Washington (AFP) - People entering the United States from the Ebola-hit nations of Liberia, Guinea and Sierra Leone will undergo "active monitoring" for signs of the deadly virus for 21 days, health authorities said Wednesday.
"We have to keep up our guard against Ebola," said the US Centers for Disease Control and Prevention director Tom Frieden.
The "new program of active monitoring of every person coming back to the country" applies to those whose travel originated in the three West African nations facing the world's largest Ebola epidemic, he told reporters.
Travelers concerned -- most of whom are US citizens or longtime US legal residents -- will be asked to carry out daily self-checks for fever and provide contact details of friends or family in case follow-up is needed, he said.
The system aims to "further protect Americans against Ebola" by monitoring travelers for the entirety of the virus's 21-day incubation period, Frieden said.
The program will be rolled out from Monday, beginning in six states -- New York, Pennsylvania, Maryland, Virginia, New Jersey and Georgia -- where 70 percent of incoming travelers are located.
In the coming days, the program is to be extended to all 50 states, and local and state health departments will be closely involved in setting it up, Frieden said.
The new CDC measures came a day after the US Department of Homeland Security announced that all travelers from the affected region would have to fly into one of five airports that have additional screening measures in place.
Passengers whose journeys begin in Guinea, Liberia or Sierra Leone were ordered to fly to New York's JFK or Newark airports, Washington Dulles, Atlanta or Chicago -- airports entered by 94 percent of travelers from the region.
- Care kit -
Since Ebola typically begins with a fever and progresses to vomiting and diarrhea, temperatures are recommended to be taken twice per day and reported once per day.
People traveling into the United States from the affected West African countries will also receive a "care kit" that includes a tracking log, instructions for monitoring temperature, and pictorial description of symptoms, Frieden said.
It includes a phone number to call if symptoms develop and information on what to say over the phone.
"If you become sick, get care quickly because that could save your life and protect your family," said Frieden.
About 150 people per day enter the United States after traveling from West Africa, according to CDC and border officials.
The new CDC system was similar to the process undertaken in Nigeria, where some 20 people were infected with Ebola and eight died after a Ebola-stricken airline traveler flew from Liberia to Lagos in late July.
Nigeria was declared Ebola-free on Monday by the World Health Organization, after 42 days passed without any new cases of the hemorrhagic fever among its 170 million citizens.
However, Ebola is still spreading in Sierra Leone, Guinea and Liberia, where more than 4,800 people have been killed by the virus since the beginning of the year.
Frieden said the program of active monitoring would last until the outbreak is controlled in the affected countries.
"Until the outbreak is over, we anticipate this continuing," said Frieden.
The first case of the virus diagnosed in the United States was anounced in late September after a Liberian man who was infected with Ebola flew to Dallas, Texas.
Thomas Eric Duncan died of Ebola on October 8. Two US nurses were infected with the virus while caring for him in the intensive care unit at Texas Health Presbyterian Hospital.