What is cysticercosis?
Cysticercosis is an infection caused by the larval stages of the parasite Taenia solium, after a person ingests tapeworm eggs. The larvae embed in tissues such as muscle and brain, forming cysticerci (cysts). When cysticerci are found in the brain, the condition is called neurocysticercosis.
Where is cysticercosis found?
Cysticercosis is found worldwide. Infection is found most often in rural, developing countries with poor hygiene where pigs are allowed to roam freely and eat human feces. Neurocysticercosis can occur, though rarely, even if a person has never traveled outside of the United States. 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.
What is the relationship between human tapeworm and porcine (pig) cysticercosis?
Humans acquire the tapeworm infection after eating raw or undercooked pork contaminated with cysticerci, the larval form of T. solium. When ingested, the cysticerci attach to the intestinal wall when they reach the small intestine and within approximately two months develop into adult tapeworms.
How do humans get cysticercosis?
Human cysticercosis occurs when a person ingests T. solium eggs that are passed in the feces of a human tapeworm carrier. Tapeworm eggs are spread through food, water, or surfaces contaminated with feces. This can happen by drinking contaminated water or food, or by putting contaminated fingers to your mouth. Importantly, a human tapeworm carrier can infect him-or herself with tapeworm eggs, resulting in cysticercosis (autoinfection), and can contaminate others in the family. Eating pork cannot give you cysticercosis.
What are the signs and symptoms of cysticercosis?
Signs and symptoms will depend on the location and number of cysticerci in your body.
- Cysticerci in the muscles:
- Cysticerci in the muscles generally do not cause symptoms. However, you may be able to feel lumps under your skin.
- Cysticerci in the eyes:
- Although rare, cysticerci may float in the eye and cause blurry or disturbed vision. Infection in the eyes may cause swelling or detachment of the retina.
- Neurocysticercosis (cysticerci in the brain, spinal cord):
- Symptoms of neurocysticercosis depend upon where and how many cysticerci (often called lesions) are found in the brain. Seizures and headaches are the most common symptoms. However, confusion, lack of attention to people and surroundings, difficulty with balance, excess fluid around the brain (called hydrocephalus) may also occur. The disease can result in death.
How long will I be infected before symptoms begin?
Symptoms can occur months to years after infection, usually when the cysts are in the process of dying. When this happens, the brain tissue around the cyst can swell. The pressure caused by swelling is what causes most of the symptoms of neurocysticercosis. Most people with cysticerci in muscles have no symptoms of infection.
How is cysticercosis diagnosed?
Diagnosis may require several testing methods. Your health care provider will ask you about where you have traveled and your eating habits. Diagnosis of neurocysticercosis is usually made by MRI or CT brain scans. Blood tests are available to help diagnose an infection, but may not always be accurate. If surgery is necessary, confirmation of the diagnosis can be made by the laboratory.
What should I do if I think I have cysticercosis?
See your health care provider.
Is there treatment for cysticercosis?
Yes. Infections are generally treated with anti-parasitic drugs in combination with anti-imflammatory drugs. Surgery is sometimes necessary to treat cysts in certain locations, when patients are not responsive to drug treatment, or to reduce brain edema (swelling). Not all cases of cysticercosis are treated.
I have been diagnosed with neurocysticercosis. My health care provider has decided not to treat me with anti-parasitic drugs. How was this decision made?
Often, the decision of whether or not to treat neurocysticercosis with anti-parasitic drugs is based upon the number of lesions found in the brain and the symptoms you have. When only one lesion is found, often treatment is not given. If you have more than one lesion, specific anti-parasitic treatment is generally recommended.
If the brain lesion is considered calcified (this means that a hard shell has formed around the cysticercus), this is an indication that the larva is dead and specific anti-parasitic treatment is not beneficial.
As the cysticercus dies, the lesion will shrink. The swelling will go down, and often symptoms (such as seizures) may go away. However, sometimes a scar remains which can cause seizures. Antiseizure medications are often necessary in managing neurocysticercosis.
Can cysticercosis be spread from person to person?
No. Cysticercosis is not spread from person to person. However, 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
If I have cysticercosis should I also be tested for an intestinal tapeworm infection?
Yes. Family members may also need to be tested. Because the tapeworm infection can be difficult to diagnose, your health care provider may ask you to submit several stool specimens over several days or to examine your stools for evidence of a tapeworm.
How can I prevent cysticercosis and other infections spread through fecal contamination?
- Wash your hands with soap and warm water after using the toilet, changing diapers, and before handling food.
- Teach children the importance of washing hands to prevent infection.
- Wash and peel all raw vegetables and fruits before eating. Avoid food that may be contaminated with feces.
- When in a developing country, drink only bottled or boiled (1 minute) water or carbonated (bubbly) drinks in cans or bottles. Do not drink fountain drinks or any drinks with ice cubes. Another way to make water safe is by filtering it through an "absolute 1 micron or less" filter AND dissolving iodine tablets in the filtered water. "Absolute 1 micron" filters can be found in camping/outdoor supply stores.
More on: Handwashing
- Centers for Disease Control and Prevention
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