Leishmaniasis in humans and small animals: Updates and insights through a one health

Leishmaniasis is neglected infectious disease caused by a type of microscopic parasite called Leishmania spp. This disease can affect both humans and animals, as well as sandflies. There are more than 90 species of sandflies that can transmit Leishmania parasites, with Lutzomyia being the primary transmitter in the Americas and Phlebotomus being the primary transmitter elsewhere. The disease, prevalent in tropical and subtropical regions, including southern Europe, poses a significant global health concern due to increasing outbreaks spurred by climate change and heightened human and animal mobility. Leishmaniasis is categorized into three main forms: cutaneous, visceral (kala-azar), and mucocutaneous. These forms vary in clinical presentation, ranging from skin lesions to severe systemic involvement of internal organs and mucosal damage. The treatment of leishmaniasis is complex and depends on factors such as the disease type, parasite species, geographic region, and the host's health status. This review adopts a One Health approach, integrating human, animal, and environmental perspectives to provide a comprehensive update on leishmaniasis. It synthesizes recent advances in understanding the epidemiology, clinical manifestations, diagnostic techniques, and treatment strategies of cutaneous, mucocutaneous, and visceral leishmaniasis in humans and small animals. Understanding interconnection between animals and humans requires a holistic approach such as One Health perspective. This framework emphasizes the need for coordinated research, innovative treatments, and integrated prevention strategies to combat its growing global burden.