The Ebola outbreak of 2014 that has claimed 7,500 lives may have originated from bats. According to a report published on Tuesday by the Robert-Koch Institute in Berlin, bats infected with the virus could have spread it to “patient-zero”, or the first individual affected in the Ebola outbreak. Doctor Fabian H. Leendertz published the report in the EMBO Molecular Medicine journal.

The first case of Ebola is currently thought to be a two-year-old boy from the village of Meliandou in Guinea. Emile Ouamouno potentially received the Ebola virus when he played with other children near a bat-infested tree near the village, which contains 31 homes. The hollow tree was home to a multitude of bats that are thought to have carried the virus. Emile died from the virus last year in December, and within four months of his death about 14 members of his village also died of the virus.

Meliandou villagers burned the tree in March after hearing of the possibility that Ebola can be spread through bats. Leendertz and his team of scientists studied samples of bats in the village and tested them for traces of the Ebola virus. However, because the tree was burned back in March, only the stump remains and all the bats that lived in the tree either burned or relocated. The scientists did not find any signs of Ebola in the live bats captured near the village, but Leendertz stated that much research was still needed before any conclusive reports about the origin of the outbreak could be made. The doctor then stated the possibilities of the original Ebola bats spreading the disease to other bats that migrated to other colonies. In Western African cuisine, bats are used as ingredients in some dishes.

“They have moved into human settlements. They do not just live in the trees but also under the roofs of houses in the villages,” he said

Ebola has infected about 20,000 people according to the World Health Organization and has a mortality rate of 70 percent. The virus has affected 9 countries, and most recently entered the United Kingdom.