"Leishmaniasis is transmitted by the bite of female phlebotomine sandflies.
The sandflies become infected during blood meals on an infected host when they ingest macrophages infected with amastigotes.
In the sandfly, the parasites differentiate into promastigotes that multiply and mature.
A minimum of 7 days are required before infective promastigotes are present
The promastigotes block the insect's pharynx and hypostome, and are regurgitated by the sandfly during a subsequent blood meal.
Promastigotes that reach the puncture wound and are phagocytized by macrophages transform into amastigotes and multiply, thus closing the life cycle.
Multiplication is by binary fission, and no sexual stage has been identified."
Primary Reference:
Centers for Disease Control
