ABSTRACT
Leishmania, a parasitic protozoan, a single-celled organism of the genus trypanosomes that are responsible for the disease leishmaniasis. Transmission occured by sandflies of the genus Phlebotomus in the Old World, and of the genus Lutzomyia in the New World. Globally, at least 93 sandfly species are proven or probable vectors. Their primary hosts are vertebrates; Leishmania commonly infects hyraxes, canids, rodents, and humans. Leishmaniasis encompasses diverse clinical syndromes, including cutaneous, mucosal, and potentially life-threatening visceral forms. Three widely known virulence factors belongs to the genus Leishmania include the active compound named proteophosphoglycan (PPG), GP63 metalloprotease and lipophosphoglycan (LPG). these substance established on the surface of the parasite. The aim of this review article is to make an insight of the biochemical characteristics of Leishmania spp virulence factors, the armamentarium that predispose their pathogenesis, its invasion and virulence to the mammalian host.