In a report published in the New England Journal of Medicine, researchers say that the virus may not even be new to the area, and could have been circulating undetected for some time.
It suggests that there was probably “a single introduction of the virus into the human population” prior to December 2013, adding, “it is suspected that the virus was transmitted for months before the outbreak became apparent.”
It’s now believed that “patient zero” was a 2-year-old girl who died in December.
A related version of the disease’s most virulent Zaire strain has been identified as the cause of that fatality in Guinea before Ebola spread elsewhere across that country and into neighboring Liberia.
The study said fruit bats, found throughout western Africa, were “potential reservoirs” of the virus.