"On September 29, the U.S. Department of State ordered the departure of nonemergency personnel assigned to the U.S. Embassy in Havana, Cuba, as well as their families, in order to minimize the risk of their exposure to harm because of a series of unexplained injuries suffered by embassy personnel since November 2016. According to the State Department, 22 persons suffered from 'attacks of unknown nature,' most recently in late August 2017, at U.S. diplomatic residences and hotels where temporary duty staff were staying, with symptoms including 'ear complaints, hearing loss, dizziness, headache, fatigue, cognitive issues, and difficulty sleeping.' Since the incidents were first made public by the State Department in August 2017, numerous press reports have referred to the attacks as being caused by some type of sonic device. State Department officials maintain, however, that the U.S. investigation has not reached a definitive conclusion regarding the cause, source, or any kind of technologies that might have been used."
CRS Insight, IN10798
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html