In early March, Canadian officials began alerting doctors and provincial health officials in New Brunswick to tell them that federal health authorities were monitoring a cluster of 43 cases of neurological disease with an unknown cause. The first case was identified in 2015, but the number of people with the condition has risen sharply since, with 24 cases reported in 2020 and six so far in 2021. Five people have died due to complications as a result of the disease.
The province of New Brunswick is to the northeast of the U.S. state of Maine. The cases seem to be concentrated around the Acadian Peninsula region in the province's northeast and the Moncton metropolitan area in the southeast. Health officials have refused to disclose the precise locations of the cases.
Doctors first thought the disease was Creutzfeldt-Jakob Disease (CJD), a rare and fatal brain disease caused by abnormally folded proteins called prions. But tests conducted showed no evidence of CJD, nor any other related condition.
A leaked memo from New Brunswick's public health agency told the province's doctors to look out for patients bearing symptoms similar to CJD.
Some of the symptoms physicians in the province were told to look out for include memory loss, visual hallucinations, changes in behavior, sleep disturbances, coordination problems and severe muscle and brain atrophy. (Related: Got memory loss, brain fog and chronic fatigue? Here are the top 5 causes.)
"We are collaborating with different national groups and experts; however, no clear cause has been identified at this time," read the memo.
Dr. Alier Marrero, a neurologist working at Dr. Georges-L.-Dumont University Hospital Center in Moncton, has been researching the new disease and believes it is not genetic. His leading theory is that it could be contracted from water, food or air since it has not been reported anywhere else in Canada.
"For now, it has only been found here," said Marrero.
Marrero's team currently believes it is some kind of prion disease, despite the inconclusive tests, due to its symptoms. But he has also cautioned doctors against rushing to assume the current cases are caused by prion disease.
"Before coming out with a definition of a new condition, you need to have a lot of information to be sure that you are not diagnosing something else."
According to Marrero, patients initially come to the hospital complaining about unexplained pains, spasms and behavioral changes. Doctors in the area should watch out for these, as they can easily be misdiagnosed as anxiety or depression.
The symptoms of this new brain disease then progress over a period of 18 to 36 months. Patients start to experience cognitive decline, muscle wasting, drooling and teeth chattering. Several patients also experience very frightening hallucinations, including the feeling that there are insects crawling on their skin.
People who come in with similar symptoms have to go through a lot of diagnostic exams before their case can be included in the New Brunswick "cluster."
Marrero's team begins by conducting an extensive study of the patient's history. They then proceed with a battery of tests including spinal taps, metabolic and toxicology tests and brain imaging to rule out other potential diseases like possible infections, dementia, neurodegenerative disorders and autoimmune conditions.
"We have not seen over the last 20-plus years a cluster of diagnosis-resistant neurological diseases like this one," said Michael Coulthart, head of the Canadian Creutzfeldt-Jakob Disease Surveillance System.
Health officials are monitoring the situation very closely, and further research is required to understand the "common links" that could help them pinpoint the exact cause of the disease.
"At this point, we have more questions than answers," said Dr. Jennifry Russell, New Brunswick's Chief Medical Officer of Health.
Marrero and other doctors have consulted experts in neurology, toxicology, environmental health, field epidemiology and zoonotics to better understand the cause of the illness, but so far have been unable to figure out much.
"I don't really know if we even have a defined syndrome. There just isn't enough information yet," said Valerie Sim, a researcher of neurological diseases working at the University of Alberta. "We see odd neurological syndromes from time to time. Sometimes we figure them out. Sometimes we don't."
Learn more about other conditions that can affect the brain by reading the latest articles at Brain.news.