A newly emerged cutaneous leishmaniasis focus in central Iran

Abstract

Objectives: This study was performed to evaluate the epidemiological status of cutaneous leishmaniasis (CL) in the most important endemic foci of Qom Province, central Iran. The city of Qom is the largest center for Shi'a scholarship in the world and is a significant pilgrimage destination.

Methods: During 2006-2011, all suspected CL patients with skin lesion(s) referred to regional health centers of Ghomrood and Ghanavat regions, and all actively detected cases, were examined clinically and parasitologically for CL. Patient information was recorded and patients were categorized based on the number and size of the lesions. Odds ratios (OR) of different risk factors were calculated.

Results: A total of 849 (59.2% male, 40.8% female) confirmed cases of CL were enrolled; the average incidence rate of the disease was 14.9 per 100000 people. During the study period 2006-2011, the trend in CL incidence showed no sudden variations in the areas studied, except for an outbreak of CL in 2009. Leishmania major was identified as the causative agent based on internal transcribed spacer 1 (ITS1) ribosomal DNA PCR analysis. During the study period, the age distribution of CL cases was relatively stable, with the majority (50%) of patients aged 1-25 years. Most cases (n=468; 55.1%) had a single lesion and 82 (9.6%) patients had four or more lesions (range 1-29). The risk of developing multiple lesions was significantly increased in patients with seasonal jobs (summer workers) (p=0.023; OR 1.516) and significantly decreased in patients who were affected in winter (p=0.010; OR 0.398). The risk of developing large-sized lesions (>1cm) was significantly increased in patients in the age groups>25 years (p=0.001-0.015; OR 2.5-3.5) and decreased in patients with seasonal jobs (summer workers) (p=0.005; OR 0.570).

Conclusions: The present data show the importance of CL as a health problem in suburban areas of Qom Province. In order to identify other epidemiological aspects of leishmaniasis in this area, studies on vectors and reservoirs are recommended. Since leishmaniasis caused by L. major is typically zoonotic, control measures should focus on rodents as the main reservoirs and Phlebotomus papatasi as the main vector. Awareness should be raised in the high-risk populations comprising people with diabetes, young adults (<25 years old), and those who work outdoors during the summer.

Keywords: Cutaneous leishmaniasis; Epidemiology; Iran; Qom.