New York: A team of researchers think they have pinpointed how the Ebola epidemic in West Africa started with a small boy playing in a hollowed-out tree where infected bats lived.

The researchers explored an area in southeastern Guinea where 2-year-old Emile Ouamouno fell ill a year ago and died. Health officials believe he was the first case in the epidemic, which wasn't recognised until spring. The Ebola virus wasn't found in the bats they tested, the scientists reported in a study published yesterday.