Mystery in Cuba: What Is Causing Strange Illnesses at U.S. and Canadian Embassies?

Canada is halving the number of staff at its embassy in Cuba after a number of its diplomats reported mysterious health problems with a range of symptoms.

There have now been 14 confirmed cases of unexplained health issues among workers at the facility in Havana since early 2017, according to The Associated Press.

It is not known if the illnesses are related to those reported by U.S. diplomats at the nearby American Embassy, of whom 26 have fallen ill and been diagnosed with a range of injuries including mild traumatic brain injury, also known as concussion.

Cuban authorities have denied any involvement in the strange symptoms. When American diplomats at their Havana embassy fell ill, there were suggestions their symptoms may have been caused by some sort of sonic attack launched by Cuban agents.

Observed symptoms of the "attacks" include hearing loss, balance issues, headaches, nausea, swelling of the brain, damage to the nervous system and signs of concussion. But despite the serious effects, no one is any the wiser to the cause.

Allegations of a high-tech Cuban attack have never been proved, and there are multiple theories as to what may be behind the illnesses. One hypothesis is some kind of outbreak of mass hysteria where anxiety and stress among a group of people spreads to the point of illness.

The expectation of trauma can be enough to set off associated symptoms in some people, which can then transfer to others by giving them the same expectations and anxieties,The Guardian explained.

Recent research published by British and American scientists argued that the call of a local species of cricket might be behind the strange symptoms. In their analysis, which has not been published in an academic journal or peer-reviewed by other scientists, the investigators posited that the Indies short-tailed cricket, or Anurogryllus celerinictus, could be to blame.

According to Alexander Stubbs of the University of California, Berkeley, and Fernando Montealegre-Zapata of the University of Lincoln in the U.K., a recording of the sounds believed to be causing symptoms, published by the AP, matched the call of the cricket "in duration, pulse repetition rate, power spectrum, pulse rate stability and oscillations per pulse."

The lack of uniformity in reported experiences and symptoms have made investigation difficult. According to the Guardian, some described the noise as grinding or like the sound of cicadas, while others said they heard buffeting similar to that caused by an open car window. Others heard the sounds and suffered no ill effects.

The Cuban authorities have always rejected any suggestion that their agents were behind the bizarre incidents.

Cuba's ambassador to Canada, Josefina Vidal, said the Cuban authorities thought the Canadian decision was "incomprehensible," though stressed "Cuba remains committed to keeping the good state of bilateral relations."

Vidal argued that reducing staffing levels at the Canadian embassy would "not help find answers to the health symptoms reported by Canadian diplomats," and may lend credence to "those who in the United States use this issue to attack and denigrate Cuba."

US embassy Havana Cuba sonic attack
This file photo shows a view of the U.S. embassy in Havana, Cuba, on December 17, 2015. YAMIL LAGE/AFP/Getty Images