(CNN) – For the first time, cases of leprosy have been identified in wild chimpanzees, according to a new study that has surprised experts.

Cases of leprosy in chimpanzees have been found in Guinea-Bissau and Ivory Coast, making it the first case of leprosy in non-human species in Africa, researchers said in a study released Wednesday.

Leprosy is an infectious disease that causes severe damage to human nerves, skin and respiratory tract. This can lead to the development of ulcers and nodules, as well as loss of numbness and blindness in the hands.

Scientists used camera traps to study chimpanzee behavior between 2015 and 2019. By looking at the pictures, the researchers found two men and two women with “severe leprosy-like lesions.” Symptoms – similar to those experienced by humans – progress over time.

“When I first saw the pictures with the knots and sores on the chimpanzee’s face, I immediately realized it was leprosy because it looks like leprosy in humans,” said Kimberly Hawkings, a senior lecturer at the university. One of the authors of Exeter and the study in the UK told CNN on Thursday.

It is not yet known exactly how chimpanzees were affected, but it is believed to have been the result of exposure to humans or “other unknown environmental sources”.

These wild West African chimpanzees show physical symptoms of leprosy, including nodules and facial ulcers.

Leprosy has previously been found in wild animals such as red squirrels in the UK and armadillos in the United States, but it was shocking to see the sudden appearance of leprosy in chimpanzees because they have done well research, ”Hawkings said.

He said more research will now be conducted on how wild chimpanzees interacted with the disease and what it means for a species that is already endangered due to factors such as poaching and habitat loss.

Hawkings said the findings involved researchers and conservation efforts.

Treating leprosy in wild chimpanzees is challenging.

“The treatment of leprosy in humans is relatively straightforward, especially if it is diagnosed early,” Hawkings said.

“But antibiotics are very difficult to administer to non-human-inhabited animals, especially in this population. There are limitations in treating animals for leprosy, and we need to consider the ethical implications of shooting darts at chimpanzees.

Hawkings said the findings link to his extensive research focusing on the interactions between humans and large apes, as humans have traditionally been considered the main host for leprosy.

Published in Research Journal Natural.