The World Health Organization has warned that "drastic action" is needed to halt the killer in its tracks.
It reports there have been 759 cases, including 467 deaths, in Guinea, Sierra Leone and Liberia as of June 30. The outbreak began in March.
This makes it the "largest in terms of the number of cases and deaths as well as geographical spread," said WHO.
Not only is it uncontained, but this strain of the Ebola virus can kill up to 90% of those infected.