Answer to Case 647

 Answer:Leishmaniaspecies amastigotes within a host phagocytic cell. Note the characteristic " dot-dash " morphology of the amastigotes, representing the nucleus and rod-shaped kinetoplast:Given the travel history to Costa Rica, additional testing is indicated to determine the species ofLeishmaniapresent. Some species in Latin America are capable of causing mucocutaneous leishmaniasis - a destructive form of disease that is difficult to treat. If the patient is infected with one of these species (e.g.,L braziliensis), then more aggressive treatment is warranted. Species identification is best accomplished by first growing the organism in culture and then performing isoenzyme analysis, or more commonly today, sequencing. 
Source: Creepy Dreadful Wonderful Parasites - Category: Parasitology Source Type: blogs