This has proven to be fabricated.....
..Yes, the Indians got smallpox, but it was acquired from human contact with Europeans arriving in country
A British (not American) officer suggested the smallpox blanket idea in a letter to another officer. There is no record of it ever being carried out.
BTW, Ebola is such a tremendously virulent disease that outbreaks tend to “burn themselves out.” It kills so efficiently that it prevents itself from spreading farther.