**1. Introduction**

American cutaneous leishmaniasis (ACL) is a vector-borne protozoan zoonotic disease widely spread in Latin America. At least 12 different *Leishmania* species cause ACL. The disease occurs

© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

in countries from the United States to Argentina, except in Uruguay and Chile. ACL is an important health problem affecting the poorer population and is thus one of the most neglected diseases. Depending mainly on the *Leishmania* species and the host immune response, the spectrum of clinical forms includes localized cutaneous leishmaniasis (LCL), disseminated and diffuse cutaneous leishmaniasis (DCL) and mucocutaneous leishmaniasis (MCL). The former is the most commonly occurring disease with approximately 0.7–1.2 million new cases every year [1, 2].

In south-eastern Mexico, the Yucatan Peninsula is an important endemic area of LCL, locally known as the "chiclero´s (gum collectors) ulcer". The LCL was first described by Seidelin in 1912, who classified the agent as morphologically indistinguishable from *Leishmania tropica* [3]. Since then, the humid forest of the Yucatan Peninsula has been documented as an endemic focus of LCL [4–6].

The purpose of this chapter is to review the most relevant studies performed in the last 30 years in the Laboratory of Immunology of the Autonomous University of Yucatan. This research has covered the characterization of the "chiclero´s ulcer", its diagnosis and treatment, and the identification of risk factors as well as the *Leishmania* vectors and reservoir species that are important to be known in order to develop control strategies.
