Genetic polymorphisms and drug susceptibility in four isolates of Leishmania tropica obtained from Canadian soldiers returning from Afghanistan

Modelling the number of dermal lesions in anthroponotic cutaneous leishmaniasis and its associated factors in Herat province, western Afghanistan, during 2012-2013

Cutaneous leishmaniasis (CL), caused by Leishmania tropica, is the main causative agent of CL in the Herat province, western Afghanistan. In CL patients, one of the most important indicators for reducing the amount of body damage and the choice of treatment is the number of dermal lesions, but there is no strong evidence in this regard. Therefore, using count regression models, the main objective of this historical cohort study was to identify the distribution of the number of dermal lesions and determine the associated factors among CL patients referring to leishmaniasis reference laboratory in Herat province, from January 2012 to December 2013. In a total of 4,127 clinically suspected CL cases, 50.20% were female and 49.80% male. Based on the results of ZINB model, which is the best model suggested by goodness-of-fit criteria, age variables (IRR = 1.007), duration of lesion (6-12 weeks compared to < 6 weeks with IRR = 1.36 and >12 weeks with IRR = 1.39 compared to <6 weeks), type of lesion(both nodule and ulcer compared to papule with IRR = 2.03), location of lesion (trunk with IRR = 1.90, upper with IRR = 1.66, lower with IRR = 1.61 and mix with IRR = 10.35 compared to head/neck/ears) and type of lesion (ulcer compared to papule with IRR = 0.50, nodule and lupoid, respectively, as IRR = 0.72 and IRR = 0.51 compared to papule) had a significant effect on the mean number of dermal lesions (p < .05). Also, our results showed that among four models used, the ZINB model represented a better performance to determine the associated probable factors about the number of dermal lesions in ACL patients. Moreover, there was a direct association between age and number of dermal lesions; in addition, duration of lesion, type of lesion and location of lesion had a significant effect on the number of dermal lesions. Therefore, a comprehensive planning is necessary for controlling and reducing the number of dermal lesions.

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.

Evaluation of MDR1 and MRPA genes expression in different types of dry cutaneous leishmaniasis

Objective

The resistance to antimony-containing glucantime is a major obstacle to successful treatment, especially in endemic areas. Looking the molecular mechanisms involved in this drug resistance will help in choosing the best treatment. The aim of this study was to evaluate the expression of multidrug-resistance 1 (MDR1) and multidrug-resistance protein A (MRPA) genes in acute, chronic non-lupoid, and chronic lupoid forms of dry type cutaneous leishmaniasis (DTCL).

Results

MDR1 gene was over-expressed as 14.4- and 1.56-folds in the chronic lupoid and acute forms compared with the chronic non-lupoid form, respectively. Results comparison showed P < 0.05 between the chronic non-lupoid and acute groups, P < 0.01 between acute and chronic lupoid groups, and P < 0.001 between the chronic non-lupoid and chronic lupoid groups. MRPA gene was over-expressed as 266 and 17.7-fold in the chronic lupoid and chronic non-lupoid forms compared with the acute form, respectively. Statistical analysis showed P < 0.01 between the chronic non-lupoid and chronic lupoid groups, P < 0.05 between acute and chronic non-lupoid groups, and P < 0.001 between the acute and chronic lupoid groups.

Effects of time-lagged meteorological variables on attributable risk of leishmaniasis in central region of Afghanistan

BACKGROUND

Leishmaniasis remains one of the world's most neglected vector-borne diseases, affecting predominantly poor communities mainly in developing countries. Previous studies have shown that the distribution and dynamics of leishmaniasis infections are sensitive to environmental factors, however, there are no studies on the burden of leishmaniasis attributable to time-varying meteorological variables.

METHODS

This study used data from 3 major leishmaniosis afflicted provinces of Afghanistan, between 2003 and 2009, to provide empirical analysis of change in heat/cold-leishmaniosis association. Non-linear and delayed exposure-lag-response relationship between meteorological variables and leishmaniasis were fitted with a distributed lag non-linear model applying a spline function which describes the dependency along the range of values with a lag of up to 12 months. We estimated the risk of leishmaniasis attributable to high and low temperature.

RESULTS

The median monthly mean temperature and rainfall were 16.1 °C and 0.6 in., respectively. Seasonal variations of leishmaniasis were consistent between males and females, however significant differences were observed among different age groups. Temperature effects were immediate and persistent (lag 0-12 months). The cumulative risks were highest at cold temperatures. The cumulative relative risks (logRR) for leishmaniasis were 6.16 (95% CI: 5.74-6.58) and 1.15 (95% CI: 1.32-1.31) associated with the 10th percentile temperature (2.16 °C) and the 90th percentile temperature (28.46 °C). The subgroup analysis showed increased risk for males as well as young and middle aged people at cold temperatures, however, higher risk was observed for the elderly in heat. The overall leishmaniasis-temperature attributable fractions was estimated to be 7.6% (95% CI: 7.5%-7.7%) and mostly due to cold.

CONCLUSION

Findings in this study highlight the non-linearity, delay of effects and magnitude of leishmaniasis risk associated with temperature. The disparity of risk between different subgroups can hopefully advise policy makers and assist in leishmaniasis control program.

Oral activity of the antimalarial endoperoxide 6-(1,2,6,7-tetraoxaspiro[7.11]nonadec-4-yl)hexan-1-ol (N-251) against Leishmania donovani complex

Visceral leishmaniasis (VL) is a major problem worldwide and causes significant morbidity and mortality. Existing drugs against VL have limitations, including their invasive means of administration long duration of treatment regimens. There are also concerns regarding increasing treatment relapses as well as the identification of resistant clinical strains with the use of miltefosine, the sole oral drug for VL. There is, therefore, an urgent need for new alternative oral drugs for VL. In the present study, we show the leishmanicidal effect of a novel, oral antimalarial endoperoxide N-251. In our In vitro studies, N-251 selectively and specifically killed Leishmania donovani D10 amastigotes with no accompanying toxicity toward the host cells. In addition, N-251 exhibited comparable activities against promastigotes of L. donovani D10, as well as other L. donovani complex parasites, suggesting a wide spectrum of activity. Furthermore, even after a progressive infection was established in mice, N-251 significantly eliminated amastigotes when administered orally. Finally, N-251 suppressed granuloma formation in mice liver through parasite death. These findings indicate the therapeutic effect of N-251 as an oral drug, hence suggest N-251 to be a promising lead compound for the development of a new oral chemotherapy against VL.

Isolation of Crithidia spp. from lesions of immunocompetent patients with suspected cutaneous leishmaniasis in Iran

OBJECTIVE

Leishmania major has been considered as the main aetiological agent of cutaneous leishmaniasis in Iran. However, there are recent reports about the existence of Crithidia spp in cutaneous lesions in southern Iran. Therefore, this study was designed to decipher some morphological, biological and molecular aspects of this phenomenon.

METHODS

Clinical isolates were obtained from 167 patients with cutaneous ulcers. A set of specific primers based on GAPDH (Glyceraldehyde-3-Phosphate Dehydrogenase) gene were used to distinguish between Crithidia and Leishmania genera. For molecular analysis, Pulsed Field Gel Electrophoresis and Mi-Seq Illumina platform were applied. Then, morphological analysis and some biological features (including potential growth at 37 °C and the ability of infecting mammalian macrophages) were studied.

RESULTS

In 92.8% of clinical cases, L. major was the only causative microorganism isolated; in 5.4% of cases, co-infection of L. major and Crithidia spp. was identified; and in 1.8% of lesions, only Crithidia spp. were found.

CONCLUSION

We isolated Crithidia spp. from clinical samples of patients suspected of cutaneous leishmaniasis in Iran, indicating that Crithidia spp. are capable of surviving at human body temperature and infecting macrophage cells. This raises questions on the influence of this phenomenon on pathogenicity, therapeutic outcome and disease control strategies.

Gene expression analysis of antimony resistance in Leishmania tropica using quantitative real-time PCR focused on genes involved in trypanothione metabolism and drug transport

Pentavalent antimonials remain the treatment of choice for all the clinical forms of leishmaniasis. The increasing rates of antimony resistance are becoming a serious health problem in treatment of anthroponotic cutaneous leishmaniasis (ACL). Accordingly, unraveling molecular markers is crucial for improving medication strategies and monitoring of drug-resistant parasites. Different studies have suggested the importance of genes involved in trypanothione metabolism and drug transport. In this regard, present study was designed to investigate the RNA expression level of five genes including γ-GCS, ODC, TRYR (involved in trypanothione metabolism), AQP1 (acts in drug uptake) and MRPA (involved in sequestration of drug) in sensitive and resistant Leishmania tropica isolates. Seven antimony-resistant and seven antimony-sensitive L. tropica clinical isolates were collected from ACL patients. Drug sensitivity test was performed on the samples as well as reference strains; afterwards, gene expression analysis was performed on clinical isolates by quantitative real-time PCR. The results revealed that the average expression level of AQP1 gene was decreased (0.47-fold) in resistant isolates compared to sensitive ones whereas MRPA (2.45), γ-GCS (2.1) and TRYR (1.97) was upregulated in resistant isolates. The average expression of ODC (1.24-fold) gene was not different significantly between sensitive and resistant isolates. Our findings suggest that AQP1, MRPA, GSH1 and TRYR can be considered as potential molecular markers for screening of antimony resistance in some L. tropica clinical isolates.

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.

Variability of Cutaneous Leishmaniasis Lesions Is Not Associated with Genetic Diversity of Leishmania tropica in Khyber Pakhtunkhwa Province of Pakistan

Leishmania tropica is the causative agent of cutaneous leishmaniasis in Pakistan. Here, intraspecific diversity of L. tropica from northern Pakistan was investigated using multilocus microsatellite typing. Fourteen polymorphic microsatellite markers were typed in 34 recently collected L. tropica isolates from Pakistan along with 158 archival strains of diverse Afro-Eurasian origins. Previously published profiles for 145 strains of L. tropica originating from different regions of Africa, Central Asia, Iran, and Middle East were included for comparison. Six consistently well-supported genetic groups were resolved: 1) Asia, 2) Morroco A, 3) Namibia and Kenya A, 4) Kenya B/Tunisia and Galilee, 5) Morocco B, and 6) Middle East. Strains from northern Pakistan were assigned to Asian cluster except for three that were placed in a geographically distant genetic group; Morocco A. Lesion variability among these Pakistani strains was not associated with specific L. tropica genetic profile. Pakistani strains showed little genetic differentiation from strains of Iraq, Afghanistan, and Syria (F_ST = 0.00-0.06); displayed evidence of modest genetic flow with India (F_ST = 0.14). Furthermore, genetic structuring within these isolates was not geographically defined. Pak-Afghan cluster was in significant linkage disequilibrium (I_A = 1.43), had low genetic diversity, and displayed comparatively higher heterozygosity (F_IS = -0.62). Patterns of genetic diversity observed suggest dominance of a minimally diverse clonal lineage within northern Pakistan. This is surprising as a wide clinical spectrum was observed in patients, suggesting the importance of host and other factors. Further genotyping studies of L. tropica isolates displaying different clinical phenotypes are required to validate this potentially important observation.

Gene Expression in Leishmania Is Regulated Predominantly by Gene Dosage

Leishmania tropica, a unicellular eukaryotic parasite present in North and East Africa, the Middle East, and the Indian subcontinent, has been linked to large outbreaks of cutaneous leishmaniasis in displaced populations in Iraq, Jordan, and Syria. Here, we report the genome sequence of this pathogen and 7,863 identified protein-coding genes, and we show that the majority of clinical isolates possess high levels of allelic diversity, genetic admixture, heterozygosity, and extensive aneuploidy. By utilizing paired genome-wide high-throughput DNA sequencing (DNA-seq) with RNA-seq, we found that gene dosage, at the level of individual genes or chromosomal "somy" (a general term covering disomy, trisomy, tetrasomy, etc.), accounted for greater than 85% of total gene expression variation in genes with a 2-fold or greater change in expression. High gene copy number variation (CNV) among membrane-bound transporters, a class of proteins previously implicated in drug resistance, was found for the most highly differentially expressed genes. Our results suggest that gene dosage is an adaptive trait that confers phenotypic plasticity among natural Leishmania populations by rapid down- or upregulation of transporter proteins to limit the effects of environmental stresses, such as drug selection.IMPORTANCELeishmania is a genus of unicellular eukaryotic parasites that is responsible for a spectrum of human diseases that range from cutaneous leishmaniasis (CL) and mucocutaneous leishmaniasis (MCL) to life-threatening visceral leishmaniasis (VL). Developmental and strain-specific gene expression is largely thought to be due to mRNA message stability or posttranscriptional regulatory networks for this species, whose genome is organized into polycistronic gene clusters in the absence of promoter-mediated regulation of transcription initiation of nuclear genes. Genetic hybridization has been demonstrated to yield dramatic structural genomic variation, but whether such changes in gene dosage impact gene expression has not been formally investigated. Here we show that the predominant mechanism determining transcript abundance differences (>85%) in Leishmania tropica is that of gene dosage at the level of individual genes or chromosomal somy.

In vitro drug susceptibility of two strains of the wildlife trypanosome, Trypanosoma copemani: A comparison with Trypanosoma cruzi

Trypanosomes are blood protozoan parasites that are capable of producing illness in the vertebrate host. Within Australia, several native Trypanosoma species have been described infecting wildlife. However, only Trypanosoma copemani has been associated with pathological lesions in wildlife hosts and more recently has been associated with the drastic decline of the critically endangered woylie (Bettongia penicillata). The impact that some trypanosomes have on the health of the vertebrate host has led to the development of numerous drug compounds that could inhibit the growth or kill the parasite. This study investigated and compared the in vitro susceptibility of two strains of T. copemani (G1 and G2) and one strain of Trypanosoma cruzi (10R26) against drugs that are known to show trypanocidal activity (benznidazole, posaconazole, miltefosine and melarsoprol) and against four lead compounds, two fenarimols and two pyridine derivatives (EPL-BS1937, EPL-BS2391, EPL-BS0967, and EPL-BS1246), that have been developed primarily against T.cruzi. The in vitro cytotoxicity of all drugs against L6 rat myoblast cells was also assessed. Results showed that both strains of T. copemani were more susceptible to all drugs and lead compounds than T. cruzi, with all IC50 values in the low and sub-μM range for both species. Melarsoprol and miltefosine exhibited the highest drug activity against both T. copemani and T. cruzi, but they also showed the highest toxicity in L6 cells. Interestingly, both fenarimol and pyridine derivative compounds were more active against T. copemani and T. cruzi than the reference drugs benznidazole and posaconazole. T. copemani strains exhibited differences in susceptibility to all drugs demonstrating once again considerable differences in their biological behaviour.

Pathways leading to interleukin-12 production and protective immunity in cutaneous leishmaniasis

Leishmaniasis affects millions of people worldwide and continues to pose public health problem. There is extensive evidence supporting the critical role for IL-12 in initiating and maintaining protective immune response to Leishmania infection. Although gene deletion studies show that CD40-CD40L interaction is an important pathway for IL-12 production by antigen-presenting cells and subsequent development of protective immunity in cutaneous leishmaniasis, several studies have uncovered other pathways that could also lead to IL-12 production and immunity in the absence of intact CD40-CD40L signaling. Here, we review the literature on the role of IL-12 in the induction and maintenance of protective T cell-mediated immunity in cutaneous leishmaniasis and the different pathways leading to IL-12 production by antigen-presenting cells following Leishmania major infection.

[Epidemiology and prevention of leishmaniasis in northern Afghanistan]

BACKGROUND

Leishmaniasis is estimated to cause the ninth largest disease burden among infectious diseases worldwide and it is not preventable by vaccination or chemoprophylaxis, but only by personal protective measures preventing bites of infectious arthropod vectors.

OBJECTIVES

Which leishmania species are endemic in northern Afghanistan, what are the clinical characteristics of skin lesions produced by cutanizing leishmania species, what are their epidemiological characteristics, and which preventive measures are feasible?

METHODS

The medical literature was reviewed, knowledge gaps were analyzed and completed by our own data collected locally.

RESULTS

Four Leishmania species are considered endemic in northern Afghanistan, of which Leishmania tropica, L. major, and L. donovani can produce skin lesions while L. donovani and L. infantum visceralize. Transmission modes and seasons vary markedly among focally epidemic urban anthroponotic L. tropica and rural enzootic L. major. Combined preventive measures may reduce the infection rate by more than 10,000-fold.

CONCLUSION

Cutaneous as well as visceral leishmaniasis can occur among returnees from Afghanistan. Atypical, poorly healing skin lesions can be caused by L. donovani. Extensive use of personal protective measures against arthropod vectors is strongly recommended for all travelers.

[Cutaneous leishmaniasis. Diagnosis and therapy in northern Afghanistan]

BACKGROUND

The German S1 guidelines from 2009 contain a variety of recommendations for the treatment of cutaneous leishmaniasis.

PATIENTS AND METHODS

We report the results of our diagnostic procedures and treatment of 32 international patients in autumn 2010 in northern Afghanistan.

RESULTS

Giemsa stain confirmed the clinical diagnosis within 24 hours. Eleven simple lesions and one larger ulcer responded well to cryotherapy and intralesional sodium stibogluconate. More complex lesions in 19 patients responded well to oral miltefosine. One patient refused outpatient therapy.

CONCLUSIONS

Cryotherapy and intralesional antimony compounds showed good results in early lesions of cutaneous leishmaniasis in northern Afghanistan. Outpatient treatment of complex lesions with miltefosine was successful in all cases.

Rapid healing of cutaneous leishmaniasis by high-frequency electrocauterization and hydrogel wound care with or without DAC N-055: a randomized controlled phase IIa trial in Kabul

Background

Anthroponotic cutaneous leishmaniasis (CL) due to Leishmania (L.) tropica infection is a chronic, frequently disfiguring skin disease with limited therapeutic options. In endemic countries healing of ulcerative lesions is often delayed by bacterial and/or fungal infections. Here, we studied a novel therapeutic concept to prevent superinfections, accelerate wound closure, and improve the cosmetic outcome of ACL.

Methodology/Principal Findings

From 2004 to 2008 we performed a two-armed, randomized, double-blinded, phase IIa trial in Kabul, Afghanistan, with patients suffering from L. tropica CL. The skin lesions were treated with bipolar high-frequency electrocauterization (EC) followed by daily moist-wound-treatment (MWT) with polyacrylate hydrogel with (group I) or without (group II) pharmaceutical sodium chlorite (DAC N-055). Patients below age 5, with facial lesions, pregnancy, or serious comorbidities were excluded. The primary, photodocumented outcome was the time needed for complete lesion epithelialization. Biopsies for parasitological and (immuno)histopathological analyses were taken prior to EC (1^st), after wound closure (2^nd) and after 6 months (3^rd). The mean duration for complete wound closure was short and indifferent in group I (59 patients, 43.1 d) and II (54 patients, 42 d; p = 0.83). In patients with Leishmania-positive 2^nd biopsies DAC N-055 caused a more rapid wound epithelialization (37.2 d vs. 58.3 d; p = 0.08). Superinfections occurred in both groups at the same rate (8.8%). Except for one patient, reulcerations (10.2% in group I, 18.5% in group II; p = 0.158) were confined to cases with persistent high parasite loads after healing. In vitro, DAC N-055 showed a leishmanicidal effect on pro- and amastigotes.

Conclusions/Significance

Compared to previous results with intralesional antimony injections, the EC plus MWT protocol led to more rapid wound closure. The tentatively lower rate of relapses and the acceleration of wound closure in a subgroup of patients with parasite persistence warrant future studies on the activity of DAC N-055.

Trial Registration

ClinicalTrails.gov NCT00947362

In many countries of the Middle East such as Afghanistan, cutaneous leishmaniasis is a highly prevalent, chronic and stigmatizing skin disease. Poor hygiene conditions frequently aggravate the lesions due to bacterial and fungal superinfections. Classical treatments with injections of pentavalent antimony are hampered by costs, side effects, resistance development, supply and manufactural quality problems. In the present study on Afghan patients with Leishmania tropica-induced skin lesions we evaluated the clinical effect of an initial removal of lesion tissue by electrocoagulation using a bipolar high-frequency electrosurgery instrument, followed by daily moist wound treatment with or without a preparation of pharmaceutical sodium chlorite (DAC N-055). DAC N-055 is a compound with anti-infective, immunomodulatory and tissue repair-promoting effects. Our analysis revealed that the carefully performed moist wound treatment led to a rapid healing of the wounds within an average period of 6 weeks, even in the absence of the sodium chlorite preparation. This is considerably faster than the time spans previously reported for local or systemic antimony treatment. We believe that the current standard for local care of chronic wounds should also be applied to Leishmania skin lesions. If combined with an initial single high-frequency electrocoagulation, it is a highly effective, inexpensive and well-tolerated treatment option for cutaneous leishmaniasis.