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  • Independent presidential candidate Robert F. Kennedy Jr. told the New York Times that a parasitic worm infected his brain and may have caused some of his past health problems.
  • The pork tapeworm can cause a condition called neurocysticercosis, which leads to symptoms such as seizures and headaches and can occasionally be fatal.
  • While neurocysticercosis is common in many parts of the world, only 1,300 to 5,000 new cases are reported in the United States each year. Some cases, though, may not cause any symptoms.

Some of Independent presidential candidate Robert F. Kennedy Jr.’s past health issues may be due to a parasitic worm that entered his brain and died, The New York Times reported on May 8.

His symptoms, which occurred in 2010, included severe memory loss and mental fog. These were severe enough to affect his earning power, according to the Times.

A New York doctor who reviewed a scan of Kennedy’s brain told him his health issues could be “caused by a worm that got into my brain and ate a portion of it and then died,” the Times reported. The parasite did not require treatment, he told the paper, and his memory loss and brain fog cleared up.

Around the same time, the Times reported, Kennedy suffered from mercury poisoning, which can lead to movement issues, memory loss, and vision, hearing, and speech problems.

Kennedy didn’t indicate which parasite had infected his brain.

However, the pork tapeworm can cause a condition called neurocysticercosis, which can lead to symptoms such as seizures and headaches. In some cases, people may experience cognitive problems, although this is less common.

What is neurocysticercosis?

Cysticercosis is a parasitic infection caused by the larvae, or juvenile form, of the pork tapeworm, also known as Taenia solium. This infection can occur in the muscle, brain or other parts of the body. When it affects the brain and spinal cord, it is known as neurocysticercosis.

“The main manifestation of neurocysticercosis is seizures,” said Clinton White, MD, a professor of infectious diseases at the University of Texas Medical Branch at Galveston in Texas. “It also is associated with headaches, and in a minority of cases, can cause what’s called hydrocephalus.”

Hydrocephalus is a blockage that causes the accumulation of cerebrospinal fluid in the brain, a potentially fatal condition.

The symptoms of neurocysticercosis are mainly due to the body’s inflammatory response to the worm rather than the parasite itself.

“When the parasite gets into the brain, it usually doesn’t cause any problems. It sits there and tries to prevent the inflammatory response from attacking it,” White told Healthline. “But eventually, when the inflammation attacks the parasite, it can cause some damage in the brain associated with seizures and headaches.”

This condition “can range from something that is asymptomatic — meaning the patient is not aware of it — to causing severe cases and sometimes death,” said Walavan Sivakumar, MD, a neurosurgeon and director of neurosurgery at Pacific Neuroscience Institute-South Bay in Torrance, Calif.

In some people, when the parasite dies, it can form a calcified cyst, or scar, in the brain. “When this scarring is present, it can be associated with seizures that recur over a long period of time,” said White. “So, in essence, people have a chronic epilepsy.”

Memory loss or other cognitive problems are not a common occurrence with neurocysticercosis, said White, unless someone had recent seizures or hydrocephalus, both of which can damage the brain.

How do you get it?

Cysticercosis occurs when someone swallows the eggs of the pork tapeworm, which are present in the feces of someone with a tapeworm in their small intestine.

The eggs are spread through food, water and surfaces contaminated with feces. For example, this can happen if a person infected with a tapeworm doesn’t wash their hands properly while preparing food for others. People living in the same household with someone with an intestinal tapeworm are at higher risk of infection.

Once in the intestine, the eggs develop into spheres that pass through the wall of the intestine and into the bloodstream. These travel to the muscles, brain, or other tissues and form larval cysts.

Pigs can also get cysticercosis by eating the feces of a person with an intestinal tapeworm, with the larval cysts ending up in the pigs’ muscles and other tissues.

In fact, “neurocysticercosis is found pretty much anywhere in the world where pigs are raised and have access to human fecal material,” said White.

However, you can’t get cysticercosis by eating raw or undercooked pork. But if the pork contains larval cysts, those cysts can attach to the wall of the small intestine and develop into a tapeworm. Cooking pork fully kills the parasite.

“So, getting the tapeworm in your [gastrointestinal] tract really isn’t going to pass worms to your head,” said Sharon Nachman, MD, chief of the Division of Pediatric Infectious Diseases at Stony Brook Children’s Hospital in Stony Brook, New York. “You have to eat the eggs of someone else’s worms.”

A person with an intestinal tapeworm can also develop cysticercosis by eating worm eggs passed in their own feces, what’s known as auto-infection. However, Nachman said this is less likely to occur.

How common is it?

Tapeworm infection and cysticercosis are more common in parts of Latin America, Asia, and Africa where free-roaming pigs have access to human feces and there is poor sanitation. In low-income countries, neurocysticercosis is a major cause of seizures that begin in adulthood.

“[Cysticercosis] is a common disease around the world, and we should be able to eradicate it,” said White. “We have the tools to do that. But so far, there hasn’t been the political will because it mainly affects poor people and large rural populations in poorer countries.”

A program in northern Peru, funded by the Bill and Melinda Gates Foundation and others, showed that elimination of cysticercosis from communities is possible. The strategies used by public health officials included vaccinating all pigs for the tapeworm and treating people who may be carrying the tapeworm.

In the United States, an estimated 1,300 to 5,000 new cases of neurocysticercosis occur every year, although accurate information is not available because people with no symptoms or mild symptoms may not realize they are infected.

“Most of the [U.S.] cases are in immigrants [from areas where neurocysticercosis is endemic],” said White, “and a few are in people who have lived extensively overseas.”

Nachman said the low rate of this condition in the United States is due, in part, to government oversight of the food industry. All meat sold commercially in the country undergoes inspections, as does meat being imported.

In addition, in this country, “people who prepare food, for the most part, have to be healthy, have to wash their hands, and have to wear gloves,” she told Healthline, “and those things are all going to prevent the passing of any worms to other people.”

So, “unless you have your own farm and are killing your own pork and then eating it raw or undercooked, [neurocysticercosis] is not really an issue,” said Nachman.

How is it diagnosed?

If you have possible symptoms of neurocysticercosis, your doctor will ask about your travel history and what foods you ate, said Nachman.

Your eating history is important because, in some countries, there may not be a lot of oversight of how street vendors prepare food. So “thinking about where you’re going and what you’re eating is probably the best way to protect yourself,” she said.

Blood tests or imaging tests may also be needed. This condition is usually diagnosed by MRI or CT scan, although Nachman said sometimes both tests are needed.

“These exams reveal different things about the brain,” she said. “Together, they will tell us if it’s one or more worms present, if they’re dead or alive, where they are located, and if there is inflammation around them.”

How is it treated?

Treatment for neurocysticercosis depends upon several factors, but in general, has multiple phases, said Nachman.

“We almost always give you steroids because the inflammation around the dead worm is causing the headaches and seizures,” she said. “Steroids will cool that [inflammation] down.”

A doctor may also prescribe an anticonvulsant to help control the seizures. Or other medication to treat symptoms such as headache.

And if the worm is still alive, “we’ll give you something called albendazole,” said Nachman, “which is available in pharmacies across the country.”

This drug, which is taken by mouth, works by killing the worms. It is usually taken for eight to 30 days. However, “in some patients, longer, or repeat, courses of medication may be needed, depending on how extensive their disease is,” said Nachman.

After treatment, your doctor will monitor you to see how you are progressing. Steroids are not usually given long-term, she said, although some people may need to stay on anti-seizure medication longer.

In some cases, surgery is necessary to remove cysts from the brain. “That’s where I get involved,” Sivakumar told Healthline.

“Because the infection can happen anywhere in the brain, there can be risks with surgery,” he said, “but we use minimally invasive approaches to minimize the collateral damage to the brain.”

In general, people recover well after surgery, although it depends on how extensive the infection and inflammation were.

“Oftentimes, you can have a near complete or complete recovery after surgery,” said Sivakumar, especially “if you get to them early enough and the surgery goes well, meaning you remove the cause of the infection, the inflammation, and the blockages of spinal fluid flow that can be caused by the cysts.”

With medical treatment, “for the most part, the long-term outlook is [also] excellent,” said Nachman. “We know how to treat it, we know how to cool [your inflammatory response] down, and we know how to treat the side effects of the inflammation.”


The New York Times reported that Independent presidential candidate Robert F. Kennedy Jr.’s past health issues may be due to a parasitic worm that infected his brain. Kennedy’s symptoms included memory loss and brain fog.

While Kennedy didn’t indicate which parasitic worm had infected his brain, the pork tapeworm can cause a condition called neurocysticercosis. The main manifestation of this condition is seizures, although headaches and more serious symptoms can also occur.

Treatment for this condition involves using steroids to reduce inflammation in the brain, which is the main cause of seizures and headaches. Some people may also need medication to kill the tapeworm.

The outlook for most people is good, although some people may require surgery, which also generally has good outcomes.