Cysticercosis is a parasitic tissue infection caused by larval cysts of the tapeworm Taenia solium. These larval cysts infect brain, muscle, or other tissue, and are a major cause of adult onset seizures in most low-income countries. A person gets cysticercosis by swallowing eggs found in the feces of a person who has an intestinal tapeworm. People living in the same household with someone who has a tapeworm have a much higher risk of getting cysticercosis than people who don’t.

People do not get cysticercosis by eating undercooked pork. Eating undercooked pork can result in intestinal tapeworm if the pork contains larval cysts. Pigs become infected by eating tapeworm eggs in the feces of a human infected with a tapeworm.

Both the tapeworm infection, also known as taeniasis, and cysticercosis occur globally. The highest rates of infection are found in areas of Latin America, Asia, and Africa that have poor sanitation and free-ranging pigs that have access to human feces. Although uncommon, cysticercosis can occur in people who have never traveled outside of the United States. For example, a person infected with a tapeworm who does not wash his or her hands might accidentally contaminate food with tapeworm eggs while preparing it for others.

Cysticercosis is an infection caused by the pork tapeworm, Taenia solium. The condition develops when tapeworm eggs, which can be found in contaminated food, enter the body and form cysticeri (cysts). In most cases, the worms stay in the muscles and do not cause symptoms. However, symptoms may be present when the infection is found in the brain, eyes, heart or spine. Although rare in the United States, cysticercosis is common in many developing countries.

Treatment may include medications to kill the parasites and powerful anti-inflammatory medications (steroids) to reduce swelling. In severe cases, surgery may be needed to remove the infected area.

Neurocysticercosis refers to a condition in which cysticercosis affects the brain and spinal cord. The symptoms of neurocysticercosis depend on the location and the number of cysticeri (cysts) in the brain. Seizures and headaches are the most common symptoms; however, confusion, inattentiveness, difficulty with balance, and swelling of the brain (hydrocephalus) may also occur. Death may occur with more severe infections.

Treatment might be recommended in certain cases of neurocysticercosis and depend on the number and location of cysts. For example, treatment might not be necessary for cases in which only one cysticeri is found. On the other hand, a person who has multiple cysticeri that are not calcified (i.e. dead) may require anti-parasitic treatment. Usually neurological symptoms such as swelling subside if the cysticeri die and shrink.

What is cysticercosis?

Cysticercosis is an infection caused by the larvae of the parasite Taenia solium. This infection occurs after a person swallows tapeworm eggs. The larvae get into tissues such as muscle and brain, and form cysts there (these are called cysticerci). When cysts are found in the brain, the condition is called neurocysticercosis.

How do humans get cysticercosis?

People get cysticercosis when they swallow T. solium eggs that are passed in the feces of a human with a tapeworm. Tapeworm eggs are spread through food, water, or surfaces contaminated with feces. Humans swallow the eggs when they eat contaminated food or put contaminated fingers in their mouth. Importantly, someone with a tapeworm can infect him-or herself with tapeworm eggs (this is called autoinfection), and can infect others in the family. Eating pork cannot give you cysticercosis.

What is the relationship between human tapeworm and porcine (pig) cysticercosis?

Humans get the tapeworm infection after eating raw or undercooked pork contaminated with cysts of T. solium. When swallowed the cysts pass through the stomach and attach to the lining of the small intestine. In the small intestine the cysts develop into adult tapeworms over about two months.

Where is cysticercosis found?

Cysticercosis is found worldwide. Infection is found most often in rural areas of developing countries where pigs are allowed to roam freely and eat human feces and where hygiene practices are poor. Cysticercosis is rare in people who live in countries where pigs do not have contact with human feces. People can sometimes get cysticercosis even if they have never traveled outside of the United States.

What are the signs and symptoms of cysticercosis?

Signs and symptoms will depend on the location and number of cysts in your body.

• Cysts in the muscles:
  • Cysts in the muscles generally do not cause symptoms. However, you may be able to feel lumps under your skin. The lumps sometimes become tender.
• Cysts in the eyes:
  • Although rare, cysts may float in the eye and cause blurry or disturbed vision. Infection in the eyes may cause swelling or detachment of the retina.
• Neurocysticercosis (cysts in the brain, spinal cord):
  • Symptoms of neurocysticercosis depend upon where and how many cysts 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 start dying. When cysts die, the brain or other tissue around the cyst may swell. The pressure of the swelling is what usually causes the symptoms of the infection. Sometimes symptoms are caused by the pressure of cyst in a small space.

What should I do if I think I have cysticercosis?

See your health care provider.

How is cysticercosis diagnosed?

Your health care provider will ask you about your symptoms, where you have traveled, and the kinds of foods you eat. Diagnosis may require blood tests and/or imaging studies. 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 to remove a cyst, the diagnosis can be made by the pathologist who looks at the cyst.

Is there treatment for cysticercosis?

Yes. Infections are generally treated with anti-parasitic drugs in combination with anti-inflammatory drugs. Surgery is sometimes necessary to treat cysts in certain locations, when patients are not responsive to drug treatment, or to reduce brain swelling. Not all cases of cysticercosis need treatment. Even if you don’t need treatment to kill the parasite, you may need treatment for the symptoms caused by the infection, such as medication to reduce the number of seizures you have.

Can cysticercosis be spread from person to person?

No. Someone with cysticercosis cannot spread the disease to other people. However, people with taeniasis (tapeworm infection in the intestine) may spread tapeworm eggs to other people if they do not practice good hygiene (e.g. hand washing after they use the toilet), which may result in cysticercosis if people swallow the eggs.

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
• Use good food and water safety practices while travelling in developing countries such as:
  • Drink only bottled or boiled (1 minute) water or carbonated (bubbly) drinks in cans or bottles
  • Filter unsafe water through an “absolute 1 micron or less” filter AND dissolve iodine tablets in the filtered water; “absolute 1 micron” filters can be found in camping and outdoor supply stores

Cysticercosis is an infection caused by the larvae of the tapeworm, Taenia solium. A person with an adult tapeworm, which lives in the person’s gut, sheds eggs in the stool. The infection with the adult tapeworm is called taeniasis. A pig then eats the eggs in the stool. The eggs develop into larvae inside the pig and form cysts (called cysticerci) in the pig’s muscles or other tissues. The infection with the cysts is called cysticercosis. Humans who eat undercooked or raw infected pork swallow the cysts in the meat. The larvae then come out of their cysts in the human gut and develop into adult tapeworms, completing the cycle.

People get cysticercosis when they swallow eggs that are excreted in the stool of people with the adult tapeworm. This may happen when people

• Drink water or eat food contaminated with tapeworm eggs
• Put contaminated fingers in their mouth

Cysticercosis is not spread by eating undercooked meat. However, people get infected with tapeworms (taeniasis) by eating undercooked infected pork. People who have tapeworm infections can infect themselves with the eggs and develop cysticercosis (this is called autoinfection). They can also infect other people if they have poor hygiene and contaminate food or water that other people swallow. People who live with someone who has a tapeworm infection in their intestines have a much higher risk of getting cysticercosis than other people.

Human cysticercosis is found worldwide, especially in areas where pig cysticercosis is common. Both taeniasis and cysticercosis are most often found in rural areas of developing countries with poor sanitation, where pigs roam freely and eat human feces. Taeniasis and cysticercosis are rare among persons who live in countries where pigs are not raised and in countries where pigs do not have contact with human feces. Although uncommon, cysticercosis can occur in people who have never traveled outside of the United States if they are exposed to tapeworm eggs.

Causal Agent:

The cestode (tapeworm) Taenia solium (pork tapeworm) is the main cause of human cysticercosis. In addition, the larval stage of other Taenia species (e.g., multiceps, serialis, brauni, taeniaeformis, crassiceps) can infect humans in various sites of localization including the brain, subcutaneous tissue, eye, or liver.

Life Cycle:

Cysts, called cysticerci, can develop in the muscles, the eyes, the brain, and/or the spinal cord. Symptoms caused by the cysts depend on the location, size, number, and stage of the cysts.

Cysts in the brain or spinal cord:

• Cause the most serious form of the disease, called neurocysticercosis
• May cause no symptoms
• May cause seizures and/or headaches (these are more common)
• May also cause confusion, difficulty with balance, brain swelling, and excess fluid around the brain (these are less common)
• May cause stroke or death

Cysts in the muscles:

• Generally do not cause symptoms
• May cause lumps under the skin, which can sometimes become tender

If you think that you may have cysticercosis, please see your health care provider. Your health care provider will ask you about your symptoms, where you have travelled, and what kinds of foods you eat. The diagnosis of neurocysticercosis usually requires MRI or CT brain scans. Blood tests may be useful to help diagnose an infection, but they may not always be positive in light infections.

If you have been diagnosed with cysticercosis, you and your family members should be tested for intestinal tapeworm infection. See the taeniasis section for more information on intestinal tapeworm infections.

Some people with cysticercosis do not need to be treated. There are medications available to treat cysticercosis for those who do need treatment. Sometimes surgery may be needed. Your doctor will advise you on which treatment is best for you.

To prevent cysticercosis, the following precautions should be taken:

• 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
• Use good food and water safety practices while traveling in developing countries such as:
  • Drink only bottled or boiled (1 minute) water or carbonated (bubbly) drinks in cans or bottles
  • Filter unsafe water through an “absolute 1 micron or less” filter AND dissolve iodine tablets in the filtered water; “absolute 1 micron” filters can be found in camping and outdoor supply stores

Handwashing is critical for public health and should be emphasized in a clinical setting. For the general public, the CDC recommends handwashing before, during, and after food handling; before eating; before and after interacting with someone who is ill; before and after treating a wound; after using the toilet or changing diapers; after coughing, sneezing, or blowing the nose; after handling garbage; and after interacting with an animal, its feed, or its waste. Figure 13.27 illustrates the five steps of proper handwashing recommended by the CDC.

Handwashing is even more important for health-care workers, who should wash their hands thoroughly between every patient contact, after the removal of gloves, after contact with bodily fluids and potentially infectious fomites, and before and after assisting a surgeon with invasive procedures. Even with the use of proper surgical attire, including gloves, scrubbing for surgery is more involved than routine handwashing. The goal of surgical scrubbing is to reduce the normal microbiota on the skin’s surface to prevent the introduction of these microbes into a patient’s surgical wounds.

There is no single widely accepted protocol for surgical scrubbing. Protocols for length of time spent scrubbing may depend on the antimicrobial used; health-care workers should always check the manufacturer’s recommendations. According to the Association of Surgical Technologists (AST), surgical scrubs may be performed with or without the use of brushes (Figure 13.27).

Figure 13.27 (a) The CDC recommends five steps as part of typical handwashing for the general public. (b) Surgical scrubbing is more extensive, requiring scrubbing starting from the fingertips, extending to the hands and forearms, and then up beyond the elbows, as shown here. (credit a: modification of work by World Health Organization; credit b: b: Staff Sgt. Kevin Iinuma / US Air Force; Public Domain)