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

Date Published: February 7, 2018

Publisher: Public Library of Science

Author(s): Mehdi Bamorovat, Iraj Sharifi, Mohammad Reza Aflatoonian, Hamid Sharifi, Ali Karamoozian, Fatemeh Sharifi, Ahmad Khosravi, Saeid Hassanzadeh, Adriana Calderaro.


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.

Partial Text

Leishmaniasis imposes a major health impact all over the tropical and subtropical regions of the world [1]. An estimated 0.9 to 1.3 million new cases and 20000 to 30000 deaths occur annually in the world [2]. Cutaneous leishmaniasis (CL) is the most common form of the disease which constitutes approximately 75% of the global cases. Anthroponotic cutaneous leishmaniasis (ACL) caused by Leishmania tropica and zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania major are endemic in many parts of Iran with high outbreak rates [3–6]. Therefore, CL has recently become an important health issue in the country. Recently, its incidence has risen considerably and is expanding to new foci [7].

Cutaneous leishmaniasis is one of the most serious health problems in Iran, especially in Kerman province, southeastern Iran [5,19]. Previous studies have shown that CL in Kerman district was predominantly of ACL type. Similarly, the majority of the cases which occurred in southern districts were ACL [19]. However, in this study, attempt was made to use molecular methods powered by sequencing amplification regions of Hsp70 and ITS1 to identify the Leishmania isolates. Nucleotide polymorphism as discriminative molecular marker in these regions is highly recommended [17,20–22]. Based on the method used, all samples were L. tropica, due to the widespread prevalence of this endemic species in this area.

In this study, four major risk factors, including interior housing conditions, history of chronic diseases, duration of lesion, and age groups were significantly associated with the development of unresponsive forms. Improving interior house construction, early detection and effective treatment, protecting persons and those with debilitating diseases from being bitten by sand flies, especially in older age groups with the history of chronic diseases are exceedingly important measures for prevention of unresponsive forms of ACL in southeastern Iran. To prevent the disease, it is therefore essential that the national health authorities implement appropriate control strategies.




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