By now you’ve likely heard the news that at some point in or before 2010, a worm crawled into Robert F. Kennedy Jr.’s brain, ate part of it, and died, according to the presidential candidate. And because of the words worm, crawled into, brain, and ate part of it, you likely have a lot of questions. Questions like:

The New York Times revealed Wednesday that in a 2012 divorce deposition, Kennedy said that two years prior, he was experiencing such severe memory loss and mental fogginess that a friend worried he had a brain tumor. After Kennedy underwent brain scans, several doctors concluded that a dark spot was a tumor, and he was scheduled for a procedure at Duke University Medical Center. But before he departed, Kennedy got a call from a doctor who had come to a different conclusion, which was that the dark spot was not a tumor but a dead parasite. The abnormality on the scan, Kennedy said in the deposition, “was caused by a worm that got into my brain and ate a portion of it and then died.” Other doctors, the Times noted, “ultimately concluded that the cyst they saw on scans contained the remains of a parasite.”

Infectious disease specialists and neurosurgeons, who have not treated Kennedy, told the Times the worm was likely a pork tapeworm larva. According to the Centers for Disease Control and Prevention:

Neurocysticercosis is a preventable parasitic infection caused by larval cysts (enclosed sacs containing the immature stage of a parasite) of the pork tapeworm (Taenia solium). The larval cysts can infect various parts of the body, causing a condition known as cysticercosis. Larval cysts in the brain cause a form of cysticercosis called neurocysticercosis, which can lead to seizures.

A person gets neurocysticercosis by swallowing microscopic eggs passed in the feces of a person who has an intestinal pork tapeworm. For example, a person eats undercooked, infected pork and gets a tapeworm infection in the intestines. She passes tapeworm eggs in her feces. If she doesn’t wash her hands properly after using the bathroom, she may contaminate food or surfaces with feces containing these eggs. These eggs may be swallowed by another person if they eat contaminated food. Once inside the body, the eggs hatch and become larvae that find their way to the brain. These larvae cause neurocysticercosis.

Kennedy said he didn’t know where he picked up the parasite, but, per the Times, “he suspected it might have been during a trip through South Asia.”

It would seem so? Speaking to the Times, Scott Gardner, who works at the Manter Laboratory for Parasitology at the University of Nebraska-Lincoln, said that once a worm gets into the brain, cells harden around it. “And you’re going to basically have almost like a tumor that’s there forever. It’s not going to go anywhere.”

According to the Times, “Kennedy was arguing that his earning power had been diminished by his cognitive struggles.” In the deposition, Kennedy said that as a result of the brain-eating worm, “I have cognitive problems, clearly. I have short-term memory loss, and I have longer-term memory loss that affects me.”

The Times reported that around the time Kennedy learned of the worm, “he was also diagnosed with mercury poisoning, most likely from ingesting too much fish containing the dangerous heavy metal, which can cause serious neurological issues.” According to Kennedy, bloodwork revealed his mercury levels were 10 times the levels deemed safe by the Environmental Protection Agency. In an interview with the Times, Kennedy attributed the mercury poisoning to his love of tuna. “I loved tuna fish sandwiches,” he said. “I ate them all the time.”

He’s also dealt with other, non-tuna-related health issues. Per the Times:

For decades, Mr. Kennedy suffered from atrial fibrillation, a common heartbeat abnormality that increases the risk of stroke or heart failure. He has been hospitalized at least four times for episodes, although in an interview with the Times this winter, he said he had not had an incident in more than a decade and believed the condition had disappeared.

He also said in the deposition and the interview that he had contracted hepatitis C through intravenous drug use in his youth. He said he had been treated and had no lingering effects from the infection.

Mr. Kennedy has spoken publicly about one other major health condition—spasmodic dysphonia, a neurological disorder that causes his vocal cords to squeeze too close together and explains his hoarse, sometimes strained voice.

According to his campaign, not in the slightest. Asked about his fitness to serve as president, a spokeswoman for the Kennedy campaign told the Times last week: “That is a hilarious suggestion, given the competition.”