U.S. officials cite numerous incidents of mysterious ailments afflicting some diplomatic and intelligence personnel

im 372713?width=860&height=573

The Havana Syndrome was first reported in diplomats stationed in Cuba in 2016.

Photo: fernando medina/Reuters

Roughly 200 U.S. diplomats, intelligence officers, military officers and other government personnel, mostly based abroad, have experienced a strange and often debilitating set of symptoms, prompting a series of government and scientific investigations into what some officials have called anomalous health incidents and others refer to as attacks.

Here is a primer on what is and isn’t known.

Resume Subscription

We are delighted that you’d like to resume your subscription.

You will be charged $ + tax (if applicable) for The Wall Street Journal. You may change your billing preferences at any time in the Customer Center or call Customer Service. You will be notified in advance of any changes in rate or terms. You may cancel your subscription at anytime by calling Customer Service.

Please click confirm to resume now.