According to research published Tuesday by the Robert Koch-Institute, fruit bats are almost certainly to blame for the current Ebola outbreak, which has claimed 7,800 lives. But while most outbreaks caused by a fruit bat would have someone who hunted or handled the mammal for meat to blame for the contagion, the researchers believe that this case was sparked by children at play.

The first case of 2014's outbreak has been traced to someone who should not have had much contact with hunting or bushmeat. In October, researchers reported that patient zero of the outbreak was likely a 2-year-old boy named Emile Ouamouno, who lived in the Guinea village of Meliandou.

In the new study, published Tuesday in EMBO Molecular Medicine, researchers sleuthed around Emile's village for clues about how he had contracted the deadly virus. They checked large local mammals, but none of them showed signs of an Ebola outbreak that could have spilled over into the human population. Bats seem more likely in this case, the researchers say.

But that left another question: If hunting or eating bat meat had caused the first infections, why hadn't an adult - who surely would have had more contact with the bats than a toddler who might nibble on them - get Ebola first?

By interviewing local villagers, the researchers found an answer: a large, hollow tree, often filled with colonies of bats, where children from the village are known to play.

But other experts caution that the evidence that these particular bats can carry and spread Ebola is still sparse, and more lab work will be needed.

But as David Quammen points out at National Geographic, the implications of this theory are troubling because the bat is so common in many areas.