Skip to main content

Tourists in a vintage car pass by the U.S. embassy in Havana, Cuba, on Nov. 1, 2018.

Alexandre Meneghini/Reuters

Fumigation against mosquitoes in Cuba and not “sonic attacks” may have caused about 40 U.S. and Canadian diplomats and family members in Havana to fall ill, according to a new study commissioned by the Canadian government.

The incidents took place from late 2016 into 2018, causing the administration of U.S. President Donald Trump to charge that diplomats were attacked by some sort of secret weapon. Canada has refrained from such charges.

The United States in 2017 reduced its embassy staff to a minimum and Canada followed more recently, citing the incidents and the danger posed to staff from what has become known as the “Havana Syndrome.”

Story continues below advertisement

Various scientific studies have yet to identify the cause of the diplomats’ cognitive ailments, ranging from dizziness and blurred vision to memory loss and difficulty concentrating.

The Canadian study by a team of researchers affiliated with the Brain Repair Centre at Dalhousie University and the Nova Scotia Health Authority studied Canadian victims and even the brain of a pet dog after its demise in Canada.

The study was the first to include diplomats for whom there was baseline medical testing from before their postings in Havana, so as to better compare with the tests from afterward. Canada started implementing the practice after diplomats first started complaining of sickness.

The researchers said they had detected different levels of brain damage in an area that causes symptoms reported by the diplomats and which is susceptible to neurotoxins. They then concluded that cholinesterase, a key enzyme required for the proper functioning of the nervous system, was being blocked there.

Some pesticides work by inhibiting cholinesterase, the report said, and during the 2016-2018 period when diplomats became ill normal fumigation in Cuba was stepped up due to the Zika epidemic in the Caribbean.

The report said the diplomats’ illnesses coincided with increased fumigation in and around residences where they lived. One of the authors of the study, Professor Alon Friedman, clarified in an e-mail to Reuters that both Canadian and Cuban authorities were fumigating.

“We report the clinical, imaging and biochemical evidence consistent with the hypothesis of overexposure to cholinesterase inhibitors as the cause of brain injury,” the study concluded, while cautioning that other causes could not be ruled out and more study was needed.

Story continues below advertisement

Prof. Friedman said it was not clear whether the broader Cuban population was affected by the fumigation and if not, why, but his team was planning a further study on this together with Cuban scientists.

Our Morning Update and Evening Update newsletters are written by Globe editors, giving you a concise summary of the day’s most important headlines. Sign up today.

Report an error
Due to technical reasons, we have temporarily removed commenting from our articles. We hope to have this fixed soon. Thank you for your patience. If you are looking to give feedback on our new site, please send it along to feedback@globeandmail.com. If you want to write a letter to the editor, please forward to letters@globeandmail.com.

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff. Non-subscribers can read and sort comments but will not be able to engage with them in any way. Click here to subscribe.

If you would like to write a letter to the editor, please forward it to letters@globeandmail.com. Readers can also interact with The Globe on Facebook and Twitter .

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff. Non-subscribers can read and sort comments but will not be able to engage with them in any way. Click here to subscribe.

If you would like to write a letter to the editor, please forward it to letters@globeandmail.com. Readers can also interact with The Globe on Facebook and Twitter .

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff.

We aim to create a safe and valuable space for discussion and debate. That means:

  • Treat others as you wish to be treated
  • Criticize ideas, not people
  • Stay on topic
  • Avoid the use of toxic and offensive language
  • Flag bad behaviour

Comments that violate our community guidelines will be removed.

Read our community guidelines here

Discussion loading ...

Cannabis pro newsletter
To view this site properly, enable cookies in your browser. Read our privacy policy to learn more.
How to enable cookies