Liberian Doctor Infected With Ebola Dies Despite ZMapp Treatment

A Liberian doctor has died despite taking an experimental anti-Ebola drug, Liberia's information minister says.
 Abraham Borbor was one of three doctors in Liberia who had been given ZMapp and were showing signs of recovery.
ZMapp has been credited with helping several patients recover, including two US doctors. According to Liberian Information Minister Lewis Brown told the BBC that the deceased was showing improvement until yesterday Aug 24th.

 It is believed Dr Borbor died in the capital Monrovia. He was the deputy chief medical doctor at the country's largest hospital.

So this leaves me with the question, is ZMapp only meant for Americans?. The Spanish preist who was also treated with the same vaccine died while two Americans who were infected with the virus and treated with ZMapp survived. How come?.

BBC