Search

• Severe visceral leishmaniasis with non-ulcerated cutaneous leishmaniasis. • A Crithidia -related parasite was isolated from bone marrow aspirate and spleen. • Whole-genome sequencing of clinical isolates suggested a novel parasite species. • Clinical implications of this trypanosomatid co-infection remain unknown in visceral leishmaniasis. [Display omitted] We report a refractory and relapsed visceral leishmaniasis case in a male child patient followed from 2016 to 2020, whose clinical isolates from multiple relapses were analyzed at the genome level. To the best of our knowledge, it is the first report that both visceral leishmaniasis and non-ulcerated cutaneous leishmaniasis have concomitantly manifested in the same patient. Importantly, sequence analysis revealed that the patient was co-infected with Leishmania infantum and a Crithidia -related parasite, which was previously found in a fatal case of visceral leishmaniasis from the same endemic region. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a tropical parasitic disease caused by Leishmania spp. They cause several presentations of illness ranging from cutaneous leishmaniasis to visceral leishmaniasis. The current arsenal of drugs to treat leishmaniasis is limited, and drug resistance further impedes the problem. Therefore, it is necessary to revisit the available information to identify an alternative or new target for treatment. The glycoprotein 63 (gp63), is a potential anti-leishmanial target that plays a significant role in host-pathogen interaction and virulence. Many studies are ongoing to develop gp63 inhibitors or use it as a vaccine target. In this review, we will discuss the potential of gp63 as a drug target. This review summarises the studies focusing on gp63 as a drug target and its inhibitors identified using in silico approaches. [Display omitted] • gp63 a potential drug and vaccine target. • Active site is conserved in all Leishmania spp. • May serve as pan drug target. • In silico studies identify its inhibitors. [ABSTRACT FROM AUTHOR]

The obligate intracellular parasite Leishmania binds several receptors to trigger uptake by phagocytic cells, ultimately resulting in visceral or cutaneous leishmaniasis. A series of signaling pathways in host cells, which are critical for establishment and persistence of infection, are activated during Leishmania internalization. Thus, preventing Leishmania uptake by phagocytes could be a novel therapeutic strategy for leishmaniasis. However, the host cellular machinery mediating promastigote and amastigote uptake is not well understood. Here, using small molecule inhibitors of Mitogen-activated protein/Extracellular signal regulated kinases (MAPK/ERK), we demonstrate that ERK1/2 mediates Leishmania amazonensis uptake and (to a lesser extent) phagocytosis of beads by macrophages. We find that inhibiting host MEK1/2 or ERK1/2 leads to inefficient amastigote uptake. Moreover, using inhibitors and primary macrophages lacking spleen tyrosine kinase (SYK) or Abl family kinases, we show that SYK and Abl family kinases mediate Raf, MEK, and ERK1/2 activity and are necessary for uptake. Finally, we demonstrate that trametinib, a MEK1/2 inhibitor used to treat cancer, reduces disease severity and parasite burden in Leishmania -infected mice, even if it is started after lesions develop. Our results show that maximal Leishmania infection requires MAPK/ERK and highlight potential for MAPK/ERK-mediated signaling pathways to be novel therapeutic targets for leishmaniasis. [ABSTRACT FROM AUTHOR]

In visceral and mucocutaneous leishmaniasis, humoral immune response can reflect disease severity and parasite burden. Cutaneous leishmaniasis (CL) in Sri Lanka is caused by a usually visceralizing parasite, Leishmania donovani. We assessed the parasite burden (relative quantity—RQ) in 190 CL patients using quantitative real-time PCR (qPCR—with primers designed for this study) and smear microscopy, then correlated it with clinical parameters and IgG response. RQ of parasite DNA was determined with human-specific glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as the internal control. The qPCR sensitivity was tested with serially diluted DNA from cultured L. donovani parasites. Smears were assigned a score based on number of parasites per high power field. Data from previous studies were used for comparison and correlation; nested Internal Transcribed Spacer 1 (ITS1) PCR as reference standard (RS) and IgG antibody titers to the Leishmania rKRp42 antigen as the immune response. The qPCR amplified and quantified 86.8% of the samples while demonstrating a fair and significant agreement with ITS1-PCR and microscopy. Parasite burden by qPCR and microscopy were highly correlated (r = 0.76; p = 0.01) but showed no correlation with the IgG response (r = 0.056; p = 0.48). Corresponding mean RQs of IgG titers grouped by percentiles, showed no significant difference (p = 0.93). Mean RQ was higher in early lesions (p = 0.04), decreased with lesion size (p = 0.12) and slightly higher among papules, nodules and wet ulcers (p = 0.72). Our study established qPCR's efficacy in quantifying parasite burden in Sri Lankan CL lesions but no significant correlation was observed between the parasite burden and host IgG response to the Leishmania rKRP42 antigen. [Display omitted] • qPCR effectively quantified parasite burden in Sri Lankan cutaneous leishmaniasis. • Microscopic- and qPCR-based quantification of parasite burden correlated well. • Parasite burden and anti-rKRP42 IgG level showed no correlation in cutaneous form. • Parasite burden was higher in early lesions, decreasing with lesion size. [ABSTRACT FROM AUTHOR]

Leishmania , a protozoan parasite, is responsible for the occurrence of leishmaniasis, a disease that is prevalent in tropical regions. Visceral Leishmaniasis (VL), also known as kala-azar in Asian countries, is one of the most significant forms of VL, along with Cutaneous Leishmaniasis (CL) and Mucocutaneous Leishmaniasis (ML). Management of this condition typically entails the use of chemotherapy as the sole therapeutic option. The current treatments for leishmaniasis present several drawbacks, including a multitude of side effects, prolonged treatment duration, disparate efficacy across different regions, and the emergence of resistance. To address this urgent need, it is imperative to identify alternative treatments that are both safer and more effective. The identification of appropriate pharmacological targets in conjunction with biological pathways constitutes the initial stage of drug discovery. In this review, we have addressed the key metabolic pathways that represent potential pharmacological targets as well as prominent treatment options for leishmaniasis. • Target-based drug discovery. • Essential metabolic pathways in Leishmania like sterol biosynthesis, trypanothione route, glycolytic, Protein kinases, arginase and polyamine biosynthesis, trypanothione synthase and trypanothione reductase, topoisomerases, purine salvage, mannose biosynthesis etc. that are possible pharmacological targets. • Some important drugs for the treatment of leishmaniasis. [ABSTRACT FROM AUTHOR]

• Our research investigated the genetic variations among CL, VL, and CanL strains in northern Morocco. • Molecular and genetic analyses uncovered a complex array of genetic variants in the L. infantum and L. tropica species. The number of these variants is 7 and 9 for L. tropica and L. infantum species, respectively. • The Discriminant Analysis of Principal Components (DAPC) revealed significant genetic divergences among L. infantum strains. This suggests the influence of species origin on their genetic makeup. This study investigated nine provinces in northern Morocco and collected 275 skin scraping, 22 bone marrow aspirates, and 89 fine needle aspirations from suspected cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) patients and potentially infected dogs. Molecular analysis using ITS1 RFLP PCR and RT-PCR revealed a higher prevalence of L. infantum (66.18 %; χ2 = 28.804; df = 1; P-value = 8.01e−08) than L. tropica in skin scraping, with L. infantum being the sole causative agent for both VL and canine leishmaniasis. L. infantum was predominantly found in most provinces, while L. tropica was relatively more dominant in Taza Province. Discriminant Analysis of Principal Components (DAPC) revealed distinct clustering between L. tropica and the other three species. However, no small subset of SNPs could clearly differentiate between Infantum_CL, Infantum_VL, and CanL, as they likely share a significant genetic background. The high rate of L. infantum could be attributed to the abundance of sand fly species transmitting VL. In Taza Province, Phlebotomus sergenti, responsible for anthroponotic CL, is the most abundant species. DNA sequencing demonstrated sequence heterogeneity in L. infantum (variants 1-9) and L. tropica (variants 1-7). Phylogenetic analysis showed a distinct separation between L. tropica and L. infantum strains, with an overlap among L. infantum strains isolated from cutaneous, visceral, and canine cases, and dogs serving as the central population for L. infantum. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a parasitic disease caused by different Leishmania species. L. infantum is found in the Mediterranean area. It usually causes visceral or cutaneous leishmaniasis, but rarely mucosal leishmaniasis (ML). A 62-year-old man with metastatic non-small-cell lung carcinoma visited the outpatient clinic because of a painful and swollen tongue. Initially, oral candidiasis was suspected and patient was unsuccessfully treated accordingly. Subsequently, a biopsy from the tongue was taken. Histology of the tongue biopsy showed an inflammation with histiocytes and Leishmania amastigotes. Molecular analysis determined these parasites as L. donovani complex. Based on the patient's travel history, ML caused by L. infantum was diagnosed. ML is an unusual presentation of L. infantum. ML is not only caused by Leishmania species endemic in Latin America, but also should be considered in the differential diagnosis for European patients. A biopsy of the affected location is needed to confirm the diagnosis. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a neglected parasitic disease for which the conventional treatment can be considered inefficient and extremely aggressive, generating several and severe side effects. Therefore, the discovery of new drug candidates is important for the improvement in the quality of life of patients. Previously, we reported the promising results of isopentyl caffeate (ICaf) against Leishmania chagasi (agent of visceral leishmaniasis) and Leishmania amazonensis (agent of cutaneous leishmaniasis) promastigotes, displaying IC 50 of 1.56 and 1.71 μM, respectively. Herein, we aimed to decipher the mechanisms of anti- Leishmania action of ICaf. Light and scanning electron microscopy assays showed relevant morphological changes in promastigotes when treated with ICaf, including rounding of the parasite body, shortening of the flagellum, blebs on the plasma membrane and cellular aggregation. The parasite mitochondrion was targeted by ICaf, resulting in a significant reduction in its metabolic activity and electric membrane potential followed by an increase in the production of reactive oxygen species, which culminated in the loss of plasma membrane integrity and parasite death. Relevantly, ICaf also had a potent anti-amastigote action. The IC 50 values calculated for intracellular amastigotes of L. amazonensis were 3.27, 1.60 and 1.52 μM, while for L. chagasi the values were 2.48, 1.84 and 1.60 μM, respectively, after treating the infected macrophages with ICaf for 24, 48 and 72 h. ICaf was well tolerated by THP-1 macrophages, which gave rise to excellent selectivity indexes considering both Leishmania species. The current results suggest that ICaf may emerge as a chemotherapeutic alternative for the treatment of leishmaniasis. • Treatment of leishmania with conventional drugs is regarded as inefficient and extremely aggressive. • Isopentyl caffeate was well tolerated by THP-1 macrophages with high selectivity. • Isopentyl caffeate may emerge as a chemotherapeutic treatment alternative. [ABSTRACT FROM AUTHOR]

• The last record of human leishmaniasis from Dagestan was reported in 1938. • Locally-acquired Leishmania disease was diagnosed in 2 patients from Dagestan. • Problems in notification and timely diagnosis and treatment may occur in the future. Eighty years after the last published record of human leishmaniasis from Dagestan, Russian Federation, we report two recent cases which were most probably acquired locally: one case of visceral leishmaniasis in a 2-year old child, and one cutaneous leishmaniasis case in a 39-year-old man co-infected with HIV, both resident in Dagestan. [ABSTRACT FROM AUTHOR]

• Leishmania donovani can undergo sexual life cycle in natural environment. • Extensive phenotypic diversity of L. donovani could be the result of genetic hybridization. • More leishmaniasis disease polymorphisms may appear in the Indian subcontinent. Leishmaniasis is a neglected tropical disease caused by protozoan parasites of genus Leishmania, and transmitted by different species of Phlebotomine sand flies. More than 20 species of Leishmania are known to cause disease in humans and other animals. Leishmania donovani species complex is known to have a vast diversity of clinical manifestations in humans, but underlying mechanisms for such diversity are yet unknown. Long believed to be strictly asexual, Leishmania have been shown to undergo a cryptic sexual cycle inside its sandfly vector. Natural populations of hybrid parasites have been associated with the rise of atypical clinical outcomes in the Indian subcontinent (ISC). However, formal demonstration of genetic crossing in the major endemic sandfly species in the ISC remain unexplored. Here, we investigated the ability of two distinct variants of L. donovani associated with strikingly different forms of the disease to undergo genetic exchange inside its natural vector, Phlebotomus argentipes. Clinical isolates of L. donovani either from a Sri Lankan cutaneous leishmaniasis (CL) patient or an Indian visceral leishmaniasis (VL) patient were genetically engineered to express different fluorescent proteins and drug-resistance markers and subsequently used as parental strains in experimental sandfly co-infection. After 8 days of infection, sand flies were dissected and midgut promastigotes were transferred into double drug-selective media. Two double drug-resistant, dual fluorescent hybrid cell lines were recovered, which after cloning and whole genome sequencing, were shown to be full genomic hybrids. This study provides the first evidence of L. donovani hybridization within its natural vector Ph. argentipes. [ABSTRACT FROM AUTHOR]

• Co-infection of SARS-CoV-2 and visceral or cutaneous leishmaniasis may lead to changes in susceptibility and/or severity of COVID-19. • IFN-γ- responses to Leishmania could play a role in controlling SARS-CoV-2. • Parasitic neglected tropical diseases (NTDs) can alter the immunologic responses to SARS-CoV-2. [ABSTRACT FROM AUTHOR]

• Lmp27−/− mutant induces Th1 responses against challenge with L. major parasites in BALB/c mice. • Lmp27−/− mutant induces Th1 responses against challenge with L. infantum parasites in BALB/c mice. • Lmp27−/− induces protection against homologous challenge in BALB/c mice. • Lmp27−/− induces cross-protection against heterologous challenge in BALB/c mice. Leishmaniasis is a growing health problem in many parts of the world and efforts to find vaccine against the disease are a public health priority. Live attenuated vaccines are the gold standard for protection against intracellular pathogens such as Leishmania spp. Defined genetic alteration of the Leishmania genome can be achieved using a gene-targeted disruption strategy that allows for the selection of parasites lacking genes essential for long-term survival and virulence. Previously, we demonstrated that genetically modified live attenuated Leishmania major , lacking the p27gene (Lmp27−/−) is safe and induces cellular immunity in BALB/c mice. p27 is a component of the COX complex that is responsible for ATP synthesis. In the current study, the Lmp27−/− strain was assessed as a live attenuated vaccine. Overall protective immunity and efficacy were evaluated at various time periods following Leishmania major (L. major) and Leishmania infantum (L. infantum) challenges separately in BALB/c mice. Cytokine and anti- Leishmania antibody levels, splenocyte proliferation, delayed type hypersensitivity (DTH), skin lesion development, and parasite burden in the liver and spleen were the measured variables. The results demonstrated that immunized mice had a significant T-helper type 1 (Th1) response, smaller skin lesions and lower parasite burdens in their liver and spleens following a L. major challenge. Furthermore, the Lmp27−/− mutant also granted cross-protection against L. infantum infection. These results suggest that immunization with Lmp27−/− parasites provide significant protective immunity and efficacy against infection with homologous as well as heterologous species of Leishmania parasites. [ABSTRACT FROM AUTHOR]

Abstract Antimicrobial resistance (AMR) threatens the prevention and treatment of infections caused by a large range of microorganisms. Leishmania is not an exception and treatment failure due to drug-resistant organisms is increasingly reported. Currently, no molecular methods and marker are validated to track drug-resistant organism and antimicrobial susceptibility tests are roughly not amenable to a clinical setting. Taking these facts into account, it is essential to reflect on ways to translate basic knowledge into methodologies aimed to diagnose leishmania drug resistance. As a matter of fact, a meta-analysis of the literature discloses the reliability of the promastigotes antimicrobial susceptibility tests (AST) to predict intracellular amastigotes susceptibility status. Promastigote cultures that are easy to perform, typically inexpensive and amenable to standardization should represent a candidate to diagnose resistance. Using AST performed on promastigote, we propose a way to improve leishmania drug resistance diagnosis in the framework of guidance and guideline of the bacterial drug resistance diagnosis. In this review, we highlight challenges that remained and discuss the definition of clinical breakpoints, including the epidemiological cutoff (ECOFF), to track drug-resistant isolates. Our analysis paves the ways to standardize and analyze anti-leishmania susceptibility tests output in order to guide the characterization of drug-resistant isolates, the clinical decision during treatment and the search for new molecular markers. [ABSTRACT FROM AUTHOR]

Leishmania (Leishmania) amazonensis and Leishmania infantum (= Leishmania chagasi ) are protozoa that cause American cutaneous and visceral leishmaniasis, respectively. These diseases show a high incidence in developing countries such as Brazil. The treatments used for leishmaniasis are still limited due to their high cost and toxicity. Currently, some natural products are considered an important alternative source of new leishmanicidal agents. Euterpe oleracea Martius, a palm producing black fruits, is frequently consumed in the Amazon region, as a juice, known as açai, with potent antioxidant, anti-inflammatory and anticonvulsant properties. Interestingly, the biological activity of clarified açai juice (EO) on L. (L.) amazonensis and L. infantum (= L. chagasi) is unknown. Therefore, the mechanism of anti-leishmanial action of EO has been evaluated on L. (L.) amazonensis and L. infantum (= L. chagasi) . EO reduced the number of promastigotes and caused morphological alterations, increased the production of reactive oxygen species (ROS) and induced cell death phenotypes probably seems by apoptosis in the promastigotes of L. (L.) amazonensis (IC 50  = 1:40) and L. infantum (= L. chagasi) (IC 50  = 1:38). EO also presented activity against Leishmania amastigotes. Treatment with EO for 72 h strongly reduced IL-17 cytokine levels at all tested concentrations and decreased the number of intracellular amastigotes in macrophages infected with L. ( L.) amazonensis (IC 50  = 1:30) and L. infantum (= L. chagasi) (IC 50  = 1:38). Additionally, no cytotoxic effect was observed in murine macrophages treated with EO (72 h – CC 50  > 1:1). Our results demonstrated that EO has leishmanicidal activity against two different species that cause American visceral and cutaneous leishmaniasis without cytotoxic effects for the host cell. [ABSTRACT FROM AUTHOR]

In Central America, Leishmania (L.) infantum chagasi infection causes visceral leishmaniasis (VL) and non-ulcerated cutaneous leishmaniasis (NUCL). The aim of the present study was to evaluate the course of an experimental infection in hamsters caused by L. (L.) infantum chagasi isolated from patients affected by NUCL compared with a strain isolated from a patient with VL. Stationary phase parasites in culture were inoculated through subcutaneous and intraperitoneal routes in hamsters. Following the post-infection times, a histopathological study, parasite load and cytokine determination in skin from the cutaneous inoculation site and viscera were performed. Animals subcutaneously infected with the different strains did not develop macroscopic lesions at the inoculation site, and the histopathological changes in the dermis were very slight. Regarding the histopathological study of the viscera, we observed the portal mononuclear inflammatory infiltrate, the presence of nodules in the hepatic parenchyma and the proliferation of macrophages in the spleen, which increased over the infection course. Overall, the parasite load in the liver and spleen and in the total IgG titres in the sera of infected hamster showed an increase with the time of infection, regardless of the route of inoculation. Regarding cellular immunity, we did not observe an increase or decrease in pro- and anti-inflammatory cytokines compared to the healthy control, except for IL-10, which was evident in the infected animals. The data showed that strains isolated from NUCL cause visceral lesions in the hamsters regardless of the route of inoculation, and they were similar to parasites isolated from VL humans. [Display omitted] • Strains isolated from LV and NUCL cause visceral disease in hamster. • Parasitism increases with time of infection regardless of the inoculation route. • Total IgG titers increase with the time of infection. • Cellular immunity shows to be weak with discreet presence of IL-10. [ABSTRACT FROM AUTHOR]

• Previous ELISA studies showed a high sero-positivity in Leishmania donovani induced cutaneous leishmaniasis (CL). • Visceral Leishmaniasis (VL) is very rare in Sri Lanka and unresponsive to established rK39 dipstick test. • The described assay was highly sensitive and specific for detection of local VL. Sri Lanka reports a focus of L. donovani i nduced cutaneous leishmaniasis (CL). Our more recent parasite and clinical studies and historical evidence point towards long term existence of Leishmania in the country, indicating a possible evolution leading to antigenic heterogenicity as well. In-house enzyme-linked immunosorbent assay (ELISA) that was developed during phase 1 study indicated >80% sero-positivity in local CL, while visceral leishmaniasis (VL) remained very rare with majority being negative when tested with rK39 assay. A novel serological tool was developed and sero-positivity of VL was assessed for the first time. The assay showed 100.0% sensitivity and 98.3% specificity for detection of VL. Samples were showed less positivity with established direct agglutination test (DAT) and rK39 strip test. The assay was less expensive than that of established rapid diagnostic tests (RDTs), culture and PCR assays. This assay may be useful in diagnosing clinical VL infections, detection of light microscopy (LM) negative patients, tracking post treatment stages, field screening of asymptomatic cases and in further serological studies. [ABSTRACT FROM AUTHOR]

The leishmaniasis are a group of vector-borne diseases caused by a protozoan parasite from the genus Leishmania. In this study, a series of thiazolopyrimidine derivatives were designed and synthesized as novel antileishmanial agents with Lm PTR1 inhibitory activity. The final compounds were evaluated for their in vitro antipromastigote activity, Lm PTR1 and h DHFR enzyme inhibitory activities, and cytotoxicity on RAW264.7 and L929 cell lines. Based on the bioactivity results, three compounds, namely L24f , L24h and L25c , were selected for evaluation of their in vivo efficacy on CL and VL models in BALB/c mice. Among them, two promising compounds, L24h and L25c, showed in vitr o antipromastigote activity against L. tropica with the IC 50 values of 0.04 μg/ml and 6.68 μg/ml; against L. infantum with the IC 50 values of 0.042 μg/ml and 6.77 μg/ml, respectively. Moreover, the title compounds were found to have low in vitro cytotoxicity on L929 and RAW264.7 cell lines with the IC 50 14.08 μg/ml and 21.03 μg/ml, and IC 50 15.02 μg/ml and 8.75 μg/ml, respectively. Lm PTR1 enzyme inhibitory activity of these compounds was determined as 257.40 μg/ml and 59.12 μg/ml and their selectivity index (SI) over h DHFR was reported as 42.62 and 7.02, respectively. In vivo studies presented that L24h and L25c have a significant antileishmanial activity against footpad lesion development of CL and at weight measurement of VL group in comparison to the reference compound, Glucantime®. Also, docking studies were carried out with selected compounds and other potential Leishmania targets to detect the putative targets of the title compounds. Taken together, all these findings provide an important novel lead structure for the antileishmanial drug development. [Display omitted] • A series of thiazolopyrimidine derivatives were synthesized as novel antileishmanials. • L24f , L24h and L25c showed in vitro antipromastigote activity and low cytotoxicity. • L24f , L24h and L25c showed moderate Lm PTR1 inhibition and h DHFR selectivity. • L24h and L25c have shown in vivo activity on CL and VL models of BALB/c mice. [ABSTRACT FROM AUTHOR]

Background Leishmaniasis has been estimated to cause the ninth largest burden amongst global infectious diseases. Occurrence of the disease has been anecdotally associated with periods of conflict, leading to its referral as a disease of ‘guerrilla warfare.’ Despite this, there have been few studies that quantitatively investigate the extent to which leishmaniasis coincides with conflict or political terror. Methodology This study employed a longitudinal approach to empirically test for an association between cutaneous and visceral leishmaniasis incidence with occurrence of conflict and political terror at the national level, annually for 15 years (1995–2010). Leishmaniasis incidence data were collected for 54 countries, and combined with UCDP/PRIO Armed Conflict and Amnesty International political terror datasets. Mixed effects negative binomial regression models clustered at the country-level were constructed to evaluate the incidence rate ratios against the predictors, while controlling for wealth. Additionally, to understand how and why conflict-terror may be associated with leishmaniasis incidence, we conducted a historical analysis. We identify and discuss posited causal mechanisms in the literature, and critically assessed pathways by which leishmaniasis might occur in places and times of conflict-terror. Results There was a significant dose-response relationship for disease incidence based on increasing levels of conflict and terror. Country-years experiencing very high levels of conflict-terror were associated with a 2.38 times higher [95% CI: 1.40–4.05] and 6.02 times higher [95% CI: 2.39–15.15] incidence of cutaneous and visceral leishmaniasis, respectively. Historical analysis indicated that conflict and terror contribute to—or coincide with—leishmaniasis incidence through processes of population displacement and health system deterioration. Conclusions This research highlights the potentially increased risks for cutaneous and visceral leishmaniasis incidence in areas of high conflict-terror. Notably, conflict-terror may act as an empirical proxy for indirect and concomitant processes of social breakdown, migration, and instability, which emerge as the dominant processes associated with disease incidence. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a neglected tropical disease affecting millions of people worldwide, with 650 000 to 1.1 million new infections reported annually by the World Health Organization. Current antileishmanial treatments are unsatisfactory due to the development of parasitic resistance and the toxicity associated with the drugs used, and this highlights the need for the development of new antileishmanial drugs. In this study, a series of nifuroxazide analogues were synthesized in a single step reaction and investigated for their antileishmanial potential. The sulfonate 1l, bearing pyridine ring, was deemed an antileishmanial hit, targeting the amastigotes of Leishmania (L.) donovani and L. major , the pathogens of visceral and cutaneous leishmaniasis, respectively, with micromolar potencies. The benzyl analogues 2c and 2d were also confirmed as submicromolar active leads against amastigotes of L. major. These analogues stand as promising candidates for further investigation involving the evaluation of their in vivo activities and molecular targets. [Display omitted] [ABSTRACT FROM AUTHOR]

A number of leishmaniasis vaccine candidates are at various stages of pre-clinical and clinical development. Leishmaniasis is a vector-borne neglected tropical disease (NTD) caused by a protozoan parasite of the genus Leishmania and transmitted to humans by the bite of a sand fly. Visceral leishmaniasis (VL, kala-azar ) is a high mortality NTD found mostly in South Asia and East Africa, while cutaneous leishmaniasis (CL) is a disfiguring NTD highly endemic in the Middle East, Central Asia, North Africa, and the Americas. Estimates attribute 50,000 annual deaths and 3.3 million disability-adjusted life years to leishmaniasis. There are only a few approved drug treatments, no prophylactic drug and no vaccine. Ideally, an effective vaccine against leishmaniasis will elicit long-lasting immunity and protect broadly against VL and CL. Vaccines such as Leish-F1, F2 and F3, developed at IDRI and designed based on selected Leishmania antigen epitopes, have been in clinical trials. Other groups, including the Sabin Vaccine Institute in collaboration with the National Institutes of Health are investigating recombinant Leishmania antigens in combination with selected sand fly salivary gland antigens in order to augment host immunity. To date, both VL and CL vaccines have been shown to be cost-effective in economic modeling studies. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a parasitic disease caused by hemoflagellates of the genus Leishmania and is transmitted to humans by the bite of infected phlebotomine sandflies. Depending on the Leishmania species, the disease has different clinical forms including cutaneous, mucocutaneous, and visceral manifestations. Previous studies performed in endemic zones of northwestern-Argentina, during epidemic outbreaks, have been important for detecting patients suffering from the acute phase of the disease, but have not given a complete representation of the clinical and epidemiological features in the region. Furthermore, due to the resurgence of leishmaniasis worldwide and in particular the large increase of international tourism to the region, it seems pertinent to update the current epidemiological and clinical profile of leishmaniasis in northwestern-Argentina. Here we present a retrospective analysis of 95 Leishmania positive cases, presenting between 2000 and 2014. Patients were derived from hospitals and diagnosed in our lab at the University of Salta, located in a non-endemic area in Salta, Argentina. We detected numerous extensive mucocutaneous cases (34/95, 35.8%) distinct from mucosal affected patients, some instances originating in locations with no previously reported human cases. Additionally patients suffering from concomitant diseases, besides leishmaniasis, were assessed. These included Chagas disease, syphilis, deep mycoses, tuberculosis, toxoplasmosis and intestinal parasitosis. This study updates the clinical and epidemiological features of leishmaniasis in northwestern-Argentina, and discusses the implications and management strategy for patients who acquire the disease in this region. [ABSTRACT FROM AUTHOR]

Summary Background Leishmaniasis is a neglected tropical disease, endemic in many worldwide foci including the Middle East. Several outbreaks have occurred in the Middle East over the past decades, mostly related to war-associated population migration. With the start of the Syrian war, the frequency and magnitude of these outbreaks increased alarmingly. We describe the epidemiology of Leishmania infection in Lebanon and the most recent outbreak relevant to the Syrian war. Methods We reviewed all leishmaniasis cases reported to the Epidemiologic Surveillance Department at the Lebanese Ministry of Public Health between 2001 and the first quarter of 2014. The demographics and distribution of Syrian refugees in Lebanon were linked to reports of new Leishmania cases. Results In total, 1033 new cases of leishmaniasis were reported in 2013 compared to a previous annual number in the range of 0–6 cases. The majority of cases reported in 2013 involved Syrian refugees and their relevant areas of concentration. Conclusions This new outbreak of leishmaniasis in Lebanon is the first of its kind for more than a decade. The sudden increase in Leishmania cases in Lebanon in 2013 is attributed to the increasing numbers and wide distribution of Syrian refugees in Lebanon. This serves as an example of the risks associated with military conflicts and the ability of communicable diseases to cross borders. [ABSTRACT FROM AUTHOR]

• Between April 2014 to April 2015, 247 bats were captured in the municipality of Montes Claros, Minas Gerais, Brazil. • The overall infection rate of Leishmania spp. in bats was 4.4% (11/247). • Of the 11 bats infected, eight were of the Artibeus planirostris species. • Phylogenetic analysis classified the isolates from bats as: Leishmania (Viannia) sp. , L. (L.) infantum, L. (L.) amazonensis. • This is the first record of the bat Artibeus cinereus as a host of L. (L.) amazonensis. This study aimed to determine the occurrence of Leishmania infection in bats in urban and wild areas in an endemic municipality for visceral and cutaneous leishmaniasis in Minas Gerais, Brazil. Between April 2014 to April 2015, 247 bats were captured and classified into 26 species belonging to Phyllostomidae (90.7%), Vespertilionidae (8.1%) and Molossidae (1.2%) families. Blood samples from 247 bats were collected and submitted to nested-PCR, targeting the variable V7-V8 region of the SSU rRNA gene, followed by sequencing of the PCR product. The overall infection rate of Leishmania spp. in bats was 4.4%. Of the eleven bats infected, ten were frugivorous bats: Artibeus planirostris (8/11), Artibeus lituratus (1/11) and Artibeus cinereus (1/11) and one a nectarivorous bat (Glossophaga soricina). None of the individuals exhibited macroscopic alterations in the skin, spleen or liver. Phylogenetic analysis separated Leishmania species in clades corresponding to the subgenera Viannia, Leishmania , and Mundinia , and supported that the isolates characterized in the present study clustered closely with Leishmania (Viannia) sp., Leishmania (Leishmania) infantum and Leishmania (Leishmania) amazonensis. Here we report for the first time the bat Artibeus cinereus as a host of Leishmania (Leishmania) amazonensis. In the study we found that the mean abundance of bats did not differ in wild habitats and urban areas and that bat-parasite interactions were similarly distributed in the two environments. On the other hand, further studies should be conducted in more recent times to verify whether there have been changes in these parameters. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a disease of the subtropical and tropical spheres of the earth and has various clinical manifestations. The different form of leishmaniasis includes cutaneous leishmaniasis, mucocutaneous leishmaniasis, most lethal visceral leishmaniasis and PKDL form. These different forms depend on many factors such as parasite and vector species, geographical, environmental conditions and population ethnicity. Host genetic factors have been widely investigated for their role in developing the disease in various infections. There are several reports on associations or resistance between candidate gene polymorphisms and the risk and outcome of Leishmania infection. Polymorphism in genes involved in both innate and adaptive immune systems, as well as genes of metabolic processes contributes to disease manifestation. The wide availability and advancement of molecular techniques permits to exploration of hereditary factors related to leishmaniasis. Many candidate gene studies were conducted on family-based and population to identify novel biomarkers for understanding disease pathogenesis pathways and possible drug targets. This comprehensive review presents an update on various human genes polymorphism that influence the outcome of different forms of Leishmania infection in endemic regions of the world. Various electronic databases were searched systematically for relevant publications and thoroughly analyzed. Most of the candidate gene studies were found with discrepancies in findings. Genetic and functional studies with adequate power are needed to validate the contribution of host genes in susceptibility or resistance towards Leishmania infection and understanding pathogenesis. • Leishmaniasis a vector-born parasitic disease has three major clinical manifestations. • Host genetic factors affect susceptibility or resistance towards Leishmania infection. • Molecular techniques advancement permits investigation of host genetics in infection outcome. • Host genetic factors can provide novel biomarkers and drug targets for leishmaniasis. [ABSTRACT FROM AUTHOR]

The figure shows anti- Leishmania activity of artesunate against promastigotes and amastigotes of L. martiniquensis and its combination with amphotericin B against amastigotes of L. martiniquensis. [Display omitted] • Promastigote and intracellular amastigote stages of Leishmania martiniquensis are susceptible to artesunate. • Artesunate in combination with amphotericin B provides a strong synergism against L. martiniquensis without toxicity to host cells. • The strong synergistic combination had the highest dose reduction index (DRI), approximately a 9.7-fold reduction in amphotericin B used. • Combination of artesunate and amphotericin B might lead to application in leishmaniasis treatment to improve the therapeutic outcome for the Leishmania species. Leishmaniasis is an emerging disease in several countries over the world, especially in tropical regions. In Thailand, Leishmania (Mundinia) martiniquensis is the most frequent cause of visceral leishmaniasis and disseminated cutaneous leishmaniasis among HIV/AIDs patients. Amphotericin B (AmB) is the only drug currently available for the treatment of leishmaniasis in Thailand, but has some limitations like high renal toxicity and the prolonged hospitalization required for the treatment. Moreover, recurrence of the disease has been reported in several cases, indicating that new drugs or treatment strategies should be improved. In this study, Artesunate (ARS) was determined for anti- Leishmania activity against L. martiniquensis in promastigotes and amastigotes. In addition, the combination effects of ARS and AmB against intracellular amastigotes on THP-1 derived macrophages were also investigated for the first time. The result showed that L. martiniquensis was susceptible to ARS in both stages of the parasite. ARS was effective against intracellular amastigotes and safe to macrophage host cells, showing a SI value of 1,065. Furthermore, combination effects of ARS and AmB showed five synergistic combinations with a combination index (CI) value less than 1.0 (0.28–0.92) for intracellular amastigotes ranging from slight synergism to strong synergism. The strong synergistic combination had the highest dose reduction index (DRI), approximately a 9.7-fold reduction in AmB used. None of the treatments in combination had noticeable toxicity to THP-1 derived macrophages in the concentration range examined. The data provided in this study lead to further study in vivo and to develop a novel formulation of drug combinations to improve the outcome of leishmaniasis treatment. [ABSTRACT FROM AUTHOR]

Highlights: [•] Sodium antimony gluconate contributes towards the pathogenesis of PKDL. [•] UV light plays a pivotal role in the development of PKDL. [•] Development of PKDL can be viewed as a reinfection or activation of latent Leishmania parasites. [•] PKDL can be resolved by mounting an effective tissue-specific memory T cell response. [•] Host genetic factors play a contributory role. [Copyright &y& Elsevier]

• Miltefosine is currently the only oral drug available to treat the neglected tropical disease leishmaniasis. • All clinical pharmacokinetic and pharmacodynamic data for miltefosine in the treatment of leishmaniasis are summarized. • Several recent studies established exposure-response relationships for various miltefosine treatment regimens. • An overview is provided of pharmacokinetic targets predictive of clinical relapse and outcome. Miltefosine is an alkylphosphocholine agent with a broad spectrum of antiparasitic properties. For over two decades, miltefosine has remained the only oral drug licensed and used in the treatment of the neglected tropical disease, leishmaniasis. The last extensive review of the pharmacology of miltefosine was published in 2012. Additional data on the clinical pharmacokinetics (PK) and pharmacodynamics (PD) of miltefosine have become available in the last decade, and there are ongoing and future studies in this area. Miltefosine PK are characterized by slow absorption and elimination, resulting in accumulation of drug in plasma until the end of treatment. Several recent studies established exposure-response relationships for various regimens of miltefosine in the treatment of visceral and cutaneous leishmaniasis, leading to the identification of PK parameters predictive of clinical relapse and outcome. This review provides an update on the most recent developments in the area of clinical pharmacology of miltefosine, including a discussion of the current dosing regimens. [ABSTRACT FROM AUTHOR]

• Lmp27−/− mutant as a vaccine candidate is safe in dogs. • Lmp27−/− mutant induces protective immunity against heterologous challenge in dogs. • Lmp27−/− mutant as vaccine candidate induces protection against canine leishmaniasis. Canine leishmaniasis (CanL) is an important parasitic e disease caused by Leishmania infantum and is transmitted by female phlebotomine sand flies primarily between canines and secondarily to humans. Recently, we showed that immunization with Leishmania major p27 gene knockout (Lmp27−/−) as a live attenuated vaccine was safe, induced immunogenicity, and protected against the development cutaneous and visceral leishmaniasis in mice. The p27 protein is a component of the COX protein complex which is responsible for ATP production. In this study, we analyzed the Lmp27−/− candidate vaccine potential with this regard to the safety and induction of immunogenicity and protection against CanL. Variables such a clinical manifestation, anti- Leishmania antibodies using direct agglutination test (DAT), lymphocyte proliferation, delayed-type hypersensitivity (DTH), bone marrow aspiration (BMA) and parasite burden using parasitological and molecular examinations were measured. The results demonstrated that the Lmp27−/− vaccinated group showed no clinical signs after inoculation with Lmp27−/− mutant during a 12-month follow-up, and had significantly higher T-cell responses (Lymphocyte proliferation and DTH), lower seroconversion and parasite burdens following a challenge inoculation with L. infantum after 6-mounth. In conclusion, vaccination with Lmp27−/− parasites would be safe and provide significant immunoprotectivity and efficacy against infection with wild type (WT) L. infantum. [ABSTRACT FROM AUTHOR]

Abstract: The transmission of Leishmania involves several species of sand flies that are closely associated with various parasites and reservoirs, with differing transmission cycles in Brazil. A study on the phlebotomine species composition has been conducted in the municipality of Divinópolis, Minas Gerais, Brazil, an endemic area for cutaneous leishmaniasis (CL), which has intense occurrence of visceral leishmaniasis (VL) cases. In order to study the sand flies populations and their seasonality, CDC light traps (HP model) were distributed in 15 houses which presented at least one case of CL or VL and in five urban parks (green areas). Collections were carried out three nights monthly from September 2010 to August 2011. A total of 1064 phlebotomine specimens were collected belonging to two genera and seventeen species: Brumptomyia brumpti, Lutzomyia bacula, Lutzomyia cortelezzii, Lutzomyia lenti, Lutzomyia sallesi, Lutzomyia longipalpis, Lutzomyia migonei, Lutzomyia intermedia, Lutzomyia neivai, Lutzomyia whitmani, Lutzomyia christenseni, Lutzomyia monticola, Lutzomyia pessoai, Lutzomyia aragaoi, Lutzomyia brasiliensis, Lutzomyia lutziana, and Lutzomyia sordellii. L. longipalpis, the main vector of Leishmania infantum in Brazil, was the most frequent species, accounting for 76.9% of the total, followed by L. lenti with 8.3%, this species is not a proven vector. Green and urban areas had different sand flies species composition, whereas the high abundance of L. longipalpis in urban areas and the presence of various vector species in both green and urban areas were also observed. Our data point out to the requirement of control measures against phlebotomine sand flies in the municipality of Divinópolis and adoption of strategies aiming entomological surveillance. [Copyright &y& Elsevier]

Abstract: Leishmaniasis is a neglected tropical disease caused by Leishmania protozoa and associated with three main clinical presentations: cutaneous, mucocutaneous and visceral leishmaniasis. Visceral leishmaniasis is the second most lethal parasitic disease after malaria and there is so far no human vaccine. Leishmania donovani is a causative agent of visceral leishmaniasis in South East Asia and Eastern Africa. However, in Sri Lanka, L. donovani causes mainly cutaneous leishmaniasis, while visceral leishmaniasis is rare. We investigate here the possibility that the cutaneous form of L. donovani can provide immunological protection against the visceral form of the disease, as a potential explanation for why visceral leishmaniasis is rare in Sri Lanka. Subcutaneous immunization with a cutaneous clinical isolate from Sri Lanka was significantly protective against visceral leishmaniasis in BALB/c mice. Protection was associated with a mixed Th1/Th2 response. These results provide a possible rationale for the scarcity of visceral leishmaniasis in Sri Lanka and could guide leishmaniasis vaccine development efforts. [Copyright &y& Elsevier]

Abstract: Hypoxanthine-guanine phosphoribosyl transferase (HGPRT; EC 2.4.2.8) is a central enzyme in the purine recycling pathway. Parasitic protozoa (Leishmania donovani) cannot synthesize purines de novo and utilize the salvage pathway to produce purine bases. Thus, this enzyme is targeted in drug discovery and development. The model of the monomeric L. donovani HGPRT showed that this enzyme is an α/β type protein with a PRTase type I folding pattern. Among all of the computationally screened compounds, pentamidine, 1,3-dinitroadamantane, acyclovir and analogs of acyclovir had higher binding affinities than the real substrate (guanosine monophosphate). Amino acids of HGPRT that are frequently involved in the binding of these compounds are Lys 66, Asp 74, Arg 77, Asp 81, Val 88, Tyr 182, Arg 192 and Arg 194. It is predicted that patients suffering from both HIV and visceral leishmaniasis (VL) may benefit if they are treated with acyclovir or pentamidine in conjunction with first-line antileishmanial therapies such as miltefosine and AmBisome. [Copyright &y& Elsevier]

Abstract: The species of the Leishmania donovani species complex cause visceral leishmaniasis, a debilitating infectious disease transmitted by sandflies. Understanding molecular changes associated with population structure in these parasites can help unravel their epidemiology and spread in humans. In this study, we used a panel of standard microsatellite loci and genome-wide SNPs to investigate population-level diversity in L. donovani strains recently isolated from a small geographic area spanning India, Bihar and Nepal, and compared their variation to that found in diverse strains of the L. donovani complex isolates from Europe, Africa and Asia. Microsatellites and SNPs could clearly resolve the phylogenetic relationships of the strains between continents, and microsatellite phylogenies indicated that certain older Indian strains were closely related to African strains. In the context of the anti-malaria spraying campaigns in the 1960s, this was consistent with a pattern of episodic population size contractions and clonal expansions in these parasites that was supported by population history simulations. In sharp contrast to the low resolution provided by microsatellites, SNPs retained a much more fine-scale resolution of population-level variability to the extent that they identified four different lineages from the same region one of which was more closely related to African and European strains than to Indian or Nepalese ones. Joining results of in vitro testing the antimonial drug sensitivity with the phylogenetic signals from the SNP data highlighted protein-level mutations revealing a distinct drug-resistant group of Nepalese and Indian L. donovani. This study demonstrates the power of genomic data for exploring parasite population structure. Furthermore, markers defining different genetic groups have been discovered that could potentially be applied to investigate drug resistance in clinical Leishmania strains. [Copyright &y& Elsevier]

Clin Microbiol Infect 2011; 17: 1478-1483 Abstract Although there have been significant advances in the treatment of visceral leishmaniasis (VL), there remain challenges to ensure that treatments effective in India are also effective in other regions of the world and to identify treatment for post kala-azar dermal leishmaniasis as well as the opportunity to develop a safe oral short-course treatment. At the same time, there have been few advances for the treatment of simple or complex forms of cutaneous leishmaniasis (CL), other than topical paromomycin formulations. The main challenge for CL is to ensure that this disease is on the research and development agenda, so that new drugs are evaluated or compounds are screened in appropriate models, and that the standardization of quality of clinical trials is guaranteed. Problems also remain in the treatment of HIV/leishmaniasis co-infected patients. We are some way from having the ideal treatments for VL and CL and drug research and development for these diseases must remain focused. [ABSTRACT FROM AUTHOR]

Abstract: A community-based epidemiological study was carried out in a rural area in northeastern Brazil, where visceral leishmaniosis is endemic, but the primary vector Lutzomyia longipalpis has never been found. Forty-one dogs were screened by an indirect immunofluorescence antibody test (IFAT) for the presence of anti-Leishmania antibodies and 12 (29.3%) of them were positive. One of the IFAT-positive dogs was also positive for Leishmania amastigotes in bone marrow cytology and for Leishmania infantum by real-time polymerase chain reaction (PCR) on blood. One IFAT-negative dog was positive for L. infantum by PCR on bone marrow and other for Leishmania amastigotes in skin stained-smears. When tested for L. braziliensis by PCR, 20 dogs were positive. Considering all diagnostic tests, the estimated prevalence of Leishmania spp. infection in the studied rural dog population was 58.5%. There was no significant difference in IFAT-positivity in relation to age, gender, and clinical status of the dogs. When tested for L. infantum by real-time PCR, 20 ticks collected from IFAT-positive dogs were all negative. This study shows a high level of exposure to Leishmania spp. infection in dogs from a rural community in northeastern Brazil. In general, the results do not support the participation of ticks as vectors of L. infantum in this area, which is likely to be transmitted by Lutzomyia spp. other than L. longipalpis. Finally, this study highlights that the use of IFAT in areas where both L. infantum and L. braziliensis are present should be withdraw in order to avoid the unnecessary culling of dogs that are actually infected only by L. braziliensis. [Copyright &y& Elsevier]

Abstract: We develop a mathematical model to understand the role of cross-immunity between two different strains of leishmania. Our results show that , the basic reproduction number of the model decreases as the cross-immunity increases; moreover, if the cross-immunity between the two different strains is perfect, then the disease-free equilibrium is globally asymptotically stable. Results also show that in the case of partial cross-immunity the model undergoes backward bifurcation, where is not enough for eradication of the disease. We find that if the force of infection of both strains in not equal to zero, then both strains will coexist without competition. Numerical results show that at the endemic equilibrium the number of infected humans with one strain is higher than the number of infected humans with the same strain after they recovered from the infection of the other one, which shows that the cross-immunity reduces the number of infections. [Copyright &y& Elsevier]

Abstract: The Leishmania strains belonging to cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) have been reported to possess close homology in genome profiles. To confirm this on genetic basis an attempt was made to differentiate Leishmania major; Leishmania tropica and Leishmania donovani genetically for the first time using amplified fragment length polymorphism (AFLP)—a high throughput DNA fingerprinting technique. The objective of this research work was to identify DNA markers of CL and VL. Ten combinations of selective primers detect a total of 1487 informative AFLP marker. Percentage of polymorphism was 45.12%. Three hundred and thirty-seven unique AFLP markers were also identified in three species of Leishmania. A clear distinction was revealed between L. major and L. donovani. It was inferred by AFLP analysis that a higher rate of polymorphisms occurred among Leishmania species which indicate the distinguished pattern of the disease cause by Leishmania, i.e. VL and CL. Analysis based on polymorphic AFLP markers revealed considerably high genetic variation among the genome of these species which was sufficient to distinguish between CL and VL. [Copyright &y& Elsevier]

Abstract: The identification and characterization of Leishmania are relevant to diagnosis, treatment, eco-epidemiology studies, prophylactic measures and control of the disease. Two strains of Leishmania (MHOM/BR/1971/BH49 and MHOM/BR/1971/BH121), isolated from human cutaneous leishmaniasis, were studied using biological and molecular characteristics, in comparison with WHO reference strains. These studies are important because both strains were incorporated in a vaccine against American cutaneous leishmaniasis, and one of these strains has been used to prepare specific and sensitive antigen for serodiagnosis of visceral leishmaniasis in Brazil. Studies were made on the growth rates of promastigotes in Grace''s insect medium, infectivity to C57BL/6 and BALB/c mice, electrophoresic mobility patterns of isoenzymes, random amplification of polymorphic DNA (RAPD), simple sequence repeat-anchored PCR amplification (SSR-PCR) and DNA fingerprinting profiles, infectivity to murine macrophages and cellular immune response. Infections of mice and macrophages were significantly different among the strains studied. Attempts to infect mice with culture promastigotes were unsuccessful with BH121, but BH49 infected BALB/c and C57BL/6 mice. Isoenzyme electrophoretic mobility patterns, RAPD and SSR-PCR using DNA amplified by polymerase chain reaction (PCR) with nine arbitrary primers, as well as DNA fingerprinting studies with a biotin-labeled 33.15 fingerprinting probe showed similar profiles to those of the Leishmania major WHO reference strain. [Copyright &y& Elsevier]

Abstract: In this population genetic study of Leishmania donovani parasites in the Indian subcontinent, 132 isolates obtained from patients in Bangladesh, India, Nepal and Sri Lanka suffering from Kala-azar (100), post-Kala-azar dermal leishmaniasis (PKDL) (25) and cutaneous leishmaniasis (CL) (2), and from 5 patients whose clinical patterns were not defined, were analysed by using 15 hyper-variable microsatellite loci. Multilocus microsatellite typing (MLMT) data were analysed by using a Bayesian model-based clustering algorithm and constructing phylogenic tree based on genetic distances. In total, 125 strains from Bangladesh, Bihar (India) and Nepal formed a very homogeneous population regardless of geographical origin, clinical manifestation, and whether they presented in vitro or in vivo susceptibility to antimonial drugs. Identical multilocus microsatellite profiles were found for 108 strains, other strains differed in only one marker. Considerably different microsatellite profiles were identified for three Indian strains most closely related to L. donovani from Kenya, and for four strains from Indian and Sri Lankan CL cases. The circulation of a single homogeneous population of L. donovani in Bihar (India), Bangladesh and Nepal is, most probably, related to the epidemic spread of visceral leishmaniasis in this area. [Copyright &y& Elsevier]

• Thi-Qar province considers one of the mixed foci of cutaneous and visceral leishmaniasis, which is considered as widely health problem and is an uncontrolled disease. • The phylogenetic relationship and sequncing analysis of L. tropica isolates have not been studied before in the local area. • The nested PCR assay is considered a suitable method for identifying Leishmania parasites in clinical samples. The Kinetoplast DNA minicircle gene has showed high sensitivity and specificity to characterize the parasite. • The kDNA minicircle sequences analysis results have showed variation of the local isolates that decrease whenever approached from the Iranian border. This means that L.tropica may transmit from Iran. Cutaneous leishmaniasis (CL) is one of wobbling endemic disease in Iraq, that cause intracellular obligate protistan parasite returned to the genus Leishmania. This study is aimed to identify epidemiology of CL, detect the prevalence of Leishmania tropica and find the phylogenetic relationship. The current study was conducted in the main hospitals of Thi-Qar province-south of Iraq for period from November 2018 to October 2019. Nested-PCR was used to amplify kinetoplast minicircle fragments DNA. It was recorded 247 clinical cases with CL, the infections of males were higher than females, while infection rate appeared gradual reduction with age progress. Furthermore, the most CL infections were as single lesions and occurred in December. The infections of upper limbs were high when compared with other body regions. The molecular diagnosis showed L. tropica was more frequently. DNA sequences of kDNA gene of L. tropica showed confirmative genetic detection of local isolates using NCBI-Blast data and phylogenetic tree analysis after comparison with global recorded isolates. The local L. tropica isolates showed genetically closed related to NCBI-Blast L. tropica with accession number AB678350.1. Generally, the analysis of kDNA nitrogen bases sequences showed that all of samples were consistent with those recorded at the NCBI. The kDNA minicircle sequences analysis results showed mismatching of the local isolates decrease whenever approached from the Iranian border. In addition, genetic heterogeneity diagnosis is important for detection of therapy, control and epidemiological studies. [ABSTRACT FROM AUTHOR]

Abstract: The present study applies multilocus microsatellite typing (MLMT) for studying the polymorphism among 55 strains of Leishmania infantum from Algeria. These strains from different Algerian foci representing different zymodemes, hosts and clinical forms were analysed using 14 microsatellite markers. All 55 strains had individual MLMT profiles and no relationship was observed between them and different host or geographical origins. Three populations of Algerian L. infantum were identified by a Bayesian clustering approach implemented in STRUCTURE software and supported by genetic distance analysis. Two populations, A and B, consisted mainly of strains belonging to zymodeme MON-1, and the third population, C, mainly of MON-24 strains isolated from cutaneous leishmaniasis cases. Interestingly, a small group of strains appeared as a mixture of different populations and might be putative hybrids. Genetic migration was noticed among the two MON-1 populations, A and B, as well as between populations A and C. Due to its high discriminatory power MLMT could be also successfully applied for differentiating relapses or re-infection for patients suffering from multiple episodes of visceral leishmaniasis. [Copyright &y& Elsevier]

• Different strais of L. amazonensis can cause different clinical forms. • Visceral L. amazonensis strains causes slow-onset disease in mice. • Cutaneous L. amazonensis strains quickly induces disease and inflammation in mice. • Genomic alteration in L. amazonensis metabolism genes might increase virulence. Leishmania (Leishmania) amazonensis is an important etiological agent of American cutaneous leishmaniasis (ACL) in Brazil. The species causes a large spectrum of clinical manifestations in humans and dogs, ranging from cutaneous, cutaneous diffuse, mucocutaneous, and visceral involvement, however, the factors that drive the development of different disease forms by the same species are not yet fully known. In the present work, it was systematically reviewed the studies addressing phenotypic and genotypic characteristics of Leishmania (L.) amazonensis isolates causing cutaneous and visceral clinical frames in humans and dogs, comparing the results observed. For this, four research databases were searched for the following keywords: (Leishmania amazonensis AND visceral leishmaniasis) AND (tropism OR virulence OR visceralization OR adaptations OR mutation OR clinical presentation OR resistance OR survival OR wide spectrum). The results revealed that the complexity disease seems to involve the combination of genetic factors of the parasite (as modifications in molecules related to the virulence and metabolism) and also of the host's immune background and status. Nonetheless, the exact mechanism that leads to different clinical manifestations between strains of the same species is still uncertain and future studies must be developed to better elucidate this phenomenon. [ABSTRACT FROM AUTHOR]

Abstract: As in the countries edging the Mediterranean basin, Leishmania infantum zymodeme MON-1 is the main causative agent of visceral leishmaniasis in Morocco, where visceral leishmaniasis is most active in the North-Eastern slopes of the Rif mountains. The dog was confirmed to be the main reservoir of L. infantum MON-1, while the reservoir of L. infantum MON-24 causative agent of both infantile visceral leishmaniasis and cutaneous leishmaniasis has not yet been identified. Here we report the first detection of this last zymodeme in a dog in Morocco. The isolated strain was first identified by the use of genotyping markers and confirmed by isoenzyme analysis. Phylogenetic analysis with the use of concatenated sequences from 26 Leishmania donovani complex strains revealed strong geographical correlation with the MON-24 strain from Morocco clustering with other East African strains whereas two other MON-24 strains clustered with L. infantum strains. Interestingly, the two distinct populations of MON-24 identified with the use of genotyping markers cannot be distinguished by multilocus enzyme electrophoresis. [Copyright &y& Elsevier]

Abstract: We previously showed that intranasal (i.n.) vaccination with pCIneo plasmid encoding the leishmanial LACK gene (pCIneo-LACK) induces long-lasting protective immunity against cutaneous leishmaniasis in mice. In this work, we proposed to investigate whether the efficacy of i.n. pCIneo-LACK is extensive to visceral leishmaniasis. BALB/c mice received two i.n. doses of 30μg pCIneo-LACK prior to intravenous (i.v.) infection with Leishmania chagasi. Vaccinated mice developed significantly lower parasite burden in the liver and spleen than control mice receiving empty pCIneo or saline. The spleen cells of vaccinated mice produced significantly increased IFN-γ and IL-4 concomitant with decreased IL-10 production during infection. Serum levels of specific IgG were elevated whereas TNF-α were decreased as compared with controls. These results show that the practical needle-free i.n. pCIneo-LACK vaccine displays potential broad-spectrum activity against leishmaniasis. [Copyright &y& Elsevier]

During a blood meal, parasites are inoculated into the host skin together with sand fly gut microbiota and salivary proteins, as well as Leishmania-derived proteophosphoglycans and exosomes. Alten, Seasonal dynamics of phlebotomine sand fly species proven vectors of Mediterranean leishmaniasis caused by Leishmania infantum. 2 H. Aslan, New insights into the transmissibility of Leishmania infantum from dogs to sand flies: experimental vector-transmission reveals persistent parasite depots at bite sites. [Extracted from the article]

The gene encoding type I signal peptidase (Lmjsp) has been cloned from Leishmania major. Lmjsp encodes a protein of 180 amino residues with a predicted molecular mass of 20.5 kDa. Comparison of the protein sequence with those of known type I signal peptidases indicates homology in five conserved domains A–E which are known to be important, or essential, for catalytic activity. Southern blot hybridisation analysis indicates that there is a single copy of the Lmjsp gene. A recombinant SPase protein and a synthetic peptide of the L. major signal peptidase were used to examine the presence of specific antibodies in sera from either recovered or active individuals of both cutaneous and visceral leishmaniasis. This evaluation demonstrated that sera from cutaneous and visceral forms of leishmaniasis are highly reactive to both the recombinant and synthetic signal peptidase antigens. Therefore, the Leishmania signal peptidase, albeit localised intracellularly, is a significant target of the Leishmania specific immune response and highlights its potential use for serodiagnosis of cutaneous and visceral leishmaniasis. [Copyright &y& Elsevier]

A case of feline cutaneous leishmaniasis is reported in a domestic cat (Felis catus) as an apparently natural infection in a non-endemic area. Amastigotes were seem in smears of a nodular lesion on the cat’s nose. No parasite could be seen in cytological preparations of liver or spleen but DNA obtained from a sample of the spleen produced the expected fragment in a Leishmania specific rDNA based PCR assay. The PCR product, a 520 bp fragment, was sequenced and the nucleotide sequence was identical to that of Leishmania (Leishmania) infantum chagasi. These results are surprising since no autochthonous human or canine cases of visceral leishmaniasis have ever been reported from this region. This case suggests that natural transmission of this disease is occurring in this area, and that cats could act as a reservoir of L. (L.) infantum chagasi. [Copyright &y& Elsevier]

Cutaneous leishmaniasis in Venezuela has been associated with different Leishmania species and the visceral form is frequently related to L. chagasi. However, in this study we have characterized as L. colombiensis by molecular techniques some isolates of Leishmania from patients presenting either cutaneous or visceral leishmaniasis. Three different molecular markers (two DNA and one protein) were used to investigate the diversity among the L. colombiensis isolates. The analysis revealed the isolates to be similar although distinct from the reference strain of L. colombiensis. Slight variation among the isolates could not be correlated with any epidemiological features of the samples however the visceral isolates were observed to cluster on a phenetic tree derived from one DNA marker. The results confirm previous findings that L. colombiensis can cause both the cutaneous and visceral forms of the disease and that there exists at least two distinct etiological agents of American visceral leishmaniasis (AVL). The report also shows the necessity of careful differentiation of leishmanial isolates in any clinical or epidemiological study of human leishmaniasis. [Copyright &y& Elsevier]

Some Leishmania species affect humans in two principal forms: visceral and cutaneous leishmaniosis (CL). Several studies have identified dogs as the main reservoirs of the visceral leishmaniosis (VL) caused by Leishmania infantum. The purpose of this work was to carry out a survey of the canine population associated with human cases of American tegumentary leishmaniosis (ATL), in order to establish the clinical, parasitological, serological and immunological characteristics of the canine disease, in an endemic region for both ATL and Chagas’ disease in the province of Salta, in northwestern Argentina. Two hundred and eight dogs from the endemic area were examined and 41 (19.7%) of them presented lesions compatible with leishmaniosis. In order to investigate the presence of antibodies against Leishmania spp. and Trypanosoma cruzi, sera were screened by ELISA using two complex antigens from these parasites and, because of cross-reactions between them, a specific antigen for diagnosis of T. cruzi infection. Sixty-two (29.8%) of 208 dogs were positive for the complex antigen F45 from Leishmania and 50 (24%) were positive for the complex antigen F105 from T. cruzi. Nine dogs (4.3%) were positive for the specific Ag163B6-cruzipain suggesting that these dogs were truly infected with T. cruzi. Furthermore, three of these nine dogs presented Leishmania sp. in their skin lesions and therefore were considered as infected by both, T. cruzi and Leishmania parasites. The prevalence of Leishmania infection detected by lesions and/or positive serology was 27.4% (57/208). On the basis of previous observations regarding the clustered appearance of human ATL, the dog population was divided into two groups: zone A, dogs living within a 100 m radius from houses with human cases, and zone B, dogs living beyond this limit. The prevalence of ATL in dogs was significantly higher in zone A (34.6%) than in zone B (7.3%), suggesting a strong correlation between canine and human cases. The average time required for a parasitological diagnosis by microscopy was six times longer for dog samples than human ones, and the average number of parasites per 100 microscopic fields was 14-fold lower in canine samples. The high prevalence of Leishmania infection and the close association with human cases, demonstrated that dogs are a very susceptible host for Leishmania infection, but the scarcity of parasites in their lesions suggests that they may not be the main reservoir of the parasite in this endemic area. [Copyright &y& Elsevier]

Natural disasters (NDs) may increase the outbreaks and transmissions of vector-borne diseases such as cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL). However, the relationship between leishmaniases and NDs has not yet been clearly established. Here, we systematically reviewed all reported articles in this field to answer whether NDs increase the frequency of leishmaniases. All the related articles published during January 2000 till January 2020 were reviewed. Moreover, all NDs and the associated leishmaniases frequencies reports in 17 leishmaniases endemic countries were searched to find any ND-leishmaniases relationship. After the initial screening, 39 articles on ND-leishmaniases were selected and systematically reviewed. These articles showed different frequencies of CL in the endemic areas before and after NDs in some regions of Pakistan and Iran and in case of VL in Brazil, Ethiopia, and Sudan. After thorough deliberation, four studies for CL-ND and five studies for VL-ND relationships were selected for meta-analysis. The results showed increases in the leishmaniases incidences after NDs, although not robustly. The lack of a strong leishmaniases-ND relationship could be attributed to the local compilations of such data in scattered regions of the endemic countries. Therefore, currently a substantial knowledge gap on leishmaniases-ND relationship is apparent. [ABSTRACT FROM AUTHOR]

• Clinical isolates were typed as Leishmania (Viannia) braziliensis, L. (Leishmania) amazonensis and L. (V.) guyanensis. • Strains and clinical isolates responsible for tegumentary leishmaniasis presented variation in in vitro susceptibility to paromomycin in both stages of parasite. • Intracellular amastigotes were more susceptible to paromomycin than promastigotes. Treatment of tegumentary leishmaniasis in Brazil is limited to pentavalent antimonial, amphotericin B and pentamidine. These drugs, administered parenterally, cause several side effects and have a varied clinical response, depending on the species of Leishmania. Urgent expansion of the therapeutic arsenal against the disease is therefore necessary. Paromomycin is an aminoglycoside antibiotic that has already been approved for the treatment of visceral leishmaniasis in Southeast Asia. Here, we provide an in vitro evaluation of the activity of paromomycin in fifteen clinical isolates from patients with tegumentary leishmaniasis at a reference center for the treatment of the disease. Furthermore, the in vitro susceptibility to this drug in reference strains of Leishmania species that are endemic in Brazil has also been evaluated. Among the clinical isolates, nine were typed as Leishmania (Viannia) braziliensis , five as L. (Leishmania) amazonensis and one as L. (V.) guyanensis. Although never exposed to paromomycin, we found variable susceptibility among these isolates and reference strains in promastigotes and intracellular amastigotes, with the drug being more active in the amastigote form of the parasite. This study provides a preclinical dataset that is useful for the evaluation of paromomycin in the treatment of tegumentary leishmaniasis caused by species that are endemic in Brazil. Image, graphical abstract [ABSTRACT FROM AUTHOR]