More than $1bn (£618m) will be needed to fight the West African Ebola outbreak. According to The UN's Ebola co-ordinator, Davis Nabarro.He made the announcement,as the World Health Organization (WHO) described the outbreak as "Unparalleled in modern times".There have been 394 cases within the last 5 days,and will require an exceptional response." the U.N. says.

The World Health Organization issued an update on 16th September.Here are a few of their findings.

Number of cases as of September 13th 2014. 4,985

Number of deaths as of September 13th 2014.

2, 461

Number of new cases as of September 7th -12th. 394

The disease is spreading more rapidly in Liberia,driven by a surge of cases in the capital Monrovia.Say the W.H.O.At present the need for doctors and nurses to staff a 80 bed Ebola treatment centre is 200,The number of beds available to treat Ebola patients anywhere in Liberia is zero.The humanitarian response to the disaster is running short of almost everything from body bags to mobile laboratories.

The Ebola epidemic in Nigeria show how the virus spreads.All the 21 cases,which included eight deaths.Have been found to have a transmission chain that began when a Liberian government official Patrick Sawyer,travelled to Lagos from Liberia on July 20th 2014.The family of the official were immediately isolated and moved from their West Point home.which is a congested slum,and the authority's feared that the epidemic would spread to the 75,000 inhabitants of West Point.

Ebola is a virus so serious,and for which there is no treatment or vaccines.It was first identified in Africa in the 1970's.The outbreak that began in March 2014 is the most serious to date.By August 2014 it had killed more than 1,000 people across Guinea, Liberia, Sierra Leone, and Nigeria.

It is thought that the Ebola virus had been living harmlessly in fruit bats for many years,then spreading to other forest animals,which included gorillas and chimpanzees.It is believed that the virus crossed over to humans when people butchered dead animals that were contaminated with the virus,for meat (Bush meat).

People can become infected with Ebola if they come in direct contact with body fluids,or organs of an infected person.Traditional African burial right have also been responsible for spreading the Ebola virus.It can survive for several days outside the body,including on the skin of an infected person.It is common practise in African countries for mourners to touch the body of the deceased person,they only then need to touch their mouth,to become infected themselves.The Virus is not an air born transmitted infection unlike,for example influenza.The Ebola virus is not generally spread through social contact with patients who do not have any symptoms.

An infected person will typically develop a fever,headache,joint and muscle pains,sore throat,and intense muscle weakness.The patientwill have Diarrhoea,Vomiting,a rash,and impaired kidney and liver functions,in the later stages of the infection.These symptoms can start suddenly from between 2 and 21 days after becoming infected.

The Ebola disease is fatal in 50 to 90% of cases. The sooner the patient is given care,the better their chances of their survival.There are currently no licenced treatments or vaccines for Ebola,although new drug therapies are being developed and tested. ZMapp,is being developed by Mapp Biopharmaceutical Inc.This is an experimental treatment,that has not been tested on humans.The treatment combines three different antibodies that bind to the protein of the Ebola virus.To date there are only two Ebola vaccines being fast tracked through the approval process.One designed by scientists at the U.S National Institute of Health,and licenced to GlaxoSmithKlin.Their human trials began early in September of this year.The second vaccine,thought to be more promising,is being developed by scientists at the National Microbiology Laboratory in Winnipeg, Canada.The federal government has licenced this vaccine to NewLink Genetics,who are a small biotech company in Ames,Iowa.USA.

Another doctor from Sierra Leon has been tested positive for Ebola.Doctor Olivetta Buck is the fourth doctor from the West African country to have contracted the disease.The other three have all died."She is being sent to another country for treatment",said Health Ministry spokesman Sidie Yaha Tunis.The epidemic is taking a heavy toll on the medical teams.The number of deaths among health care workers as of September 7th 2014 was 301.They are at put at risk by the very nature of their job.Exacerbating the shortage of doctors and nurses in countries that had too few medical workers to begin with.

The W.H.O said "So far the epidemic has killed 2,461 people this year, half of those 4,985 who were infected by the virus".There has been criticism of the slow international response to the outbreak.In the U.S.President Obama, has announced plans to send 3,000 troops to Liberia,one of the worst affected countries,to help fight the epidemic".The amount that the US government has so far spent on medical aid for the infected areas amounts to more than $100 million".According to Ned Price of the National Security Council.The U'S Agency for International Development announced last week that it would spend up to $75 million,to provide 1,000 treatment beds,and 130,000 protective suits for health workers in Liberia.In addition,President Obama is to ask Congress to provide an additional $88 million to send supplies and public health experts to the area,and to fast track the development of potential Ebola medication and vaccines.

The US military response is part of a heightened roll that will also include European countries.The aim of this task force is to supply and erect 17 new treatment and isolation facilities with 100 beds each, the training of 500 health care worker a week,increasing communications and transport by setting up a joint command headquarters in Monrovia.Liberia,to co-ordinate between U.S.and international relief efforts.It will also provide home health care kits to hundreds of thousands of households.This includes the 50,000 that will be sent out by The International Development Agency this week.The international aid package will also include home and community based campaigns to train local populations on how to handle exposed patients.

President Obama told public health officials,on Tuesday."Here is the truth.In West Africa, Ebola is now an epidemic,the likes of which we have not seen before.It is spiralling out of control,it's getting worse."He went on to say"If the outbreak is not stopped now,we could be looking at hundreds of thousands of people affected,with profound economic, political,and security implications for all of us".

Joanna Liu, who is the president of Doctors without Borders.Told a meeting of the United Nations in Geneva."The global response was falling short. The window of opportunity to contain this outbreak is closing".The W.H.O (The World Health Organization)warned that the number of Ebola cases in West Africa could start to double every three weeks and the epidemic could end up costing over $1 billion to contain.