Doctors in Canada may be dealing with an entirely new brain disease that's specific to one part of their country. A cluster of 43 cases is under investigation in the Canadian province of New Brunswick, reports the Guardian. Symptoms are similar to well-known "prion diseases" such as Creutzfeldt-Jakob, but tests have ruled out CJD and variants such as mad cow disease, per Medscape. The first case surfaced in 2015, and numbers have since escalated to 11 in 2019 and 24 in 2020. Diagnosis can be tricky because initial symptoms such as insomnia, muscle spasms, and increased anxiety can be explained by a host of ailments. But over the course of 18 to 36 months, symptoms grow more serious. Patients suffer brain atrophy, muscle wasting, hallucinations, and more. Researchers say five of the cases have proved fatal, per the CBC.
"We have not seen over the last 20-plus years a cluster of diagnosis-resistant neurological disease like this one," says Michael Coulthart, who's leading the government's investigation, per the Guardian. The cases are centered around the city of Moncton and an area known as the Acadian Peninsula. For now, researchers' best guess is that some kind of environmental factor is to blame. "Everything that we have analyzed so far suggests this is an environmental exposure of some kind that is acquired through food, water, air, professional activities, or leisure activities," says Alier Marrero of the Dumont University Hospital Centre in Moncton, per Medscape. The cluster came to light earlier this month when a memo asking doctors to watch for symptoms was leaked to the media. (A hunter is believed to have contracted CJD after eating a squirrel.)