Phylogenetic position of Leishmania tropica isolates from an old endemic focus in south-eastern Iran; relying on atypical cutaneous leishmaniasis.

Cutaneous leishmaniasis (CL) is a major health problem in Iran, with a heavy burden on human health and society. There is little knowledge about the molecular epidemiology of the disease, as well as phylogenetic relationship of causative agents in south-eastern Iran. The aim of the present study was to investigate the molecular aspects of CL, especially atypical CL in the Bam district, Kerman province, south-eastern Iran, as an endemic region of CL in Iran. The smears were collected from lesion samples of 353 patients clinically suspected to CL, who attended local health centres in the Bam district during 2016-2017. Direct smears were examined for Leishmania parasites using the Giemsa staining technique. Amplification of kinetoplast DNA (kDNA) and the ribosomal internal transcribed spacer 1(ITS-1) gene were carried out using polymerase chain reaction (PCR). Then, the ITS1-PCR products were sequenced for phylogenetic analysis. Overall, 278 cases were confirmed as CL by microscopic examination of Giemsa-stained slides. Clinical presentation of the lesions was basically of two types: (a) typical lesions and (b) atypical including lupoid ulcers, sporotrichoid, nodular and exudative lesions. The PCR assay on all specimens of skin lesions proved L. tropica as the main pathogenic agent. Phylogenic analysis revealed high similarity among isolates from the Bam district in the south-east with isolates from Birjand in eastern Iran, as well as with isolates from Herat province in western Afghanistan. The study provided valuable information concerning the genetic diversity of the parasite as one of the factors influencing the clinical manifestations in CL in south-eastern Iran, which could be the basis for planning future control strategies.

HRM-PCR is an accurate and sensitive technique for the diagnosis of cutaneous leishmaniasis as compared with conventional PCR.

BACKGROUND: Cutaneous leishmaniasis (CL) is considered one of the main health problems in Iran. Therefore, it is required for control and therapeutic purposes, an accurate and fast tool for the diagnosis and identification of Leishmania species. METHODS: In the present study, three techniques, including microscopic examination, conventional PCR, and high-resolution melting (HRM)-PCR, have been evaluated, to find the most accurate and rapid test. In total, 105 skin scraping smears were taken from suspected dermal lesions of patients belonging to two known endemic CL areas, Gonbad and Bam districts, in Iran. Subsequently, the specimens were analyzed with microscopic, conventional PCR, and HRM-PCR techniques. RESULTS: Most positive samples (89.5%) were observed using HRM-PCR, and among the three techniques, HRM-PCR was the most sensitive (89%, 95% CI 81-94) technique. Microscopic examination test had the lowest sensitivity (57%, 95% CI 47-66%). The highest agreement among positive samples was observed between HRM-PCR and conventional PCR tests. DISCUSSION: Our results showed that the HRM-PCR technique is the most accurate and sensitive test for recognizing CL, and also a valuable alternative test for conventional PCR to detect various species.

Geo-climatic factors in a newly emerging focus of zoonotic visceral leishmaniasis in rural areas of north-eastern Iran.

Visceral leishmaniasis (VL) is the fatal form of leishmaniasis. A newly emerging focus of zoonotic VL (ZVL) including 13 villages has been reported from Maraveh Tappeh County, Golestan province, north-eastern Iran. We investigated the effect of climatic and environmental factors on the occurrence of disease in this focus by geographical information systems (GIS) approaches and logistic regression models. The incidence rate of ZVL in human and dog population was estimated 1.2% and 27.3%, respectively, in the studied areas. Rock soil type (OR = 11.7), rainfall (OR = 1.04) and elevation (OR = 0.99) were found as determinants of ZVL. Also, almost all infected villages were in close proximity of rivers. Cavities of rock soil around rivers are assumed as suitable areas for sandfly resting and growth by providing shadow and moisture. Rainfall also provides appropriate moisture in semi-arid regions for survival of sandflies. The negative effect of higher altitude can be explained by some sandfly life-limiting conditions like freezing weather. Accordingly, regions with lower altitude and higher rainfall, covered by rock and in close proximity of rivers, are the hazard zones for ZVL in the Maraveh Tappeh. Air humidity, temperature, land cover type and slope were not predictors of disease in the current study. Further investigations on human population movement, probable reservoirs and vectors of disease can provide valuable data for modelling the future distribution of ZVL in the Iranian province.