A team of scientists recently discovered chimpanzees infected with leprosy in isolated populations in two West African countries, specifically the Ivory Coast and Guinea-Bissau.

A Live Science report specified that the team detected the disease in the wild primates for the first time, and the symptoms observed were similar to those in infected humans.

According to a new study, facial lesions in some of the animals looked like those in humans who have advanced leprosy. The genetic analysis of the tool samples of chimps verified that animals in both groups were carrying bacteria that caused the mutilating disease, also known as Mycobacterium leprae.

It's the first case to be detected in wild chimpanzees (Pan troglodytes verus). However, leprosy in captive chimpanzees has been reported previously, and they are the first known non-human case of the disease in Africa.

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Leprosy in Wild Primates Previously Unknown

Before this study was recently published in Nature, lead study author Kimberly Hockings said, "nothing was known at all" about this disease in wild primates.

Hockings, also a senior lecturer in conservation science at the University of Exeter's Centre for Ecology and Conservation in the United Kingdom, added that there were published reports of captive primates with leprosy, including chimps.

"But the source of infection was unclear, as it is possible that they contracted leprosy whilst in captivity."

A Centers for Disease Control and Prevention report said leprosy, also called Hansen's disease, is an infectious disease that mainly impacts people and is caused by the bacteria M. leprae, which researchers identified during the late 19th century. On the other hand, M. lepromatosis was detected in 2008. 

According to the World Health Organization, bacteria pass in droplets between people from nose to mouth during frequent and close contact.

Leprosy Indications

Guinea-Bissau's The scientists looked at two wild populations of chimpanzees, one in Cantanhez National Park, and the other in the Ivory Coast's Taï National Park.

The camera-captured footage of the CNP chimps documented from 2015 and 2019 capture more than 240 chimp images showing severe lesions similar to leprosy, as well as growths on their trunks, genitals, and faces.

Affected chimpanzees exhibited facial disfigurement, excessive nail growth, hair loss, and deformed digits as well, also known as "claw hand," another sign of leprosy, as indicated in the study.

According to a Phys.org report, when the study authors examined fresh fecal specimens, they discovered DNA evidence suggesting that the chimpanzees were infected with M. leprae.

Unlike the other chimp population, the Ivory Coast chimps were adjusted to scientists following and observing them in the wild.

And in 2018, biologists noticed that one of the animals, an adult called "Woodstock," had lesions on his face which were similar to leprosy that grew bigger and increased in number over the next two years.

DNA analysis and fecal sampling again revealed the existence of M. leprae, as did the female chimp called Zora's necropsy. The latter-mentioned chimp was killed in 2009 by a leopard but started to develop lesions roughly two years prior to her death.

Genetic data revealed that the variants of M. leprae affecting the two chimpanzee populations were different. Both were rare variants, not only unusual in humans but in other animal reservoirs as well.

Related report about leprosy in chimpanzees is shown on NewzTech20's YouTube video below:

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