and Prevention. Traveler's Health—Yellow Book: Taeniasis. Centers for Disease Control and Prevention website. Available at: https://wwwnc.cdc.gov/travel/yellowbook/2018/infectious-diseases-related-to-travel/taeniasis. Updated May 31, 2017. Accessed April 4, 2018.
Last reviewed April 2018 by
EBSCO Medical Review Board Daus Mahnke, MD
Last Updated: 5/11/2013
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