Neurologist Calls for Independent Investigation Amid Ongoing Health Concerns
A neurologist from New Brunswick, who was among four doctors raising alarms about neurological issues affecting numerous patients, is urging for an independent scientific investigation into the matter.
In a letter sent to health ministers and public-health officials, Dr. Alier Marrero expressed the deep frustration felt by patients, families, and advocates following a recent assessment by New Brunswick’s Chief Medical Officer of Health. The assessment concluded no environmental factors were linked to reported neurological illnesses.
This marks the second time investigations led by the province’s health officials have failed to identify a shared illness among patients. The prior investigation, which started in 2021, examined 48 patients showing neurological symptoms, resulting in a report issued in February 2022.
Dr. Marrero’s correspondence appealed for the launch of an “independent, multidisciplinary scientific investigation” that should involve patient representatives in a collaborative setting.
Back in 2020, Dr. Marrero, together with three colleagues, alerted health officials to an increasing number of patients suffering from undiagnosed neurological conditions, alongside elevated levels of certain herbicides and metals in their systems.
The New Brunswick provincial government stated it started investigating cases in 2021 but found no common illness at that time. With more patients reporting symptoms in early 2023, the Chief Medical Officer of Health initiated a review of patient data in March 2025.
A report released in January by Chief Medical Officer of Health Yves Léger concluded that there was no substantial evidence linking herbicides or metals to the illnesses suffered by most patients. However, he hinted at emerging evidence that these patients likely have diagnosable medical conditions.
In a recent interview, Dr. Marrero expressed that he feels like a scapegoat for the criticism directed at him and emphasized that his patients deserve clear answers. “We’re asking questions and providing evidence, and they should be answered in a scientific manner,” he noted.
Dr. Marrero confirmed that his letter responded to findings from Dr. Léger’s earlier examination, although officials mentioned in the letter have not yet provided feedback.
Dr. Léger’s report indicated that toxins weren’t present in levels likely to contribute to most patients’ neurological conditions. Nonetheless, he acknowledged that patients might have medical issues that could be diagnosed.
Dr. Léger remarked in a press conference that the situation is alarming—patients are suffering without proper diagnoses or treatment plans.
Furthermore, Dr. Marrero’s letter criticized the lack of patient consultations during the examination and the absence of environmental tests or patient evaluations.
While Dr. Léger’s report, reviewed by the Public Health Agency of Canada, suggested a “formal, robust process” for a secondary clinical assessment for patients, it also accused media coverage of fostering a damaging narrative that fuels distrust toward public health institutions.
Following the report’s release, patient advocates rallied around Dr. Marrero, disputing both the report’s methods and its findings. Stacie Quigley Cormier, an advocate for over 40 patients, asserted that the report aimed to undermine Dr. Marrero’s credibility. Her stepdaughter, Gabrielle, has faced debilitating neurological symptoms since she was 18.
Another advocate, Katherine Lanteigne, criticized the report for cherry-picking data and called for an independent panel of neuroscientists and toxicologists to conduct the investigation.
