OTTAWA, Canada—It’s not just America’s problem with Cuba. The Canadian Government has admitted it sent a doctor to Cuba last summer to examine Canadian diplomats who suffered everything from nosebleeds to short-term memory loss amid concern about mysterious acoustic attacks, newly declassified memos show.

The June visit to Havana by Dr. Jeffrey Chernin of Health Canada revealed symptoms similar to those experienced by U.S. personnel in Cuba, the internal Global Affairs Canada notes say.

Word of the perplexing phenomenon — which remains unexplained — emerged during the summer, prompting the United States to bring many diplomats home from Havana and to expel Cuban representatives from Washington.

In August, Ottawa acknowledged that an unspecified number of Canadians in Cuba had been affected, but Global Affairs has said little about the events.

The newly disclosed records, obtained by The Canadian Press under the Access to Information Act, show that as early as May, Canada’s mission in Havana was seeking help in working out “next steps” for Canadian staff having problems.

“Many of the symptoms are similar to signs of extreme stress, and there is the possibility that there could be mental health effects caused by the fear of being targeted,” wrote diplomat Karen Foss. “Either way, testing should help to rule out cases and reassure personnel that we have the means to be able to provide duty of care.”

Symptoms included headaches, dizziness, nausea, hearing loss, nosebleeds and cognitive issues including loss of short-term memory.