In a development that transforms the fight against Ebola, two experimental treatments are working so well that they will now be offered to all patients in the Democratic Republic of Congo, scientists announced on Monday.

The antibody-based treatments are quite powerful — “Now we can say that 90 percent can come out of treatment cured,” one scientist said — and they raise hopes that the disastrous epidemic in eastern Congo can soon be stopped and future outbreaks more easily contained.

Offering patients a real cure “may contribute to them feeling more comfortable about seeking care early,” said Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, who joined the World Health Organization and the Congolese government in making the announcement.

That prospect should greatly lessen the aura of terror that surrounds Ebola, a hemorrhagic fever virus whose reputation has been shaped by its deadliness and its incurability. Since its discovery 40 years ago, the virus has haunted Africa. Until now, many believed that anyone catching Ebola was doomed to die alone among space-suited strangers and to be buried without ceremony in a bleach-misted body bag.