Cutaneous leishmaniasis is the most common form of leishmaniasis affecting humans. It is a skin infection caused by a single-celled parasite that is transmitted by the bite of a phlebotomine sand fly. There are about twenty species of Leishmania that may cause cutaneous leishmaniasis. This disease is considered to be a zoonosis (an infectious disease that is naturally transmissible from animals to humans), with the exception of Leishmania tropica — which is often an anthroponotic disease (an infectious disease that is naturally transmissible from humans to vertebrate animals).