(CNN)Leprosy has been identified in wild chimpanzees for the first time, according to a new study, in findings that have stunned experts.
The leprosy cases in chimpanzees were found in Guinea-Bissau and the Ivory Coast, making this the first time leprosy has been found in any nonhuman species in Africa, researchers said in a study published Wednesday.
Leprosy is an infectious disease that can seriously damage nerves, skin and the respiratory tract in humans. It can lead to the development of lesions and nodules, as well as the loss of sensation in the limbs and blindness.
Scientists used camera traps to study the behavior of chimpanzees between 2015 and 2019. When looking through the images, the researchers found two males and two females with "severe leprosy-like lesions," according to the study. Symptoms -- similar to those humans experience -- progressed over time.
"When I first saw the images of a chimpanzee with nodules and lesions on its face, it struck me right away that this was leprosy because it looked so much like leprosy does in humans," Kimberley Hockings, a senior lecturer in conservation science at the University of Exeter in the United Kingdom and one of the study's authors, told CNN Thursday.
It is so far not known exactly how the chimps became infected, but it is thought that it came about either as a result of exposure to humans or "other unknown environmental sources," the study said.
Leprosy has been seen in wild animals befo