Scientists at the French Institut Pasteur have warned that the Ebola virus is mutating. They are now analyzing Guinean Ebola patients' blood samples to determine whether the virus may have become more contagious.

The researchers emphasized that Ebola could eventually morph into an airborne disease, though there is no evidence that this has happened so far. The Institut Pasteur is developing two vaccines that may reach human trials by the end of 2015.

The Ebola outbreak has killed about 8,795 people so far and has infected more than 22,000 people, with Liberia, Guinea, and Sierra Leone hit the hardest.