Search Results (241)

Leishmaniasis is an infectious disease common in tropical and subtropical regions worldwide. This study aimed to develop a topical meglumine antimoniate gel (MA-gel) for the treatment of cutaneous leishmaniasis. The MA-gel was characterized in terms of morphology, pH, swelling, porosity, rheology, and thermal properties by differential scanning calorimetry (DSC). Biopharmaceutical evaluation included in vitro drug release and ex vivo skin permeation. Safety was evaluated through biomechanical skin property measurements and cytotoxicity in HaCaT and RAW 267 cells. Leishmanicidal activity was tested against promastigotes and amastigotes of Leishmania infantum, and in silico studies were conducted to explore possible mechanisms of action. The composition of the MA-gel included 30% MA, 20% Pluronic^® F127 (P407), and 50% water. Scanning electron microscopy revealed a sponge-like and porous internal structure of the MA-gel. This formula exhibited a pH of 5.45, swelling at approximately 12 min, and a porosity of 85.07%. The DSC showed that there was no incompatibility between MA and P407. Drug release followed a first-order kinetic profile, with 22.11 µg/g/cm² of the drug retained in the skin and no permeation into the receptor compartment. The MA-gel showed no microbial growth, no cytotoxicity in keratinocytes, and no skin damage. The IC₅₀ for promastigotes and amastigotes of L. infantum were 3.56 and 23.11 µg/mL, respectively. In silico studies suggested that MA could act on three potential therapeutic targets according to its binding mode. The MA-gel demonstrated promising physicochemical, safety, and antiparasitic properties, supporting its potential as a topical treatment for cutaneous leishmaniasis. Full article

Canine leishmaniosis (CanL), caused by Leishmania infantum, is a major zoonotic disease primarily transmitted by sand flies. Unlike in adult dogs, the clinical course of CanL in puppies remains poorly characterized, regardless of the transmission pathway (i.e., vertical transmission or vector exposure). This study presents the first systematic literature review (SLR) focused on juvenile CanL, alongside an atypical clinical case report. A PRISMA-compliant search across four databases identified three eligible studies describing CanL in puppies (≤9 months, according to the current canine life stage guidelines). The case involves a 4.5-month-old puppy adopted from southern Italy with papulo-nodular skin lesions and generalized lymphadenomegaly as well as a mild normocytic normochromic anemia and increased C-reactive protein. L. infantum infection was confirmed by serology, polymerase chain reaction (PCR), and cytology. The SLR suggests that dermatological lesions and/or lymphadenomegaly, whether associated with laboratory abnormalities, represent the most common clinical manifestations of CanL in puppies. In the presented case, the coexistence of systemic dissemination signs and papulo-nodular skin lesions, typically associated with vector-borne transmission, suggests the possibility of a dual route of infection by L. infantum. Juvenile CanL should be considered in differential diagnoses and supported by thorough diagnostic evaluation and appropriate follow-up protocols. Full article

Kala-azar is a protracted disease caused by the protozoan Leishmania infantum (zoonotic) or L. donovani (anthroponotic), transmitted by sandflies. Patients present with fever, anemia, and hepatosplenomegaly, potentially progressing to hemorrhaging, secondary infections, and death. Its pathogenesis is linked to an exaggerated cytokine response. We studied 72 hospitalized patients, analyzing clinical data and outcomes in relation to L. infantum DNA loads in blood and bone marrow, and plasma concentrations of IL-1β, IL-6, IL-8, IL-10, IL-12, TNF-α, and TGF-β. Cytokine levels were found to be elevated. L. infantum kDNA loads in blood and bone marrow were strongly correlated and increased with disease duration. Higher parasite loads were observed in men, adults, and HIV-infected patients, and they were significantly associated with mortality. IL-6 was independently linked to sepsis. In multivariate analysis, IL-12 was the only cytokine inversely associated with blood parasite load. Parasite load, but not cytokine levels, correlated with disease severity, suggesting additional mechanisms drive progression. IL-12 appears to limit parasitemia, indicating a weak, persistent adaptive immune response that is ultimately overwhelmed by a progressive, inefficient, and inflammatory innate response. Full article

Feline leishmaniasis (FeL), caused by Leishmania infantum, is increasingly reported in areas of endemic Mediterranean canine leishmaniasis (CanL), making it an emerging feline disease. This cross-sectional study investigated L. infantum seroprevalence and risk factors in 229 domestic cats from the Campania region of southern Italy, a CanL endemic area, between January 2023 and December 2024. Serum samples were tested for L. infantum antibodies (IFAT) and for FIV/FeLV. Seropositivity (IFAT titre ≥ 1:40) for FeL was detected in 12/229 (5.2%) of the cats tested. No statistically significant correlation was found between seropositivity for L. infantum and the variables considered. However, outdoor cats and FIV/FeLV-seropositive cats had higher prevalence rates: 10.6% and 7.4%, respectively. Of the 12 seropositive cats, 7 (58.3%) had an antibody titre of 1:40, 2 (16.6%) of 1:80 and 3 (25.0%) a titre of 1:160. Of the 12 cats positive for FeL, 2 (16.6%) were also positive for FIV. Our results confirm the exposure to L. infantum and the serological response in cats from southern Italy. The low prevalence could be due to owners using mosquito control products in the household that would also protect cats. Further investigation is essential to clarify risk factors and improve our understanding of the epidemiology of FeL in this endemic area. Full article

Compounds in sand fly saliva elicit specific immune responses that may play a role in the establishment of canine Leishmania infection. Although canine antibodies to anti-sand fly saliva antigens have been extensively studied, little is known about cellular immune responses against Phlebotomus perniciosus salivary proteins. This study aimed to explore humoral and T-cell-mediated immunity against P. perniciosus salivary proteins in dogs (n = 85) from Mallorca (Spain), a leishmaniosis-endemic area, and find correlations with demographic (age, sex, and breed) and parasite-specific immunological parameters. Anti-sand fly saliva IgG was examined using a P. perniciosus whole salivary gland homogenate (SGH) ELISA and recombinant salivary protein rSP03B ELISA. Interferon gamma (IFN-γ) release whole blood assays with L. infantum soluble antigen (LSA), SGH, and rSP03B were also performed. Positive correlations were found between IgG levels in the SGH and rSP03B tests and between concentrations of SGH IFN-γ and rSP03B IFN-γ. While concentrations of SGH IFN-γ and rSP03B IFN-γ were low and produced only by a minority of dogs (less than 20%), high levels and frequencies of LSA IFN-γ as well as anti-saliva IgG for SGH and rSP03B were detected in a majority of dogs (61% and 75%, respectively). LSA IFN-γ levels were positively correlated with age and Leishmania-specific antibodies. In conclusion, dogs from a leishmaniosis-endemic area presented high humoral immunity against P. perniciosus salivary proteins, but their cellular immunity to these proteins was low and less frequent. Full article

Leishmaniasis is a serious zoonotic parasitic disease caused by the protist Leishmania infantum and transmitted by phlebotomine sandflies in the countries of the Mediterranean basin. Dogs are the species most susceptible to the disease and serve as a reservoir for transmission to humans, making the Iberian Peninsula an endemic region for this infection. Although the regions close to the Mediterranean coast are the most prevalent regions of leishmaniasis in Spain, climatic factors are favouring the expansion of the vectors to more northern latitudes, where the disease was hardly known decades ago. This paper presents a prevalence study of L. infantum infection in the province of Zamora (northwestern Spain) using a non-invasive sample from canine buccal swabs and an innovative qPCR method to determine the etiologic agent. The parasite load of 151 randomly selected dogs from different points of the province was analysed during the period 2021–2022, with an estimated prevalence of 30%. In addition, the most common clinical signs of leishmaniasis in the dogs are described, and intrinsic factors associated with the nature of the dogs—such as sex, size, age as well as other factors related to the habitat in which they live and their geographical location—which could favour the disease, are evaluated. Full article

Background/Objectives: The anti-Leishmania potential of Curcuma longa and its derivatives, such as curcuminoids, is well-established, yet their mechanisms of action remain underexplored. This study investigates the inhibitory effects of C. longa extracts and curcumin on Leishmania infantum arginase, a key enzyme in polyamine and trypanothione biosynthesis, and evaluates their antiparasitic activity. Methods: Extracts were prepared via rhizome successive maceration with hexane (HEXCURC), dichloromethane (DCCURC), and ethanol (ETOHCURC) and chemically characterized by a combination of chromatographic and spectrometric methods. The inhibition of recombinant L. infantum arginase (LiARG) was assessed by urea quantification, while molecular docking explored interactions between the main compounds annotated in the extracts and the enzyme’s active site. Biological activity was tested against L. infantum promastigotes, intracellular amastigotes, and mammalian cells. Results: LC-MS and GC-MS revealed curcuminoids and turmerones as main compounds annotated in the extracts. DCCURC, HEXCURC, and curcumin showed the strongest LiARG inhibition (IC₅₀ = 10.04, 14.4, and 17.55 μg/mL, respectively). Docking analysis revealed that curcumin, demethoxycurcumin, and bisdemethoxycurcumin bind near the active site, with binding energies of –3.43, –4.14, and –3.99 kcal/mol, respectively. Curcumin demonstrated superior anti-promastigote activity (IC₅₀ = 15.01 μg/mL) and selectivity (SI = 12.7) compared to the extracts. It also significantly reduced amastigote burden in infected macrophages (IC₅₀ = 13.6 μg/mL). Conclusions: This is the first report demonstrating that C. longa extracts and curcumin inhibit LiARG. These findings support curcumin’s potential as a lead compound for developing multi-target therapies against leishmaniasis, combining enzyme inhibition with direct antiparasitic effects. Full article

Background/Objectives: Timely and effective clinical management of leishmaniasis depends on a deep understanding of parasite biology and drug resistance mechanisms. Phosphatidylinositol-specific phospholipase C (PI-PLC) enzymes are critical for parasite survival and immune evasion and possibly influence treatment outcomes. This study aimed to characterize the PI-PLC gene family in the Leishmania infantum and Leishmania major genomes, with a focus on their expression profiles in antimony-susceptible and -resistant strains to uncover their diagnostic and prognostic relevance. Methods: This study conducted a comprehensive genome-wide screening to identify PI-PLC genes in L. infantum and L. major, followed by detailed analyses of their gene structures, conserved motifs, chromosomal localization, and phylogenetic relationships. To explore potential roles in drug resistance and clinical prognosis, RNA-seq data from antimony-resistant and -susceptible L. infantum strains were analyzed for differential gene expression. Results: Twenty-two PI-PLC genes were identified in each species, displaying conserved catalytic domains and diverse biochemical characteristics. Phylogenetic and chromosomal analyses revealed gene clustering and distribution patterns. Importantly, expression profiling highlighted several PI-PLC genes with differential regulation in resistant strains, suggesting a role in treatment response and potential as molecular markers. Conclusions: Our findings suggest that PI-PLC genes may be associated with drug susceptibility in L. infantum, warranting further functional investigation to validate their role as potential molecular markers. Full article

Leishmaniasis is a neglected tropical disease caused by Leishmania sp. The therapeutic arsenal is reduced and limited. In this context, acridine derivatives present themselves as promising leishmanicidal compounds. This paper involved synthesizing and evaluating the antileishmanial and immunomodulatory potential of spiro-acridine derivatives. Six spiro-acridine derivatives were obtained through nucleophilic substitution reactions between the acetohydrazide/acetamide intermediates and 9-carbaldehydeacridine, followed by spontaneous cyclization. IR, NMR, and HRMS confirmed the structures. These were analyzed in vitro against L. infantum and L. amazonensis to determine anti-promastigote, anti-amastigote, and cytotoxicity effects. Immunomodulatory activity was evaluated using CBA, DCF-DA, and DAF-FM diacetate. In silico evaluation included molecular docking and dynamics. The spiro-acridines showed a wide range of anti-promastigote activities (IC₅₀ = 0.73–234.95 µM) and non-toxicity to red blood cells. AMTAC-02 and ACMD-03 demonstrated satisfactory anti-amastigote effect (IC₅₀ = 10.47–13.50 µM), low toxicity to macrophages (CC₅₀ = 27.22–569.50 µM), and cytokine and reactive species modulation. Molecular docking proposed cysteine protease B of L. amazonensis as a target, and molecular dynamics analysis highlighted the complex’s stability using RMSD, R_g, SASA, DCCM, PCA, and MM-PBSA (ΔG = −65.225 kJ/mol). Furthermore, QM-MM calculation provided the best energy for ACMD-03 (−199.30 au). Hence, AMTAC-02 and ACMD-03 demonstrated antileishmanial potential, making them promising entities for the development of leishmanicidal drug candidates. Full article

Leishmaniasis are infectious diseases caused by several parasitic species of Leishmania, mainly transmitted by the bite of infected phlebotomine sandflies. Humans, dogs, rodents, and other domestic and wild animals can act as reservoir hosts for the different Leishmania species. It is a neglected tropical disease that is endemic in Asia, the Middle East, North and East Africa, the Mediterranean region, and South and Central America. Clinical manifestations and disease severity depend on the species of the infecting parasites and the immunity status of the host. Leishmania represses the protective host immune response by manipulating the macrophage function, subverting cytokine expression to favor its survival and dissemination. A balance between pro-inflammatory and regulatory cells is necessary to bring a positive outcome. Accurate diagnosis and effective treatment represent the cornerstone in the control of this disease, although these are difficult in an environment of precariousness and poverty. Some recent studies highlighted the progressing work on diagnosis and treatments, such as the development of new benzimidazole-triazole derivatives for blocking the parasite growth, feline leishmaniasis with a comparison of immune responses in cats and dogs, and a transglutaminase that has been purified from L. infantum. The results of these studies could open new avenues in combating leishmaniasis. Full article

Leishmaniasis by Leishmania infantum has a zoonotic transmission cycle involving an increasing number of mammalian hosts, forming a cooperative network. The sand fly feeding on livestock is evidenced, but clinical confirmation regarding their infection is limited. We aimed to evaluate Leishmania seroprevalence in livestock to assess its impact on leishmaniasis epidemiology in an endemic area located in the Mediterranean region. A cross-sectional serological study screened livestock exposure to L. infantum and risk factors in Southern Spain. A total of 864 serum samples of clinically healthy sheep, goats, cattle, and pigs were examined by an indirect fluorescence antibody test, using a 1/80 cut-off titre to minimize cross-reactions. Global seroprevalence was 10.8%: 21.6% cattle, 15.4% sheep, 7.3% goats, and 0.6% pigs. Statistically significant differences in positive detection were observed among species (p < 0.001) and natural regions (p < 0.001). High positive reactions in cattle, goats, and sheep suggest livestock exposure to Leishmania spp. and potential asymptomatic infection. Livestock presence in biotopes could promote a dilution effect, reducing human leishmaniasis incidence. Further investigation is needed to confirm livestock roles in leishmaniasis maintenance and transmission. Full article

The aim of this study was to evaluate bioactive properties of Basidiomycota fungi, mainly Suillus sp. Wide spectrum of activities were revealed for S. variegatus, S. luteus, S. bovinus and S. granulatus; and obtained results were compared with other common fungi. Total Phenolic Content (TPC) varied from 245.32 ± 5.45 to 580.77 ± 13.10 (mg (GAE) per 100 g of dry weight) in methanolic extracts of S. bovinus and S. granulatus fruiting bodies, respectively. In ethyl acetate extracts, the highest TPC were obtained for S. variegatus (310 ± 9.68, mg (GAE)/100 g, dry matter), and the lowest means for S. luteus (105 ± 3.55, mg (GAE)/100 g dry weight). The ethyl acetate extracts of the tested Suillus species exhibited a stronger antioxidant activity (AA) to scavenge DPPH^● and ABTS^•+ than the methanolic ones, and the highest effects were determined for S. luteus (EC₅₀, 0.15 ± 0.05 and 0.23 ± 0.05%, respectively). In the case of methanolic extracts, the highest AA were evaluated for S. granulatus. (EC₅₀ for DPPH^● and ABTS^•+, 0.81 ± 0.30 and 0.95 ± 0.22%, respectively). The ABTS^•+ scavenging potential varied from 0.25 ± 0.05 to 0.74 ± 0.10 (mmol/L, TROLOX equivalent, for S. granulatus and S. variegatus fruiting body extracts, respectively) in the ethyl acetate extracts. S. granulatus extracts demonstrated the widest range of antimicrobial effects against both gram-positive and gram-negative bacteria (from 11.7 ± 1.3 to 28.5 ± 3.3 mm against Pseudomonas aeruginosa and Bacillus mycoides, respectively); and against two fungal strains (up to 13.6 ± 0.4 mm on Meyerozyma guilliermondii) in agar disc diffusion tests. Our study revealed that methanolic extracts of the most tested Suillus sp. were not active enough against the tested parasites: Trypanosoma cruzi, Trypanosoma brucei, Leishmania infantum and Plasmodium falciparum. Only S. variegatus extracts showed good antiprotozoal effects against P. falciparum (12.70 µg/mL). Cytotoxic activity was observed on human diploid lung cells MRC-5 SV2 by S. granulatus extracts (64.45 µg/mL). For comparative purposes, extracts of other common Lithuanian fungi, such as Xerocomus sp. (X. badius, X. chrysenteron and X. subtomentosus), Tylopilus felleus, Phallus impudicus and Pycnoporus cinnabarinus were investigated for their activity. The P. cinnabarinus extracts demonstrated the highest and broadest overall effects: 1.32 µg/mL against T. brucei, 1.46 µg/mL against P. falciparum, 3.93 µg/mL against T. cruzi and 21.53 µg/mL against L. infantum. Additionally, this extract exhibited strong cytotoxicity on MRC-5 cells (13.05 µg/mL). The investigation of bioactive fungal metabolites is important for the development of a new generation of antioxidants, antimicrobials, antiparasitic and anticancer agents. Full article

Background/Objectives: Leishmaniasis is a neglected tropical disease caused by a protozoan parasite of Leishmania. This study aimed to evaluate the in vitro efficacy and toxicity of a previously developed amphotericin gel as a possible treatment for cutaneous leishmaniasis. Methods: First, quality control of the AmB-gel was carried out, including microbiological stability. The permeated and retained drug was tested on healthy and lacerated human skin. Tolerance to the AmB-gel was tested in vitro using HaCaT, RAW 264.7, and J774 cell lines and by an irritation test (HET-CAM). Promastigotes and amastigotes of various Leishmania species were tested, and the microscopic morphology of promastigotes exposed to the formulation was analyzed. Computational analysis was performed on the drug, polymer, and ergosterol in the promastigote. Results: The AmB-gel presented appropriate characteristics for topical use, including no microbial contamination after storage. The amount of drug retained on the intact and injured skin was 1180.00 ± 13.54 µg/g/cm² and 750.18 ± 5.43 µg/g/cm², respectively. The AmB-gel did not cause significant signs of toxicity. The IC₅₀ of the AmB-gel for promastigotes was less than 1 µg/mL for the four species examined, i.e., Leishmania infantum, Leishmania tropica, Leishmania major, and Leishmania braziliensis, and less than 2 µg/mL for amastigotes of Leishmania infantum and Leishmania tropica. The AmB-gel caused notable effects on the surface of promastigotes. Computational analysis revealed primarily hydrophobic and van der Waals interactions between AmB and Pluronic^® F127 and ergosterol. Conclusions: Based on the drug retention content and IC₅₀ values observed for both parasite stages, the AmB-gel may be a promising candidate for in vivo studies in patients with cutaneous leishmaniasis. Full article

Background/Objectives: Malnutrition and visceral leishmaniasis are major public health problems that are responsible for millions of deaths across many countries. Leishmaniasis development and progression are associated with the host immune status. In this context, malnutrition can directly affect the course of leishmaniasis, impairing several components of the immune system. Moreover, malnutrition directly interferes with the tropism of Leishmania in organs, affecting host susceptibility. Therefore, this work aimed to evaluate the influence of nutritional status on the establishment, progression, and treatment of Leishmania infantum infection in malnourished and refed mice. Methods: BALB/c mice were fed either a control or restricted diet, infected with L. infantum promastigotes, and treated with meglumine antimoniate, the standard drug for treating visceral leishmaniasis. The effects of infection were evaluated through limiting dilution analysis (LDA). Results: Compared with control mice, malnourished and refed mice presented a lower parasitic load in the spleen, which correlated with spleen atrophy, and the refeeding process partially reversed but did not fully rescue the infection status. Both groups presented a high parasitic load in the liver. Marasmic malnutrition appeared to impair the efficacy of leishmaniasis treatment; however, the refed groups exhibited a robust decrease in the parasite load, which was comparable to that in the control group subjected to treatment. Conclusions: Our data suggested that marasmic malnutrition affects the establishment and progression of Leishmania infection, in addition to reducing the efficacy of standard treatment. Furthermore, the refeeding intervention used did not fully reverse the observed effects. These findings highlight the potential importance of nutritional interventions in the clinical management of visceral leishmaniasis in malnourished populations. Full article

This study aimed to identify Leishmania species in small non-flying mammals captured in semi-deciduous forest fragments of the Atlantic Forest and pastures in the Southwest region of Bahia state, Northeast Brazil. A total of 445 animals belonging to 11 different species were captured, the majority being rodents (75.7%; 337), followed by marsupials (24.2%; 108), and the most prevalent species were Cerradomys vivoi, Calomys expulsus, Necromys Lasiurus, and Marmosops incanus. Liver, spleen, kidney, heart, and lung fragments were collected for subsequent molecular diagnosis. Leishmania spp. kDNA amplification in positive samples was performed using real-time polymerase chain reaction (qPCR). Species identification of Leishmania was conducted through nested PCR, followed by sequencing. Leishmania spp. infection was detected in 2.92% (13/445) of the animals. Sequencing revealed that L. infantum infected three animals, while the species of the agent in the other animals could not be determined. The results indicate the presence of Leishmania spp. in the studied region, primarily affecting the local wildlife. These findings not only highlight the risk of transmission to domestic animals and humans in close contact with forest remnants, but also underscore the critical role of these fragments in supporting native fauna. However, it is worth noting that the continuous deforestation of these forest remnants could lead to increased contact between wildlife, domestic animals, and humans, thereby elevating the risk of transmission. Full article