25
Sep
Mysterious “Havana syndrome†Linked to Neurotoxic Pesticide Exposure
(Beyond Pesticides, September 24, 2019) In 2016, Canadians and Americans residing in Havana reported symptoms of headaches, dizziness, nausea. They described hearing strange buzzing and high-pitched sounds – some woke in the middle of the night fumbling for alarm clocks that were not going off. Media used the term “Havana syndrome†to describe the illness. Diplomats, scared by symptoms that seemed to only hit them in their hotel rooms or at home, speculated that a sonic weapon was being used against them. The Trump administration accused Cuban leaders of misconduct and removed all but essential employees. Later, some suspected that the diplomats could have experienced “mass hysteria.†A new Canadian study provides a more likely explanation to this mysterious illness that impacted diplomats in Havana: neurotoxic pesticide exposure.
Researchers conducted testing on 14 individuals who had resided in Havana and a control group of 12 that had never lived there. Some of the experimental group had been recently exposed while others, tested 19 months after their return, were classified as “remotely exposed.†Tests included brain imaging and self-reported symptom questionnaires. They analyzed blood samples for routine biochemistry, kidney, liver, and metabolic functions. Individuals that showed symptoms of brain injury went through further neurological, visual, movement, auditory, and vestibular assessments.
The self-rated questionnaires from individuals who had lived in Havana were consistent with “post-concussion syndrome†and disabling headaches. Auditory and visual tests showed no significant problems, but some tests suggested brain-stem dysfunction and other neurological damage. The authors reported, “Cognitive tests showed significant reduction in spatial memory and a milder decrease in decision making quality in both exposed groups.†Further, they stated, “The clinical course, pattern of injury, brain regions involved, cortical and sub-cortical dysfunction, together with a history of common exposure, all raise the hypothesis of recurrent, low-dose exposure to neurotoxins.â€
Mass spectrometry tests found the presence of cholinesterase-inhibiting insecticides including Temephos, an organophosphate, as well as pyrethroids. The enzyme cholinesterase is critical to the creation of neurotransmitters and, therefore, healthy neuron communication.
Lead author Alon Friedman, PhD told CBC in an interview that they only developed the working hypothesis after getting most of the test results. “There are very specific types of toxins that affect these kinds of nervous systems … and these are insecticides, pesticides, organophosphates — specific neurotoxins,” said Dr. Friedman. “So that’s why we generated the hypothesis that we then went to test in other ways.”
Beginning in 2016, Cuba responded aggressively to the threat of Zika virus by spraying for mosquitoes. The embassies sprayed both inside and outside offices and diplomatic residences, increasing frequency of fumigations up to five times more than normal – sometimes every two weeks. The report found a correlation between individuals with strongest symptoms and the number of fumigations conducted at their residence. More research will be conducted on current residents of Havana.
Organophosphates were developed during World War II as nerve gas agents for military use – there is, therefore, some bitter irony to be found in the mystery of the “Havana Syndrome†being attributed to a government attack. Many groups, including Beyond Pesticides, have long advocated for the total discontinuation of the use of organophosphates and other neurologically damaging pesticides because of the known health effects described by the diplomats. In the U.S., farmworkers and their children are on the frontlines of this ongoing debate.
A group of leading toxics experts called for a ban on organophosphates after the publication of their 2018 paper in the journal PLOS that researched the impact of organophosphate exposure during pregnancy as well as impacts on child development. They concluded: (1) widespread use of organophosphate pesticides to control insects has resulted in ubiquitous human exposures; (2) acute exposures to OPs is responsible for poisonings and deaths, particularly in developing countries; and (3) evidence demonstrates that prenatal exposures, even at low levels, put children at risk for cognitive and behavioral deficits, and for neurodevelopmental disorders.
Pyrethroids, too, are known neurotoxins that have been linked to learning and development issues in children. Despite this, the Trump administration recently lowered safety measures on pyrethroids for children in the US.
Toxic pesticides are furtive and largely characterized as benign, often escaping notice until it is too late. Victims of chemical poisoning are frequently, like these diplomats, dismissed as “hysterical.†As Dr. Friedman told CNN, “There is a lot we don’t know about how much we can expose people to these chemicals and what are toxic levels, or if the damage in the brain is reversible, but it’s not called a neurotoxin for nothing. The hint is in the name.”
To help move the nation and world to a more cautionary approach to pesticides engage with the Action of the Week, check out Tools for Change, and consider joining the organization as one more way to advocate for the transition away from toxic chemicals. A better, less-toxic world is possible.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Sources: CBC, Buzzfeed, CNN, The Guardian