Stepping up their vigilance against Ebola, federal authorities said Wednesday that everyone traveling into the U.S. from Ebola-stricken nations will be monitored for symptoms for 21 days. That includes returning American aid workers, federal health employees and journalists, as well as West African travelers.

The program will start Monday in six states that represent 70 percent of people arriving from Liberia, Sierra Leone and New Guinea, said the Centers for Disease Control and Prevention.

CDC Director Tom Frieden said monitoring would extend to other states in coming days and reach “every person coming back to the country for the 21 days they are at risk for Ebola,” and would continue until the outbreak in West Africa is controlled.

“We have to keep our guard up,” Frieden told reporters on a conference call.

Local and state officials will perform the daily health checks, which may consist of keeping up with people daily by phone or visits. The first states are New York, Pennsylvania, Maryland, Virginia, New Jersey and Georgia.

Individuals arriving from West Africa will receive “care kits” that include thermometers, detailed information on how take their temperature twice a day, and logs for recording the information. Temperatures must be reported to health officials at least once per day, he said.

Frieden said the message to travelers is: “If you become sick, get care quickly because that could save your life and protect your family.”

The kits also will include information on whom to call if symptoms occur and a card the traveler can present to health care providers if they need medical attention.

(AP)