The U.S. Embassy in Cuba.

The U.S. Embassy in Cuba. 

The federal government is looking into reports of “Havana syndrome,” a mysterious illness that has affected more than 200 American personnel around the world in recent years, including diplomats and members of the CIA.

The sensory attacks have affected Americans overseas and in the U.S. It has also affected several Canadian diplomats.

While U.S. intelligence officials believe they are closer to understanding what is causing the incidents, the phenomenon is still shrouded in mystery.

Here’s what is known so far about the syndrome:

What are the symptoms of Havana syndrome?

The term “Havana syndrome” refers to the mysterious illness affecting U.S. personnel across the globe.

Diplomats at the U.S. Embassy in Havana first began reporting the strange symptoms in 2016.

Victims of the syndrome have included diplomats, members of the CIA, the military, and the National Security Council, as the Miami Herald has reported.

Symptoms include dizziness, tinnitus, visual problems, vertigo and cognitive difficulties. Some affected Americans said they heard a sound or felt some type of pressure or vibration.

Doctors at the University of Pennsylvania and the University of Miami, who first treated U.S. diplomats in Havana affected by the ailment, also found evidence of brain injury and damage to the inner ear’s vestibular system.

Where have Americans been hit by Havana syndrome?

Besides Cuba, symptoms have been reported in U.S. officials across the world, including China, Britain and Russia. In July, NBC News reported that there were possible cases on every continent except Antarctica.

The hotbed: Vienna, where dozens of U.S. personnel, including some of their children, have reported symptoms in higher numbers than in any other city except for Havana, according to The Washington Post.

Some Havana syndrome cases also occurred on U.S. soil, possibly even in Miami.

In April, Politico reported that the U.S. was investigating a “suspected directed-energy attack” that affected federal government personnel in Miami last year. The people had symptoms similar to Havana syndrome.

Incidents have also occurred in the Washington, D.C., area. At least one was near the White House.

Most recently, an employee who traveled with CIA Director Bill Burns to India earlier this month reported symptoms consistent with the syndrome and had to seek medical attention.

And in August, Vice President Kamala Harris’ Vietnam visit was slightly delayed over a possible case of Havana syndrome in the capital of Hanoi. At least two U.S. diplomats were medically evacuated from the country.

The reported cases in Vietnam and India are under investigation, the McClatchy Washington bureau reports.

What is causing it?

The National Academies of Sciences, in a report last year, concluded that the symptoms were likely caused by directed microwave energy.

But there are still unknowns: What or who is behind the directed energy and how are they doing it?

Officials suspect the incidents are attacks from a foreign power and are investigating.

The McClatchy Washington bureau reports that three consecutive administrations have suspected the same culprit: Russia.

U.S. response to Havana syndrome?

In June, President Joe Biden directed the creation of two panels to study Havana syndrome. One of the panels will focus on identifying the cause while the other will focus on identifying ways to protect U.S. personnel.

The U.S. Senate this year also unanimously passed the HAVANA Act, a bill that would provide additional compensation to victims seeking medical treatment for the health incidents. The bill recently passed in the U.S. House of Representatives and is now headed to Biden’s desk.

The CIA also created a task force last year to investigate the mysterious attacks that occurred in Havana. A yearlong FBI investigation failed to find a cause. Another investigation by the Centers for Disease Control and Prevention failed to identify a cause for the injuries.

The U.S. Embassy in Havana has been operating with a reduced staff since late 2017 because of concerns over the syndrome.

The Biden administration has recently started taking steps to increase staffing at the embassy again. One of its recent changes: Diplomats in its Havana Embassy will be allowed to have some adult family members accompany them.

Distributed by Tribune Content Agency, LLC.