The World Health Organization's (WHO) Emergency Committee announced Thursday that enhanced Ebola screening procedures may only have a "limited effect" on the virus' spread.

The committee's statement comes two days after Homeland Security mandated that anyone traveling from Liberia, Sierra Leone, or Guinea to the United States must fly into one of five airports: JFK International in New York, Newark Liberty International in New Jersey, Washington Dulles International in Virginia, O'Hare International in Chicago, or Hartsfield-Jackson International in Atlanta.

Travelers from the targeted African countries will have their temperature checked upon their arrival, and must report their temperature to the CDC daily throughout the virus' three-week incubation period. These temperature checks were already in place at the five selected airports, which account for 94 per cent of arrivals from the affected countries.

Fever is one of the first symptoms of Ebola infection, but it can take over a week before symptoms develop.

WHO Health and Security Assistant Director-General Dr. Keiji Fukuda was skeptical about the effectiveness of entry screenings on disease containment.

"You need a lot of resources to do it well," Dr. Fukada said. "If you find people who have fever, how are you going to handle them? How are you going to treat them?"

"Entry screening may have a limited effect in reducing international spread when added to exit screening, and its advantages and disadvantages should be carefully considered," the Emergency Committee said in a statement.

Exit screenings in Africa have deferred 100 persons from leaving the continent, WHO Health and Security Global Capacities Alert and Response Director Isabelle Nuttall told Reuters this week.

While some senators pushed for a travel ban from the affected African countries, the Committee cautioned against such measures.

"A general travel ban is likely to cause economic hardship, and could consequently increase the uncontrolled migration of people from affected countries, raising the risk of international spread of Ebola," the WHO committee said.

The organization reported Wednesday that at least 9,936 people have been infected and at least 4,877 people have died from Ebola this year.