Old World Leishmaniasis: an ancient disease with nonstandardized microscopic and clinical classifications

Microscopic and clinical classifications of cutaneous leishmania have been set in the 1980s. Since then, they have been used invariably. Lebanon, a nonendemic country, is suffering from a leishmaniasis epidemic because of the massive population influx from endemic Syria.

Patients diagnosed and speciated with leishmania (n = 169) using molecular and microscopic analysis were studied. General demographic data, microscopic data [Ridley's pattern (RP), microscopic pattern, Parasitic Index (PI)] and clinical stage were documented. Clinical score was scored as: 1: inflammatory; 2: proliferative/reorganization; 3: healed phases. The three patterns were studied in comparison to the lesion age and PI.

At low PI, the clinical score and microscopic pattern showed healing scores (scores 3 and 4, respectively). In contrast, RP showed variable distribution at low PI. The same pattern is noted when correlating the different patterns with high PI. In comparison to lesion age, none of the three patterns showed the predicted linear correlation with lesion progression.

In the studied population, the previously adopted classifications did not correlate with the disease progression. Such findings may raise the possibility of evolving disease. The proposed clinical and microscopic patterns showed better correlation with the disease progression.