The syndrome appeared in the staff of the U.S. Embassy in Colombia, all before the visit of Secretary of State Antony Blinken to the capital Bogota.
The official added that he suspected that the problem appeared in several other people, the "Wall Street Journal" reported. An American family left the country for treatment because of that.
Growing number of migrants wants to enter the EU along that route.
After a few months ago, in response to Brussels' sanctions, Belarusian President Lukashenko allowed migrants from the Middle East, mainly from Syria and Iraq, to enter the country unhindered, the situation on the Polish border is becoming a new crisis hotspot.
A welcoming ceremony was held on Oct. 8 by the Turkish Trade Ministry in Istanbul after the Islamabad-Tehran-Istanbul Road Transport Corridor Project successfully carried commercial cargo on Pakistani trucks to Turkey.
The trucks departed Sept. 27 from Karachi and reached the Turkish metropolitan city of Istanbul on Thursday, covering 5,300 kilometers (3,293 miles).