Patient Zero, two-year-old Guinean Emile Ouamouno, may have been infected while hunting or playing with bats inside a hollow tree near his home in a small village named Meliandou.
The study determined Ouamouno's interaction with bats is the likely cause of transmission by ruling out other possibilities, namely that the virus was spread by the consumption of bushmeat. Only children and women presented symptoms or died in the beginning of the current epidemic.
Research published in the EMBO Molecular Medicine journal finds that the single transmission, from bat to boy, was then spread human to human.
Anything free is worth what you pay for it.