Sand fly (Phlebotomos papatasi) feeding on a human. This fly feeds on human blood and transmits the parasitic human disease leishmaniasis in Africa, Asia and Europe. Leishmaniasis is caused by the Leishmania protozoan and causes breakdown of tissue in humans. The female sand fly carries the protozoan in its salivary glands and injects it into the human host as it feeds. This fly's abdomen is full of the blood (red) it has drunk.