Cutaneous and mucocutaneous leishmaniasis

Leishmania donovani Growth Inhibitors from Pathogen Box Compounds of Medicine for Malaria Venture

INTRODUCTION

Leishmaniasis is a collective term used to describe various pathological conditions caused by an obligate intracellular protozoan of the genus Leishmania. It is one of the neglected diseases and has been given minimal attention by drug discovery and development stakeholders to narrow the safety and efficacy gaps of the drugs currently used to treat leishmaniasis. The challenge is further exacerbated by the emergence of drug resistance by the parasites.

METHODS

Aiming to look for potential anti-leishmanial hits and leads, we screened Medicines for Malaria Venture (MMV) Pathogen Box compounds against clinically isolated Leishmania donovani strain. In this medium-throughput primary screening assay, the compounds were screened against promastigotes, and then against amastigote stages.

RESULTS

From the total 400 compounds screened, 35 compounds showed >50% inhibitory activity on promastigotes in the initial screen (1 μM). Out of these compounds, nine showed >70% inhibition, with median inhibitory concentration (IC50) ranging from 12 to 491 nM using the anti-promastigote assay, and from 53 to 704 nM using the intracellular amastigote assay. Identified compounds demonstrated acceptable safety profiles on THP-1 cell lines and sheep red blood cells, and had appropriate physicochemical properties suitable for further drug development. Two compounds (MMV690102 and MMV688262) were identified as leads. The anti-tubercular agent MMV688262 (delamanid) showed a synergistic effect with amphotericin B, indicating the prospect of using this compound for combination therapy.

CONCLUSION

The current study indicates the presence of additional hits which may hold promise as starting points for anti-leishmanial drug discovery and in-depth structure-activity relationship studies.

Characterization of serum cytokines and circulating microRNAs that are predicted to regulate inflammasome genes in cutaneous leishmaniasis patients

Leishmaniasis is a neglected disease caused by an intracellular protozoan parasite of the genus Leishmania. Infection starts when this protozoan replicates in a phagolysosomal compartment in macrophages, after evading host immune responses. The balance of Th1 and Th2 immune responses is crucial in leishmaniasis because it will determine whether the infection will be under control or if clinical complications will occur. The inflammasome, which is activated during Leishmania infection, involves the action of caspase-1 and release of the proinflammatory cytokines interleukin-1β and interleukin-18. Together, they contribute to the maintenance of an inflammatory response and pyroptosis. Here, we evaluated the serum levels of cytokines and the expression of circulating microRNAs related to inflammasome regulation in twenty-seven patients with cutaneous leishmaniasis in comparison to nine healthy individuals, in the context of the inflammasome activation. Evaluation of serum cytokines activation (IL-1β, IL-2, IL-4, IL-6, IL-10, and IL-17) was performed by flow cytometry using CBA kits (cytometric beads array) while the expression of circulating microRNAs (miR-7, miR-133a, miR-146b, miR-155, miR-223, miR-328, and miR-342) in plasma was measured by quantitative polymerase chain reaction. Our results showed an increase of the expression of miR-7-5p (p < 10^-5), miR-133a (p = 0.034), miR-146b (p = 0.003), miR-223-3p (p = 10^-5), and miR-328-3p (p = 0.002), and cytokine levels for IL-1β (p = 0.0005), IL-6 (p = 0.001), and IL-17 (p = 0.001) in patients with cutaneous leishmaniasis compared to the controls. These results suggest that microRNAs and cytokines can play an important role in regulating the human immune responses to Leishmania infection. Our findings may contribute to the understanding of the mechanisms of the gene regulation during the cutaneous leishmaniasis and to the identification of possible biomarkers of the infection.

Structural characterization by scattering and spectroscopic methods and biological evaluation of polymeric micelles of poloxamines and TPGS as nanocarriers for miltefosine delivery

Miltefosine (MF), an alkylphospholipid originally developed for breast cancer treatment, is a highly active drug for the treatment against leishmaniasis, a neglected tropical disease considered the world's second leading cause of death by a parasitic agent after malaria. MF exhibits dose-limiting gastrointestinal side effects in patients and its penetration through lipophilic barriers is reduced. In this work we propose a reformulation of MF by incorporating the drug to poly(ethylene)oxide (PEO)-based polymeric micelles, specifically, D-α-tocopheryl polyethylene glycol succinate (TPGS) and Tetronic block copolymers (T904 and T1107). A full structural characterization of the aggregates has been carried out by SANS (small-angle neutron scattering) and dynamic light scattering (DLS), in combination with proton 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, to determine the precise location of the drug. The structure of MF micelles has been characterized as a function of the temperature and concentration. In the presence of the block-copolymers, MF forms mixed micelles in a wide range of temperatures, TPGS being the co-surfactant that incorporates more MF unimers. The hydrophobic tail of MF and those of the block copolymers are in close contact within the micelles, which present a core-shell structure with a hydrophilic corona formed by the PEG blocks of the TPGS and the zwitterion head group of the MF. In order to identify the best carrier, the antileishmanicidal activity of MF in the different formulations has been tested on macrophages, promastigotes and intracellular amastigotes. The combination of the three vehicles with MF makes the formulated drug more active than MF alone against L. major promastigotes, however, only the combination with T904 increases the MF activity against intracellular amastigotes. With the aim of exploring gel-based formulations of the drug, the combination of MF and T1107 under gelation conditions has also been investigated.

Cutaneous and mucocutaneous leishmaniasis: experience of a Mediterranean hospital

Background

Leishmaniasis, considered by the World Health Organization as one of the most important tropical diseases, is endemic in the Mediterranean Basin. The aim of this study was to evaluate epidemiological and clinical characteristics of cutaneous (CL) and mucocutaneous leishmaniasis (MCL) in La Fe University Hospital, Valencia, Spain. The particular focus was on diagnosis techniques and clinical differences according to the immunological status of the patients.

Methods

An eleven-year retrospective observational study of CL and MCL episodes at the hospital was performed. Epidemiological, clinical and therapeutic variables of each case, together with the microbiological and anatomopathological diagnosis, were analyzed.

Results

A total of 42 patients were included, 30 of them were male and 28 were immunocompetent. Most of the cases (36/42) were diagnosed in the last 5 years (2013–2017). The incidence of CL and MCL increased from 3.6/100,000 (2006–2012) to 13.58/100,000 (2013–2017). The majority of the patients (37/42) exhibited CL, in 30 cases as single lesions (30/37). Ulcerative lesions were more common in immunosuppressed patients (13/14) than in immunocompetent patients (20/28), (P = 0.2302). The length of lesion presence before diagnosis was 7.36 ± 6.72 months in immunocompetent patients and 8.79 ± 6.9 months in immunosuppressed patients (P = 0.1863). Leishmania DNA detection (92.3%) was the most sensitive diagnostic technique followed by Giemsa stain (65%) and histopathological examination (53.8%). Twelve patients (12/42) had close contact with dogs or were living near to kennels, and 10 of them did not present underlying conditions. Intralesional glucantime (21/42) and liposomal amphotericin B (7/42) were the most common treatments administered in monotherapy. All patients evolved successfully and no relapse was reported.

Conclusions

Some interesting clinical and epidemiological differences were found in our series between immunocompetent and immunosuppressed patients. Future studies can take these results further especially by studying patients with biological therapy. Skin biopsies combining NAAT with histological techniques are the most productive techniques for CL or MCL diagnosis.

Optimization of phthalazin-based aryl/heteroarylhydrazones to design new promising antileishmanicidal agents: synthesis and biological evaluation of 3-aryl-6-piperazin-1,2,4-triazolo[3,4-a]phthalazines

1-Monosubstituted and 1,4-substituted phthalazins based on aryl/heteroarylhydrazinyl have demonstrated attractive antileishmanial profiles against amastigote forms of the Leishmania braziliensis parasite.

Protein glycosylation inLeishmaniaspp

Protein glycosylation is a co- and post-translational modification that, inLeishmaniaparasites, plays key roles in vector–parasite–vertebrate host interaction.

Leishmania RNA virus exacerbates Leishmaniasis by subverting innate immunity via TLR3-mediated NLRP3 inflammasome inhibition

Leishmania RNA virus (LRV) is an important virulence factor associated with the development of mucocutaneous Leishmaniasis, a severe form of the disease. LRV-mediated disease exacerbation relies on TLR3 activation, but downstream mechanisms remain largely unexplored. Here, we combine human and mouse data to demonstrate that LRV triggers TLR3 and TRIF to induce type I IFN production, which induces autophagy. This process results in ATG5-mediated degradation of NLRP3 and ASC, thereby limiting NLRP3 inflammasome activation in macrophages. Consistent with the known restricting role of NLRP3 for Leishmania replication, the signaling pathway triggered by LRV results in increased parasite survival and disease progression. In support of this data, we find that lesions in patients infected with LRV+ Leishmania are associated with reduced inflammasome activation and the development of mucocutaneous disease. Our findings reveal the mechanisms triggered by LRV that contribute to the development of the debilitating mucocutaneous form of Leishmaniasis.

Cutaneous leishmaniasis: A great imitator

Cutaneous leishmaniasis (CL) is called "the great imitator," because it can mimic almost all types of dermatoses. This similarity may sometimes lead to misdiagnosis, resulting in inappropriate treatment and morbidities. Atypical forms occur due to the interaction between parasitic factors and the host immune response. Secondary infection or mistreatment of CL can also alter the natural course, resulting in bizarre and misdiagnosed cases. Atypical leishmaniasis should be considered in longstanding and painless lesions that may simulate erysipelas, dermatitis, verruca, herpes zoster, paronychia, and sporotrichosis. Less commonly, sarcoidosis, deep mycosis, basal and squamous cell carcinoma, cutaneous lymphoma, or pseudolymphomalike lesions may need to be considered in the differential diagnosis. A high index of suspicion is required to consider a diagnosis of CL, especially in nonendemic or newly endemic regions. Smear, histopathologic examination, culture, and polymerase chain reaction serve as important tools to differentiate CL from its clinical and histologic look-alikes. CL is discussed from various perspectives, with emphasis on CL and its broad differential diagnosis.

Transcriptional Analysis of Human Skin Lesions Identifies Tryptophan-2,3-Deoxygenase as a Restriction Factor for Cutaneous Leishmania

Disease manifestation after infection with cutaneous Leishmania species is the result of a complex interplay of diverse factors, including the immune status of the host, the infecting parasite species, or the parasite load at the lesion site. Understanding how these factors impact on the pathology of cutaneous leishmaniasis (CL) may provide new targets to manage the infection and improve clinical outcome. We quantified the relative expression of 170 genes involved in a diverse range of biological processes, in the skin biopsies from patients afflicted with CL caused by infection with either L. major or L. tropica. As compared to healthy skin, CL lesions bear elevated levels of transcripts involved in the immune response, and conversely, present a significant downregulation in the expression of genes involved in epidermal integrity and arginine or fatty acid metabolism. The expression of transcripts encoding for cytotoxic mediators and chemokines in lesions was inversely correlated with the expression of genes involved in epidermal integrity, suggesting that cytotoxicity is a major mediator of CL pathology. When comparing the transcriptional profiles of lesions caused by either L. major or L. tropica, we found them to be very similar, the later presenting an aggravated inflammatory/cytotoxic profile. Finally, we identified genes positively correlated with the parasite load in lesions. Among others, these included Th2 or regulatory cytokines, such as IL4 or IL10. Remarkably, a single gene among our dataset, encoding for tryptophan-2,3-deoxygenase (TDO), presented a negative correlation with the parasite load, suggesting that its expression may restrict parasite numbers in lesions. In agreement, treatment of macrophages infected with L. major in vitro with a TDO inhibitor led to an increase in parasite transcripts. Our work provides new insights into the factors that impact CL pathology and identifies TDO as a restriction factor for cutaneous Leishmania.

Cutaneous leishmaniasis: A neglected disfiguring disease for women

Leishmaniasis is one of eight neglected tropical diseases currently endemic in 102 countries/areas around the world. In recent years, cutaneous leishmaniasis (CL) has been increasingly observed among migrants, travelers, ecotourists, and military personnel. Because of its great capacity to mimic other dermatoses, CL is one of the great imitators and can mislead practitioners, which can result in untreated lesions that cause scars. CL is a disfiguring disease, especially for women, and often leaves scars on visible body sites, causing psychological, social, and economic problems. CS is a challenge, especially in nonendemic regions, such as Australia, because experience with diagnosis and management of the disease is limited.

Route map for the discovery and pre-clinical development of new drugs and treatments for cutaneous leishmaniasis

Although there have been significant advances in the treatment of visceral leishmaniasis (VL) and several novel compounds are currently in pre-clinical and clinical development for this manifestation of leishmaniasis, there have been limited advances in drug research and development (R & D) for cutaneous leishmaniasis (CL). Here we review the need for new treatments for CL, describe in vitro and in vivo assays, models and approaches taken over the past decade to establish a pathway for the discovery, and pre-clinical development of new drugs for CL. These recent advances include novel mouse models of infection using bioluminescent Leishmania, the introduction of PK/PD approaches to skin infection, and defined pre-clinical candidate profiles.

Identification of dehydroxy isoquine and isotebuquine as promising antileishmanial agents

Traditional antimalarial drugs based on 4-aminoquinolines have exhibited good antiproliferative activities against Leishmania parasites; however, their clinical use is currently limited. To identify new 4-aminoquinolines to combat American cutaneous leishmaniasis, we carried out a full in vitro evaluation of a series of dehydroxy isoquines and isotebuquines against two Leishmania parasites such as Leishmania braziliensis and Leishmania mexicana. First, the antiproliferative activity of the quinolines was studied against the promastigote forms of L. braziliensis and L. mexicana parasites, finding that five of them exhibited good antileishmanial responses with micromolar IC₅₀ values ranging from 3.84 to 10 μM. A structure-activity relationship analysis gave evidence that a piperidine or a morpholine attached as N-alkyamino terminal substituent as well as the inclusion of an extra phenyl ring attached at the aniline ring of the isotebuquine core constitute important pharmacophores to generate the most active derivatives, with antileishmanial responses by far superior to those found for the reference drug, glucantime. All compounds showed a relatively low toxicity on human dermis fibroblasts, with CC₅₀ ranging from 69 to >250 μM. The five most active compounds displayed moderate to good antileishmanial activity against the intracellular amastigote form of L. braziliensis, compared to the reference drug. In particular, compound 2j was identified as the most potent agent against antimony-resistant amastigotes of L. braziliensis with acceptable biological response and selectivity, emerging as a promising candidate for further in vivo antileishmanial evaluation. Diverse mechanism-of-action studies and molecular docking simulations were performed for the most active 4-aminoquinoline.

Cutaneous schistosomiasis and leishmaniasis coinfection: a case report

BACKGROUND

The polymorphic clinical presentations of schistosomiasis and leishmaniasis allow their inclusion in the differential diagnoses of several conditions. Although an overlap in distribution of these diseases has been reported in endemic areas, coinfection with cutaneous schistosomiasis and cutaneous leishmaniasis in the same patient is rare.

OBJECTIVES

We report an unusual case of concomitant cutaneous schistosomiasis and cutaneous leishmaniasis. Actions for the management and diagnosis were proposed.

METHODS

A patient presented with cutaneous lesions on the abdomen and left elbow. The presence of degenerated ova of Schistosoma mansoni in the skin biopsy led to perform a complementary investigation with immunohistochemical techniques, rectal biopsy and abdominal ultrasonography. After the left elbow lesions had failed to improve after several weeks of standard treatment, a new biopsy was performed and led to diagnosis of another infection.

RESULTS

The patient lived in an endemic area for two infectious diseases (schistosomiasis and leishmaniasis). Biopsies revealed chronic granulomatous dermatitis. Degenerated S. mansoni eggs were found in the abdominal lesion and in a rectal biopsy specimen. Ultrasonography revealed hepatic involvement. Despite combination treatment with oxamniquine and praziquantel, a cutaneous lesion persisted on the left elbow; a new biopsy revealed amastigote forms of Leishmania. The patient was successfully treated with intramuscular and intralesional meglumine antimoniate.

CONCLUSIONS

The presence of a similar granulomatous infiltrate in lesions caused by the two different infectious agents led to a delay in the diagnosis of cutaneous leishmaniasis. This report serves as a warning of the unusual possibility of cutaneous schistosomiasis and leishmaniasis coinfection in an endemic area.

Leishmanicidal Activity of Isoselenocyanate Derivatives

Conventional chemotherapy against leishmaniasis includes agents exhibiting considerable toxicity. In addition, reports of drug resistance are not uncommon. Thus, safe and effective therapies are urgently needed. Isoselenocyanate compounds have recently been identified with potential antitumor activity. It is well known that some antitumor agents demonstrate effects against Leishmania In this study, the in vitro leishmanicidal activities of several organo-selenium and organo-sulfur compounds were tested against Leishmania major and Leishmania amazonensis parasites, using promastigotes and intracellular amastigote forms. The cytotoxicity of these agents was measured in murine peritoneal macrophages and their selectivity indexes were calculated. One of the tested compounds, the isoselenocyanate derivative NISC-6, showed selectivity indexes 2- and 10-fold higher than those of the reference drug amphotericin B when evaluated in L. amazonensis and L. major, respectively. The American strain (L. amazonensis) was less sensitive to NISC-6 than L. major, showing a trend similar to that observed previously for amphotericin B. In addition, we also observed that NISC-6 significantly reduced the number of amastigotes per infected macrophage. On the other hand, we showed that NISC-6 decreases expression levels of Leishmania genes involved in the cell cycle, such as topoisomerase-2 (TOP-2), PCNA, and MCM4, therefore contributing to its leishmanicidal activity. The effect of this compound on cell cycle progression was confirmed by flow cytometry. We observed a significant increase of cells in the G₁ phase and a dramatic reduction of cells in the S phase compared to untreated cells. Altogether, our data suggest that the isoselenocyanate NISC-6 may be a promising candidate for new drug development against leishmaniasis.

Mannosyltransferase (GPI-14) overexpression protects promastigote and amastigote forms of Leishmania braziliensis against trivalent antimony

BACKGROUND

Glycosylphosphatidylinositol is a surface molecule important for host-parasite interactions. Mannosyltransferase (GPI-14) is an essential enzyme for adding mannose on the glycosylphosphatidyl group. This study attempted to overexpress the GPI-14 gene in Leishmania braziliensis to investigate its role in the antimony-resistance phenotype of this parasite.

RESULTS

GPI-14 mRNA levels determined by quantitative real-time PCR (qRT-PCR) showed an increased expression in clones transfected with GPI-14 compared to its respective wild-type line. In order to investigate the expression profile of the surface carbohydrates of these clones, the intensity of the fluorescence emitted by the parasites after concanavalin-A (a lectin that binds to the terminal regions of α-D-mannosyl and α-D-glucosyl residues) treatment was analyzed. The results showed that the clones transfected with GPI-14 express 2.8-fold more mannose and glucose residues than those of the wild-type parental line, indicating effective GPI-14 overexpression. Antimony susceptibility tests using promastigotes showed that clones overexpressing the GPI-14 enzyme are 2.4- and 10.5-fold more resistant to potassium antimonyl tartrate (Sb^III) than the parental non-transfected line. Infection analysis using THP-1 macrophages showed that amastigotes from both GPI-14 overexpressing clones were 3-fold more resistant to Sb^III than the wild-type line.

CONCLUSIONS

Our results suggest the involvement of the GPI-14 enzyme in the Sb^III-resistance phenotype of L. braziliensis.

The therapeutic effect of ozonated olive oil plus glucantime on human cutaneous leishmaniasis

OBJECTIVES

Leishmaniasis is one of the main health problems in developing countries, caused by intracellular protozoan parasites of the Leishmania genus. Although research has been successful in discovering vaccines and anti-parasitic drugs like antimony compounds, their side effects like high toxicity, prolonged regeneration, etc., have raised the replacement importance of natural products with antioxidant and antibacterial properties. It can be said that an appropriate alternative to this is the ozonated olive oil. Ozone by introducing O2 in involved tissues and bloodstream could degrade parasite amastigotes and lead to cleared leishmaniasis infections. So, the present study aimed to evaluate the effect of ozonated olive oil in Iranian leishmaniasis patients compared to glucantime, a choice drug for the treatment of Leishmaniasis.

MATERIALS AND METHODS

Thirty patients with confirmed leishmaniasis lesions were included and divided into two groups, 15 cases as control and 15 cases as test with lesions of 30-50 mm2 in diameter. The control group received glucantime intralesionally and the test group ozonated olive oil plus glucantime, 2 times daily.

RESULTS

The mean of lesion size was (50.94±33.20) before and (15±14.34) after treatment in control (P<0.00) and (50.88±31.74) before and (9.93±14.18) after treatment in the test group (P<0.00). Moreover, the mean course of therapy was 10.4(±1.84) weeks and 8.93(±2.15) weeks in control and test groups, respectively (P=0.636). Significant differences were reported in lesion size after treatment between the two groups (P<0.00).

CONCLUSION

Data suggested ozonated olive oil can have synergistic effects with glucantime in the treatment of cutaneous leishmaniasis.

Draft Genome Sequence of French Guiana Leishmania (Viannia) guyanensis Strain 204-365, Assembled Using Long Reads

We present here the draft genome sequence for Leishmania (Viannia) guyanensis. The isolate was obtained from a clinical case of cutaneous leishmaniasis in French Guiana.

We present here the draft genome sequence for Leishmania (Viannia) guyanensis. The isolate was obtained from a clinical case of cutaneous leishmaniasis in French Guiana. Genomic DNA was sequenced using PacBio and MiSeq platforms.

Ascorbate peroxidase overexpression protects Leishmania braziliensis against trivalent antimony effects

Ascorbate peroxidase (APX) is a redox enzyme of the trypanothione pathway that converts hydrogen peroxide (H2O2) into water molecules. In the present study, the APX gene was overexpressed in Leishmania braziliensis to investigate its contribution to the trivalent antimony (SbIII)-resistance phenotype. Western blot results demonstrated that APX-overexpressing parasites had higher APX protein levels in comparison with the wild-type line (LbWTS). APX-overexpressing clones showed an 8-fold increase in the antimony-resistance index over the parental line. In addition, our results indicated that these clones were approximately 1.8-fold more tolerant to H2O2 than the LbWTS line, suggesting that the APX enzyme plays an important role in the defence against oxidative stress. Susceptibility tests revealed that APX-overexpressing L. braziliensis lines were more resistant to isoniazid, an antibacterial agent that interacts with APX. Interestingly, this compound enhanced the anti-leishmanial SbIII effect, indicating that this combination represents a good strategy for leishmaniasis chemotherapy. Our data demonstrate that APX enzyme is involved in the development of L. braziliensis antimony-resistance phenotype and may be an attractive therapeutic target in the design of new strategies for leishmaniasis treatment.

Leishmaniasis

Leishmaniasis is a poverty-related disease with two main clinical forms: visceral leishmaniasis and cutaneous leishmaniasis. An estimated 0·7-1 million new cases of leishmaniasis per year are reported from nearly 100 endemic countries. The number of reported visceral leishmaniasis cases has decreased substantially in the past decade as a result of better access to diagnosis and treatment and more intense vector control within an elimination initiative in Asia, although natural cycles in transmission intensity might play a role. In east Africa however, the case numbers of this fatal disease continue to be sustained. Increased conflict in endemic areas of cutaneous leishmaniasis and forced displacement has resulted in a surge in these endemic areas as well as clinics across the world. WHO lists leishmaniasis as one of the neglected tropical diseases for which the development of new treatments is a priority. Major evidence gaps remain, and new tools are needed before leishmaniasis can be definitively controlled.

Investigation of anti-leishmanial efficacy of miltefosine and ketoconazole loaded on nanoniosomes

Leishmaniasis is a group of parasitic disease caused by protozoa of Leishmania genus. Leishmania major accounts for the cutaneous leishmaniasis (CL). The current treatments of this disease are expensive with high toxicity and are associated to difficulties of healing and parasite resistance. Miltefosine and ketoconazole have been found to be effective against CL. In this study, miltefosine- and ketoconazole-loaded nanoniosomes were prepared by the thin film-hydration method, and their anti-leishmanial effects against Leishmania major promastigotes and amastigotes were evaluated. The particle size and zeta potential of the nanoniosomes were determined. Release from the formulations showed enhanced and controlled dissolution of the drugs. The miltefosine- and ketoconazole-loaded nanoniosomes inhibited the growth of promastigote and amastigote forms of Leishmania major in vitro after 48 h of incubation and had IC₅₀ values of 53.39 ± 0.02 and 86.38 ± 0.07 μg mL^-1, respectively. The formulations provided improved anti-leishmanial activities for the treatment of cutaneous leishmaniasis.

Synthesis, leishmanicidal activity, structural descriptors and structure-activity relationship of quinoline derivatives

AIM

Considering the epidemiology of leishmaniasis, the emergence of resistant parasites to the approved drugs, and severe clinical manifestations, the development of novel leishmanicidal molecules has become of considerable importance.

RESULTS

In this work, three commercially available and 19 synthesized quinoline derivatives were evaluated against promastigote and amastigote forms of Leishmania (Leishmania) amazonensis. In addition, structural parameters and molecular electrostatic potentials were obtained by theoretical calculations, allowing statistical (principal component analyses and hierarchical cluster analyses) and comparative (molecular electrostatic potentials vs leishmanicidal activities) studies, respectively.

CONCLUSION

Principal component analyses and hierarchical cluster analyses suggested volume and polar surface area as possible structural descriptors for the leishmanicidal activity. Furthermore, a comparison between molecular electrostatic potentials and leishmanicidal activities afforded a reasonable structure-activity relationship.

Efficacy of Four Solanum spp. Extracts in an Animal Model of Cutaneous Leishmaniasis

Background: Leishmaniasis is a complex protozoa disease caused by Leishmania genus (Trypanosomatidae family). Currently, there have been renewed interests worldwide in plants as pharmaceutical agents. In this study, the in vivo efficacy of Solanum spp. is assessed in an L. amazonensis BALB/c mice model for experimental cutaneous leishmaniasis. Methods: Animals were infected with 5 × 10⁶ metacyclic promastigotes and 30-day post-infection, a treatment with 30 mg/kg of Solanum extracts or Glucantime^® (GTM) was applied intralesionally every four days to complete 5 doses. Results: Neither death nor loss of weight higher than 10% was observed. All the tested extracts were able to control the infection, compared with the infected and untreated group. Solanum havanense Jacq. extract showed the highest efficacy and was superior (p < 0.05) to GTM. Solanum myriacanthum Dunal., S. nudum Dunal. and S. seaforthianum Andr. extracts demonstrated a similar effect (p > 0.05) to GTM. An increase of IFN-γ (p < 0.05) was displayed only by animals treated with S. nudum compared to the group treated with a vehicle, while no differences (p > 0.05) were observed for IL-12. Conclusions:In vivo effects of Solanum extracts were demonstrated, suggesting that this genus could be further explored as a new antileishmanial alternative.

Treatment of cutaneous leishmaniasis with thermotherapy in Brazil: an efficacy and safety study

BACKGROUND

Pentavalent antimonials remain as the standard drugs in the treatment of cutaneous leishmaniosis. The high cost, difficult administration, long treatment time, toxicity and increasing morbidity are factors that limit the use of these drugs.

OBJECTIVES

To describe the response to radiofrequency thermotherapy in the treatment of localized cutaneous leishmaniasis in Brazil, and to evaluate its safety and tolerability.

METHODS

We conducted a non-comparative open trial with a total of 15 patients confirmed to have cutaneous leishmaniasis on parasitological examination. A single radiofrequency thermotherapy session at 50ºC for 30 seconds was applied to the lesion and its edges. In patients with more than one lesion, only the largest one was treated initially. If after 30 days there was no evidence of healing, the smaller lesion was also treated with thermotherapy. Clinical cure was defined as visible healing for three months after treatment. The patients were followed-up for six months and there was no follow-up loss.

RESULTS

Of all 23 lesions, only two evolved to complete healing without the need of treatment. Of 21 lesions, 18 (85.7%) achieved full healing. The main observed side effects were itching, burning sensation, pain and blisters.

STUDY LIMITATIONS

Sample with a small number of patients and short follow-up.

CONCLUSION

Thermotherapy can be considered a therapeutic alternative in localized cutaneous leishmaniasis, especially in cases of single cutaneous lesions and with formal contraindications to conventional treatment with pentavalent antimonials.

Prevalence of and Factors Associated with Negative Microscopic Diagnosis of Cutaneous Leishmaniasis in Rural Peru

Cutaneous leishmaniasis is endemic to South America where diagnosis is most commonly conducted via microscopy. Patients with suspected leishmaniasis were referred for enrollment by the Ministry of Health (MoH) in Lima, Iquitos, Puerto Maldonado, and several rural areas of Peru. A 43-question survey requesting age, gender, occupation, characterization of the lesion(s), history of leishmaniasis, and insect-deterrent behaviors was administered. Polymerase chain reaction (PCR) was conducted on lesion materials at the Naval Medical Research Unit No. 6 in Lima, and the results were compared with those obtained by the MoH using microscopy. Factors associated with negative microscopy and positive PCR results were identified using χ² test, t-test, and multivariate logistic regression analyses. Negative microscopy with positive PCR occurred in 31% (123/403) of the 403 cases. After adjusting for confounders, binary multivariate logistic regression analyses revealed that negative microscopy with positive PCR was associated with patients who were male (adjusted odds ration [OR] = 1.93 [1.06-3.53], P = 0.032), had previous leishmaniasis (adjusted OR = 2.93 [1.65-5.22], P < 0.0001), had larger lesions (adjusted OR = 1.02 [1.003-1.03], P = 0.016), and/or had a longer duration between lesion appearance and PCR testing (adjusted OR = 1.12 [1.02-1.22], P = 0.017). Future research should focus on further exploration of these underlying variables, discovery of other factors that may be associated with negative microscopy diagnosis, and the development and implementation of improved testing in endemic regions.

Analysis of Leishmania mimetic neoglycoproteins for the cutaneous leishmaniasis diagnosis

Oligosaccharides are broadly present on Leishmania cell surfaces. They can be useful for the leishmaniases diagnosis and also helpful in identifying new cell markers for the disease. The disaccharide Galα1-3Galβ is the immunodominant saccharide in Leishmania cell surface and is the unique non-reducing terminal glycosphingolipids structure recognized by anti-α-Gal. This study describes an enzyme-linked immunosorbent assay (ELISA) used to measure serum levels of anti-α-galactosyl (α-Gal) antibodies in patients with cutaneous leishmaniasis (CL). Optimal ELISA conditions were established and two neoglycoproteins (NGP) containing the Galα1-3Gal terminal fraction (Galα1-3Galβ1-4GlcNAc-HAS and Galα1-3Gal-HAS) and one Galα1-3Gal NGP analogue (Galα1-3Galβ1-3GlcNAc-HAS) were used as antigens. Means of anti-α-Gal antibody titres of CL patients were significantly higher (P < 0.05) than the healthy individuals for all NGPs tested. Sensitivity and specificity of all NGPs ranged from 62.2 to 78.4% and 58.3 to 96.7%, respectively. In conclusion, the NGPs can be used for CL diagnosis.

Synthesis of 4-substituted ethers of benzophenone and their antileishmanial activities

Leishmaniasis is a vector-borne protozoan disease; it mainly originates from the bite of sandfly and initiated when parasite is transmitted to human at metacyclic flagellated promastigote form. In the current study, a synthesis of a series of 4-substituted benzophenone ethers 1-20 was carried out in good yields and their in vitro antileishmanial activities were also screened. Among synthetic derivatives, 15 compounds 1, 3, 5-12, 15 and 17-20 showed antileishmanial activities against promastigotes of Leishmania major with IC50 values in the range of 1.19-82.30 µg ml-1, and the values were compared with those of the standard pentamidine (IC50 = 5.09 ± 0.09 µg ml-1). Our study identified a series of new antileishmanial molecules as potential leads. Structures of these synthetic compounds were deduced by different spectroscopic techniques, such as 1H and 13C nuclear magnetic resonance, electron impact and high-resolution electron impact mass spectrometry and IR.

Synergistic combination of alkylphosphocholines with peptaibols in targeting Leishmania infantum in vitro

Anti-leishmanial treatment increasingly encounters therapeutic limitations due to drug toxicity and development of resistance. The effort for new therapeutic strategies led us to work on combinations of chemically different compounds that could yield enhanced leishmanicidal effect. Peptaibols are a special type of antimicrobial peptides that are able to form ion channels in cell membranes and potentially affect cell viability. We assayed the antileishmanial activity of two well studied helical peptaibols, the 16-residue antiamoebin and the 20-residue alamethicin-analogue suzukacillin, and we evaluated the biological effect of their combination with the alkylphosphocholine miltefosine and its synthetic analogue TC52. The peptaibols tested exhibited only moderate antileishmanial activity, however their combination with miltefosine had a super-additive effect against the intracellular parasite (combination index 0.83 and 0.43 for antiamoebin and suzukacillin respectively). Drug combinations altered the redox stage of promastigotes, rapidly dissipated mitochondrial membrane potential and induced concatenation of mitochondrial network promoting spheroidal morphology. These results evidenced a potent and specific antileishmanial effect of the peptaibols/miltefosine combinations, achieved with significantly lower concentrations of the compounds compared to monotherapy. Furthermore, they revealed the importance of exploring novel classes of bioactive compounds such as peptaibols and demonstrated for the first time that they can act in synergy with currently used antileishmanial drugs to improve the therapeutic outcome.

Modulation of inflammation response to murine cutaneous Leishmaniasis by homeopathic medicines: Antimonium crudum 30cH

Background: Leishmaniasis is a zoonotic disease caused by protozoan parasites of the mononuclear phagocytic system. The modulation activity of these cells can interfere in the host/parasite relationship and influences the prognosis.

Methods: We evaluated the effects of the homeopathic preparation Antimonium crudum 30cH on experimental infection induced by Leishmania (L.) amazonensis. Male Balb/c mice were inoculated with 2 × 106 Leishmania (L.) amazonensis promastigotes into the footpad and, after 48 h (acute phase) or 60 days (chronic phase), cell population of lymphocytes and phagocytes present in the peritoneal washing fluid and spleen were analyzed by flow cytometry and histopathology, with histometry of the subcutaneous primary lesion, local lymph node and spleen. Immunohistochemistry was performed to quantify CD3 (T lymphocyte), CD45RA (B lymphocyte) and CD11b (phagocytes) positive cells.

Results: In treated mice, during the acute phase, there was significant increase of the macroscopic lesion, associated to inflammatory edema, as well increase in the number of free amastigotes and B lymphocytes inside the lesion. Increase of B lymphocytes (predominantly B-2 cells) was also seen in the local lymph node, spleen and peritoneum. In the chronic phase, the inflammatory process in the infection focus was reduced, with reduced phagocyte migration and peritoneal increase of B-1a cells (precursors of B-2 immunoglobulin producers cells) and T CD8+ cells.

Conclusion: The treatment of mice with Antimonium crudum 30cH induced a predominantly B cell pattern of immune response in Leishmania (L.) amazonensis experimental infection, alongside the increase of free amastigote forms number in the infection site. The clinical significance of this study is discussed, further studies are suggested.

Function of Macrophage and Parasite Phosphatases in Leishmaniasis

The kinetoplastid protozoan parasites belonging to the genus Leishmania are the causative agents of different clinical forms of leishmaniasis, a vector-borne infectious disease with worldwide prevalence. The protective host immune response against Leishmania parasites relies on myeloid cells such as dendritic cells and macrophages in which upon stimulation by cytokines (e.g., interferon-γ) a complex network of signaling pathways is switched on leading to strong antimicrobial activities directed against the intracellular parasite stage. The regulation of these pathways classically depends on post-translational modifications of proteins, with phosphorylation events playing a cardinal role. Leishmania parasites deactivate their phagocytic host cells by inducing specific mammalian phosphatases that are capable to impede signaling. On the other hand, there is now also evidence that Leishmania spp. themselves express phosphatases that might target host cell molecules and thereby facilitate the intracellular survival of the parasite. This review will present an overview on the modulation of host phosphatases by Leishmania parasites as well as on the known families of Leishmania phosphatases and their possible function as virulence factors. A more detailed understanding of the role of phosphatases in Leishmania–host cell interactions might open new avenues for the treatment of non-healing, progressive forms of leishmaniasis.

Leishmaniasis in the major endemic region of Plurinational State of Bolivia: Species identification, phylogeography and drug susceptibility implications

The Plurinational State of Bolivia is one of the Latin American countries with the highest prevalence of leishmaniasis, highlighting the lowlands of the Department of La Paz where about 50% of the total cases were reported. The control of the disease can be seriously compromised by the intrinsic variability of the circulating species that may limit the efficacy of treatment while favoring the emergence of resistance. Fifty-five isolates of Leishmania from cutaneous and mucocutaneous lesions from patients living in different provinces of the Department of La Paz were tested. Molecular characterization of isolates was carried out by 3 classical markers: the rRNA internal transcribed spacer 1 (ITS-1), the heat shock protein 70 (HSP70) and the mitochondrial cytochrome b (Cyt-b). These markers were amplified by PCR and their products digested by the restriction endonuclease enzymes AseI and HaeIII followed by subsequent sequencing of Cyt-b gene and ITS-1 region for subsequent phylogenetic analysis. The combined use of these 3 markers allowed us to assign 36 isolates (65.5%) to the complex Leishmania (Viannia) braziliensis, 4 isolates (7, 27%) to L. (Viannia) lainsoni. and the remaining 15 isolates (23.7%) to a local variant of L. (Leishmania) mexicana. Concerning in vitro drug susceptibility the amastigotes from all isolates where highly sensitive to Fungizone^® (mean IC₅₀ between 0.23 and 0.5μg/mL) whereas against Glucantime^® the sensitivity was moderate (mean IC₅₀ ranging from 50.84μg/mL for L. (V.) braziliensis to 18.23μg/mL for L. (L.) mexicana. L. (V.) lainsoni was not sensitive to Glucantime^®. The susceptibility to miltefosine was highly variable among species isolates, being L. (L.) mexicana the most sensitive, followed by L. (V.) braziliensis and L. (V.) lainsoni (mean IC₅₀ of 8.24μg/mL, 17.85μg/mL and 23.28μg/mL, respectively).

Discovery of novel, orally bioavailable, antileishmanial compounds using phenotypic screening

Leishmaniasis is a parasitic infection that afflicts approximately 12 million people worldwide. There are several limitations to the approved drug therapies for leishmaniasis, including moderate to severe toxicity, growing drug resistance, and the need for extended dosing. Moreover, miltefosine is currently the only orally available drug therapy for this infection. We addressed the pressing need for new therapies by pursuing a two-step phenotypic screen to discover novel, potent, and orally bioavailable antileishmanials. First, we conducted a high-throughput screen (HTS) of roughly 600,000 small molecules for growth inhibition against the promastigote form of the parasite life cycle using the nucleic acid binding dye SYBR Green I. This screen identified approximately 2,700 compounds that inhibited growth by over 65% at a single point concentration of 10 μM. We next used this 2700 compound focused library to identify compounds that were highly potent against the disease-causing intra-macrophage amastigote form and exhibited limited toxicity toward the host macrophages. This two-step screening strategy uncovered nine unique chemical scaffolds within our collection, including two previously described antileishmanials. We further profiled two of the novel compounds for in vitro absorption, distribution, metabolism, excretion, and in vivo pharmacokinetics. Both compounds proved orally bioavailable, affording plasma exposures above the half-maximal effective concentration (EC50) concentration for at least 12 hours. Both compounds were efficacious when administered orally in a murine model of cutaneous leishmaniasis. One of the two compounds exerted potent activity against trypanosomes, which are kinetoplastid parasites related to Leishmania species. Therefore, this compound could help control multiple parasitic diseases. The promising pharmacokinetic profile and significant in vivo efficacy observed from our HTS hits highlight the utility of our two-step phenotypic screening strategy and strongly suggest that medicinal chemistry optimization of these newly identified scaffolds will lead to promising candidates for an orally available anti-parasitic drug.

Distribution and identification of sand flies naturally infected with Leishmania from the Southeastern Peruvian Amazon

Background

Cutaneous leishmaniasis (CL) is an important health problem in the New World affecting civilian and military populations that are frequently exposed in endemic settings. The Peruvian region of Madre de Dios located near the border with Brazil is one of the most endemic CL regions in South America with more than 4,451 reported cases between 2010 and 2015 according to the Peruvian epidemiology directorate. However, little is known regarding the diversity and distribution of sand fly vectors in this region. In this study, we aimed to characterize the sand fly fauna in this endemic setting and identify sand fly species naturally infected with Leishmania possibly involved in pathogen transmission.

Methods

Sand fly collections were carried out during 2014 and 2015 in the communities of Flor de Acre, Villa Primavera, Mavila and Arca Pacahuara using CDC light traps and Shannon traps. Collected specimens were identified and non-blood-fed females were selected for Leishmania infection screening using kinetoplastid DNA-PCR (kDNA-PCR) and nested Real time PCR for species identification.

Results

A total of 10,897 phlebotomines belonging to the genus Lutzomyia (58 species) and Brumptomyia (2 species) were collected. Our study confirmed the widespread distribution and abundance of Lutzomyia (Trichophoromyia) spp. (24%), Lu. whitmani (19.4%) and Lu. yucumensis (15.8%) in the region. Analysis of Shannon diversity index indicates variability in sand fly composition across sites with Villa Primavera presenting the highest sand fly diversity and abundance. Leishmania screening by kDNA-PCR resulted in 45 positive pools collected from Flor de Acre (34 pools), Mavila (10 pools) and Arca Pacahuara (1 pool) and included 14 species: Lu. yucumensis, Lu. aragoi, Lu. sallesi, Lu. sherlocki, Lu. shawi, Lu. walkeri, Lu nevesi, Lu. migonei, Lu. davisi, Lu. carrerai, Lu. hirsuta, Lu. (Trichophoromyia) spp., Lu. llanosmartinsi and Lu. whitmani. Lutzomyia sherlocki, Lu. walkeri and Lu. llanosmartinsi had the highest infection rates (8%, 7% and 6%, respectively). We identified Leishmania guyanensis in two Lu. whitmani pools, and L. braziliensis in two Lu. llanosmartinsi pools and one Lu. davisi pool.

Conclusions

Based on our collections there is high sand fly diversity in Madre de Dios, with differences in sand fly abundance and species composition across sites. We identified 14 sand fly species naturally infected with Leishmania spp., having detected natural infection with L. (V.) guyanensis and L. (V.) braziliensis in three sand fly species. These results suggest the presence of several potential vectors that vary in their spatial and geographical distribution, which could explain the high prevalence of CL cases in this region.

Leishmaniasis is a neglected disease that affects more than 2 million people worldwide. The identification of putative Leishmania vectors is an important step towards the design of better control strategies and estimating the risk of transmission in endemic areas. In this paper the authors explored the distribution of sand flies and identified potential vectors in a largely unexplored setting in the Southeastern Peruvian Amazon Basin. Three new sand fly species Lutzomyia naiffi, Lu. dereuri and Lu. flabellata are reported for Peru. In addition, they found fourteen sand fly species naturally infected with Leishmania that comprised seven new reports for Peru and one for the Americas. This information will serve as a baseline for future surveillance and intervention studies in this highly endemic area.

Dynamics of American tegumentary leishmaniasis in a highly endemic region for Leishmania (Viannia) braziliensis infection in northeast Brazil

Background

American Tegumentary Leishmaniasis (ATL) caused by Leishmania braziliensis is endemic in Corte de Pedra, Northeast Brazil. Most L. braziliensis infections manifest as localized cutaneous leishmaniasis (CL). Disseminated manifestations include mucosal leishmaniasis (ML), present at a low constant level for several decades, and newly emerging disseminated leishmaniasis (DL). Surprisingly, DL has recently surpassed ML in its spatial distribution. This led us to hypothesize that distinct forms of ATL might spread in different patterns through affected regions.

Methodology/Principal findings

We explored the incidence and geographic dispersion of the three clinical types of ATL over a span of nearly two decades in Corte de Pedra. We obtained the geographic coordinates of the homes of patients with ATL during 1992–1996, 1999–2003 and 2008–2011. The progressive dispersion of ML or DL in each time period was compared to that of CL in 2008–2011 with the Cusick and Edward’s geostatistical test. To evaluate whether ATL occurred as clusters, we compared each new case in 2008–2011 with the frequency of and distance from cases in the previous 3 to 12 months. The study revealed that DL, ML and CL actively spread within that region, but in distinct patterns. Whereas CL and DL propagated in clusters, ML occurred as sporadic cases. DL had a wider distribution than ML until 2003, but by 2011 both forms were distributed equally in Corte de Pedra. The incidence of ML fluctuated over time at a rate that was distinct from those of CL and DL.

Conclusions/Significance

These findings suggest that CL and DL maintain endemic levels through successive outbreaks of cases. The sporadic pattern of ML cases may reflect the long and variable latency before infected patients develop clinically detectable mucosal involvement. Intimate knowledge of the geographic distribution of leishmaniasis and how it propagates within foci of active transmission may guide approaches to disease control.

American tegumentary leishmaniasis (ATL) caused by Leishmania braziliensis is characterized by lesions to the skin and/or mucosal surfaces of the oropharynx. It is widely distributed in endemic regions of northeast Brazil and has been difficult to control. Three common clinical forms of L. braziliensis infections are localized skin ulcers called cutaneous leishmaniasis (CL), mucosal leishmaniasis (ML) affecting mucosal surfaces, and disseminated leishmaniasis (DL), a recently described form with widespread skin lesions. Using GPS and epidemiologic data we explored the incidence and pattern of spread of ATL in the highly endemic region of Corte de Pedra, Brazil between 1992 and 2011. Geographic clusters of CL and DL cases were observed. In contrast, there was a sporadic non-clustered pattern of ML cases in the study area. The numbers of new cases of CL and DL presented similar fluctuation during the study period, but ML incidences were never correlated to those of CL and DL. We conclude that all forms of ATL actively spread within affected foci, but in different patterns. CL and DL cases occur in clusters suggesting active spread of causative parasite strains, whereas ML cases occurred in a sporadic pattern suggesting it may emerge due to factors such as host immunity or environmental conditions.

Atypical presentations of cutaneous leishmaniasis: A systematic review

Cutaneous Leishmaniasis (CL) is endemic in 88 countries, showing relevant prevalences. The aim of this study was to perform a systematic review on atypical lesions of CL around the world, addressing clinico-epidemiological, immunological and therapeutic aspects. A search of the literature was conducted via electronic databases Scopus and PubMed for articles published between 2010 and 2015. The search terms browsed were "cutaneous leishmaniasis", "atypical" and "unusual". Based on the eligibility criteria, 34 out of 122 articles were included in the final sample. Atypical lesions may include the following forms: erythematous volcanic ulcer, lupoid, eczematous, erysipeloid, verrucous, dry, zosteriform, paronychial, sporotrichoid, chancriform and annular. In any cases, they seem to be another disease like subcutaneous and deep mycosis, cutaneous lymphoma, pseudolymphoma, basal and squamous cell carcinoma. The lesions have been reported in the face, cheeks, ears, nose, eyelid, limbs, trunk, buttocks, as well as in palmoplantar and genital regions; sometimes occurring in more than one area. The reason for clinical cutaneous leishmaniasis pleomorphism is unclear but immunosuppression seems to play an important role in some cases. There are no established guidelines for the treatment of atypical cutaneous leishmaniasis. However, pentavalent antimonials remain as first line treatment for all forms of leishmaniasis even for HIV-infected patients and atpical forms. Finally, to diagnose an atypical lesion properly, the focus has to be on the medical history and the origin of the patient, comparing them to the natural history of leishmaniasis and always reminding of possible atypical presentations, to then start searching for the best diagnostic method and treatment, reducing the misdiagnosis rate and, subsequently, controlling the disease progression. Thereby, contributing for breaking the transmission chain of the parasite, due to early correct diagnosis which, in turn, contributes to reduce the prevalence.

Case Report: Lupoid cutaneous leishmaniasis mimicking verruca plana

Cutaneous leishmaniasis (CL) is an infectious disease caused by various species of leishmania protozoan parasites. Lupoid CL is a rare form of CL that has a stunning similarity to other granulomatous cutaneous conditions of infectious or inflammatory origin. Verruca plana, also known as a "flat wart", is a benign proliferation of the skin resulting from infection with human papilloma virus (HPV). Herein, we presented a case of lupoid CL mimicking verruca plana on the face.

Unraveling the genetic diversity and phylogeny of Leishmania RNA virus 1 strains of infected Leishmania isolates circulating in French Guiana

Introduction

Leishmania RNA virus type 1 (LRV1) is an endosymbiont of some Leishmania (Vianna) species in South America. Presence of LRV1 in parasites exacerbates disease severity in animal models and humans, related to a disproportioned innate immune response, and is correlated with drug treatment failures in humans. Although the virus was identified decades ago, its genomic diversity has been overlooked until now.

Methodology/Principles findings

We subjected LRV1 strains from 19 L. (V.) guyanensis and one L. (V.) braziliensis isolates obtained from cutaneous leishmaniasis samples identified throughout French Guiana with next-generation sequencing and de novo sequence assembly. We generated and analyzed 24 unique LRV1 sequences over their full-length coding regions. Multiple alignment of these new sequences revealed variability (0.5%–23.5%) across the entire sequence except for highly conserved motifs within the 5’ untranslated region. Phylogenetic analyses showed that viral genomes of L. (V.) guyanensis grouped into five distinct clusters. They further showed a species-dependent clustering between viral genomes of L. (V.) guyanensis and L. (V.) braziliensis, confirming a long-term co-evolutionary history. Noteworthy, we identified cases of multiple LRV1 infections in three of the 20 Leishmania isolates.

Conclusions/Significance

Here, we present the first-ever estimate of LRV1 genomic diversity that exists in Leishmania (V.) guyanensis parasites. Genetic characterization and phylogenetic analyses of these viruses has shed light on their evolutionary relationships. To our knowledge, this study is also the first to report cases of multiple LRV1 infections in some parasites. Finally, this work has made it possible to develop molecular tools for adequate identification and genotyping of LRV1 strains for diagnostic purposes. Given the suspected worsening role of LRV1 infection in the pathogenesis of human leishmaniasis, these data have a major impact from a clinical viewpoint and for the management of Leishmania-infected patients.

Leishmaniasis is a well-known parasitosis due to an infection by the protozoan Leishmania parasites firmly established in South America. In French Guiana, where leishmaniasis is a public health problem, having an annual incidence of 5.6 cases/10,000 inhabitants, 80% of Leishmania spp. parasites are infected by an endosymbiotic virus, Leishmania RNA virus 1 (LRV1). The purpose of this study was to gain insights on the genetic variability and evolution of LRV1 at the genomic level. We subjected 20 Leishmania isolates obtained from cutaneous lesions with next generation sequencing and de novo sequence assembly. This allowed generating 24 LRV1 full-length coding sequences presenting among themselves a significant genetic diversity. The inferred phylogenetic relationships enabled to identify distinct well-supported genotypes and support the hypothesis of co-evolution between LRV1 strains and their parasite hosts. In addition, we identified multiple LRV1 infections in three parasite isolates. Based on these data, future characterization of new strains from other geographic areas and other parasite species should extend knowledge of LRV1 diversification processes. Finally, these results allowed us to identify genomic regions where best to allocate resources for subsequent analyses of LRV1 viral diversity and genotyping that could serve for accurate routine molecular diagnostic applications.

The evolution of trypanosomatid taxonomy

Trypanosomatids are protozoan parasites of the class Kinetoplastida predominately restricted to invertebrate hosts (i.e. possess a monoxenous life-cycle). However, several genera are pathogenic to humans, animals and plants, and have an invertebrate vector that facilitates their transmission (i.e. possess a dixenous life-cycle). Phytomonas is one dixenous genus that includes several plant pathogens transmitted by phytophagous insects. Trypanosoma and Leishmania are dixenous genera that infect vertebrates, including humans, and are transmitted by hematophagous invertebrates. Traditionally, monoxenous trypanosomatids such as Leptomonas were distinguished from morphologically similar dixenous species based on their restriction to an invertebrate host. Nonetheless, this criterion is somewhat flawed as exemplified by Leptomonas seymouri which reportedly infects vertebrates opportunistically. Similarly, Novymonas and Zelonia are presumably monoxenous genera yet sit comfortably in the dixenous clade occupied by Leishmania. The isolation of Leishmania macropodum from a biting midge (Forcipomyia spp.) rather than a phlebotomine sand fly calls into question the exclusivity of the Leishmania-sand fly relationship, and its suitability for defining the Leishmania genus. It is now accepted that classic genus-defining characteristics based on parasite morphology and host range are insufficient to form the sole basis of trypanosomatid taxonomy as this has led to several instances of paraphyly. While improvements have been made, resolution of evolutionary relationships within the Trypanosomatidae is confounded by our incomplete knowledge of its true diversity. The known trypanosomatids probably represent a fraction of those that exist and isolation of new species will help resolve relationships in this group with greater accuracy. This review incites a dialogue on how our understanding of the relationships between certain trypanosomatids has shifted, and discusses new knowledge that informs the present taxonomy of these important parasites.

An ELISA immunoassay employing a conserved Leishmania hypothetical protein for the serodiagnosis of visceral and tegumentary leishmaniasis in dogs and humans

In the present study, a conserved Leishmania hypothetical protein, namely LiHypA, was evaluated for the serodiagnosis of visceral and tegumentary leishmaniasis in dogs and humans. This protein showed a high amino acid sequence homology between viscerotropic and cutaneotropic Leishmania species. An enzyme-linked immunosorbent assay (ELISA) was developed using the recombinant antigen (rLiHypA), in addition to the A2 protein and two parasite antigenic preparations, which were used as controls. Regarding human diagnosis, results showed that rLiHypA was more sensitive and specific than ELISA-L. braziliensis SLA in detecting both cutaneous or mucosal leishmaniasis patients, but not those from Chagas disease patients or healthy subjects. Regarding canine diagnosis, this recombinant antigen showed higher sensitivity and specificity values, as well as a perfect accuracy to identify asymptomatic and symptomatic visceral leishmaniasis (VL) in dogs, but not those from vaccinated animals or those developing babesiosis, ehrlichiosis, or Chagas disease. However, using the rA2 protein or L. braziliensis SLA as controls, significant cross-reactivity was found when these samples were used, hampering their sensitivity and specificity values for the diagnosis. In this context, LiHypA could be considered a candidate to be evaluated for the serodiagnosis of visceral and tegumentary leishmaniasis in dogs and humans.

Efficiency of noninvasive sampling methods (swab) together with Polymerase Chain Reaction (PCR) for diagnosing American Tegumentary Leishmaniasis

Traditional diagnostic methods used to detect American Tegumentary Leishmaniasis, such as histopathology using biopsy samples, culture techniques, and direct search for parasites, have low sensitivity and require invasive collection procedures. This study evaluates the efficiency of noninvasive sampling methods (swab) along with Polymerase Chain Reaction (PCR) for diagnosing American Tegumentary Leishmaniasis using skin and mucous samples from 25 patients who had tested positive for leishmaniasis. The outcome of the tests performance on swab samples was compatible with PCR results on biopsy samples. The findings have also shown that PCR-kDNA test is more efficient than PCR-HSP70 and qPCR tests (sensitivity of 92.3%, 40.7%, and 41%, respectively). Given the high sensitivity of the tests and the fact that the sampling method using swabs affords greater patient comfort and safety, it could be said that this method is a promising alternative to conventional biopsy-based methods for the molecular diagnosis of leishmaniasis.

Anti-Leishmania activity of essential oil of Myracrodruon urundeuva (Engl.) Fr. All.: Composition, cytotoxity and possible mechanisms of action

Myracrodruon urundeuva (Engl.) Fr. All., commonly known as "aroeira-do-sertão", is a medicinal plant from Anacardiaceae family. In this study, the chemical composition of M. urundeuva essential oil (MuEO) was evaluated by gas chromatography-mass spectrometry (GC-MS), as well as its anti-Leishmania potential, cytotoxicity, and macrophage activation capability as possible antiprotozoal mechanism of action were assessed. Fourteen compounds were identified, which constituted 94.87% of total oil composition. The most abundant components were monoterpenes (80.35%), with β-myrcene (42.46%), α-myrcene (37.23%), and caryophyllene (4.28%) as the major constituents. The MuEO inhibited the growth of promastigotes (IC₅₀ 205 ± 13.4 μg mL^-1), axenic amastigotes (IC₅₀ 104.5 ± 11.82 μg mL^-1) and decreased percentage of macrophage infection and number of amastigotes per macrophage (IC₅₀ of 44.5 ± 4.37 μg⋅mL^-1), suggesting significant anti-Leishmania activity. The cytotoxicity of MuEO was assessed by MTT test in Balb/c murine macrophages and by human erythrocytes lysis assay and low cytotoxicity for these cells was observed. The CC₅₀ value against macrophages were 550 ± 29.21 μg mL^-1, while cytotoxicity for erythrocytes was around 20% at the highest concentration assessed, with HC₅₀ > 800 μg mL^-1. While MuEO-induced anti-Leishmania activity is not mediated by increases in both lysosomal activity and nitric oxide production in macrophages, the results suggest the antiamastigote activity is associated with an immunomodulatory activity of macrophages due to an increase of phagocytic capability induced by MuEO. Thus, MuEO presented significant activity against Leishmania amazonensis, probably modulating the activation of macrophages, with low cytotoxicity to murine macrophages and human erythrocytes.

Lip leishmaniasis: a case series with molecular identification and literature review

BACKGROUND

Mucocutaneous leishmaniasis (MCL), a protozoan infectious disease, is very rare in Iran despite the endemicity of both cutaneous and visceral forms. It is transmitted by the Phlebotomus sand fly. The lip is considered one of the extraordinary sites. Lesions usually initiate with erythematous papules, slowly enlarges and then it ulcerates. The diagnosis of MCL encompasses epidemiological, clinical and laboratory aspects. Usually, the combination of some of these elements is necessary for the final diagnosis. So, lip leishmaniasis lesions can be challenging to diagnose.

CASE PRESENTATION

We presented seven rare cases of lip leishmaniasis. Tissue impression smear, culture, PCR and phylogenetic analysis were carried out for explicit diagnosis. Skin scraping investigation showed several Leishmania spp. amastigotes in the cytoplasm of macrophages. Culture examination was positive for Leishmania spp. PCR was positive for L. major, L. tropica, and L. infantum. Differential diagnosis includes orofacial granulomatosis, basal cell carcinoma, squamous cell carcinoma, and mesenchymal tumors. The cases were treated with systemic meglumine antimoniate (Glucantime®). No relapses were observed during 1 year of follow-up. Early detection of the infection are necessary in order to start effective treatment and prevent more serious complications.

CONCLUSIONS

In this paper, we reported seven rare cases of lip leishmaniasis in Iran, emphasized the importance of clinical and diagnostic features of lesions, characterized the phylogenetic kinship of isolated parasites, and reviewed the literature on lip leishmaniasis.

Sclerosing Orbital Inflammation Caused by Leishmania braziliensis

Orbital biopsy of nonspecific orbital inflammation, commonly referred to as "orbital pseudotumor," typically shows a combination of polyclonal lymphocytes, plasmocytes, leukocytes, macrophages, and variable degrees of collagen deposition. Herein, we report a patient with a positive history of mucocutaneous leishmaniasis who presented with an orbital mass with a histological profile of idiopathic orbital inflammation. Immunohistochemical and molecular analysis of the orbital specimens demonstrated that the orbital inflammation was associated with the presence of antigens of Leishmania braziliensis and DNA from the parasite.