A comparative morphometrics of amastigote forms of <em>Leishmania donovani</em> found in cutaneous leishmaniasis patients in Sri Lanka: evidence for the presence of promastigote-like structures

Abstract

Objective: Investigations have not yet been carried out to identify the different morphological forms of amastigotes present in patients with cutaneous leishmaniasis (CL) in Sri Lanka. Thus, this paper describes the existence of different amastigote forms in cutaneous lesions for the first time in Sri Lanka.Methods: This was a retrospective study. One hundred and thirty skin smears were investigated to identify the different morphometric forms of L. donovani. In addition, demographic data (age, gender, occupation, household characteristics, and geographic area) were analyzed using department records.Results: Of the 130 samples, 84 (60.83%) samples had amastigote forms. Three (2.31%) samples had amastigotes in intracellular locations while 43 (33.08%) had amastigotes extracellularly. Nineteen (14.62%) samples had amastigotes in intracellular and extracellular locations simultaneously. Promastigote-like structures (PLS) were found in 65 (50%) samples. Of the 65 samples, 19 (14.62%) had both PLS and amastigote forms. PLS alone (no association with amastigote forms) were found in 46 (35.38%) samples. Amastigotes were found predominantly in lesions <2 months old while PLS were more common in 8 to 12 months old lesions.Conclusion: Microscopic examinations of skin smears revealed the presence of promastigote-like structures for the first time in patients with CL in Sri Lanka. Therefore, we suggest that different morphometric features of amastigotes should not be ignored as they may be useful in diagnosis of CL in clinically suspected patients.

Keywords

• cutaneous leishmaniasis, leishmania donovani, amastigote, morphometrics, promastigote-like structures, chronicity, sri lanka