Ebola-affected countries should immediately begin exit screening all passengers leaving international airports, sea ports and major ground crossings, the U.N. health agency urged on Monday.
The risk of the Ebola virus being transmitted during air travel is low because unlike infections such as influenza or tuberculosis, it is not spread by breathing air and airborne particles from an infected person.
Nonetheless, the World Health Organization said anyone with an illness consistent with the virus should not be allowed to travel normally and all passengers should routinely wash their hands and avoid direct contact with body fluids of infected people.
"Transmission requires direct contact with blood, secretions, organs or other body fluids of infected living or dead persons or animals, all unlikely exposures for the average traveler," the agency said in a statement. "There should be no international travel of Ebola contacts or cases, unless the travel is part of an appropriate medical evacuation."
The only way to contain the disease, for which there is no licensed treatment, is by isolating the sick and closely watching for signs of infection in those they have come into contact with. A person usually has no symptoms for two to 21 days, but after the incubation period the symptoms include fever, weakness, muscle pain, headache and sore throat, according to WHO. Then comes vomiting, diarrhea, rash, and in some cases, bleeding.
All countries, even those unaffected by the Ebola outbreak in West Africa, need to strengthen their ability to detect and immediately contain new cases without doing anything that unnecessarily interferes with international travel or trade, the agency said. But countries don't need to impose travel restrictions and active screening of passengers if they do not share borders with Ebola-affected countries, it said.
The Geneva-based agency has been criticized by non-U.N. health organizations as being slow to call for an emergency response to the Ebola crisis.
Some countries already have banned direct flights to countries hit by the disease. Most airlines flying in and out of the Liberian capital of Monrovia have suspended their flights. The Ivory Coast, which shares borders with Liberia and Guinea, has banned direct flights from those countries.
A task force to monitor the impact of the Ebola virus on travel and transport has been launched by the U.N. health agency along with the International Civil Aviation Organization, the World Tourism Organization, the Airports Council International, the International Air Transport Association and the World Travel and Tourism Council.
Most of the infections in Liberia, Guinea and Sierra Leone have occurred when family members or friends act as caregivers for those who are ill or during burials that don't follow strict infection prevention and control measures, according to WHO officials.