The Ebola virus is a deadly virus in the filovirus family. The filovirus family consists of Ebola Zaire, the most dangerous of the Ebola viruses, Ebola Sudan, Ebola Reston, and Marburg. The Ebola Zaire virus has a 90% kill rate but has not yet been proven to be airborne. Ebola Zaire broke out in 1976 and killed around 500 people according to most sources. Ebola Sudan is less brutal but still kills almost 70% of all it's victims over 50% more then yellow fever which is considered to be very deadly. Ebola Reston doesn't aplly to humans- only monkeys. It originally broke out in a monkey warehouse type (like the animal place in Outbreak) in Reston Virgina- hence the Ebola Reston. Marburg is the least powerful in the filorvirus family killing a mere 50% of it's victims. It first broke out in 50 in Marburg, Germany. Ebola Reston is the only strain of Ebola that has been proven to transmit through the air and it's been the only Ebola not fatal to humans being a virus that strictly attacks monkeys. All the other known strains of Ebola are transmitted by direct contact. The first outbreak of Ebola was in 1976 in Zaire, Africa. The next was in Sudan Africa in 1979. Then Ebola remained dormant for almost 20 years, but then in 1995 it showed its ugly face again- this time in Kikwit, Africa. (This outbreak killed around 200 people.).
There is no known vaccine for Ebola yet but there's testing for a vaccine that has worked on mice infected with Ebola. They are currently testing Humans with the same vaccine. (Once someone catches Ebola they supposedly can't catch it again.) Because there is not yet a human vaccine or cure for Ebola it is a level four virus. (Meaning that it must be worked on in an air tight room and anyone working on it must be in a space suit, similar to the suits in Outbreak.) .
The reason that there has been no cure or human vaccine found for Ebola mainly is because it's similar to the flu and AIDS -every time it breaks out there's a mutation again so even with a vaccine it might only work for one outbreak.