On Tuesday evening, the legendary folk singer Joni Mitchell was hospitalized after she fainted in her Los Angeles home. It’s unclear what caused her to pass out, but Mitchell has long identified herself as a sufferer of a strange and controversial condition, Morgellons Disease, which she told the L.A. Times in 2010 "seems like it’s from outer space." "I couldn’t wear clothing,” Mitchell wrote of her symptoms in her 2014 memoir. “I couldn’t leave my house for several years. Sometimes it got so I’d have to crawl across the floor. My legs would cramp up, just like a polio spasm.”

Morgellons patients generally complain of fatigue and memory difficulties, and, even more strangely, crawling and stinging sensations beneath the skin and itchy dermatological lesions that sprout white, blue, red, or black fibers ("[F]ibers in a variety of colors protrude out of my skin like mushrooms after a rainstorm," Mitchell said to the Times). If the name of the disease sounds familiar, that’s because about a decade ago it was the subject of widespread media attention — attention that peaked in 2006, when Morgellons garnered coverage from CNN, Good Morning America, and the Today show.

Since then, media attention has abated, in part because the medical Establishment has failed to find any conclusive proof the condition actually exists. In fact, neither Mitchell nor any of the other estimated thousands of Americans who complain of Morgellons symptoms would have a name for the condition if it weren’t for the one-woman medical crusade launched in 2001 by someone who has since fallen off the map entirely.

That was the year Mary Leitao, then a 43-year-old stay-at-home mom and former lab technician in South Carolina, first noticed something very wrong with her son Drew. The 2-year-old had begun to develop lesions on the inside of his lip, and they didn’t look like typical canker sores. Even more troubling, when she asked him what was wrong, he pointed at his lips and said, “bugs.”

Leitao used a toy microscope purchased at RadioShack for $8 to investigate Drew’s sores, and found what looked like multicolor fibers growing out of his skin. Alarmed, she took her toddler to a doctor near her home, followed by several others. None of them could say for sure what was causing the lesions, because none of them could find anything biologically wrong with Drew. In fact, some concluded that Mary suffered from Munchausen by proxy, a psychological condition where people invent illnesses for attention, and that her son wasn't actually sick.

Perhaps the most pointed diagnosis came from Dr. Fred Heldrich, a specialist in medical mystery cases at Johns Hopkins. "I found no evidence of [anything suspicious] in Andrew," Dr. Heldrich wrote to Leitao’s referring physician, according to a 2006 story in the Pittsburgh Post-Gazette. “Ms. Leitao would benefit from a psychiatric evaluation and support, whether Andrew has Morgellons disease or not. I hope she will cease to use her son in further exploring this problem.”

Thus began Leitao’s exhaustive fight to have the condition, which she coined “Morgellons” after a 17th-century French term describing a similar illness, recognized by the medical community. Her efforts both online and off instigated a rash of Morgellons self-diagnoses that many now chalk up to a unique type of internet-proliferated mass hysteria (Mitchell decided she had it in the early 2000s). In 2004, Leitao launched a website where she published amateur findings about the disease — Drew was her test subject in experiments where she used her biology background to pluck fibers from his wounds and closely study them — hoping she would be able to connect with others suffering from similar symptoms.

Almost as soon as the site went live, others began describing symptoms identical to Drew’s. Leitao and her husband, Edward, an internist at a hospital in Pittsburgh, soon established the Morgellons Research Foundation, a nonprofit dedicated to researching the condition, and began soliciting donations. Close to 11,500 people officially “registered” with the nonprofit as patients or family members of people with Morgellons, and the disease began to gain national attention.

But even as unofficial diagnoses proliferated, most experts remained steadfast in their skepticism that Morgellons was a real medical condition. Instead, they believed people reporting Morgellons symptoms actually suffered from delusional parasitosis, a psychological condition wherein patients become convinced their skin is infested with bugs. Dr. Marc D. Feldman, a psychiatrist and specialist in Factitious Disorders, said he believes that Morgellons is an example of “mass hysteria,” sometimes known as “mass sociogenic illness,” a situation in which a group of people connect over a constellation of symptoms and together come to believe that they suffer from the same unique illness.

“The moment a disease or supposed disease is identified it’s going to migrate onto the internet,” he explained, “and because it’s so easy to upload factually incorrect information to the internet and have it still appear authoritative, we began to see more and more and more patients claiming to be victims of Morgellons.” Other doctors, like New Jersey psychiatrist Dr. Robert Bransfield, saw several patients who said they were suffering from Morgellons, and believes that though there are psychological components of the condition, it also has a physical cause.

Naturally, it didn’t take long for conspiracy theories about the cause of Morgellons to begin cropping up across the web as well. Some believed the fibers were caused by aliens inhabiting their bodies, while others argued that skeptical doctors were complicit in a government cover-up. (One website devoted to exposing Morgellons as a hoax also cropped up, much to Leitao’s dismay.)

Despite the prevailing Establishment skepticism and internet kookery, because Leitao’s website had already collected a passionate and vocal group of purported victims, the pressure to investigate Morgellons as a real condition continued to grow, dividing the medical community in the process. This momentum culminated in a 2012 Centers for Disease Control study. Unfortunately for Morgellons advocates, the study found “no common underlying medical condition or infectious source was identified, similar to more commonly recognized conditions such as delusional infestation.” Researchers also concluded that the fibers were likely from clothing that got trapped in the patients’ sores, and were not the cause of the skin irritation.

Though her website morgellons.org still exists, the study was a major blow to Leitao and her research, and shortly after the CDC’s findings were published she shut down her foundation and donated all of its findings to Oklahoma State University. Leitao then disappeared entirely from the Morgellons community and hasn’t been heard from since; emails sent to her morgellons.org address bounced back, and phone calls to numbers assigned to her name went unanswered. One woman who had spent a long time working with Leitao said neither she nor anyone else in the Morgellons community had spoken to her since 2012, and that no one had any idea how to get in touch with her.

Despite Leitao’s absence, determined members of the community she spawned are continuing their Morgellons advocacy. In 2007, Cindy Casey-Holman, a sufferer herself, founded the Charles E. Holman Morgellons Foundation, a grassroots activist group that attempts to raise awareness and provide grants for Morgellons research. She believes that labeling the condition a psychiatric illness will turn out to be “the most shameful thing that has ever happened in the medical community.”

“[Those who dismiss Morgellons] are doing a huge disservice to humanity and they are contributing to the debilitation and the loss of lives,” Casey-Homan said over the phone. “Some people have died from the infections, and some people have died because they lost hope and took their own life.” (Science of Us couldn’t independently confirm whether anyone has died as a result of Morgellons symptoms.)

Even if Morgellons has receded from the spotlight since the CDC’s damning report, Mitchell's recent illness has once again highlighted her role as the illness's most famous flag-bearer. “I’m actually trying to get out of the music business to battle for Morgellons sufferers," she told the L.A. Times in 2010, “[So they can] receive the credibility that’s owed to them." It's a battle they're still fighting — and without Leitao, the crusading mother who sparked an international medical controversy before vanishing into thin air.