The State Department announced Friday that the US embassy in Havana will now operate permanently with minimal staff following mysterious “health attacks” that have harmed at least 24 Americans, the Associated Press reports.
The attacks took place from late 2016 to August 2017 and caused widespread injuries to brain networks in many of the affected Americans, according to a recent medical case report in JAMA. Those injuries and a wide range of symptoms — from hearing problems, vertigo to memory problems — developed after diplomats and their families experienced unexplained episodes of focused, irritating noises, pressure and vibration. This initially led some to speculate that a hidden “sonic weapon” was involved in the episodes, but scientists and doctors were quick to point out that sounds in the audible range are not known to cause such brain damage.
With an ongoing investigation into the attacks, the State Department had removed non-essential personnel from the embassy in October, citing health concerns, and issued a travel warning to US citizens. That initial staff shortage was only temporary and lasted for six months, what would have been this past weekend.
Now the State Department has drafted a new staffing plan to include only “the minimum staff necessary to perform key diplomatic and consular functions”. This would leave about two dozen staff members to perform essential functions, such as helping Americans traveling. The ministry also said the embassy will function as an “unaccompanied post”, meaning diplomats will not allow their families to live with them while stationed there.
The AP reports that the cutbacks in staff and the travel warning have had “significant effects” on the Cuban economy and that the embassy has halted visa processing for Cubans wishing to travel to the US. Cubans now have to apply for visas through US embassies in other countries.
Still, Secretary of State Rex Tillerson signed the plan, which the ministry said in a statement Friday out of concern for “the health, safety and well-being of U.S. government personnel and family members.”
“We still have no definitive answers about the source or cause of the attacks and the attacks are under investigation,” the ministry said.
In December, an investigation by a panel of Cuban scientists concluded that there were probably no attacks. The panel determined that the most likely explanation was massive psychogenic illness (MPI), which is essentially a collective delusion among a cohesive group of people that a disease is spreading among them. But the US doctors who evaluated the affected individuals rejected this idea, noting that their perceived symptoms and injuries could not be consciously or unconsciously manipulated. The doctors also suggested that the noise episodes that led to their symptoms may have been related only to the cause — not the immediate cause — of their injuries.
Nevertheless, researchers continue to speculate as to what the real cause may be. For example, computer scientist Kevin Fu of the University of Michigan along with Chinese colleagues speculated last week that the piercing and abrasive sounds that victims heard could be due to intermodulation distortion of ultrasound sources in office environments, such as room occupancy sensors. Intermodulation distortion occurs when “two signals of different frequencies are combined to produce synthetic signals with the difference, sum, or multiples of the original frequencies,” thus IEEE spectrumwho reported the researchers’ hypothesis.
The researchers say this phenomenon may explain the sounds heard on a short audio clip of the sound. However, they did not investigate whether they could explain the brain injury in victims.