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Mystery Brain Disease Outbreak In Canada Continues To Go Unanswered


Tom Hale

Senior Journalist

clockJan 4 2022, 17:30 UTC
Brain scans.

The disease was made public by a leaked memo in March 2021, but reports of the symptoms have been slowly mounting since 2018. Image credit: Utthapon wiratepsupon/

In Spring 2021, it was revealed that 48 people in the Canadian province of New Brunswick had fallen ill with a mysterious neurological condition over the past few years. Doctors were left stumped and the cause of the condition remained unknown.

Now, whistleblowers speaking to the Guardian have claimed that there could potentially be over 100 more cases than the official records show. Furthermore, they claim there have been a number of cases in which people in close contact with the affected have developed symptoms. 


Individuals afflicted with the condition currently known as the "New Brunswick neurological syndrome of unknown cause" display a range of neurological symptoms that appear to progressively get worse, including changes in behavior, sleep disturbances, memory loss, hallucinations, coordination problems, and muscle pain.

The disease was made public when an internal memo from the New Brunswick public health agency was leaked in early 2021, but reports of the symptoms had been documented since 2018. One case that started around 2013 has since been identified retroactively too, according to the Office of the Chief Medical Officer of Health. All of these reported cases had been limited to New Brunswick with no similar cases being referred from other provinces or territories. Of the original 48 cases, nine have died. However, authorities claim that all the bodies that have undergone an autopsy had died of causes unrelated to the unknown neurological disease. 

There is some doubt that there are still just 48 cases of the condition, however. Anonymous sources from the province's health authorities have told the Guardian that they suspect the cluster could now be as many as 150 people, with a backlog of young people still waiting for proper assessment.

Most unusually, they also suggested a possible link between a few of the cases. According to one source, at least nine cases involve people that have been in close contact with others suffering from unusual neurological symptoms. In these cases, there is no genetic link between the pairs and many appear to be caregivers that are looking after affected individuals.


In such one instance, a woman in her thirties was non-verbal and required feeding through a tube. Their carer, a nursing student in their twenties, started to show possible signs of neurological decline after caring for the patient.

When news of the cluster first broke, some scientists felt that the symptoms sounded worryingly like Creutzfeldt-Jakob disease (CJD), a rare and fatal brain disease caused by prions – misfolded proteins that act as infectious agents that can be picked up by consuming the brain tissue of an infected individual or animal. However, a report from October 2021 ruled this out, finding that all of the patients tested negative for known forms of human prion diseases.

Another avenue of investigation is environmental contaminants. One suspect is β-Methylamino-L-alanine (BMAA), a neurotoxin produced by cyanobacteria often found in marine environments. It has previously been found that certain seafood can have significant quantities of BMAA and there have even been suggestions that it could be linked to all kinds of neurological disease in humans, from Alzheimer’s to Amyotrophic Lateral Sclerosis (ALS). Toxic algal blooms, where huge amounts of cyanobacteria suddenly blossom in a marine environment, could also be a factor. However, authorities have so far ruled this out, arguing that very few of the patients have come into potential contact with algal blooms.

In January 2022, New Brunswick authorities are due to release a report on the condition, to set the record straight on whether these cases are the result of misdiagnosis or represent a real neurological illness. However, insiders have expressed concerns that investigations into the condition are not being given the resources they deserve. Much to the annoyance of anonymous sources, they also anticipate the report to conclude the cluster of cases is simply the result of misdiagnoses that have mistakenly been linked together.

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