A globe-spanning U.S. intelligence investigation has concluded it is "very unlikely" that a foreign adversary is responsible for the "Havana syndrome" ailment that has afflicted U.S. diplomats, spies and other personnel worldwide, according to declassified findings released on Wednesday.
The symptoms of the mysterious ailment, first reported by U.S. embassy officials in the Cuban capital of Havana in 2016, have included migraines, nausea, memory lapses and dizziness.
About 1,500 cases now have been reported by U.S. government agencies and departments, including some from this year.