Although it’s hard to say that there will never be a cure for Ebola, it’s important to realize that no viral infection has ever really been cured. With bacteria, we can kill them directly with antibiotics, but this doesn’t work for viruses. Our way of dealing with deadly viruses is through vaccination. Vaccination prevent an infection, but does nothing for someone that is already affected. A vaccine “trains” your body to recognize the virus so as soon as the virus enters your body, your immune system can deal with it immediately. A way to think of a vaccine is that it’s sort of like a fire drill for your immune system. Your body deals with the dead virus like it would an alive one so that when the real thing comes, it knows what to do. Once the virus has already spread through your body, training the immune system doesn’t really help because it’s too late. People have been working on vaccines for Ebola and there seems to be a good chance that they’ll be effective. So basically, we don’t talk about curing a virus like Ebola, we talk about preventing it through vaccination. We don’t have any way of selectively killing the virus so we prep the immune system to do the job.

Ebola is caused by a virus, and viral diseases are very, very difficult to cure (it's why there isn't any cure for AIDS or, for that matter, the flu). Viruses also evolve very quickly, so a cure wouldn't be successful for long.