Cysticercosis

by CDC

Cysticercosis is an infection caused by the pork tapeworm, Taenia solium. Infection occurs when the tapeworm larvae enter the body and form cysticerci (cysts). When cysticerci are found in the brain, the condition is called neurocysticercosis.

What is cysticercosis?

Cysticercosis is an infection caused by the pork tapeworm, Taenia solium. Infection occurs when the tapeworm larvae enter the body and form cysticerci (cysts). When cysticerci are found in the brain, the condition is called neurocysticercosis.

Where is cysticercosis found?

The tapeworm that causes 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. This allows the tapeworm infection to be completed and the cycle to continue. Infection can occur, though rarely, if you have never traveled outside of the United States. Taeniasis and cysticercosis are very rare in Muslim countries where eating pork is forbidden.

How can I get cysticercosis?

By accidentally swallowing pork tapeworm eggs. Tapeworm eggs are passed in the bowel movement of a person who is infected. These 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. A person who has a tapeworm infection can reinfect themselves (autoinfection). Once inside the stomach, the tapeworm egg hatches, penetrates the intestine, travels through the bloodstream and may develop into cysticerci in the muscles, brain, or eyes.

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, swelling of the brain (called hydrocephalus) may also occur. Death can occur suddenly with heavy infections.

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 can swell. The pressure caused by swelling is what causes most of the symptoms of neurocysticercosis. Most people with cysticerci in muscles won't have symptoms of infection.

How is cysticercosis diagnosed?

Diagnosis can be difficult and 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 cases in the eyes, cases that 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. How was this decision made?

Often, the decision of whether or not to treat neurocysticercosis 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 tapeworm larvae), the cysticerci is considered dead and specific anti-parasitic treatment is not beneficial.

As the cysticerci die, the lesion will shrink. The swelling will go down, and often symptoms (such as seizures) will go away.

Can infection be spread from person to person?

No. Cysticercosis is not spread from person to person. However, a person infected with the intestinal tapeworm stage of the infection (T. solium) will shed tapeworm eggs in their bowel movements. Tapeworm eggs that are accidentally swallowed by another person can cause infection.

Should I be tested for an intestinal tapeworm infection?

Yes. Family members may also 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 disease causing germs?

• Avoid eating raw or undercooked pork and other meats.
• Don't eat meat of pigs that are likely to be infected with the tapeworm.
• Wash hands with soap and water after using the toilet and before handling food, especially when traveling in developing countries.
• Wash and peel all raw vegetables and fruits before eating. Avoid food that may be contaminated with feces.
• 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.

About the Author

www.cdc.gov
The Centers for Disease Control and Prevention (CDC) is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans and for providing essential human services, especially for those people who are least able to help themselves.