We previously reported this possibility in November 2020, but now its results have been peer-reviewed and confirmed.
For the first time in history, a team of international researchers has confirmed the presence of leprosy in wild chimpanzees with striking images of these animals with bumps on their faces associated with this disease in two populations of chimpanzees that are not connected: in the National Park Cantanhez of Guinea-Bissau and in the Taï National Park in Ivory Coast. (separated by about 1,000 kilometers).
What is the cause of the appearance of leprosy?
Leprosy is a bacterial disease that usually infects humans. The bacterium in question is Mycobacterium leprae , and the main host is precisely humans, but a “contagion” is taking place to other mammals: “this is the first confirmation of leprosy in non-human animals in Africa”, comments Kimberley Hockings, from the Center for Ecology and Conservation on Exeter’s Penryn campus in Cornwall.
The origin of the infection is unclear, but scientists believe the disease is likely circulating in more wild animals than previously suspected and that it could be due to exposure to humans with leprosy or perhaps other unknown environmental sources.
The outbreaks were brought to light through hidden camera traps placed around Cantanhez National Park that showed that at least four wild chimpanzees had developed unusual lesions on the face, ears, hands and feet, as well as hair loss and pigment loss in his face, symptoms very similar to those of leprosy in humans.
“We contacted Professor Fabian Leendertz from the Robert Koch Institute to confirm these cases genetically”, clarify the experts who detail their study in the journal Nature. “We were able to surprisingly confirm Mycobacterium leprae . With several samples from two female chimpanzees (probably mother and daughter), one of those samples was enough to sequence the entire genome ,” Hockings said.
A genetic analysis of the M. leprae bacterium obtained from chimpanzee poop samples revealed some interesting insights. First, the two shoots represented two different strains, indicating that they arose separately . Second, the genotypes of the bacterial strain responsible for both outbreaks are extremely rare in humans, suggesting that the outbreak is unlikely to have originated from contact with humans.
Left untreated, this disease can lead to deformities and blindness, but routinely administering antibiotics to wild chimpanzees is a real challenge.
At least four chimpanzees in three different communities in the studied areas with severe leprosy. Although the study is the first to report the disease in wild chimpanzees, there have been cases in captive chimpanzees, the researchers say.
“Although it is impossible to rule out a human source, the low human contact coupled with the rarity of the M. leprae genotype detected in chimpanzees in Taï National Park among human populations in West Africa suggests that recent human-to-chimpanzee transmission is low. likely, ”concludes Hockings.
Western chimpanzees are critically endangered, so even the loss of a few individuals could be significant, experts say.
Referencia: Kimberley J. Hockings, Benjamin Mubemba, Charlotte Avanzi, Kamilla Pleh, Ariane Düx, Elena Bersacola, Joana Bessa, Marina Ramon, Sonja Metzger, Livia V. Patrono, Jenny E. Jaffe, Andrej Benjak, Camille Bonneaud, Philippe Busso, Emmanuel Couacy-Hymann, Moussa Gado, Sebastien Gagneux, Roch C. Johnson, Mamoudou Kodio, Joshua Lynton-Jenkins, Irina Morozova, Kerstin Mätz-Rensing, Aissa Regalla, Abílio R. Said, Verena J. Schuenemann, Samba O. Sow, John S. Spencer, Markus Ulrich, Hyacinthe Zoubi, Stewart T. Cole, Roman M. Wittig, Sebastien Calvignac-Spencer & Fabian H. Leendertz. Leprosy in wild chimpanzees. Nature, 2021 DOI: 10.1038 / s41586-021-03968-4
