The quest for an Ebola vaccine
Authorities in West Africa are struggling to deal with the Ebola outbreak which has already claimed thousands of lives in Sierra Leone, Liberia and Guinea.
Meanwhile, in labs around the world the race is on to try and develop a vaccine against the disease.
In San Diego scientists are using the blood of people who have survived the disease to try and understand more about Ebola.
Alastair Leithead reports from Texas.