One health and the ecology of Leprosy: the potential role of wildlife, environment, and arthropods in Mycobacterium leprae transmission

Leprosy remains a challenge for global public health, with a persistent number of approximately 200,000 new cases annually over the past decades. Although all efforts aimed at its control are focused on the detection and treatment of multibacillary patients, increasing evidence indicates the presence of Mycobacterium leprae (M. leprae) and Mycobacterium lepromatosis (M. lepromatosis) in natural reservoirs, suggesting the need for a One Health approach for its control. In this context, the present work aims to discuss the potential impact of natural reservoirs and arthropod vectors in the maintenance of leprosy endemicity, with a focus on integrated surveillance strategies. During this work we discuss the natural infection of armadillos, rodents, marsupials, and primates by M. leprae and M. lepromatosis, including the description of the presence of pathogen DNA and RNA in environmental samples, as well as the participation of arthropod vectors in disease transmission. We conclude that expanding epidemiological surveillance to cover environmental and entomological aspects is essential to advance our understanding of the complex ecology of leprosy and to improve control measures in endemic regions.