A Liberian doctor treated with a San Diego company's experimental Ebola drug has died.
Abraham Borbor was one of six Ebola patients to receive ZMapp, a drug previously untested in humans. Officials said he had been improving until his condition took a turn for the worse Sunday.
As of last week, two other West African health workers treated with ZMapp were said to be showing signs of recovery.
The small San Diego firm Mapp Biopharmaceutical is focused on producing more Zmapp now that existing supplies have run out.
Experts have said it's unclear whether or not the drug has been effective. A Spanish priest who took ZMapp also died, but two American recipients have already been released from the hospital.
Questions remain about how much ZMapp each patient received and how far the disease had progressed before they received treatment.
More than 1,400 people have died in the current Ebola outbreak, making it the deadliest on record.
