Geneva: Ebola-affected countries should immediately begin exit screening all passengers leaving international airports, sea ports and major ground crossings, the UN health agency has said.

The agency didn’t spell out which countries should start screening passengers, but noted in the recommendation made on Monday that the Ebola outbreak involves transmission in Guinea, Liberia and Sierra Leone and a “small number of people in Nigeria.”

All countries, even those unaffected by the 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.

Authorities in Liberia, Sierra Leone and Guinea say they are already closely inspecting departing passengers for signs of fever or illness.

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 Organisation (WHO) 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 traveller,” the agency said in a statement.

The outbreak has caused 1,229 deaths and affected 2,240 people so far this year, according to new figures released by the WHO on Tuesday.

The UN health organisation said that between last Thursday and Saturday there were 84 more deaths and 113 new infections in the four countries affected by the epidemic.

The outbreak began in Guinea in the first quarter of 2014 and rapidly spread to neighbouring countries like Liberia, where the escape two days ago of patients with Ebola from a Monrovia quarantine centre, which was attacked, has raised new fears of contagion.

Health officials in Liberia have expressed concern about the rapid pace of the epidemic in the three days running between last Thursday and Saturday, in which 53 more deaths and 48 new cases were reported.

Liberia is already the worst-hit country with 466 deaths and 834 infections, while in Guinea there have been 394 deaths and 543 cases.

In Sierra Leone, the cases jumped to 848 with 365 deaths, while Nigeria, where the virus seems to have been contained, has registered 15 cases and four deaths.