FREDERICK, Md. (AP) — Researchers at the Army Medical Research Institute of Infectious Diseases (USAMRIID) at Fort Detrick are planning a study on an experimental drug that was given to two American aid workers to treat the Ebola virus.

USAMRIID spokeswoman Caree Vander Linden said a study this fall will be designed to determine the ideal dose of a drug called ZMapp, produced by San Diego-based Mapp Biopharmaceutical Inc.

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The Frederick News-Post reports that the study will involve primate subjects, not humans.

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ZMapp is a mix of three specially engineered antibodies grown inside tobacco plants. The two American aid workers who received the drug appear to be improving, but it is not known whether their improvement is a result of receiving the drug.

USAMRIID has been studying Ebola for decades.

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