A senior Canadian federal scientist has alleged that the government shut down an investigation into a mystery brain illness in New Brunswick that he believes may have affected 350 people.

He is the second federal scientist to accuse the government of deliberately halting the investigation and to say that the caseload is higher than the government has acknowledged.

Health officials in the eastern province first said in 2021 that 40 people were suffering from an unexplained neurological condition. A year later, a committee assembled by the province determined that the patients probably had been misdiagnosed and were suffering from other diseases.

In a leaked email seen by the Guardian, Prof Samuel Weiss, a neuroscientist working for the Canadian federal agency responsible for funding medical research, wrote that the government had deliberately curtailed the search for an explanation.