Scientists have traced the beginning of the current Ebola outbreak to a two-year-old boy named Emile Ouamouno, who lived in a small village called Meliandou in Guinea and died Dec. 2013. But how did the toddler get Ebola in the first place?

A small team of anthropologists, veterinarians and ecologists think they may have the answer. In a paper published Tuesday for the journal EMBO Molecular Medicine, lead author Fabian Leendertz of the Robert Koch Institute in Germany hypothesizes that Ouamouno got Ebola from a hollowed out tree where children in his community would often play. That tree, it turned out, was home to a large colony of free-tailed bats, which have survived experimental Ebola infection in previous research. That particular species of bat has also been discussed as a potential source for the virus in past outbreaks.

Ebola is a zoonotic virus, which means that it can pass from animals to humans. In the past, Ebola outbreaks have been traced to bushmeat hunters killing and eating fresh meat from large primates. Leendertz and team ruled out that possibility for two reasons: one, usually the hunters themselves would be the first to come down with Ebola, and two, large primates are increasingly scarce and difficult to catch near Meliandou, according to villagers.

So instead Leendertz turned his attention toward fruit bats, another known Ebola virus carrier. But the fruit bat colonies were relatively far away from Ouamouno’s village and besides, fruit bat hunters weren’t the first to get sick with Ebola.

Finally, Leendertz focused on insectivorous bats, which children regularly hunted and grilled. He noted a large, hollowed-out tree stump about 55 yards from Ouamouno’s home, along a well-trafficked path where women would walk on their way to a small river to do their washing. Villagers told Leendertz that children would often play in the hollowed-out tree, which turned out to be the home of a large colony of insectivorous bats.

Children would often capture these bats and play with them, writes Leendertz, and the first cluster of Ebola cases in Meliandou were mostly children and women, he notes, but because he wasn’t able to test any of the bats that lived in the tree, there’s no way to know for sure if they did indeed transmit Ebola to the little boy.

For now, he writes that his study is enough evidence to begin including insectivorous bats in Ebola outbreak analyses, where before scientists would point the finger at fruit bats or large primates. If Ouamouno is indeed the very first Ebola patient of this current outbreak, extra care needs to be taken to “avoid retribution attacks and stigmatization of the region,” Leendertz cautioned. He also wrote that while the public needs to be informed of the risks of handling bats, they also need education about the “crucial ecosystem services” bats provide, which include benefits to humans.

So far in this Ebola outbreak, there have been 19,497 cases and 7,588 deaths, according to the latest figures from the World Health Organization.