(AP)–An experimental Ebola drug healed all 18 monkeys infected with the deadly virus in a study, boosting hopes that the treatment might help fight the outbreak raging through West Africa.

Scientists gave the drug, called ZMapp, three to five days after infecting the monkeys in the lab. Most were showing symptoms by then, and all completely recovered.

Three other infected monkeys not given the drug died.

Seven people were given ZMapp in the current outbreak and two have died, but doctors say there is no way to know if ZMapp helped. The very small supply is now gone and it will take several months to make enough to start studies in people.

The study was published online Friday by the journal Nature.