Critics call the government’s response to Ebola “shambolic” as a national exercise to test Britain’s readiness for an outbreak takes place. But what danger does the killer virus pose to Britain?
Ebola virus disease, or EVD, was first identified in 1976 near the Ebola river in Congo. The World Health Organization (WHO) has recorded more than 20 outbreaks since then, all beginning in Africa.
Scientists think Ebola was first introduced to humans by people living in remote jungle areas handling infected wild animals like fruit bats, apes and monkeys.
The disease is a haemorrhagic fever, causing internal and external bleeding along with a wide range of other symptoms that progress rapidly.
Although the deadliest strain has been known to kill up to 90 per cent of infected patients, the WHO says the average fatality rate is around 50 per cent.
There is no known cure or vaccine.
According to the latest WHO figures, there have been 8,033 confirmed cases and 3,865 deaths in 40 weeks, making this by far the deadliest outbreak of Ebola in history.
Liberia is the worst-affected country, with 2,210 deaths, followed by Sierra Leone (879 fatalities) and Guinea (768 deaths).
The WHO says the situation in the three west African countries at the centre of the outbreak “continues to deteriorate, with widespread and persistent transmission of EVD”.
Nigeria has seen eight deaths but the authorities there have been praised for effectively containing the spread of the disease.
The first confirmed case outside west Africa was Spanish nurse Teresa Romero, who is currently being treated in an isolation unit at a Madrid hospital. A Liberian man, Thomas Duncan, died in Dallas, Texas, this week.
Nurse Will Pooley remains the only Briton known to have contracted Ebola. He caught the disease while treating patients in Sierra Leone.
Mr Pooley was flown back to Britain by the RAF. He was treated at an isolation unit at the Royal Free Hospital in London, given the experimental drug ZMapp, and has made a full recovery.
There were reports that a British man who died in Skopje, Macedonia, had Ebola-like symptoms, but the authorities later said they did not believe his death was caused by the virus and a man travelling with him showed no signs of illness.
So will there be an outbreak here?
Experts say it is highly likely that someone infected with ebola will arrive in the UK at some point – but they say NHS staff are well-trained at isolating and containing diseases from abroad.
David Mabey, professor of communicable diseases at the London School of Hygiene and Tropical Medicine, said: “I think it’s bound to happen. We have a lot of links with west Africa. There is lots of coming and going so I’m sure there will be a few cases.”
Jonathan Ball, professor of molecular virology at Nottingham University, said: “Whilst the risk of imported Ebola virus remains small, it’s still a very real risk.”
The Royal Free is home to the country’s only high-level isolation unit and is likely to feature heavily if Ebola arrives in Britain.
Other hospitals in Liverpool, Sheffield and Newcastle with expertise in dealing with highly infectious diseases could take cases too.
Amid some confusion, the government has now said border staff at Heathrow, Gatwick and Eurostar rail terminals will carry out screening measures on passengers arriving from Liberia, Sierra Leone and Guineau.
Airlines cancelled direct flights from those countries some weeks ago but there are fears travellers carrying Ebola could transfer to the UK.
Downing Street’s sudden announcement of screening measures at UK ports came after Public Health England said it had no plans to introduce entry screening.
The health body says it cannot give any details of the screening process, and officials at Gatwick and Eurostar said they had not been told how the measures would be carried out.
Downing Street said there would be checks on passengers’ recent travel history, people they have been in contact with, and their onward travel arrangements, as well as a possible health assessment conducted by trained medics.
Checks are already in place to stop passengers with symptoms boarding planes leaving the stricken west African countries.
Experts have questioned how useful the screening measures will be.
Professor George Griffin, chair of the government advisory committee on dangerous pathogens, told the BBC: “It is somewhat surprising after, I think, we were all led to believe that the decision was not to screen.”
He added: “Most of the scientific community feel that the instrument is very, very blunt.”
Keith Vaz, chairman of the home affairs select committee, welcomed the new checks but said: “There is a touch of the shambolic about the way this is being handled.”
There seems little reason to panic. Most experts agree the risk of cases arriving in the UK is small and the threat of transmission is manageable.
The disease is not airborne so is very unlikely to spread through coughs and sneezes.
Ebola is mainly spread when a patient’s blood or other bodily fluids come into direct contact with the broken skin or mucous membrane of another person.
The main risk of transmission is through mourners handling dead bodies of victims or health workers coming into close contact with victims without wearing protective clothing.
The WHO says the illness is only infectious when a patient develops symptoms – typically a sudden fever followed by flu-like symptoms, then vomiting, diarrhoea and other serious complications. Symptoms can show up anywhere from two to 21 days after infection.
It can be difficult to distinguish Ebola from other infection diseases like malaria and meningitis and lab tests are needed to confirm a case.
Current advice from Public Health England states: “If you feel unwell with symptoms such as fever, chills, muscle aches, headache, nausea, vomiting, diarrhoea, sore throat or rash within 21 days of coming back from Guinea, Liberia or Sierra Leone, you should stay at home and immediately, telephone 111 or 999 and explain that you have recently visited west Africa.
“These services will provide advice and arrange for you to be seen in a hospital if necessary so that the cause of your illness can be determined.
“There are other illnesses which are much more common than Ebola (such as flu, typhoid fever and malaria) that have similar symptoms in the early stages, so proper medical assessment is really important to ensure you get the right diagnosis and treatment.
“It is also really important that medical services are expecting your arrival and calling 111 or 999 will ensure that this happen.”
The official advices stresses that there is little chance of catching Ebola unless you have come into contact with the blood or bodily fluid of an infected person in the danger zone.