It's voluntary(01 of09)
Open Image ModalNo passengers are required to be screened for symptoms.
Sorious Samura, a journalist who travelled via Brussels from Liberia, told The Guardian that he was surprised the tests were voluntary.
“I could have just come throughout without any screening. That is how scary it is,” he said. (credit:ASSOCIATED PRESS taken in Morocco)
Infected people may not be showing symptoms(02 of09)
Open Image ModalThere is an incubation period of between 2 and 21 days before symptoms start to show, according to the World Health Organisation, so the virus is undetectable with temperature screening at that stage. (credit:Jonathan Brady/PA Wire)
The virus could look like flu(03 of09)
Open Image ModalSymptoms in the late stages of Ebola include bleeding from your eyes, but early symptoms like fever and sneezing could easily be mistaken for flu or another regular illness.
Blood tests that identify the disease more precisely take hours so can't be done at an airport.
Dr Ben Neuman, a virologist at the University of Reading, told The Telegraph: “It would not surprise me if airport screening measures mainly caught unfortunate passengers with seasonal ailments who were unlucky enough to have recently been to Africa.” (credit:ASSOCIATED PRESS)
Hand-shaking(04 of09)
Open Image ModalImmigration officers have reportedly been shaking hands with passengers they screened at Heathrow.
Hand-to-hand contact is unlikely to cause Ebola to spread - US President Obama shook hands with nurses treating an Ebola patient in Atlanta.
The virus only travels through direct contact with an infected person's bodily fluid, but this does include sweat, and many observers felt that skin-to-skin contact between staff and passengers seemed unnecessary. (credit:Abdeljalil Bounhar/AP)
Airports didn’t even know it was coming(05 of09)
Open Image ModalGatwick Airport said it was in the dark over enhanced Ebola tests just three days before they were due to start.
A spokesman for the airport said it was still waiting for Public Health England to let it know the plans on the Friday before the screenings started on a Monday. (credit:Jonathan Brady/PA Wire)
Border agency workers aren't doctors(06 of09)
Open Image ModalAs the lack of up-to-date information at Gatwick shows, airport staff who do have to help assess people for Ebola were trained last minute. Many have been described - understandably - as being inexperienced at diagnosing the complex disease. (credit:LUKE MACGREGOR via Getty Images)
It would be quite possible to hide having Ebola(07 of09)
Open Image ModalCertainly in the early stages.
Those who fear they may have the virus, or are sick with a common illness like flu, can take ibuprofen to lower their temperature and wouldn't be detected by the scanners. (credit:CELLOU BINANI via Getty Images in Guinea)
You can't trust people to be honest(08 of09)
Open Image ModalExperts have said you can't rely on travellers to tell the truth about who they have had contact with - or to know if those people have Ebola.
Extra screenings would not have spotted any risk for Thomas Duncan, the Ebola victim who died in Texas. He told officials he had not been in contact with anyone with Ebola, but had actually visited someone who was dying of it - though he said he believed they had malaria. (credit:Jonathan Brady/PA Wire)
It's not that simple to work out who's been where(09 of09)
Open Image ModalThere are no direct flights to the UK from Liberia, Sierra Leone or Guinea, so means people travelling from those countries have to catch a connecting flight.
They could arrive at airports other than Heathrow and Gatwick, which are the only ones carrying out screening, or could have arrived on various routes through Europe.
Screening every passenger - an expensive and time-consuming task - would be the only way to ensure anyone who had recently been to a high-risk country would be checked. (credit:Boris Grdanoski/AP)