Dizziness, blurred vision, memory loss, problems focusing… Something serious seemed to be affecting US diplomats in Havana in late 2016 and 2017. But what? And who — or what — was responsible?
The new Trump administration, without evidence, blamed the Cuban government and hinted darkly American diplomatic personnel had been targets of “sonic attacks” using a previously unknown secret weapon.
That was the first of many theories put forward to explain what was happening — from mass hysteria to the call of the Indies short-tailed cricket. Most were debunked; nothing was proved.
But American diplomats weren’t the only ones reporting symptoms. Some Canadian diplomats complained as well and, in the spring of 2018, Global Affairs Canada commissioned Dalhousie University’s Brain Repair Centre in Halifax to investigate and report back.
On Nov. 1, 2019, Dr. Alon Friedman, the Brain Repair’s Centre’s lead researcher on the project, will discuss the findings in a keynote talk at “The Cuban Revolution at 60,” a major, three-day international academic symposium in Halifax. The conference is free and open to the public. You can register here.
The Dalhousie researchers — 15 principal investigators and their teams — began by trying to replicate the results of a preliminary study by researchers at the University of Pennsylvania. The UPenn researchers reported that what had happened to the Americans represented a “new syndrome that resembles persistent concussions,” but they were unable to identify its cause.
The Halifax researchers wanted to take the next step and figure out what had actually caused the symptoms.
They began by testing the Canadian diplomats who’d reported the symptoms using a multi-disciplinary approach for studying brain injury, including new methods of brain scanning. Perhaps most importantly, they also performed before-and-after scans on the brains of eight other diplomats who had been posted to Havana during the time of their study.
All those who’d spent time in Havana showed similar damage to distinct brain regions, which are associated with memory consolidation, concentration and the sleep-wake cycle.
Friedman — an Israeli-trained medical doctor with a PhD in neuroscience — recognized what he was seeing on the scans from his own research 30 years before. “There are very specific types of toxins that affect these regions of the brain,” he explains. Those included insecticides, specifically organophosphate pesticides as well as other organophosphates – neurotoxins that actually work by inhibiting the actions of cholinesterase, a key enzyme required for the proper functioning of the nervous system.
But that raised a critical next question. How had the diplomats come into contact with those neurotoxins?
While there were potentially nefarious explanations — a sarin gas attack on a Tokyo subway in 1995, the poisoning of Korean leader Kim Jong-Un’s half-brother in 2017 — both involved single high-dose exposures that didn’t explain what had happened in Havana.
“It was like a detective story,” Freidman recounts. The researchers explored various potential avenues of explanations, tested them and found them wanting.
“With the help of Dr. Google,” Friedman jokes, they eventually connected the dots back to a very public mass fumigation campaign the Cuban government itself launched in 2016 to combat a major outbreak of mosquito-borne Zika virus in the Americas, including in the Caribbean.
Toxicological analysis of the Canadian victims confirmed the presence of pyrethroid and organophosphate, two compounds used in the fumigation products the Cubans had sprayed.
Using the Canadian embassy’s own records, the researchers also discovered spraying had been carried out inside and outside their residences. The facilities were sprayed far more often than expected — sometimes every two weeks. And the researchers also found a correlation between the number of fumigations performed at a diplomat’s residence and the seriousness of the symptoms they reported.
Which brought the researchers to their working hypothesis. “We report the clinical, imaging and biochemical evidence consistent with the hypothesis of over-exposure to cholinesterase inhibitors as the cause of brain injury,” the study concluded.
That isn’t the end of it, of course. More research needs to be done, including figuring out how to better understand the danger levels of the various toxins and, of course, there is still the public health concern. Who else might have been affected, including Cuban citizens working at the embassies, living around the same neighborhoods or involved in the spraying?
The good news is that Dr. Friedman has met with Cuban health professionals and they are currently working together to determine those next research steps.
For more information on the upcoming symposium at Dalhousie University – “The Cuban Revolution at 60,” — visit the website here.