FREDERICTON -- Another person believed to have had a mysterious neurological syndrome in New Brunswick has died.

There have now been six deaths and 44 suspected cases linked to the mystery brain disease, health officials in the province confirmed Wednesday.

The first case dates to 2015 but wasn't identified until early 2020, when a cluster of cases was detected by the Creutzfeldt-Jakob Disease Surveillance System, operated by the Public Health Agency of Canada. The agency conducts national surveillance for prion diseases, such as Creutzfeldt-Jakob disease, which cause neurologic symptoms.

Symptoms of the mystery brain syndrome in the province include rapidly progressing dementia, muscle spasms, atrophy and a host of other complications.

New Brunswick Health Department spokesman Bruce Macfarlane says while most cases have been identified in the northeast and southeast of the province, it's unknown if geography is linked to the disease.

"So far, our investigation has not found any evidence suggesting that the residents of these regions are more at risk than those living elsewhere in the province," Macfarlane said in an email Wednesday.

Last month, a researcher with the Public Health Agency of Canada suggested a potential cause may be some kind of environmental exposure. Michael Coulthart said he was ruling out a prion disease such as Creutzfeldt-Jakob disease, but noted that many neurological disorders have features that overlap.

Coulthart said he had not seen anything like the New Brunswick cluster before.

Macfarlane said officials recognize there is confusion and concern in the community. "It is expected that the investigation will last many weeks or months and regular updates on the investigation will be provided," he said.

The province is creating a website, he said, which will include data on strategies for treatment and prevention of the disease, adding that it will be updated regularly.

This report by The Canadian Press was first published April 7, 2021.