Canadian scientists banned from investigating cases of unknown neurological disease

Microbiologist Michael Coulthart (Michael Coulthart), who heads the surveillance system for Creutzfeldt-Jakob disease in the Public Health Agency of Canada, said that he was forbidden to study cases of an unknown neurological disease that has been affecting residents of one of the provinces for almost 10 years. The scientist revealed this in emails to a colleague, which are available to The Guardian.

"All I will say is this: my scientific opinion is that there is something real going on in [New Brunswick] that cannot be explained by the bias or personal intentions of an individual neurologist," Coulthart wrote. He said the number of people who have fallen ill has already surpassed 200, and the reason authorities are failing to act could be political.

In the spring of 2021, the media began actively writing about a "mysterious" neurological disease found in the Acadian Peninsula of the eastern Canadian province of New Brunswick with a population of less than 800 thousand people. The first suspected case was identified in 2015, rising to 11 in 2019, 24 in 2020, 43 in 2021 and 48 in 2022.

Patients complained of symptoms that reminded doctors of the signs of Creutzfeldt-Jakob disease (CJD), a rapidly progressive neurodegenerative disease from the group of prion diseases: initially - pain, spasms and changes in behaviour, and after 18-36 months to this list were added cognitive decline, muscle atrophy, salivation and teeth grinding (bruxism). Some victims reported hallucinations, especially tactile hallucinations.

Then neurologist Alier Marrero began studying the cases. His team analysed patients' medical histories, performed neuroimaging, metabolic and toxicological tests, and took lumbar (spinal) punctures. They wanted to rule out other possible diseases, such as neurodegenerative diseases like dementia, autoimmune diseases and infections. But it was not possible to draw a clear parallel with IBD or other diseases.

In addition, the researchers sought to understand whether cases of atypical syndrome could be explained by environmental causes, such as contamination from insects or through water.

"In the last 20-plus years, we haven't seen a cluster of diagnosis-resistant neurological diseases like this one," Coulthart said.

In February 2024, New Brunswick authorities released a report concluding: the mystery disease did not exist, and Marrero, officials believed, "did not seek a second opinion" at the time of diagnosis. However, medics were advised to continue monitoring the growing number of patients. At that point, 10 of those who became ill had died.

"The committee unanimously agreed that these 48 people (the number of patients as of February 2024. - Editor's note) did not have any neurological syndrome of unknown aetiology. Based on the evidence reviewed, there is no such syndrome at all," Jennifer Russell, New Brunswick's chief medical officer, told reporters. No environmental factors that could have caused the disease were also found.

Patients' families and researchers have criticised officials' findings. According to Marrero, at the time 12 households had already reported sick people, there was a risk of "potential person-to-person transmission." The neurologist allowed for a possible common root cause.

The investigation seemed to have been put to rest, but Coulthart's letter, according to reporters, shows the concerns of Public Health Agency of Canada officials. The biologist emphasised that the very complexity of the issue has provided a "loophole" for politicians to conclude as if nothing suspicious is going on and the cases are unrelated.

"I believe the truth will eventually reveal itself. But all we can do now <...> is to continue to collect information on patients with suspected prion disease," Coulthart concluded.