Pathogenesis+-+Leishmaniasis

1. The sand flies inject the infective stage or parasite (called promastigotes) while feeding from the blood of a host organism. 2. Promastigotes that reach the wound or site of injection are then phagocytized by macrophages and other types of phagocytic cells. 3. Once phagocytized, promastigotes then transform within macrophages and other phagocytes into the tissue stage of the parasite (called amastigotes), which can multiple by division and proceed to infect other phagocytic cells.

Sandflies become infected by ingesting infected cells while feeding from blood. Within sandflies, amastigotes ingested from infected blood transform into promastigotes, develop in the gut, and migrate to the proboscis ( an elongated appendage from their head ).