Risk factors for anthroponotic cutaneous leishmaniasis in unresponsive and responsive patients in a major focus, southeast of Iran

Cutaneous leishmaniasis (CL) is a serious health challenge at the global level due to Leishmania tropica. This study was conducted to evaluate the risk factors associated with anthroponotic CL (ACL) in unresponsive (patient who does not heal and remains with an active lesion, despite receiving two courses of intra-lesional Glucantime along with cryotherapy and one cycle of systemic Glucantime) and responsive patients in a major focus in southeastern Iran. A case-control study was conducted from April 2015 to October 2016 in the southeast of Iran. Patients were recruited in a major ACL focus from unresponsive and responsive cases. These patients were compared for environmental, clinical, and demographic characteristic factors. Twenty-five risk related factors were analyzed using multivariate logistic regression and backward elimination stepwise models. P<0.05 was defined to be statistically significant. In general, 340 patients with ACL comprising 72 (21.2%) unresponsive cases and 268 (78.8%) responsive cases with active lesions or scars were analyzed by estimating odds ratio (OR). All isolates from 15 responsive and 15 unresponsive patients were characterized as Leishmania tropica based on the BLAST and phylogenic analyses by PCR sequences of the Hsp70 and ITS1 loci. Among the 25 variables, 4 major risk factors including poor interior housing conditions (OR = 1.99, confidence interval (CI) = 1–3.93, P<0.04), history of chronic diseases (OR = 6.22, CI = 2.51–15.44, P≤0.001), duration of lesion in the patients referred ≥13 months (OR = 74.99, CI = 17.24–326.17, P≤0.001), and 5–12 months (OR = 7.42, CI = 3.07–17.92, P≤0.001) than lesions with ≤4 months of age and age groups ≥51 years (OR = 3.85, CI = 1.04–14.22, P<0.04) than those ≤7 years, were significantly associated with unresponsive forms. Improving interior house construction protecting high risk individuals and those with debilitating diseases from being bitten by sand flies, together with the early detection and effective treatment of older age groups with history of chronic diseases are highly important measures for preventing unresponsive forms in patients with ACL in southeastern Iran.