For the past several weeks cruise lines have been advising passengers to stay in the main tourist areas in ports of call.
The vice-principal advised passengers on the bus to remain calm and be prepared to jump out.
Light flashed on a small sign advising passengers that here they could send telegrams.
He advised passengers to sharpen their awareness of what happens around them.
Delta, the third largest United States airline, said it was advising affected passengers of the threat.
"Airlines and health authorities should continue to advise passengers on how to minimize risk," the researchers wrote.
Most airlines are advising passengers to be at the airport at least an hour before departure.
Crew members advised passengers to sit quietly in order to increase their chances of survival.
Airline agents advised passengers to add two to three hours to normal travel times to account for traffic and security delays.
He advised passengers in the 62-to-64 bracket to check the details of the fare for specific age restrictions.