Page "Leishmaniasis" Paragraph 12

Leishmaniasis is transmitted by the bite of female phlebotomine sandflies.

The sandflies inject the infective stage, metacyclic promastigotes, during blood meals ( 1 ).

Metacyclic promastigotes that reach the puncture wound are phagocytized by macrophages ( 2 ) and transform into amastigotes ( 3 ).

Amastigotes multiply in infected cells and affect different tissues, depending in part on which Leishmania species is involved ( 4 ).

These differing tissue specificities cause the differing clinical manifestations of the various forms of leishmaniasis.

Sandflies become infected during blood meals on infected hosts when they ingest macrophages infected with amastigotes ( 5, 6 ).

In the sandfly's midgut, the parasites differentiate into promastigotes ( 7 ), which multiply, differentiate into metacyclic promastigotes, and migrate to the proboscis ( 8 ).