Leprosy has been discovered in two wild populations of western chimpanzees in Cantanhez National Park in Guinea-Bissau and Taï National Park in Ivory Coast, according to a new study.
Researchers discovered the animals were suffering from the disease when they were studying the behaviour of chimpanzees between 2015 and 2019.
They first noticed leprosy like symptoms on the West African chimpanzees in June 2018. An adult male chimpanzee, called Woodstock, had bumps on his ears, lips and eyes and the skin on his face, hands, feet and testicles became lighter.
“When I first saw the images of a chimpanzee with nodules and lesions on his face, it struck me right away that this was leprosy because it looked so much like leprosy does in humans,” Kimberley Hockings, one of the study’s authors, told CNN.
Leprosy, also known as Hansen’s disease, is an infection caused by slow-growing bacteria called Mycobacterium leprae and can affect the nerves, skin and eyes. Humans are considered as the main host for Mycobacterium leprae.
Researchers saw four chimpanzees with symptoms like hair loss, facial skin hypopigmentation, bumps that covered different areas of their body, facial disfigurement and ulcerated and deformed hands (claw hand) and feet.
They confirmed the presence of Mycobacterium leprae in faecal and necropsy samples. These findings suggest that leprosy may be circulating in more wild animals than suspected, according to the study, published in the journal Nature on Wednesday.
Researchers don’t know how the chimpanzees got the disease, but they think it’s “either as a result of exposure to humans or other unknown environmental sources.”
Nine-banded armadillos and red squirrels have also shown symptoms of leprosy, but this is the first time the disease has been found in wild chimpanzees in Africa.
Chimpanzees are listed as endangered, with only between 172,000 and 300,000 left in the wild.
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