Investigation into cases of undiagnosed neurological illness concludes

Release

Department of Health

January 23, 2026

FREDERICTON (GNB) – The Office of the Chief Medical Officer of Health has concluded its investigation of cases of undiagnosed neurological illness in the province.

The main findings do not suggest exposure to certain environmental substances was a potential cause of illness among all or even most of the patients studied.

“From the outset of our investigation, our goal has been to thoroughly understand the available data so we can determine the most appropriate next steps to support affected patients and their families,” said Dr. Yves Léger, the chief medical officer of health. “Our investigation is now complete. While we encountered significant limitations during this work that affected the ability to answer certain questions with confidence, we can say that the findings do not suggest that either herbicides or metals were present at levels that could have contributed to illness for most patients.”

The government has been investigating these cases since 2021, when the Office of the Chief Medical Officer of Health studied a group of 48 patients with a range of symptoms. The initial investigation found no evidence of a common illness, and a report was issued on Feb. 24, 2022.

In early 2023, new concerns – including more patients reporting unusual symptoms – were reported to Public Health. The Office of the Chief Medical Officer of Health began its analysis of patient data in March 2025.

The office’s final report, released today and available online, has been shared with the Public Health Agency of Canada, which had conducted a scientific review and provided two rounds of feedback.

Next steps and recommendations

Léger said the next steps focus on implementing recommendations from the investigation. This includes determining what support can be made available to patients.

“Regardless of the findings of our investigation, the fact remains there are patients who are very ill and need support,” said Léger.

More information about this work will be communicated to patients and care providers when available.

The final report also includes recommendations related to patient followup, as well as formalizing a requirement that two specialists must assess a patient before he or she is reported as a new case of this illness.

“Our goal is to make sure patients receive accurate information and the right care,” said Léger. “These recommendations aim to strengthen testing practices and ensure accurate diagnoses.”

Status of Public Health Agency of Canada review

The provincial government has asked the Public Health Agency of Canada to conduct a separate review of all the data collected as part of this investigation, in accordance with a request from patient representatives.

A timeline for the federal agency’s review will be determined once the informed consent process is completed, the data-sharing agreement is in place and the data has been shared.

 

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