Ebola has a 50% chance of reaching the UK within three weeks, new research has suggested, because of London's status as a major international transport hub.
According to the report published by Boston's Northeastern University, Britain is the sixth most likely country to have an Ebola outbreak resulting from a sick passenger on a flight to the country. It is the second most 'at-risk' country in Europe, with France being given a 75% chance of an outbreak, and the second most 'at-risk' country in the world.
Heathrow is one of the world's busiest airports, receiving more international passengers than any other.
The study has rated how likely the virus is to spread further
Projections for the number of cases in the infected areas of west Africa
"I would say it is a reasonable estimation," Professor Ian Jones, a virologist at the University of Reading, told HuffPost UK. "As a colonising power, we still maintain major links to these countries."
The scientists' prediction rely on air traffic from the region remaining at normal levels, but the study notes that with an 80% reduction in flights the risk then drops to around 15%.
British Airways and Emirates have suspended some flights to the worst hit countries, including to Liberia, Guinea and Sierra Leone.
“Air traffic is the driver,” Professor Alex Vespignani, who led the research, told Reuters. “But there are also differences in connections with the affected countries, as well as different numbers of cases in these three countries - so depending on that, the probability numbers change.”
“This is not a deterministic list, it’s about probabilities - but those probabilities are growing for everyone. It’s just a matter of who gets lucky and who gets unlucky.”
A Doctors Without Borders, health worker in protective clothing holds a child suspected of having Ebola in the MSF treatment center in Paynesville, Liberia
US health officials have cast doubt on the effectiveness of a travel ban from Ebola-infected countries, warning that shutting down borders could impede efforts by aid workers.
The first case in the US was diagnosed in Texas last week, Thomas Eric Duncan, a passenger travelling from Liberia to Dallas. Dr Tom Frieden, director of the federal Centers for Disease Control and Prevention, said Duncan's health had "taken a turn for the worse," but he declined to elaborate any further.
Duncan is hospitalised in isolation, and health officials are monitoring a few dozen people who may have been exposed to the virus. Before he was admitted to the hospital, Duncan stayed with Louise Troh, her 13-year-old son and two nephews in their northeast Dallas apartment. The family has been kept in isolation in an undisclosed location but no one in the family has developed Ebola symptoms.
Airline passengers have their temperatures taken as they board planes in the outbreak zone, although those infected with Ebola can go up to 21 days before they exhibit symptoms.
Passengers are also asked about contact with infected people, but that process would not be useful if a passenger lies or simply does not realise the medical condition of people they have encountered.
Republican politicians in the US have asked President Barack Obama to halt any incoming air traffic from countries hit by Ebola. Louisiana Governor Bobby Jindal, an outsider candidate for the 2016 Presidential nomination, said that the US should "stop accepting flights from countries that are Ebola stricken."
"Even countries in Africa have cut back on or stopped accepting flights from countries with Ebola outbreaks." he said.
Texas Sentator Ted Cruz has also called for monitoring to be stepped up to "prevent additional cases from arriving in the United States. The Obama administration has refused, saying there was nothing to be gained from a travel ban.
"What happened in Dallas was extremely unlikely, and stopping flights from those countries wouldn't necessarily stop it happening again," Professor Jones told HuffPost. "If you were to stop 80% of flights from the countries, the infected person might be on the minority of flights that come through. There's also nothing to stop someone taking a circuitous route, coming from somewhere like Amsterdam.
"The risk of catching Ebola even if you are sat next to someone on a flight who is infected is practically zero, unless they were in the final fatal stages of the virus when they would pretty unlikely to make it onto a plane. It's not an airborne virus, even if someone was sneezing it can't be passed on.
He also dismissed the usefulness of testing people at airports for the disease. "Screening people at airports, for example taking temperatures using body scanners, would be a massive cost and the money would be far better spent elsewhere, improving the infrastructure in the countries where it is spreading. That is far more likely to stop the disease than the huge spend required to screen people here."
Only one British person has ever been diagnosed with Ebola, volunteer nurse William Pooley who contracted the virus while in Sierra Leona. He was transported back to the Royal Free Hospital in London where he recovered from the disease. He has since been taken to Atlanta for a blood transfusion which medics hope could save the life of the doctor who contracted the virus while working in west Africa.
As one of the minority of people who survive the disease, Pooley's blood will contain antibodies which could be passed on through transfusion.
Experts have previously asserted that were an infectious passenger to land in the UK or another Western nation, the disease would be unlikely to spread in a similar manner because of sophisticated isolation techniques, and the fact that Ebola is only spread through bodily fluids - like sweat, blood, vomit, feces or semen - and is not airborne.
A victim does, however, remain infectious after death, and local burial customs which involve the manual washing of a dead body have in some part been blamed for the spread of the disease. Victims in west Africa are also most likely to stay in their communities and seek only local treatment, inadvertently passing on the disease to family members and neighbours who care for them without the proper protection.