Leishmania: Early encounters

Protozoan parasites of the genus Leishmania are the causative agents of a group of human diseases ranging from a confined cutaneous disease to a progressive visceral disease that can be fatal if left untreated. Transmission of the parasite is mediated by sand flies of either the genus Phlebotomus or the genus Lutzomyia. Upon feeding, infected sand flies inoculate the promastigote forms of the parasite into the mammalian host. This initiates a series of complex molecular, biochemical, and cellular events on both the parasite and host sides. These early events have an important impact on the subsequent interplay between the parasite and the host, and play a determining role in the outcome of infection.

This Research Topic hosted in Frontiers in Cellular and Infection Microbiology focuses on key early events that follow the inoculation of Leishmania promastigotes within mammalian hosts. Among the early events of the host response to infection are the recruitment of phagocytic cell populations which are normally associated to pathogen destruction and innate immune responses. However, Leishmania promastigotes are able to evade, resist, and subvert the functions of those phagocytes, through their ability to synthesize and release various virulence factors. Key aspects of this fascinating host-parasite interplay are addressed in the following chapters.