Heterogeneity of the internal transcribed spacer region in Leishmania tropica isolates from southern Iran

Genetic variation and geographic distribution of Leishmania orientalis and Leishmania martiniquensis among Leishmania/HIV co-infection in Thailand

Since 1999, the number of asymptomatic leishmaniasis cases has increased continuously in Thailand, particularly among patients with HIV who are prone to develop symptoms of cutaneous and visceral leishmaniasis further. The asymptomatic infection could play a key role in Leishmania transmission and distribution. Understanding population structure and phylogeographic patterns could be crucially needed to develop effective diagnoses and appropriate guidelines for therapy. In this study, genetic variation and geographic distribution of the Leishmania/HIV co-infected population were investigated in endemic northern and southern Thailand. Interestingly, Leishmania orientalis was common and predominant in these two regions with common regional haplotype distribution but not for the others. Recent population expansion was estimated, probably due to the movement and migration of asymptomatic individuals; therefore, the transmission and prevalence of Leishmania infection could be underestimated. These findings of imbalanced population structure and phylogeographic distribution patterns provide valuable, insightful population structure and geographic distribution of Leishmania/HIV co-infection to empower prevention and control of transmission and expansion of asymptomatic leishmaniasis.

First Report of Two Jaculus Rodents as Potential Reservoir Hosts of Leishmania Parasites in Tunisia

This study shows, for the first time, natural Leishmania infection among Jaculus spp. in an endemic region of Tataouine, South Tunisia. To better characterize the transmission cycles in this complex focus of mixed transmission, Leishmania detection and species identification were performed by direct examination, internal transcribed spacer-1 (ITS1)-PCR-restriction fragment length polymorphism (RFLP), and sequencing of Jaculus (J.) jaculus (Linnaeus, 1758) and J. hirtipes (Lichtenstein, 1823) rodent species, which are frequently encountered in this area. Leishmania parasites were observed in 19 (41.3%) smears, while DNA parasites were detected in 28 (60.9%) Jaculus spp. spleens; among them, 12 (54.5%) were from 22 J. jaculus individuals and 16 (66.7%) were from 24 J. hirtipes individuals. Leishmania parasites were confirmed as Leishmania (L.) killicki (syn. L. tropica) in two J. hirtipes individuals (4.3%) and L. major (n = 24; 52.2%) in 10 J. jaculus and 14 J. hirtipes individuals. This finding represents the first evidence of natural infection with Leishmania parasites in rodents belonging to the Jaculus genus, providing the rationale to consider them as potential reservoir hosts of Old World Leishmania parasites in Tunisia and North Africa.

Bionomics and phylo-molecular analysis of Leishmania species isolated from human lesions using ITS1 genes in north-east of Iran

Leishmaniasis is a zoonotic infectious disease caused by Leishmania species. The identification of parasite species and the type of disease is beneficial for treatment and preventive modalities. Leishmania tropica and L. major have been reported as the main etiological agents of cutaneous leishmaniasis (CL) in Iran. The incidence of zoonotic CL has increased and different in distinct loci of Iran. Hence, we perused the Leishmania species and its genetic traits in the North East of Iran. The investigation was conducted on 200 positive smears prepared from patients' lesions suffering from CL referred to the health care centers of northeastern provinces in Iran from 2013 to 2019. The obtained positive microscopy samples were divided to score the ranges from + 1 to + 6, of them 40 smears exhibited low-parasitemia. Leishmania species analyzed using PCR-RFLP, genetic diversity indices evaluation, phylogenetic analysis, and sequencing comparison with other species in the GeneBank based on ITS1 gene. The isolated L. major strains were similar to other Iranian isolates in this region. Pairwise fixation index (F_ST) index was statistically significant in different L. major populations and showed the genetic differences in pairwise population of different geographical locations of Iran. The current study confirmed an old pattern endemicity of zoonotic CL in North-east of Iran. Therefore, in order to assess the hybrid formation, more epidemiological, ecological, and gene polymorphism studies are needed to understand the pathogenic role of Leishmania species in Iran.

The Geographical Distribution of Human Cutaneous and Visceral Leishmania Species Identified by Molecular Methods in Iran: A Systematic Review With Meta-Analysis

Leishmaniasis is one of the most common vector-borne parasitic diseases in Iran. Leishmania species identification is necessary for epidemiological aspects, precise prognosis, control and treatment of the disease. We systematically searched all the studies, reports, and documentation related to species identification and geographical distribution of causative agents of cutaneous (CL), mucosal (ML), and visceral leishmaniasis (VL) using DNA-based molecular diagnostic techniques in Iran. International databases including PubMed, ScienceDirect, Embase, Google Scholar, Scopus, and Web of Science were systemically searched for English articles and Iran's databases including SID, IranMedex and Magiran were searched for Persian reports and articles. Searches were performed from 1999 to 2019 (20 years). The current review was conducted using the keywords: cutaneous leishmaniasis, visceral leishmaniasis, Leishmania species, Human, Molecular, PCR, and Iran. The study quality was evaluated using the NOS checklist. This meta-analysis procedure was accomplished using STATA, version 2.7.9. Of the 3,426 records identified in the initial search, 154 articles met inclusion criteria and qualified for the systematic review and meta-analysis. In subgroup analysis, the pooled frequency of causative agents of CL isolates was 67.3% (95% CI: 59.51–74.67%) for L. major and 32.1% (95% CI: 24.72–39.87%) for L. tropica. In addition, the pooled frequency of causative agents of VL isolates was 97.1% (95% CI: 94.6–98.8%) for L. infantum and 2.9% (95% CI: 1.12–5.37%) for L. tropica. The findings of this study showed that the main causative agents of CL and VL in Iran are L. major and L. infantum, respectively. Moreover, kinetoplast DNA (kDNA) and internal transcriber spacer (ITS) were the most used markers for identifying Leishmania species. The current study provides valuable data to encourage and direct researchers as well as public health managers in the comprehensive leishmaniasis control and prevention planning in Iran.

Determinants of Unresponsiveness to Treatment in Cutaneous Leishmaniasis: A Focus on Anthroponotic Form Due to Leishmania tropica

Cutaneous leishmaniasis (CL) is a curable disease; however, due to various risk factors, unresponsiveness to CL treatments is inevitable. The treatment of CL has been firmly correlated with multiple determinants, such as demographical, clinical, and environmental factors, the host’s immune response, poor treatment adherence, the parasite’s genetic make-up, and Leishmania RNA virus. This study primarily focuses on the risk factors associated with different therapeutic outcomes following meglumine antimoniate (MA; Glucantime^®) treatment and policy approaches to prevent unresponsiveness in CL patients with a focus on anthroponotic form (ACL). Findings suggest that effective preventive and therapeutic measures should be more vigorously implemented, particularly in endemic areas. Accordingly, extensive training is essential to monitor drug unresponsiveness regularly, especially in tropical regions where the disease is prevalent. Since humans are the fundamental reservoir host of ACL due to L. tropica, prompt detection, early diagnosis, and timely and effective treatment could help control this disease. Furthermore, major challenges and gaps remain: efficacious vaccine, new tools, and expert staff are crucial before CL can be definitively controlled.

Genetic diversity of Leishmania tropica: Unexpectedly complex distribution pattern

In this study, we characterized a collection of clinical samples obtained from Syrian and Turkish patients with cutaneous leishmaniasis using internal transcribed spacer 1 (ITS1) sequences. All obtained sequences belonged to Leishmania tropica. Combining them with those available from GenBank allowed us performing a broad-scale analysis of genetic diversity for this species. We demonstrated that L. tropica has a complex phylogeographic pattern with some haplotypes being widespread across endemic countries and others restricted to particular regions. We hypothesize that at least some of them may be associated with alternative vectors or animal reservoirs.

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.

The Geographical Distribution of Cutaneous Leishmaniasis Causative Agents in Iran and Its Neighboring Countries, A Review

Leishmania tropica and Leishmania major are both the main cause of anthroponotic (ACL) and zoonotic cutaneous leishmaniasis (ZCL), respectively, in the Old World. Leishmania infantum and Leishmania donovani, which are important causes of visceral leishmaniasis, have also occasionally been reported in CL patients. The present study investigates the current distribution of causative species of CL in Iran and neighboring countries in the Middle East. There has been expansion of L. tropica into new urban and rural foci in Iran, with well-documented cases of visceralization, a substantial increase of CL in Syria, and the emergence of new foci and outbreaks in Turkey and Iraq, especially due to L. major. Civil war in Syria and Iraq, population movement, poverty, and climatic change play important roles in the changing CL distribution in this region. Control programs should adopt a multidisciplinary approach based on active surveillance and case finding, especially in vulnerable refugee populations, determination of hazard maps for CL hot points using GIS and other advanced technology, the free distribution of drugs, rodent control, and greater community engagement in poor and marginalized populations. Comprehensive molecular studies that could show the species and strains of Leishmania in different areas of each country can give a better view from the distribution of CL in this region.

Leishmania cytochrome b gene sequence polymorphisms in southern Iran: relationships with different cutaneous clinical manifestations

Background

Cutaneous leishmaniasis (CL) caused by Leishmania species, is a geographically extensive disease that infects humans and animals. CL is endemic in half of the 31 provinces of Iran, with 29,201 incidence cases reported in Fars province from 2010 to 2015. CL is polymorphic and may result in lesions characterized by different clinical features. Parasite genetic diversity is proposed to be one of the factors affecting the clinical outcome and lesion characteristics in CL patients. However, there is still very limited data regarding the genetic variation of Leishmania spp. based on the sequencing of Cytochrome b (Cyt b) gene.

Methods

All patients originated from endemic regions in Fars province. The amplification of the Cyt b gene from isolates of 100 patients with disparate clinical forms of CL was accomplished using Nested-PCR. Sequence analysis of the amplified Cyt b was used to scrutinize the genetic variations among Leishmania isolates and connect the results with clinical pictures. The clinical demonstrations were basically of two types, typical and atypical lesions. Molecular phylogenetic tree was constructed using the Neighbor-Joining method, with species/strains from this study compared to species/strains from other geographical regions.

Results

Leishmania major was identified as the predominant infecting Leishmania spp. (86% of cases), with the remainder of cases being infected by Leishmania tropica. Clinical examination of patients revealed 12 different clinical CL forms. Among Leishmania samples analyzed, five distinct haplotypes were recognized: three in L. major and two in L. tropica. We found a correlation between clinical outcomes and Cyt b sequence variation of Leishmania spp. involved. Moreover, we observed a higher presence of polymorphisms in L. major compared with L. tropica. This difference may be due to the different eco-epidemiologies of both species, with L. tropica being an anthroponosis compared to L. major, which is a zoonosis.

Conclusions

The sequence analysis of Cyt b gene from 25 L. major and L. tropica strains demonstrated genetic variability of L. major and L. tropica causing CL in southern Iran, and a feasible connection amid the genetic heterogeneity of the parasite, geographical source and clinical appearance of the disease in human was detected.

Population structures of Leishmania infantum and Leishmania tropica the causative agents of kala-azar in Southwest Iran

Visceral leishmaniasis (VL) is endemic in Iran and is caused predominantly by Leishmania infantum, but L. tropica is emerging as an important cause. We studied the intra-species population structure of Leishmania spp. causing VL in southwest Iran by sequence analysis of the internal transcribed spacer (ITS) 1 of DNA samples from 29 bone marrow aspiration smears. L. infantum (n = 25) and L. tropica (n = 4) were identified, consisting of 10 and three ITS1 sequence types (STs), respectively. Compared to GenBank ITS1 STs, our L. infantum parasites displayed high heterogeneity but less heterogeneity compared than northwest Iranian isolates. VL affects mostly nomadic populations in southwest Iran, and their mobility may explain partly the L. infantum heterogeneity. The VL causing L. tropica was also genetically heterogeneous but genetically indistinguishable from L. tropica strains causing anthroponotic cutaneous leishmaniasis from southwest Iran.

Population Structure of Leishmania tropica Causing Anthroponotic Cutaneous Leishmaniasis in Southern Iran by PCR-RFLP of Kinetoplastid DNA

Iran is one of the six countries with the most cutaneous leishmaniasis (CL) patients. Understanding better the genotypes of the parasite population in relation to geography and climate is critical to achieving better CL control. We aimed to characterise the population structure of Leishmania tropica, the cause of anthroponotic cutaneous leishmaniasis (ACL), from important foci in southeast (Bam and Kerman) and southwest (Shiraz) Iran. A total of 39 L. tropica isolates from ACL patients from southeast (Bam 14, Kerman 12) and southwest (Shiraz 13) Iran were analysed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) of the kinetoplast DNA (kDNA) using restriction enzymes MspI (HpaII) and ClaI. 37 genotypes were identified among south Iran L. tropica isolates. The unweighted pair group method with arithmetic mean (UPGMA) tree obtained from the banding patterns of ClaI digested kDNA RFLP distinguished southeast from and southwest L. tropica isolates with some subclustering but the MspI derived tree showed greater discrimination with greater subclustering and divergence of the two foci of southeast region but with some overlapping. Although a monophyletic structure has been defined for southeast L. tropica, isolates from two foci of southeast Iran were partly discriminated in the current study.

Role of environmental, climatic risk factors and livestock animals on the occurrence of cutaneous leishmaniasis in newly emerging focus in Iran

INTRODUCTION

Occurrence of leishmaniasis is affected by various biological and environmental factors. Kohgiluye and Boyerahmad (K-B) province is an emerging focus of cutaneous leishmaniasis (CL) in Southwest Iran.

SUBJECTS AND METHODS

To elucidate some angles of occurrence of CL in this province, climatic and environmental factors and close proximity to livestock were studied by univariate and two multivariate logistic regression models. The dwelling addresses of 275 CL patients were obtained from Health Centers records for a 5 years period. The effect of mean annual temperature, minimum mean annual temperature, maximum mean annual temperature, mean annual rainfall, slope, elevation, land covers and close proximity to cattle and sheep/goat sheds on the occurrence of CL were analysed using geographical information systems (GIS) approach.

RESULTS

CL occurred in all counties with the most cases in Northwest, West and South semi-arid and warm regions. Land cover, slope, elevation and close proximity to cattle sheds, were the most effective factors. Urban, dry farm and thin rangeland were found as the most important land covers. Slope and elevation decreased the probability of disease. Close proximity to cattle sheds notably increased the chance of CL. The importance of other factors such as rainfall, temperature and close proximity to sheep/goat sheds only were shown when their effects were evaluated independently from other factors. So regions with urban, dry farm and thin rangeland covers with lower slope and altitude where in close proximity of cattle sheds seems to be potentially most high risk areas.

CONCLUSION

Distribution of CL cases is influenced by combination of environmental, ecological factors and close proximity to livestock sheds but control programs should be focused on cities and villages in the above-mentioned most high risk regions.

Distribution pattern of anthroponotic cutaneous leishmaniasis caused by Leishmania tropica in Western Afghanistan during 2013-2014

Anthroponotic cutaneous leishmaniasis (ACL), caused by Leishmania tropica, is the main cause of cutaneous leishmaniasis (CL) in the Herat province, Western Afghanistan. We investigated the role of environmental factors on ACL distribution in Herat. Epidemiological data from 2457 patients were retrieved from the local WHO sub-office. Shapefile layers of districts, cities, villages, land cover, soil type and digital elevation model (DEM) of the Herat province were used to assess, by logistic regression modelling, the effects of land cover, soil types, elevation, and proximity to the Harirud river on the distribution of ACL. The key determinants of distribution were: (i) close proximity to the Harirud river, (ii) elevation between 700 and 1200m, (iii) intensive and intermittent irrigated cultivated land, and (iv) Haplocalcids with Torriorthents and Torrifluvents soil types. No ACL cases were found below 700m, and a few cases were present at >1200m in irrigated areas around the Harirud river. These findings suggest that moist soil and the humidity from irrigated areas found between 700 and 1200m provide suitable breeding sites of Phlebotomus sergenti, the main sandfly vector of L. tropica in Afghanistan. The effect of elevation also explains the predominance of ACL over ZCL in this region. The present study showed that distribution of ACL is strongly associated with environmental factors in West Afghanistan where the political and socio-economic conditions may also affect the epidemiology of CL.

Phylogenetic structure of Leishmania tropica in the new endemic focus Birjand in East Iran in comparison to other Iranian endemic regions

Iran has been identified being among the countries with the highest number of cutaneous leishmaniasis (CL) cases. South Khorasan province in East Iran is an emerging focus of CL. Species identification of sixty clinical samples by ITS1 PCR-RFLP presented evidence for the dominance of Leishmania tropica (90%) in this region. Analysis of the ITS1 sequence of 19 L. tropica isolates revealed seven closely related sequence types. In addition, ITS1 sequences available in GenBank from other Iranian regions were compiled for comparison with the studied isolates. Iranian L. tropica was distributed in two main clusters. All East Iranian sequence types were grouped with strains from foci from Southeast and Central regions in cluster A, showing highly similar sequences. The highest similarity was observed between most L. tropica from East and all isolates from Southeast regions and from Savojbolagh county in Central Iran. Southwest L. tropica was shown to be paraphyletic as the isolates were distributed in both clusters A and B. All Northeastern L. tropica were part of cluster B, however they showed significant heterogeneity and were distributed in different subclusters. Distribution of L. tropica populations was to some extent congruent with genetic lineages of Phlebotomus sergenti in Iran and may be an evidence for parasite-vector co-evolution. Southeast-East L. tropica was also similar to strains from Herat province in Afghanistan at the East border of Iran. This is the first comprehensive study on population structure of L. tropica in Iran that provides a guideline for appropriate sampling for further molecular based epidemiological studies.

Detection, molecular typing and phylogenetic analysis of Leishmania isolated from cases of leishmaniasis among Syrian refugees in Lebanon

Leishmania is a parasitic protozoan with more than two-dozen species causing the disease leishmaniasis. It is transmitted to humans through the bite of an infected female phlebotomine sand-fly vector. In the past two years the incidence of leishmaniasis has been drastically increasing in Lebanon. This was in parallel with the deterioration of the security in Syria forcing thousands to flee and seek shelter in poorly maintained refugee camps and collective shelters. Cutaneous leishmaniasis (CL) is now considered a public health problem, but its epidemiology has not been fully elucidated. To our knowledge, this is the first study comparing two different molecular methods for the detection and identification of Leishmania tropica in Lebanon. Two molecular typing methods of 39 FFPE Leishmania isolates were used: the ITS1-PCR RFLP and the nested ITS1-5.8S rDNA gene amplification followed by sequencing and phylogenetic analysis. The efficiency of these two techniques in Leishmania identification was compared and the phylogenetic relationships among these isolates were illustrated based on the neighbor-joining (NJ) method. The results were statistically correlated with the parasitic index (PI). The DNA storage in formalin-fixed paraffin embedded (FFPE) tissues was assessed as well. The parasites identified were all L. tropica as determined by both techniques. ITS1-5.8S rDNA gene based typing proved to be more sensitive in the detection of parasites (positive in 69.2% of the isolates) as opposed to the ITS1-PCR RFLP method that was successful in identifying L. tropica in only 43.6% of the isolates. Sequencing and phylogenetic analysis revealed high levels of heterogeneity. A statistically significant correlation was observed between PI and the results of the nested ITS1-5.8S rDNA gene PCR. Genotyping at the species level is essential for monitoring the relative frequency of CL in the Mediterranean area that is correlated to three different Leishmania species (Leishmania infantum, Leishmania major and L. tropica), each characterized by distinct epidemiological features. The obtained results highlight the need to find a universally accepted diagnostic tool for Leishmania typing.

Inter- and Intraspecific Variations of Leishmania Strains Isolated from Patients with Cutaneous and Visceral Leishmaniases in Fars Province, South of Iran

BACKGROUND

Cutaneous and visceral leishmaniases are present in Fars Province in the south of Iran. The current study aimed to evaluate the inter- and intragenic diversities of Leishmania species isolated from patients with leishmaniasis in Fars Province, using PCR-based analyses and DNA sequencing of the N-acetylglucosamine-1-phosphate transferase (nagt) gene.

METHODS

Clinical samples were taken from the skin lesions of 120 individuals with clinical suspicion of cutaneous leishmaniasis (CL) referred to the major health centers of Shiraz. Along with microscopic examination, a part of each sample was used for in vitro cultivation. DNA was extracted from the cultured parasites and the nagt gene was PCR-amplified. For RFLP analysis, the PCR product of the nagt gene was digested with the Acc1 restriction enzyme. Moreover, the PCR products of 23 isolates were sequenced and analyzed, using MEGA5.

RESULTS

From the 120 patients with clinical suspicion of CL, 110 (91.7%) cases were found to be positive by direct microscopy while 77 (64.1%) of the cultures were positive. Digestion of the PCR product with the Acc1 restriction enzyme detected L. major in 57 out of the 77 (74.1%) and L. tropica, in 20 out of the 77 (25.9%) cases with CL. Phylogenetic analysis grouped the Leishmania isolates into 3 main clades, representing L. major, L. infantum, and L. tropica, encompassing 2, 2, and 2 haplotypes, respectively. Within the clades, the L. tropica intraspecies divergence was more pronounced in L. major.

CONCLUSION

The findings of this study demonstrated that the causative agent of CL in Fars Province was mainly L. majorz and that there was considerable heterogeneity between the Leishmania species and also within the L. major isolates.

Molecular Epidemiological Survey of Cutaneous Leishmaniasis in Two Highly Endemic Metropolises of Iran, Application of FTA Cards for DNA Extraction From Giemsa-Stained Slides

Background:

PCR has been used for confirmation of leishmaniasis in epidemiological studies, but complexity of DNA extraction and PCR approach has confined its routine use in developing countries.

Objectives:

In this study, recent epidemiological situation of cutaneous leishmaniasis (CL) in two hyper-endemic metropolises of Shiraz and Isfahan in Iran was studied using DNA extraction by commercial FTA cards and kinetoplastid DNA (kDNA)-PCR amplification for detection/identification of Leishmania directly from stained skin scraping imprints.

Patients and Methods:

Fifty four and 30 samples were collected from clinically diagnosed CL patients referred to clinical laboratories of leishmaniasis control centers in Isfahan and Shiraz cities, respectively. The samples were examined by direct microscopy and then scrapings of the stained smears were applied to FTA cards and used directly as DNA source in a nested-PCR to amplify kDNA to detect and identify Leishmania species.

Results:

Fifty four of 84 (64.2%) slides obtained from patients had positive results microscopically, while 79/84 (94%) of slides had positive results by FTA card-nested-PCR. PCR and microscopy showed a sensitivity of 96.4% and 64.2% and specificity of 100% and 100%, respectively. Interestingly, Leishmania major as causative agent of zoonotic CL was identified in 100% and 90.7% of CL cases from Isfahan and Shiraz cities, respectively, but L. tropica was detected from only 9.3% of cases from Shiraz city. All cases from central regions of Shiraz were L. tropica and no CL case was found in Isfahan central areas.

Conclusions:

Filter paper-based DNA extraction can facilitate routine use of PCR for diagnosis of CL in research and diagnostic laboratories in Iran and countries with similar conditions. Epidemiologic changes including dominancy of L. major in suburbs of Shiraz and Isfahan metropolises where anthroponotic CL caused by L. tropica had been established, showed necessity of precise studies on CL epidemiology in old urban and newly added districts in the suburbs.

Molecular epidemiology of imported cases of leishmaniasis in Australia from 2008 to 2014

Leishmaniasis is a vector borne disease caused by protozoa of the genus Leishmania. Human leishmaniasis is not endemic in Australia though imported cases are regularly encountered. This study aimed to provide an update on the molecular epidemiology of imported leishmaniasis in Australia. Of a total of 206 biopsies and bone marrow specimens submitted to St Vincent’s Hospital Sydney for leishmaniasis diagnosis by PCR, 55 were found to be positive for Leishmania DNA. All PCR products were subjected to restriction fragment length polymorphism analysis for identification of the causative species. Five Leishmania species/species complexes were identified with Leishmania tropica being the most common (30/55). Travel or prior residence in a Leishmania endemic region was the most common route of acquisition with ~47% of patients having lived in or travelled to Afghanistan. Cutaneous leishmaniasis was the most common manifestation (94%) with only 3 cases of visceral leishmaniasis and no cases of mucocutaneous leishmaniasis encountered. This report indicates that imported leishmaniasis is becoming increasingly common in Australia due to an increase in global travel and immigration. As such, Australian clinicians must be made aware of this trend and consider leishmaniasis in patients with suspicious symptoms and a history of travel in endemic areas. This study also discusses the recent identification of a unique Leishmania species found in native kangaroos and a potential vector host which could create the opportunity for the establishment of a local transmission cycle within humans.