For Kent Brantly, the American doctor who was infected and survived the highly fatal Ebola virus, divine intervention made it possible for him to recover from the disease that has so far killed nearly 2,000 in West Africa.

Brantly, who contracted the hemorrhagic fever while working with Ebola-struck patients in Liberia, received the experimental drug ZMapp, which is developed by San Diego-based Mapp Biopharmaceutical Inc., along with the other American Ebola survivor Nancy Writebol. While it is possible that the drug has helped them recover from the disease, its efficacy and safety remain unproven.

Some of the Ebola patients who received ZMapp, for instance, did not manage to survive the disease. A 75-year-old priest died from Ebola two days after he was given the drug. The deputy chief physician of Liberia's largest hospital who received the drug also died from Ebola.

It may appear that Brantly has been cured because of his faith, as some of those who received the same medication he received did not survive the disease.

"I am thrilled to be alive, to be well and to be reunited with my family. ... Above all, I am forever thankful to God for sparing my life," Brantly said when he was released from the Emory University Hospital in Atlanta, Ga.

Brantly's recovery, however, may also have something to do with the blood transfusion he received. Research suggests that blood from survivors of Ebola could prevent or treat infection in other patients, although it is not yet known if the antibodies found in the survivors' plasma would be sufficient.

Besides the experimental ZMapp drug, Brantly also received blood from a 14-year old Ebola survivor. It is unclear whether the drug or the donated blood helped the doctor with his recovery.

Blood from those who survived the disease, however, could play a crucial role in the outbreak as the World Health Organization sees the potential of using blood-derived products in treating Ebola patients. It is hoped two promising vaccines will be approved and available by the end of the year.

"There is a real opportunity that blood-derived products can be used now. This can be very effective in terms of treating patients," said WHO assistant director-general Marie-Paule Kieny. "There are also many people now who are convalescent, who survived and are doing well. These people can provide blood, serum to treat."

"What is available will be used in the field to treat real patients as soon as possible," Kieny said.

Experts said that blood from Ebola survivors could be collected and processed for treating multiple patients. Survivors could also donate blood to one patient. Both of these methods involve screening of the blood for diseases such as malaria and HIV.

In the meantime, those treating patients across West Africa must continue offering patients rest and hydration, and practice strict infection prevention and control measures. Officials also must trace and monitor people who have been exposed to the virus to help stop its spread. So far, at least 2,097 people have died in West Africa since March.