A UK military healthcare worker who was infected with Ebola in Sierra Leone has been flown home and is being treated at the Royal Free Hospital in London.
Four other healthcare workers who had been in contact with the infected person are also being assessed. Two were flown home on the same flight as the infected worker and are now being monitored at the Royal Free. The others are to be assessed at the Royal Victoria Infirmary in Newcastle-upon-Tyne. None of the four has been diagnosed with Ebola.
The latest case follows that of Glasgow nurse Pauline Cafferkey, who was found to have Ebola after arriving in Glasgow from Sierra Leone in December 2014. She recovered after specialist care at the Royal Free Hospital and was discharged.
Ms Cafferkey remains the only case confirmed in the UK, and the risk to the general public is very low. Ebola can be transmitted only by direct contact with the blood or bodily fluids of an infected person.
The UK has well-established and practised infection control procedures for dealing with cases of imported infectious disease, and these will be strictly followed to minimise the risk of transmission.
Professor Dame Sally Davies, Chief Medical Officer, said: "The UK has robust, well-developed and well-tested systems for managing Ebola virus disease. All appropriate infection control procedures have, and will continue to be, strictly followed to minimise any risk of transmission. UK hospitals have a proven record of dealing with imported infectious diseases."
More than 24,200 cases of Ebola have been confirmed in West Africa, with over 9,900 deaths – a mortality rate of around 40%.
Outbreaks of Ebola are nothing new, but health professionals are concerned about the size of the current outbreak.
Ebola is a virus that can be spread through blood and bodily fluids. The virus originated in the West African rainforest and is thought to have spread to humans by handling or butchering infected animals.
Once the virus enters the body it can replicate very quickly, causing a range of increasingly harmful symptoms, including internal bleeding. Left untreated, it can have a mortality rate as high as 90%.
An infected person will typically develop a fever, headache, joint and muscle pain, sore throat, and intense muscle weakness. These symptoms start suddenly 2 to 21 days after becoming infected.
Diarrhoea, vomiting, a rash, stomach pain, and impaired kidney and liver function follow. The infected person may then bleed internally, as well as from the ears, eyes and mouth.
People can become infected with the Ebola virus if they come into contact with the blood, body secretions or organs of an infected person.
Some traditional African burial rituals may have played a part in its spread. The Ebola virus can survive for several days outside the body, including on the skin of an infected person.
In parts of Africa, it is common for mourners to touch the skin of the deceased. A person then only needs to touch their mouth to become infected.
Other ways people can catch the virus include:
A person is infectious as long as their blood and secretions contain the virus.
Ebola virus is generally not spread through routine social contact, such as shaking hands with patients without symptoms.
The virus is not airborne, so it's not as infectious as diseases such as the flu – you'd need to get close to it to catch it.
Anyone who has close contact with an infected person or handles samples from patients is at risk of becoming infected. Hospital workers, laboratory workers and family members are at greatest risk.
It's difficult to know if a patient is infected with Ebola virus in the early stages. The early symptoms of Ebola, such as fever, headache and muscle pain, are similar to those of many other diseases.
But health workers are on standby to act quickly. If anyone in the UK develops the above symptoms and has potentially been in close contact with the virus, they will be admitted to hospital and will most likely be quarantined.
Samples of blood or body fluid can be sent to a laboratory to be tested for the presence of Ebola virus, and a diagnosis can be made rapidly. If the result is negative, doctors will test for other diseases, such as malaria, typhoid fever and cholera.
There's currently no specific treatment or cure for the Ebola virus, although potential new vaccines and drug therapies are being developed and tested.
Patients need to be treated in isolation in intensive care. Dehydration is common, so fluids may be given intravenously (directly into a vein).
Blood oxygen levels and blood pressure will be maintained at the correct level, and the body organs supported while the patient recovers.
The risk to the UK is thought to be very low, and, while someone with the virus can bring it to the UK, the risk of it spreading is very low.
Ebola virus is not airborne, so there is no credible risk of a swine flu-like global pandemic.
You cannot catch Ebola by travelling on a plane with someone who is infected, unless you come into very close physical contact with them – for example, by kissing them.
Public Health England (PHE), the body responsible for public health in England, has told health professionals about the situation in West Africa and asked for vigilance about unexplained illness in people who have visited the affected area.
PHE has provided advice for humanitarian workers planning to work in affected areas. It is also working with people from Sierra Leone living in England.
Advice has been issued to immigration removal centres on carrying out health assessments for people who may have been in Ebola outbreak areas within the preceding 21 days.
Dr Brian McCloskey, PHE's director of global health, said: "The risk to UK travellers and people working in these countries of contracting Ebola is very low.
"People who have returned from affected areas, who have a sudden onset of symptoms such as fever, headache, sore throat and general malaise [sense of feeling unwell] within three weeks of their return should immediately seek medical assistance."
Edited by NHS Choices