Answer: Leishmania spp. amastigotes. Note the small (2-5 micron) oval-shaped objects within and outside of macrophages, with a nucleus and classic rod-shaped kinetoplast. The large purple objects are macrophage nuclei.
Splenic aspiration is an excellent way of diagnosing visceral leishmaniasis. However, the procedure carries the risk of splenic rupture and should only be undertaken by a skilled practitioner. An alternative procedure for diagnosis of visceral leishmaniasis is bone marrow biopsy.
Visceral leishmaniasis is prevalent in some parts of India and Africa, the Mediterranean, and South America.