Canadian health authorities have concluded a comprehensive investigation into alleged cases of a mysterious neurological illness in New Brunswick, finding no evidence to support claims of a novel disease. The provincial study, released Friday by New Brunswick’s Chief Medical Officer of Health Dr. Yves Léger, examined 222 patients previously identified by neurologist Dr. Alier Marrero as potentially suffering from unexplained neurological symptoms.
The investigation specifically addressed Dr. Marrero’s assertions that patients exhibited elevated levels of herbicides and heavy metals that could explain their symptoms. After comparative analysis with broader population data from Atlantic Canada, officials determined herbicide levels among the patient group were normal. While a limited number of patients showed higher-than-expected metal concentrations, researchers noted methodological issues with testing procedures and found no conclusive evidence linking these levels to neurological effects.
The report highlighted several limitations in its review, including non-standardized testing protocols and insufficient retesting to establish pattern consistency. Notably, approximately 60% of the patients had been evaluated by additional neurologists, none of whom reported unusual neurological conditions to health authorities.
This represents the second official study debunking the mystery illness theory, following a 2022 examination of the initial 48 cases. The conclusions align with separate research published in JAMA Neurology last year, which reviewed 25 cases and found patients suffered from identifiable conditions including cancer and dementia.
Despite the findings, Dr. Léger acknowledged the legitimate suffering of patients, emphasizing that ‘the fact remains there are patients who are very ill and need support.’ The province will now require two specialist examinations for any patient presenting with unexplained neurological symptoms. All data will be shared with the Public Health Agency of Canada for further review.
Patient advocate Sarah Nesbitt expressed concerns about the study’s limitations while remaining hopeful it might lead to better support for affected individuals. Meanwhile, Dr. Marrero, who previously told the BBC that other scientists had initially supported the novel syndrome theory, did not immediately respond to requests for comment on the latest findings.