BLOOMINGTON - The threat of swine flu has pushed Central Illinois counties to put their pandemic influenza plans into practice.

There were no confirmed cases in Illinois as of Monday afternoon, but it's just a matter of time, said McLean County Health Department director Bob Keller.

"It bears close watching, but there is no need to panic," said MaLinda Hillman, Livingston County Health Department director.

The number of confirmed U.S. cases rose to 42 on Monday, most of them mild and none fatal. The government said it was shipping millions of doses of flu-fighting medicine from a federal stockpile to states along the Mexican border or where the virus has been detected.

But the American reaction to swine flu, which has killed up to 149 people in Mexico and on Monday led the World Health Organization to raise its alert level, was mostly limited to steps that hospitals, schools and mask-wearing individuals took on their own.

In Central Illinois, health departments urged people to see their physicians if they have flu symptoms and encouraged hospitals and doctors' offices to have people with flu symptoms tested for swine flu.

"We have sent all the information we have to all doctors and hospitals in Logan County so they know what to look for and what to do should they come across a potential case," said Mark Hilliard, Logan County health administrator.

Meanwhile, American Red Cross assured blood donors and recipients that the health history check and physical that donors are given before they donate helps to keep the blood supply safe, spokeswoman Karen Stecher said.

"Our supply is stable now to meet hospital and patient needs," she added.

At OSF St. Joseph Medical Center, Bloomington, emergency preparedness coordinator Staci Sutton said employees were reviewing surge capacity plans in case there is an influx of patients; finalizing an alternative site plan in case there isn't room to care for all patients in the hospital; and checking into the availability of medicines and medical supplies.

Patients at OSF St. Joseph with flu symptoms were tested for swine flu.

While swine flu is a respiratory disease of pigs that may infect humans, it is not transmitted by eating pork, said Amy Tippey, director of health at the Tazewell County Health Department.

The swine flu virus is a "novel" virus to which people haven't been exposed, and it is international in scope, said Keller.

The health department is:

• Contacting physicians with reminders of how to handle potential influenza cases and the protocol for reporting them to the health department.

• Working with Western Avenue Community Center to identify people who have recently traveled to Mexico and are experiencing flu symptoms.

• Contacting officials at the Central Illinois Regional Airport to give guidance for how they should handle passengers with flu symptoms.

• Working with schools and universities on how to handle students with flu symptoms who recently traveled to affected areas.

• Preparing isolation and quarantine orders with the state's attorney's office, should such orders become necessary.

The Associated Press and reporters Kevin Barlow and Tony Sapochetti contributed to this report.