Rapid detection of Leishmania amastigotes in fluid aspirates and biopsies of human tissues.

When using a genus-specific monoclonal antibody (83-J3D2) as the primary reagent in an indirect immunofluorescent antibody assay (IFA), intracellular amastigotes of Leishmania were easily identified in 9 of 9 biopsies and in 11 of 12 needle aspirates taken from human lesions. In contrast, only 5 of the biopsies and 4 of the aspirates yielded promastigotes upon culture in vitro. Similarly, all but 2 of the aspirates and one-half of the biopsies were reported as negative for parasites when stained with Wright's and hematoxylin-eosin, respectively. Serum antibody titers, ranging from 1:8 to 1:128, corroborated the results of the amastigote detection assays when histopathology and isolation were negative. These findings support the practicality of using the genus-specific monoclonal IFA in those field situations where it becomes necessary to differentiate leishmaniasis from other skin infections.