New Brunswick·CBC Investigates

No longer a sure thing: Records show how N.B. investigation into mystery illness changed over time

For three months last year, medical and environmental experts met to try to solve the mystery of a “neurological syndrome of unknown cause” in New Brunswick. But provincial public health officials halted the meetings in May.

Public Health paused meetings with several scientific experts in May

New Brunswick public health officials consulted more than 40 experts as they tried to solve the mystery of a neurological syndrome of unknown cause, before halting meetings last May. (Duk Han Lee/CBC News Graphics)

For three months last year, medical and environmental experts in New Brunswick, along with many from beyond the province, met with provincial public health officials about what they described as a "neurological syndrome of unknown cause."

But that all changed on May 6, 2021, when provincial health officials halted those meetings.

According to the province, the syndrome of unknown cause has affected 48 patients, whom they've identified as a cluster of people with symptoms such as memory problems, balance issues and behaviour changes.

Hundreds of pages of records obtained by CBC News through access to information reveal new details of those meetings, and how New Brunswick's strategy around investigating the syndrome changed over time.

An oversight committee, made up mostly of neurologists from within the province, has been doing a clinical investigation with patients from the cluster.

Their report is expected to be released early this year and could conclude there isn't a mystery syndrome.

New Brunswick Health Minister Dorothy Shephard says a report on a clinical investigation into the mystery syndrome is expected early this year. (Ed Hunter/CBC)

Health Minister Dorothy Shephard said in October that officials were questioning the validity of the theory of an unknown syndrome. 

The health minister has said eight patients, six of whom were part of the original cluster of 48, who died had autopsy results indicating they died from known diseases, such as cancer, Lewy body dementia and Alzheimer's disease.

Around the same time as the meetings with experts were cancelled, the government's messaging around the syndrome began to shift, from something definite to being described with words like "potential."

It was also then the province began to distance Dr. Alier Marrero, who identified 46 of the 48 patients, from the investigation. 

The minister of health moved from pointing to Marrero as leading the investigation in April to saying in October that he was never the lead and that an investigation "should be from an unbiased perspective."

CBC News asked Marrero to respond to Shephard's comment, but his employer, Vitalité Health Network, declined comment because the investigation is ongoing.

Province's investigation questioned

Critics, including some patients and Marrero, have questioned the province's strategy. 

"We were told we didn't have the right to update the newest cases," Marrero said in an interview with Radio-Canada's Enquête in October, as he described provincial officials' shift in strategy last spring. 

"Not divulge new statistics, not to speak of new deaths."

Several patients and their family members signed a letter to Shephard last month, calling for immediate reinstatement of collaboration with scientists from the Public Health Agency of Canada (PHAC) and "other colleagues across the country."

a man stands up wearing a suit.
Dr. Alier Marrero, the neurologist who has treated many patients who make up New Brunswick's mystery syndrome cluster, has questioned the province's investigation strategy. (Virginia Smart/CBC)

"These barriers limit scientific experts from aiding Dr. Marrero in uncovering the root cause of our diseases," the letter says.

The provincial government has denied it told federal experts to stand down, saying it has always welcomed input.

"All of the cases were in New Brunswick, and therefore it was Public Health New Brunswick's responsibility to take the lead," Shephard said in October, when asked if experts were told to stand down.

But records show the province's strategy has been to turn inwards and examine what data it already had.

The hunt begins

Last January, the provincial government launched an investigation into the cluster that would eventually see more than 40 "subject matter experts" consulted from two levels of government.

A spokesperson with the Public Health Agency of Canada said the meetings were organized at the New Brunswick government's request. Tasks included "defining the nature of the atypical neurological condition."

The group meetings began in February. On March 5, the office of New Brunswick's chief medical officer of health sent out a memo to health-care providers across the province about "a distinct atypical neurological syndrome" and warned them to look out for unusual neurological symptoms.

"It most likely is a new disease," Chief Medical Officer of Health Dr. Jennifer Russell told reporters on March 18. "We haven't seen this anywhere else."

LISTEN | Records show changing message from province:

By the end of March, the cluster investigation meeting invitation list grew to include experts in food safety, environmental health and infections that travel between animals and humans.

In April, the government launched a website with information on the syndrome, which suggested multiple doctors had noticed cases, and a thorough investigation had been done.

It most likely is a new disease.-Chief Medical Officer of Health Dr. Jennifer Russell

"Despite extensive medical investigation, a diagnosis for these individuals has not yet been determined," the website said.

Experts discussed testing

Minutes show the group of experts discussed mapping cyanobacteria blooms, toxin testing and sampling for chronic wasting disease in deer. They also suggested questions patients should be asked in an epidemiological survey.

The minutes also show Marrero told the group that doctors from a number of other provinces referred potential cases to him.

The health minister said in October that there are no cases outside New Brunswick.

An expert who had been consulted by the province, Dr. Neil Cashman, a neurology expert with the University of British Columbia's faculty of medicine, told CBC News in the spring experts were looking into the possibility an environmental toxin called BMAA could be causing patients' symptoms.

Minutes for an April 15 meeting describe BMAA as a "hotly debated topic."

At the end of April, a PHAC scientist discussed getting consent from patients for testing. The records show "brain testing" for BMAA was discussed, as well as testing samples from patients' spinal cords, kidneys and livers. It also references testing for heavy metals.

"We need to have enough/sufficient evidence before making the call for sample collections since we are responsible for funding," the minutes say.

Less than a week later, public health officials cancelled the next scheduled meeting.

Province halts meetings

"We will be pausing the current meetings concerning a neurological syndrome until we have had the time to delve more deeply into existing data," Joan McGowan, the program review and alignment lead with the Department of Health, wrote in an email to the experts on May 6.

"We thank you for sharing your invaluable expertise to date and look forward to the resumption of larger meetings in the near future." 

The group didn't meet again. 

A spokesperson with the New Brunswick Department of Health didn't answer questions about why the meetings stopped.

A spokesperson with PHAC said the meetings "were suspended by mutual agreement" between the federal and provincial government so the province could "refocus its efforts internally" on creating a new investigation, one that only includes New Brunswick experts.

Experts and New Brunswick Public Health officials discussed possible causes of an unknown neurological syndrome and conducting several kinds of tests before meetings were stopped last May. (CBC/The Fifth Estate)

"Meetings have not resumed since that time, although PHAC has in the interim provided extensive ongoing support to N.B. in response to a number of specific requests," spokesperson Kathleen Marriner wrote in an emailed statement to CBC.

The records also suggest New Brunswick Public Health stopped working closely with officials from other departments of its government.

The Department of Environment and Local Government and the Department of Natural Resources and Energy Development provided CBC News with more than 650 pages of records about the syndrome investigation.

When asked again later in the year, neither department was able to find any records related to the investigation between mid-June and mid-October.

Smaller local committee

On May 6, the same day meetings with experts were paused, Dr. Édouard Hendriks, then vice-president of medical, academic and research affairs with the Horizon Health Network, a regional health authority, came up with a new plan to investigate the cluster.

In an email to New Brunswick's deputy minister of health and a neurologist at the Moncton Hospital, Hendriks suggested the government form a smaller committee to provide oversight "by an objective group to help clinicians."

About a month earlier, the province provided funding to open the MIND Clinic, a clinic in Moncton staffed by Marrero and two other physicians and specialized in treating patients with neurodegenerative issues.

The oversight committee announcement left doctors at The Mind Clinic confused about its mandate and whether they would be "essentially conducting a review of their professional/clinical services," according to an email sent from a Horizon Health staff member to Hendriks.

Marrero, pictured here at the MIND Clinic at the Moncton Hospital, is not part of a committee set up by the Department of Health to investigate a cluster of patients who have an unknown neurological illness. (Horizon Health Network)

All three physicians felt "very disconnected" from the committee, the email said.

At first, the health minister suggested the committee would work with Marrero.

"We have put in place an oversight committee to assist Dr. Marrero with this [investigation] process and to ensure that we're covering all of our bases," Shephard said at a May 27 COVID news conference.

Marrero says syndrome 'gaining momentum'

But by an October news conference, it was clear Marrero was no longer involved.

"Dr. Marrero was not the lead on this investigation," Shephard said.

"Public Health was the lead on this investigation."

In his interview with Enquête, Marrero said he met with public health officials regularly for months until it stopped.

"All of a sudden, in the month of June, we decided that it's New Brunswick, with the created committee, which would take charge of everything and we were kept outside of that," Marrero said in French.

Earlier this month, when asked about bringing federal scientists back into the fold and conducting environmental testing, Shephard suggested the government would "go further" if they believe it's required, but only after its clinical review is done.

"This is the preliminary work that should have been done in the first place," she said.

But Marrero stands by his theory.

"I believe that there is an unknown disease for which I see more and more cases and more and more young people who must have a diagnosis and who deserve to have a thorough research by teams, experts in the field, nationally and even internationally," he told Radio-Canada.

"I am convinced that it is gaining momentum, because I see it clinically." 


Karissa Donkin is a journalist in CBC's Atlantic investigative unit. Do you have a story you want us to investigate? Send your tips to

With files from Nicolas Steinbach/Radio-Canada, Alexandre Silberman and Maeve McFadden