Many experts have diagnosed them with conversion disorder -- where a stress or psychological issue manifests in physical symptoms. But now New Jersey neurologist Dr. Rosario Trifiletti suspects that the real root cause could be something called PANDAS, TIME reported, an infection that the girls he's seen are now being treated for with antibiotics.
PANDAS, or pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections, is characterized by a sudden onset of symptoms -- including obsessive behavior, vocal or motor tics and having compulsions -- that happens seemingly overnight, according to the National Institute of Mental Health.
There is no test that can diagnose PANDAS -- instead, doctors must look at five different criteria to come to the conclusion of a PANDAS diagnosis. These criteria include having an OCD or tic disorder, having the onset of symptoms occur during childhood or adolescence, having an "episodic course" of severity of symptoms, being infected with a certain kind of streptococcal bacteria, and having neurological abnormalities, like jerky movements or hyperactive motor movements, according to the National Institute of Mental Health.
NBC affiliate WGRZ reported that Trifiletti announced his diagnosis on HLN's Dr. Drew show. The doctor had analyzed the lab data on eight of nine girls he saw while in LeRoy in January.
"I can tell you that they are testing positive for, each one is testing positive either for streptococcas or mycoplasma, which are known triggers of the PANDAS/ PANS Syndrome," WGRZ reported Trifiletti as saying.
But outside experts, such as PANDAS expert Dr. Susan Swedo, who is the branch chief of pediatrics and developmental neuropsychiatry at the National Institute on Mental Health, are skeptical of Trifiletti's diagnosis, TIME reported:
For one thing, PANDAS doesn't usually occur in clusters. Indeed, Swedo says that she is "not aware" of any epidemics of PANDAS ever occurring. The last epidemic of illness following strep infections -- a cluster of rheumatic fever, which is an inflammatory disorder -- happened in the 1980s. (Both PANDAS and rheumatic fever are caused by overzealous immune responses to infections; immune cells mistakenly attack particular organs or tissues, in addition to the infectious agents.)
In addition, PANDAS is extremely rare, with many tic or OCD-related disorders not attributed to infections, TIME added. [Read more about why experts are skeptical over at TIME.]
Michael Jenike, an OCD expert and professor of psychiatry at Harvard Medical School, told Scientific American that even though PANDAS was initially ruled out as a diagnosis when news of the mystery illness first broke, it's still possible for an infection to be a root cause.
He said in the Scientific American Q&A:
"Unless you have a really good medical history, it's easy to miss signs of many of these infections. Parents say no, the kid hasn't been sick, but maybe there was a fever one day that nobody could explain and they forgot about it. Often these infections are very subtle. If strep is in the sinuses, for instance, a throat culture might come back negative. But if you do the blood test and get the patient's antibodies, you can often figure out if there was some sort of infection without symptoms. That's what Trifiletti will be able to do.
[Click here to read Scientific American's explainer about PANDAS, also known as PANS, and how it might be linked with the mystery Le Roy illness.]
Recently, University of Buffalo neurology professor Dr. David Lichter told WKBW that the symptoms might have spread via social media by students unintentionally mimicking the symptoms they've seen in videos.
Previously, USA Today reported that Erin Brockovich -- the environmental activist who linked cancer cases with toxic drinking water in California, spurring a 2000 movie starring Julia Roberts -- has launched her own investigation into the cause of the illness.
Brockovich is getting involved upon finding out that there was a toxic chemical spill that occurred near the school 40 years ago, thereby contaminating the water and ground, USA Today reported.
However, the New York Department of Health has not found that there is any environmental or infectious cause of the mystery illness, with department spokesman Jeffrey Hammond telling ABC News that "the school is served by a public water system. ... An environmental exposure would affect many people."