Ebola virus.

Ebola virus. Image by NIAID / CC BY 2.0

Airport screening for diseases such as Ebola is ineffective and misses at least half of infected travellers, scientists have said.

Passengers worried about being delayed and therefore not being honest about their risk of exposure was found to be one of the biggest obstacles.

Researchers analysed screening for six viruses: SARS, Ebola, Middle East respiratory syndrome coronavirus (MERS-CoV), Marburg virus, Influenza H1N1 (swine flu), and Influenza H7N9 (avian flu) and highlighted what needs to be done to improve it further.

They suggest resources would be better spent on arrival screening, which would reduce but not eliminate cases.

They said questionnaires are the most effective detection method when diseases are in their early stages and not exhibiting any symptoms.

But they found that, at best, just 25% of people honestly reported on exposure to flu during the 2009 swine flu pandemic, and some might even have hidden symptoms by taking medication. They said this is the first time available information has been used to arrive at an estimated figure.

Fever testing of passengers with diseases with long incubation periods such as Ebola and Marburg is particularly ineffective, they warned, but works better for diseases such as swine flu that take a shorter time to incubate.

Symptoms of some diseases will progress during transit so can be easier to detect on arrival, they pointed out.

The research carried out at the University of California, Los Angeles (UCLA), and the London School of Hygiene and Tropical Medicine will be published in the journal eLife.

Katelyn Gostic from the Lloyd-Smith Lab at UCLA said: “Honest reporting can not only improve on-site detection but is essential to enable authorities to follow up with travellers who may have been exposed but have not yet developed symptoms.

“We need to find ways to incentivise better self-reporting.”

(Press Association)