Exactly. The other survivors were white.
Actually, most ebola survivors have been from Africa, from the jungle, where they likely have developed antibodies for something like ebola.
One of the recommended treatments are about a 20% transfusion from those who have survived ebola, then followed by full hydration and electrolytic balance.
Trying to find transfusions from blood types with similar antibodies in the western hemisphere is much less likely than in West Africa.