Alaska has no suspected or confirmed cases of swine flu.

But with the ease that this particular strain can spread from human to human, Dr. Jay Butler, Alaska's chief medical officer, said he would be surprised if Alaska ended up with no cases.

Butler said the last time the United States dealt with the fear of a swine flu pandemic was in 1976, when there was an outbreak at Fort Dix, N.J. That virus did not spread so easily, he said. "This is moving much more quickly."

So far, the disease in the United States seems less severe than the outbreak in Mexico. There have been no reported deaths in the United States.

Butler said Alaska is stocking up on anti-virals that will work against swine flu just in case a pandemic emerges. "We don't really know if this will be bad or not, but we certainly would like to stay ahead of it."

Alaska has enough Tamiflu and Relenza to treat about 80,000 people for swine flu, and the state is dipping into the national stockpile to cover another 20,000, which it expects within the next week.

The medicines can be used as prophylactics, said Greg Wilkinson, spokesman for the state Department of Health and Social Services. The state is working with local governments to dispense the prescription-only drugs.

State health officials are also asking Alaska health care facilities to be on the lookout for swine flu. If someone shows up seeking medical treatment for what they suspect is influenza, the state is asking that specimens be collected and sent to the state lab for testing, Butler said.

"We do have specimens coming to the state lab already," he said.

State officials are working with the Department of Education in hopes of getting the jump on any cases in Alaska. In the Lower 48, there was a cluster of cases that occurred in a school group that had recently returned from Mexico, Butler said.

State and federal officials are urging against most travel to Mexico.

Because of the swine flu outbreak, passengers on Alaska Airlines and Horizon Air are being allowed to reschedule their flights to Mexico without penalties, the airlines said.

Travelers heading to or coming from Mexico through May 20 can change their flights, Alaska Airlines said. No change fees or additional airfare will be collected.

Travelers who want to keep their travel date but change their destination will not be charged a change fee but will be charged or credited any difference in airfare.

Alaska Airlines spokeswoman Bobbie Egan said she didn't know how many customers were altering their Mexico plans but that the Alaska Airlines call centers by early afternoon Monday had already received double their normal call volume. The airline and its sister airline, Horizon, run 17 flights a day to Mexico, Egan said.

The airline, like many carriers, is scrubbing down its airplanes, handing out masks to employees in Mexico, and instructing crews to look for flulike symptoms, Egan said.

Shirley Biss, a receptionist at USTravel in Anchorage, said so far no one has called to ask if they shouldn't travel to Mexico. But, she said, that could change.

On the other hand, Biss said no matter what the news out of Mexico, whether it be swine flu or drug cartel violence, some people won't be dissuaded.

"There are some people that will go regardless of what they read in the newspapers," she said.

Cruise-ship companies are also watching for signs of the flu on the eve of their Alaska season. Princess Cruises, a major Alaska-tour company, is reconsidering its Mexican itineraries, according to the company Web site. It will also isolate and treat any passengers or crew with suspected swine flu. All ships have on board the anti-viral medications, it said.