Can archived lesion smears be used to identify Leishmania species in regions with high species diversity?

The identification of Leishmania species is crucial for eco-epidemiological purposes and may be useful for clinical management. Notably, archived smear slides can be valuable in this scenario. ITS-1 PCR followed by sequencing was used to identify Leishmania species from archived lesion smears of patients with suspected cutaneous leishmaniasis in Santarem city, Para State, Brazil. A total of 44 microscopically positive lesion smears were analyzed, of which 34 yielded positive PCR results. Of these, 22 were subjected to Sanger sequencing and 15 were successfully sequenced, revealing five Leishmania species. This study demonstrates the applicability of molecular testing on archived samples. ITS-1 sequencing effectively differentiated between species, revealing significant diversity of Leishmania in the Brazilian Amazon.