The experimental drug ZMapp cured all 18 monkeys infected with the deadly Ebola virus, even those who had experienced bleeding symptoms and were only a few hours away of death, according to a study published today in the journal Nature.

Even monkeys that had received no treatment until five days after infected eventually survived. According to scientists, the five days in monkeys correspond to 9-11 days of illness in humans.

Although two American volunteers who had been infected by the virus in Liberia were cured after treated with ZMapp, doctors do not yet know whether the experimental drug helped them indeed. A Liberian doctor who also received the same drug died earlier this week, as a Spanish missionary.

The Zmapp is manufactured by the company Mapp Biopharmaceutical based in San Diego and has never been tested in humans, and the study published in Nature was the first conducted on monkeys. The success, therefore, is a “monumental achievement”, as stated by Thomas Gkeismpert a virologist at the University of Texas, commenting on the survey.

To date there are no approved drugs or vaccines for Ebola. Very soon, however, are expected to begin testing of two vaccines by the companies GlaxoSmithKline and NewLink Genetics.

The scientists, led by Gary Kompingker of the Public Health of Canada, administered the drug last spring on18 macaques, three, four, five days after they got  infected with Ebola. Three other monkeys, who were the “control group” and not treated, died eight days after they were infected. All18 survived, even those who had experienced symptoms such as liver failure and bleeding, something that Kompingker characterized as “beyond expectations” .

“These are very encouraging results,” said the professor of virology at the University of Warwick David Evans, who was not involved in the study. This success indicates that ZMapp “is the best choice” for the treatment of Ebola and should be tested in humans to start using “as soon as possible,” said the team of Kompingker.

On the 12^th of August the company Mapp announced that stocks of the drug had already exhausted and although started preparing new, this process will take some time.