**1. Introduction**

The host–parasite communication and the parasite's intercellular interactions are crucial in the life cycle of the *Leishmania* parasites [1, 2]. In addition, several bioactive molecules released by the parasites have shown an important role in the parasite's adaptation in the host [3]. In mammalian hosts, molecules released by *Leishmania* contribute to the parasite's infectivity and the physiopathology of the leishmaniasis, acting by several mechanisms, such as subverting the immune response and favoring the intracellular multiplication of the parasite [3].

Several works have demonstrated that *Leishmania* species can release proteins and other molecules in extracellular vesicles (EVs) [4–6]. EVs is a generic term used to describe particles spontaneously released by prokaryotic and eukaryotic cells [7]. Deoxyribonucleic acid (DNA), ribonucleic acid (RNA), proteins, lipids, and cellular metabolites are present in EVs that can deliver information from one cell to another [8]. Thus, EVs are now considered a new mechanism of intercellular communication [7].

*Leishmania*-EVs carry parasites molecules, such as small RNA, heat shock proteins (HSPs), and virulence factors (glycoprotein 63 - GP63 and lipofosfoglican - LPG) [4, 5, 9]. Functional studies showed immunomodulatory and signaling-inducing activities properties of the *Leishmania*-EVs [10]. They are present in the intestinal lumen of sandflies and are regurgitated along with promastigote forms during the blood meal [6]. In addition, these particles modulate the macrophage's activation and alter the course of the parasite infection [4–6, 11]. Although immunomodulatory properties have been demonstrated in experimental models, additional studies are necessary to better understand the role of EVs in the parasite–host relationship. Next, we describe an overview of the extracellular vesicles relevant to *Leishmania* infection and the main findings related to EVs released by *Leishmania* parasites.
