Which parasite causes leishmaniasis, with visceral and cutaneous forms, transmitted by sandflies?

• A. Leishmania
• B. Trypanosoma cruzi
• C. Plasmodium vivax
• D. Entamoeba histolytica

Answer: (A)

Leishmania is a protozoan parasite transmitted by female sandflies and is the cause of leishmaniasis, which can present as visceral (involving liver, spleen, and bone marrow) or cutaneous disease (skin ulcers). In the human host, the parasite lives inside macrophages as an amastigote; sandflies inject promastigotes that are taken up by macrophages and transform into amastigotes, propagating within the reticuloendothelial system. Diagnosis often relies on seeing Leishman-Donovan bodies (amastigotes) in tissue samples. Other organisms listed are transmitted by different vectors or cause different diseases (Trypanosoma cruzi by kissing bugs causing Chagas disease; Plasmodium vivax by Anopheles mosquitoes causing malaria; Entamoeba histolytica via fecal-oral transmission causing amebiasis).