The Canadian government has recalled families of its diplomatic staff in the Cuban capital, Havana as 10 Canadians continue to show unexplained brain symptoms, government officials said.
The Canadians, including some minors, have suffered from dizziness, nausea and difficulty concentrating.
A report by a Canadian medical specialist says that a new type of brain injury may be the cause of a mysterious illness.
It has affected diplomatic staff and their families in Cuba.
Canada says it has discounted theories about covert sonic attacks being the cause of the illnesses.
Staff at the US embassy in Havana were similarly affected when the injuries surfaced last year.
Washington pulled out its diplomatic staff in Havana in September and warned US citizens not to visit Cuba.
It said 21 embassy employees had been injured.
Officials said that some of those who seemed to recover have since seen the symptoms reassert themselves.
Cuba previously dismissed allegations of a sonic attack against US embassy staff in Havana.
In October Cuba’s Foreign Minister Bruno Rodriguez said US claims were a “political manipulation” aimed at damaging bilateral relations.
More than a million Canadians visit Cuba every year, but Global Affairs Canada says there is no evidence of any related ailments among Canadian tourists.
Unlike the United States, Canada did not break diplomatic relations with Havana after the Cuban Revolution in 1959.