Epidemiology & Risk Factors
Cysticercosis is an infection caused by the pork tapeworm, Taenia solium. A human with a tapeworm sheds eggs in the stool. A pig then eats the eggs, becoming infected with the larval (juvenile) form of the parasite, which causes cysticerci (little encysted larvae), usually in the pig's muscles. The infected pig has porcine cysticercosis. Humans who eat undercooked or raw infected pork ingest the cysticerci in the meat. The larval parasites then come out of their cysts in the human gut, developing into adult tapeworms and completing the cycle.
More on: Taeniasis
Cysticercosis occurs in humans through:
- Drinking water or eating food contaminated with pork tapeworm eggs
- Putting contaminated fingers in your mouth
Cysticercosis is not spread by eating undercooked meat. However, infection with the adult pork tapeworm (taeniasis) is spread in this manner. A person who has a tapeworm infection can infect him- or herself with the eggs and develop cysticercosis (a process called autoinfection). A person with a tapeworm can also infect other people if he or she has poor hygiene and contaminates food or water that someone else ingests. People living in a household with a tapeworm carrier have a much higher risk of becoming infected with cysticercosis than others.
Cysticercosis is found worldwide, especially in areas where pork tapeworm is common. Both pork tapeworm and cysticercosis are most often found in rural, developing countries with poor sanitation, where pigs are allowed to roam freely and eat human feces. Taeniasis and cysticercosis are rare among persons who live in countries where pigs are not commonly raised for food, or countries where pigs raised for food do not have contact with human feces. Although uncommon, cysticercosis can occur in people who have never traveled outside of the United States. People with poor hygiene who have taeniais -- with or without symptoms -- will shed tapeworm eggs in their feces and might accidentally contaminate their environment. This can lead to transmission of cysticercosis to themselves or others unknowingly.
More on: Taeniasis
Article (EID -- June, 2011): Taenia solium Tapeworm Infection, Oregon, 2006–2009
- Centers for Disease Control and Prevention
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