Leprosy in wild chimpanzees

Leprosy-like lesions were recently reported, and confirmed by laboratory analysis, in two populations of wild chimpanzees in Guinea-Bissau and Côte d’Ivoire. Whole-genome sequencing revealed that the chimpanzees are infected by different M. leprae strains: the genotype 2F in Côte d’Ivoire, and the genotype 4N/O in Guinea-Bissau. These genotypes are rare worldwide and in West Africa.

The exact source of infection remains to be determined, but the data suggest an unknown environmental reservoir. This is the first report of an animal reservoir for the leprosy bacillus in Africa. The research report questions the assumption that humans are the main reservoir of M. leprae and suggests that eradication of the disease should include a one-health approach.