[INTERACTIVE MAP: Map and timeline of swine flu cases]
Carnival said on its Web site it has canceled all calls at Mexican ports through May 4, and in many cases will be able to substitute the canceled stop with an alternative port.
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 was 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.
Norwegian is canceling Norwegian Pearl's final two calls in Mexico this week after saying earlier in the day that it was monitoring the situation and asking passengers about their health before cruises start but keeping the trips.
Norwegian's schedules do not include any other ports in Mexico until the end of September 2009, the company said.
Evan Hanna, of Stafford, Va., was already at sea and headed to Grand Cayman and Cozumel when he and other passengers got word their Carnival ship would skip Mexico.
"There was a lot of yelling at the ship's officials," Hanna wrote in an e-mail from the oceanliner. "Most passengers still wanted to go to Cozumel, and there were a lot that wanted to go back to the home port early."
By Tuesday afternoon, most had gotten over it, Hanna said.
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.
Princess Cruises canceled calls in Puerto Vallarta and Cabo San Lucas on Tuesday and diverted its Sapphire ship from Mexican ports to San Diego and Catalina.
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.
However, Debbie Rauch, owner of Great Escapes Cruises and More in Lighthouse Point, Fla., said most of her clients aren't worried. One woman booked a trip Monday that will take her to Mexico in two months.
"She really didn't seem that concerned at this point," Rauch said. "If it's going to become a pandemic and it's going to be everywhere, it probably doesn't matter where you go."
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 66 Tuesday, and federal officials warned that deaths were likely.
Slideshow archive | ABC13 wireless | Help solve crimes