Carnival Cruise Lines and Royal Caribbean Cruises have suspended stops at Mexican ports over concerns about swine flu.
Carnival canceled Mexico port calls for three ships scheduled to visit the country Tuesday. It hasn't yet announced a decision on future stops there.
Royal Caribbean had said it was monitoring the situation but telling passengers not to worry because the outbreaks are inland, not in the Mexican coastal cities popular with cruise tourists. But later Tuesday the company said it is suspending port calls indefinitely in Mexico until more is known about the swine flu outbreak.
The move affects its Royal Caribbean International and Celebrity Cruises ships.
Meanwhile, the companies and competitor Norwegian Cruise Lines tried to allay guest fears by emphasizing how thoroughly the ships are cleaned.
Norwegian's Pearl is on a special voyage with Mexico stops. The company says it is monitoring the situation and asking passengers about their health before cruises start.
Royal Caribbean has four ships that regularly stop in Mexico and two more that were scheduled to begin port calls there. Celebrity Cruises has one ship that was scheduled to make stops in Mexico. The company says the ships will stop in other ports or spend extra time at sea.
Royal Caribbean's chief medical officer, Dr. Art Diskin, said authorities had not raised specific concerns about the ports the ships visit in Mexico, but the company was taking a cautious approach to the situation.
The company is screening embarking guests and crew members about recent visits to Mexico or contact with ill people, increasing sanitization measures on ships and giving passengers swine flu information from the Centers for Disease Control and Prevention.
The company said medical staff have the ability to isolate guests or crew members who develop flu-like symptoms.
On Monday, the World Health Organization increased its alert level from 3 to 4 — out of 6. Its influenza chief, Keiji Fukuda, warned that "at this time containment is not a feasible option," rejecting calls for a travel ban or other restrictions on Mexico or the United States.
But travelers are canceling or delaying trips to Mexico, and on Tuesday Cuba became the first nation to ban all flights to its neighbor.
By Tuesday swine flu was said to have been a factor in more than 150 deaths and over 1,600 illnesses in Mexico. The number of confirmed cases in the United States climbed to 68, and federal officials warned that deaths were likely.