RESUMEN

Leishmania infantum is the vector-borne trypanosomatid parasite causing visceral leishmaniasis in the Mediterranean basin. This neglected tropical disease is treated with a limited number of obsolete drugs that are not exempt from adverse effects and whose overuse has promoted the emergence of resistant pathogens. In the search for novel antitrypanosomatid molecules that help overcome these drawbacks, drug repurposing has emerged as a good strategy. Nitroaromatic compounds have been found in drug discovery campaigns as promising antileishmanial molecules. Fexinidazole (recently introduced for the treatment of stages 1 and 2 of African trypanosomiasis), and pretomanid, which share the nitroimidazole nitroaromatic structure, have provided antileishmanial activity in different studies. In this work, we have tested the in vitro efficacy of these two nitroimidazoles to validate our 384-well high-throughput screening (HTS) platform consisting of L. infantum parasites emitting the near-infrared fluorescent protein (iRFP) as a biomarker of cell viability. These molecules showed good efficacy in both axenic and intramacrophage amastigotes and were poorly cytotoxic in RAW 264.7 and HepG2 cultures. Fexinidazole and pretomanid induced the production of ROS in axenic amastigotes but were not able to inhibit trypanothione reductase (TryR), thus suggesting that these compounds may target thiol metabolism through a different mechanism of action.

Asunto(s)

Leishmania infantum , Nitroimidazoles , Leishmania infantum/efectos de los fármacos , Leishmania infantum/metabolismo , Nitroimidazoles/farmacología , Nitroimidazoles/química , Animales , Ratones , Humanos , Células RAW 264.7 , Antiprotozoarios/farmacología , Antiprotozoarios/química , Radicales Libres/metabolismo , Células Hep G2 , Leishmaniasis Visceral/parasitología , Leishmaniasis Visceral/tratamiento farmacológico , Muerte Celular/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Supervivencia Celular/efectos de los fármacos , Ensayos Analíticos de Alto Rendimiento , NADH NADPH Oxidorreductasas

RESUMEN

Despite promising advancements in leishmaniasis treatment, existing therapies often face limitations and significant side effects, stimulating the search for novel therapeutic alternatives. In this context, lectins, such as DVL extracted from Dioclea violacea seeds, have emerged as potential candidates due to their diverse biological activities. This study represents the first investigation of the leishmanicidal potential of DVL in vitro against Leishmania infantum. Our results demonstrate that DVL exhibits a leishmanicidal effect (IC50/24 h = 49.37 µg/mL or 2 µM), binding to glycans on L. infantum. Fluorescence assays revealed that DVL can induce the production of reactive oxygen species (ROS) and cause damage to the parasite's membrane. DVL demonstrated a modulating effect when combined with amphotericin B and glucantime, enhancing the activity of these drugs by 40 % and 80 %, respectively. It also showed no cytotoxicity in Raw 264.7 cells and was able to override the toxic effect of amphotericin B on cells and reduce the survival rate of macrophages infected with amastigote forms, as well as their percentage of infection by 31 %. Therefore, DVL shows promise as a treatment for visceral leishmaniasis caused by L. infantum. Our findings provide valuable insights for future therapeutic development targeting leishmania glycans.

RESUMEN

Macrophages are major host cells for the protozoan Leishmania parasite. Depending on their activation state, they either contribute to the detection and elimination of Leishmania spp. or promote parasite resilience. Here, we report that the activation of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) in macrophages plays a pivotal role in the progression of Leishmania infantum infection by controlling inflammation and redox balance of macrophages. We also highlight the involvement of the NOX2/reactive oxygen species (ROS) axis in early Nrf2 activation and, subsequently, prostaglandin E2 (PGE2)/EP2r signaling in the sustenance of Nrf2 activation upon infection. Moreover, we establish a ferroptosis-like process within macrophages as a cell death program of L. infantum and the protective effect of Nrf2 in macrophages against L. infantum death. Altogether, these results identify Nrf2 as a critical factor for the susceptibility of L. infantum infection, highlighting Nrf2 as a promising pharmacological target for the development of therapeutic approaches for the treatment of visceral leishmaniasis.

RESUMEN

Neglected Tropical Diseases are a significant concern as they encompass various infections caused by pathogens prevalent in tropical regions. The limited and often highly toxic treatment options for these diseases necessitate the exploration of new therapeutic candidates. In the present study, the lignan methylpiperitol was isolated after several chromatographic steps from Persea fulva L. E. Koop (Lauraceae) and its leishmanicidal and trypanocidal activities were evaluated using in vitro and in silico approaches. The chemical structure of methylpiperitol was defined by NMR and MS spectral data analysis. The antiprotozoal activity of methylpiperitol was determined in vitro and indicated potency against trypomastigote forms of Trypanosoma cruzi (EC50 of 4.5±1.1 mM) and amastigote forms of Leishmania infantum (EC50 of 4.1±0.5 mM), with no mammalian cytotoxicity against NCTC cells (CC50>200 mM). Molecular docking studies were conducted using six T. cruzi and four Leishmania. The results indicate that for the molecular target hypoxanthine phosphoribosyl transferase in T. cruzi and piteridine reductase 1 of L. infatum, the methylpiperitol obtained better results than the crystallographic ligand. Therefore, the lignan methylpiperitol, isolated from P. fulva holds potential for the development of new prototypes for the treatment of Neglected Tropical Diseases, especially leishmaniasis.

Asunto(s)

Leishmania infantum , Lignanos , Simulación del Acoplamiento Molecular , Trypanosoma cruzi , Lignanos/farmacología , Lignanos/aislamiento & purificación , Lignanos/química , Trypanosoma cruzi/efectos de los fármacos , Leishmania infantum/efectos de los fármacos , Pruebas de Sensibilidad Parasitaria , Antiprotozoarios/farmacología , Antiprotozoarios/química , Antiprotozoarios/aislamiento & purificación , Animales , Relación Estructura-Actividad , Estructura Molecular , Relación Dosis-Respuesta a Droga , Tripanocidas/farmacología , Tripanocidas/química , Tripanocidas/aislamiento & purificación

RESUMEN

Leishmaniasis is one of the most important neglected tropical parasitic diseases, manifesting various clinical forms depending on the parasite species and the genetic background of the host. In order to elucidate the underlying mechanisms of reptilian defense against pathogenic Leishmania species and to delineate the global gene expression profile alterations during host-pathogen interaction, we established experimental animal and cell models using both heterothermic lizards (Phrynocephalus przewalskii) and homothermic mammals (BALB/c mice) infected with pathogenic Leishmania infantum (high virulence HCZ strain) and Leishmania donovani (low virulence 801 strain). Overall, the lizards didn't show any obvious clinical symptoms or immune responses in vivo. Using RNA-seq methodology, differentially expressed genes identified in the HCZ and 801-comparison groups of P. przewalskii were primarily associated with arginine biosynthesis, the MAPK signaling pathway and the PI3K-Akt signaling pathway. In contrast, higher parasite loads, exacerbated hepatic inflammatory lesions and enhanced immune responses were observed in BALB/c mice, with DEGs predominantly associated with immunological diseases, innate and adaptive immune responses. By integrating transcriptional data from reptile and mammalian hosts, we elucidated the pivotal role of amino acid metabolism and lipid metabolism in parasite control. In contrast to findings from animal experiments, Leishmania parasites effectively infected peritoneal macrophages of lizards in vitro, demonstrating a high infection rate. Furthermore, we used RT-qPCR to detect changes in cytokine expression in macrophages and found that Th1-type cytokines were significantly upregulated in lizards, facilitating the clearance of the HCZ strain 24 hours post-infection. Conversely, cytokine expression was generally suppressed in BALB/c mice, allowing immune evasion by the parasites.

Asunto(s)

Perfilación de la Expresión Génica , Leishmania infantum , Leishmaniasis Visceral , Lagartos , Ratones Endogámicos BALB C , Animales , Leishmaniasis Visceral/parasitología , Leishmaniasis Visceral/inmunología , Leishmaniasis Visceral/veterinaria , Lagartos/parasitología , Ratones , Leishmania infantum/genética , Leishmania donovani/genética , Leishmania donovani/patogenicidad , Femenino , Transcriptoma , Carga de Parásitos , Interacciones Huésped-Patógeno

RESUMEN

Recent efforts in the study of vector-borne parasitic diseases (VBPDs) have emphasized an increased consideration for preventing drug resistance and promoting the environmental safety of drugs, from the beginning of the drug discovery pipeline. The intensive use of the few available antileishmanial drugs has led to the spreading of hyper-resistant Leishmania infantum strains, resulting in a chronic burden of the disease. In the present work, we have investigated the biochemical mechanisms of resistance to antimonials, paromomycin, and miltefosine in three drug-resistant parasitic strains from human clinical isolates, using a whole-cell mass spectrometry proteomics approach. We identified 14 differentially expressed proteins that were validated with their transcripts. Next, we employed functional association networks to identify parasite-specific proteins as potential targets for novel drug discovery studies. We used SeqAPASS analysis to predict susceptibility based on the evolutionary conservation of protein drug targets across species. MATH-domain-containing protein, adenosine triphosphate (ATP)-binding cassette B2, histone H4, calpain-like cysteine peptidase, and trypanothione reductase emerged as top candidates. Overall, this work identifies new biological targets for designing drugs to prevent the development of Leishmania drug resistance, while aligning with One Health principles that emphasize the interconnected health of people, animals, and ecosystems.

Asunto(s)

Antiprotozoarios , Resistencia a Medicamentos , Interacciones Huésped-Parásitos , Leishmania infantum , Proteómica , Antiprotozoarios/farmacología , Humanos , Leishmania infantum/efectos de los fármacos , Leishmania infantum/genética , Proteínas Protozoarias/metabolismo , Proteínas Protozoarias/genética , Fosforilcolina/análogos & derivados , Fosforilcolina/farmacología , Leishmaniasis/parasitología , Leishmaniasis/tratamiento farmacológico , Paromomicina/farmacología

RESUMEN

Leishmania infantum is a protozoan parasite of the family Trypanosomatidae, transmitted by the bite of phlebotomine sand flies (Diptera: Psychodidae). It is responsible for human and canine leishmaniasis in countries bordering the Mediterranean basin. Here we describe a clinical case of human cutaneous leishmaniasis in a 76-year-old female patient living in Marseille. Upon interrogation, the patient had no history of recent travel or contact with animals. The study involved clinical, serological, and molecular investigation of the occurrence of Leishmania infection in 718 dogs from five departments within a 130 km radius perimeter around Marseille. Five dogs showed signs of moderate leishmaniasis. Additionally, the serological survey of dogs revealed a global seroprevalence of 5.1%, with a significantly different prevalence in the Vaucluse department. Molecular analysis and phylogenetic studies highlighted the close relatedness of Leishmania strains between human and canine hosts with 99.6% of identity, indicating local transmission. The findings underscore the importance of serological surveillance in dogs and human. In a One Health approach, it is necessary to continue investigating Leishmania infection in all potential reservoirs, especially for zoonotic L. infantum in wildlife (red foxes, leporids, rodents, etc.) but also in dogs, cats, and equids.

RESUMEN

Leishmaniosis by Leishmania infantum is a zoonotic vector-borne disease transmitted to humans and dogs by the bite of female sand-flies. The domestic dog is the main reservoir and infected dogs may show or not clinical symptoms. The prevalence of infection in dogs varies according to the population studied, the geographic area, and the diagnostics employed. This study aims to estimate the global prevalence, subgrouping per continent, country, diagnostic test and selected risk factors. Cross-sectional studies (n=150; from 1990 to 2020) estimating the prevalence of the infection by Leishmania infantum were extracted from four electronic databases. The pooled global prevalence obtained by random-effects meta-analysis was 15.2 % (95 %CI 13.6-16.9), mostly in rural (19.5 %) and owned dogs (16.5 %). Prevalence varied if the diagnosis was made by western blot (WB, 32.9 %), cellular immunity tests (27.5 %), ELISA (17 %), PCR (16.9 %), IFAT (15.9 %), rapid tests and direct agglutination test (DAT, 11.5 %), cytology/immunohistochemistry (13.1 %), culture (8.6 %). A small studies bias (P<0.005) in the overall prevalence meta-analysis, due to the impact of small-size studies on the overall results was found. Moreover, a continent-related bias was found regarding rapid test, DAT (P=0.021), and WB (P<0.001), as these assays are mainly used in South American studies. A study period bias (P=0.033) and a publication year bias (P=0.002) were detected for PCR, as the test was not employed before the year 2000. In conclusion, a high prevalence of canine leishmaniosis worldwide and high heterogeneity among studies were found.

Asunto(s)

Enfermedades de los Perros , Leishmania infantum , Leishmaniasis Visceral , Animales , Perros , Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/parasitología , Prevalencia , Leishmaniasis Visceral/epidemiología , Leishmaniasis Visceral/veterinaria , Factores de Riesgo , Estudios Transversales , Leishmaniasis/epidemiología , Leishmaniasis/veterinaria , Salud Global , Zoonosis/epidemiología , Zoonosis/parasitología , Humanos

RESUMEN

Leishmaniosis is a vector-borne disease caused by protozoan parasites of the genus Leishmania, which are zoonotic and have an important impact on animal and public health globally. Between 2009 and 2023, blood samples from domestic dogs with clinical suspicion of leishmaniosis were received from 286 veterinary medical centres throughout mainland Portugal. An enzyme-linked immunosorbent assay (ELISA) was utilised to detect antibodies against Leishmania infantum antigens. Additionally, a complete blood count and tests for total proteins, urea, creatinine and alanine aminotransferase, as well as protein electrophoresis, were also performed. No significant relationship between sex and breed was observed. The age distribution was bimodal, with the highest prevalence of disease occurring at 2-5 years of age and a secondary peak occurring at 6 years or over (p < 0.001). No statistical correlation was observed between creatinine and urea across the ELISA serological groups. In contrast, both the gamma globulin levels (r = 0.45; p < 0.001) and the albumin/globulin ratio (r = -0.36; p < 0.001) exhibited moderate correlations with the ELISA. These findings support recent seroprevalence studies in dogs, with some geographical areas in Northern Portugal exhibiting the highest values, which may be the result of geographical shifts in parasite circulation due to climate change.

RESUMEN

Leishmania infantum is considered the predominant Leishmania species responsible for visceral leishmaniasis (VL) in Greece but limited molecular-typing-based studies have been performed so far. We retrospectively analyzed data and serum samples collected from 3661 individuals suspected for VL in a sixteen-year period, from 2005 to 2020, to study the seasonality and demographic characteristics of VL cases and to define the L. infantum genotypes circulating in the country. Serum samples were tested with immunofluorescence assay and/or molecular assay. qPCR Leishmania-positive samples were subjected to genotypic analysis based on polymorphisms in 12 microsatellite regions of the internal transcribed spacers (ITSs) 1 and 2. We diagnosed 219 definite (6%, sample with a positive molecular assay and/or antibody titer ≥ 1:400) and 230 probable (6.3%, sample with antibody titer between 1:100 and 1:200) VL cases. Data analysis revealed that amongst VL-definite cases, the age group (≥65) constitutes the most affected factor, since 36.9% of the VL cases belonged to this age group. Amongst the VL definite cases, the most frequently reported symptoms were fever (83%), splenomegaly (49%), and hepatomegaly (40%), but this was not the case for immunocompromised patients that developed non-typical symptoms of leishmaniasis. Although no statistically significant differences in the overall seasonality of VL cases were observed, February and June showed a significantly higher proportion of VL cases compared to August and December. Genotyping of ITS1 and ITS2 regions revealed that all VL cases belong to ITS type A of L. infantum. Our study provides epidemiological information on VL and demonstrates for the first time, providing genotypic data, the circulation of ITS type A L. infantum in Greece.

RESUMEN

BACKGROUND: Cats are now recognized as competent hosts for Leishmania infantum and a blood source for sand fly vectors. Although canine leishmaniosis (CanL) is endemic in Mediterranean Basin countries, large-scale epidemiological studies are lacking for feline leishmaniosis (FeL). This study aimed to assess the prevalence of L. infantum infections, associated risk factors, clinical signs, and clinicopathological abnormalities in domestic cat populations from six Mediterranean Basin countries. METHODS: From 2019 to 2022, blood and serum samples of cats (n = 2067) living in Italy (n = 300), Greece (n = 297), Portugal (n = 295), France (n = 231), Israel (n = 313), and Spain (n = 631) were collected along with animal data (i.e., age, sex, breed, housing conditions, and geographical origin), clinical signs, and laboratory blood test parameters. Cats were grouped according to their age as kittens (up to 1 year), young (older than 1 and younger than 7 years), mature (between 7 and 10 years), and senior (older than 10 years). Serum samples were tested for L. infantum by immunofluorescence antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA), and blood samples of seropositive cats were tested for L. infantum kinetoplast deoxyribonucleic acid (kDNA). Viral infection by feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) was molecularly addressed in all cats enrolled. Statistical analysis was performed to evaluate the association between the risk of L. infantum infection and independent variables, and among co-infection of L. infantum with FIV and/or FeLV, clinical signs, and clinicopathological abnormalities. RESULTS: Overall, 17.3% (358/2067) of cats scored positive for L. infantum by serological tests. Specifically, 24.7% were from Portugal, 23.2% from Greece, 16.6% from Israel, 15% from Spain, 13.3% from France, and 12.6% from Italy. Leishmania infantum DNA was detected in 15 seropositive animals. Housing condition and FIV infection proved to be risk factors for FeL. Leishmania seropositivity was significantly associated with weight loss, lymphadenomegaly, gingivostomatitis, and oral ulcers, as well as with reduced albumin and albumin/globulin ratio, increased total globulins and total proteins, leukocytosis, and thrombocytosis. CONCLUSIONS: This study provides, for the first time, a large-scale epidemiological survey on FeL and its clinical presentation, revealing that L. infantum circulates among domestic cats, especially shelter/free-roaming and FIV-infected animals, living in CanL endemic countries of the Mediterranean Basin.

Asunto(s)

Enfermedades de los Gatos , Leishmania infantum , Leishmaniasis Visceral , Animales , Gatos , Enfermedades de los Gatos/epidemiología , Enfermedades de los Gatos/parasitología , Enfermedades de los Gatos/virología , Leishmania infantum/aislamiento & purificación , Leishmania infantum/genética , Masculino , Femenino , Leishmaniasis Visceral/epidemiología , Leishmaniasis Visceral/veterinaria , Leishmaniasis Visceral/parasitología , Región Mediterránea/epidemiología , Factores de Riesgo , Prevalencia , España/epidemiología , Grecia/epidemiología , Portugal/epidemiología , Anticuerpos Antiprotozoarios/sangre , Virus de la Leucemia Felina/aislamiento & purificación , Virus de la Leucemia Felina/genética , Francia/epidemiología , Italia/epidemiología , Leishmaniasis/epidemiología , Leishmaniasis/veterinaria , Virus de la Inmunodeficiencia Felina/aislamiento & purificación , Israel/epidemiología

RESUMEN

PURPOSE: The objectives of the present study are to determine the molecular prevalence of Leishmania spp. in the owned domestic cats in the Black Sea Region of Türkiye and analyze the associated risk factors in FeL. METHODS: Conjunctival swabs (CS), blood, demographic, and clinical data were collected from 150 owned cats brought to the Veterinary Teaching Hospital during 2020-2022. Leishmania kinetoplast DNA (kDNA) from CS was screened by TaqMan Real-Time PCR (qPCR) with the genus-specific primers and a probe. RESULTS: All qPCR positive products were also amplified and sequenced to identify Leishmania species by ITS1 primers. Molecular prevalence of L. infantum found as 12.6% (19/150) in the observed cats in the Black Sea Region of Türkiye. There was a significant difference (p < 0.05) between neutered and intact cats with regarding to L. infantum positivity. Intact cats found to be 0.368 times more prone to be L. infantum-positive (L+). Dermatological lesions were found the most common (26.3%) problems in the L + cats. The median leucocyte count was the only parameter that was found statistically (p < 0.05) lower in the L + group (6.60) than the negative group (L-) (8.96), when comparing the WBC, NEU/LYM, MONO/LYM, EOS/LYM and PLT/LYM values. CONCLUSION: This study presented the molecular occurrence of FeL in the Black Sea Region of Türkiye for the first time indicating that the carrier status of the cats makes them alternative reservoirs for possible zoonotic transmission of L. infantum in this zone.

Asunto(s)

Enfermedades de los Gatos , Leishmania infantum , Animales , Gatos , Leishmania infantum/genética , Leishmania infantum/aislamiento & purificación , Enfermedades de los Gatos/parasitología , Enfermedades de los Gatos/epidemiología , Factores de Riesgo , Mar Negro , Femenino , Masculino , Leishmaniasis Visceral/veterinaria , Leishmaniasis Visceral/parasitología , Leishmaniasis Visceral/epidemiología , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Prevalencia , ADN de Cinetoplasto/genética , ADN Protozoario/genética

RESUMEN

BACKGROUND: Renal disease in canine leishmaniosis is of great importance owing to increased risk of mortality. In human visceral leishmaniosis, monocyte chemoattractant protein-1 (MCP-1) has been used as a marker of renal damage and inflammation. The purpose of this study was first to determine the serum MCP-1 and urinary MCP-1-to-creatinine ratio (uMCP-1/Cr) in healthy dogs and dogs with leishmaniosis at diagnosis, and second to determine whether these markers can differentiate disease severity at diagnosis. METHODS: In total, 19 healthy seronegative dogs and 38 dogs with leishmaniosis were included in the study. Dogs with leishmaniosis were classified as LeishVet clinical staging and as International Renal Interest Society (IRIS) staging. Serum and urinary MCP-1 concentrations were measured with an enzyme-linked immunosorbent assay. A receiver operating characteristic (ROC) curve determined disease severity at diagnosis between two LeishVet groups (Stage II versus stage III and IV). RESULTS: Dogs in Leishvet stages IIb, III, and IV had a median serum MCP-1 and uMCP-1/Cr concentration higher than healthy dogs (P < 0.0001). No statistical differences were found in serum MCP-1 and uMCP-1/Cr between dogs in LeishVet stage IIa and healthy dogs. The dogs in LeishVet stage IV had significantly higher serum MCP-1 and uMCP-1/Cr compared with the dogs in LeishVet stage IIa (P < 0.0001). Serum MCP-1 and uMCP-1 were significantly higher in dogs in IRIS stage I and II + III + IV compared with healthy dogs. Dogs stage II + III + IV of IRIS had a significantly higher serum MCP-1 compared with dogs in IRIS stage I (P < 0.0001). The area under the ROC curve for serum MCP-1 was 0.78 [95% confidence interval (CI) 0.64-0.93] and for uMCP-1/Cr it was 0.86 (95% CI, 0.74-0.99). The optimal cutoff value for serum MCP-1 and uMCP-1/Cr was 336.85 pg/ml (sensitivity of 79% and specificity of 68%) and 6.89 × 10-7 (sensitivity of 84% and specificity of 79%), respectively. CONCLUSIONS: Serum MCP-1 and uMCP-1/Cr are increased in dogs with leishmaniosis compared with healthy dogs, suggesting the presence of inflammation and renal injury. Serum MCP-1 and uMCP-1/Cr were more elevated in the advanced stages of the disease compared with the moderate stages and, therefore, can be markers of the severity of the disease process.

Asunto(s)

Biomarcadores , Quimiocina CCL2 , Enfermedades de los Perros , Inflamación , Leishmaniasis , Animales , Perros , Quimiocina CCL2/sangre , Quimiocina CCL2/orina , Enfermedades de los Perros/orina , Enfermedades de los Perros/sangre , Enfermedades de los Perros/diagnóstico , Enfermedades de los Perros/parasitología , Biomarcadores/sangre , Biomarcadores/orina , Leishmaniasis/veterinaria , Leishmaniasis/sangre , Leishmaniasis/orina , Leishmaniasis/diagnóstico , Leishmaniasis/patología , Masculino , Inflamación/veterinaria , Inflamación/sangre , Inflamación/orina , Femenino , Enfermedades Renales/veterinaria , Enfermedades Renales/sangre , Enfermedades Renales/orina , Enfermedades Renales/patología , Enfermedades Renales/diagnóstico , Enfermedades Renales/parasitología , Curva ROC , Creatinina/sangre , Creatinina/orina , Ensayo de Inmunoadsorción Enzimática/veterinaria , Índice de Severidad de la Enfermedad

RESUMEN

BACKGROUND: Abiotic factors play a significant role in the evolution of Leishmania infantum infection due to its vectorial nature. This study aims to assess the evolution in the detection of new L. infantum infection cases in Valdeorras (Ourense, Northwestern Spain) over a 20-year period and how different climatic variables and preventive measures may have affected it. METHODS: Indirect immunofluorescence antibody tests (IFAT) were performed on serum samples collected from dogs attending the 'Servicios Veterinarios de Sil' veterinary clinic (Valdeorras, Northwestern Spain) between May 2003 and April 2023 to detect L. infantum exposure. The percentage of new cases of L. infantum infection was calculated from May of one year to April of the following year. Climatic conditions in the region, global sales of ectoparasiticides and the number of vaccines against L. infantum delivered in the veterinary clinic from 2003 to 2022 were recorded. Statistical analyses were conducted to determine the associations between these factors and the percentage of new cases of L. infantum infection. RESULTS: A total of 2909 dogs were assessed, and 3785 IFAT tests were performed between May 2003 and April 2023. The mean percentage of new seropositive cases over the 20-year period studied was 21.65 ± 10.8%, with a decline from the beginning to the end of the period studied. The percentage was significantly higher between May 2003 and April 2008 compared with the other periods (May 2008 to April 2013, May 2013 to April 2018 and May 2018 to April 2023). There was a positive correlation between the percentage of new cases of L. infantum infection and the maximum relative humidity in winter. Conversely, there was a negative correlation between the percentage of new cases and sales of ectoparasiticides and vaccination against L. infantum. CONCLUSIONS: This study is one of the longest evaluations of the evolution of L. infantum infection in a fixed location and its association with external factors including climatic conditions and preventive measures. The results confirm that Valdeorras is a high-risk area for L. infantum infection. The use of ectoparasiticides and vaccines against L. infantum has been shown to play a significant role in preventing L. infantum infection, highlighting the crucial role of veterinarians in the fight against this disease.

Asunto(s)

Clima , Enfermedades de los Perros , Leishmania infantum , Leishmaniasis Visceral , Perros , Animales , España/epidemiología , Enfermedades de los Perros/parasitología , Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/prevención & control , Leishmania infantum/inmunología , Leishmania infantum/aislamiento & purificación , Leishmaniasis Visceral/veterinaria , Leishmaniasis Visceral/epidemiología , Leishmaniasis Visceral/prevención & control , Leishmaniasis Visceral/parasitología , Anticuerpos Antiprotozoarios/sangre , Masculino , Técnica del Anticuerpo Fluorescente Indirecta , Femenino

RESUMEN

Background and Aim: In urban environments, dogs serve as the primary reservoir for visceral leishmaniasis (VL). Rapidly diagnosing canine VL through tests enables early treatment and a favorable prognosis. This study aimed to assess the diagnostic performance of the SensPERT® Leishmania test kit (Dechra®), Alere® Leishmaniasis Ac test kit, and the rapid test dual path platform (TR-DPP®) Bio-Manguinhos in detecting VL. Materials and Methods: 30 serum samples from reactive VL dogs and 30 serum samples from healthy dogs were employed for assessing the sensitivity and specificity variation between SensPERT® Leishmania test kit, Alere® Leishmaniasis Ac test kit, and rapid test dual platform - TR-DPP®. Results: The SensPERT® Leishmania test outperformed Alere® and TR-DPP® in terms of sensitivity, specificity, positive and negative predictive values and demonstrated near-perfect concordance with Alere® and substantial concurrence with TR-DPP®. Conclusion: The SensPERT® Leishmania rapid test proved to be a promising test in the detection of VL in dogs.

RESUMEN

Geraniol, a primary component of several essential oils, has been associated with broad-spectrum antiprotozoal activities, although moderate to weak. This study primarily concentrated on the synthesis of hydrazinated geraniol derivatives as potential antiprotozoal agents. The synthesised compounds were tested in vitro against different parasitic protozoans of clinical relevance, including Trypanosoma brucei brucei, Trypanosoma brucei rhodesiense, Trypanosoma cruzi and Leishmania infantum. Compounds 6, 8, 13, 14 and 15 demonstrated low micromolar activity against the different parasites. Compounds 8, 13, 14 and 15 had the highest efficacy against Trypanosoma brucei rhodesiense, as indicated by their respective IC50 values of 0.74, 0.56, 1.26 and 1.00 µM. Compounds 6, 14 and 15 displayed the best activity against Trypanosoma brucei brucei, with IC50 values of 1.49, 1.48 and 1.85 µM, respectively. The activity of compounds 6, 14 and 15 also extended to intracellular Trypanosoma cruzi, with IC50 values of 5.14, 6.30 and 4.90 µM, respectively. Compound 6, with an IC50 value of 11.73 µM, and compound 14, with an IC50 value of 8.14 µM, demonstrated some modest antileishmanial activity.

RESUMEN

In Europe, Leishmania infantum is the most prevalent Leishmania species, and this protozoan is transmitted by phlebotomine sandflies. A recent publication has shown that sheep harbor L. infantum antibodies. This raises questions about the epidemiological role of small ruminants. Therefore, sera from small ruminants located in two southern German federal states, Baden-Wuerttemberg (BW) and Bavaria (BAV), were analyzed with an ELISA to determine the presence of L. infantum antibodies. The species, sex and age (gimmer vs. ewe) were recorded, and a univariate analysis was conducted to determine possible associations. In total, seven sheep flocks (274 sheep/10 goats) from BW and seven sheep flocks (277 sheep/78 goats) from BAV were examined. In BW, four sheep from three flocks tested positive for L. infantum antibodies. In BAV, the same number of positive sheep were detected but in four flocks. The total seropositivity rate in sheep was 1.45%. All goats tested negative. No significant association (p > 0.05) was detected between Leishmania seropositivity and the variables evaluated. Our study reveals the exposure of sheep to L. infantum in a non-endemic area. Further investigation is needed to determine whether sheep can be used as sentinels to identify new phlebotomine habitats and Leishmania risk areas.

RESUMEN

The feline population is extensive in urban areas worldwide, comprising stray and domestic cats. Cats, acting as reservoirs, can transmit various zoonotic organisms to humans, which can cause significant public health issues. We evaluated the seroprevalence of zoonotic pathogens in stray cats in an urban area of northeast Spain (the city of Zaragoza) to assess potential risks to human health. A total of 88 sampled cats (52 females and 36 males) underwent antibody evaluation using the indirect immunofluorescence technique. Seroprevalence rates were determined for IgG antibodies to Bartonella henselae (36.3%), Toxoplasma gondii (31.8%), Rickettsia felis (14.7%), Rickettsia typhi (9%), and Leishmania infantum (10.2%). Our results confirmed the presence in stray cats of antibodies against all those pathogens, indicating that they all circulate in the feline population in Zaragoza. Male cats exhibited a higher predisposition to T. gondii, whereas females showed an increased likelihood of contracting B. henselae. This difference may be attributed to distinct behaviors according to sex. Our findings underscore the importance of maintaining and intensifying surveillance coupled with preventive measures against zoonotic pathogens in cats. They highlight the need for comprehensive control strategies designed to mitigate public health risks associated with feline populations.

Asunto(s)

Bartonella henselae , Enfermedades de los Gatos , Toxoplasma , Toxoplasmosis Animal , Zoonosis , Animales , Gatos , España/epidemiología , Estudios Seroepidemiológicos , Enfermedades de los Gatos/epidemiología , Enfermedades de los Gatos/parasitología , Enfermedades de los Gatos/microbiología , Masculino , Femenino , Toxoplasma/inmunología , Toxoplasma/aislamiento & purificación , Bartonella henselae/inmunología , Bartonella henselae/aislamiento & purificación , Toxoplasmosis Animal/epidemiología , Zoonosis/epidemiología , Zoonosis/parasitología , Anticuerpos Antiprotozoarios/sangre , Leishmania infantum/inmunología , Leishmania infantum/aislamiento & purificación , Rickettsia typhi/aislamiento & purificación , Rickettsia typhi/inmunología , Anticuerpos Antibacterianos/sangre , Rickettsia felis/aislamiento & purificación , Humanos

RESUMEN

Canine leishmaniosis (CanL) is caused by the protozoal parasite Leishmania infantum, which is transmitted by sand flies in warm climates across the world. Because dogs are considered a primary domestic reservoir for the parasite that causes leishmaniosis in humans, it is important from a One Health perspective that CanL be properly managed. In endemic regions, CanL is a common differential diagnosis in sick dogs because the clinical signs and clinicopathological disorders of the disease are non-specific, variable, and may overlap those of other common conditions. Diagnosis is based on the presence of compatible clinical signs, laboratory abnormalities, and confirmation by serological and parasitological evidence of infection. Here, we describe the performance of a point-of-care (POC) immunoassay that uses recombinant antigens to detect canine anti- L. infantum antibodies in a convenience sample set from a diagnostic laboratory, a group of canine patients with clinical staging, and in apparently healthy dogs from endemic areas. An immunofluorescence antibody test (IFAT) was used as the semiquantitative reference method. In the convenience sample set with high IFAT titers (≥ 1:800), the POC immunoassay demonstrated perfect agreement with IFAT (100%; 90/90). Using samples from dogs staged as either LeishVet Stage 2 or 3 or LeishVet Stage 1, positive agreement of the POC immunoassay with the IFAT was 98.8% (82/83) and 83.8% (31/37), respectively. The negative agreement with IFAT was 98.9% (272/275) in apparently healthy dogs from endemic areas of Greece and Italy. Since the performance of the POC immunoassay was associated with IFAT titer and clinical stage of CanL, the test may help veterinarians when determining if CanL is likely responsible for a patient's clinical picture or when evaluating an apparently healthy patient prior to vaccination.

Asunto(s)

Anticuerpos Antiprotozoarios , Enfermedades de los Perros , Leishmania infantum , Leishmaniasis Visceral , Perros , Animales , Enfermedades de los Perros/diagnóstico , Enfermedades de los Perros/parasitología , Enfermedades de los Perros/epidemiología , Leishmania infantum/inmunología , Leishmania infantum/aislamiento & purificación , Leishmaniasis Visceral/veterinaria , Leishmaniasis Visceral/diagnóstico , Leishmaniasis Visceral/epidemiología , Leishmaniasis Visceral/parasitología , Anticuerpos Antiprotozoarios/sangre , Sistemas de Atención de Punto , Técnica del Anticuerpo Fluorescente/veterinaria , Sensibilidad y Especificidad , Masculino , Femenino , Enfermedades Endémicas/veterinaria

RESUMEN

Folate enzymes, namely, dihydrofolate reductase (DHFR) and pteridine reductase (PTR1) are acknowledged targets for the development of antiparasitic agents against Trypanosomiasis and Leishmaniasis. Based on the amino dihydrotriazine motif of the drug Cycloguanil (Cyc), a known inhibitor of both folate enzymes, we have identified two novel series of inhibitors, the 2-amino triazino benzimidazoles (1) and 2-guanidino benzimidazoles (2), as their open ring analogues. Enzymatic screening was carried out against PTR1, DHFR, and thymidylate synthase (TS). The crystal structures of TbDHFR and TbPTR1 in complex with selected compounds experienced in both cases a substrate-like binding mode and allowed the rationalization of the main chemical features supporting the inhibitor ability to target folate enzymes. Biological evaluation of both series was performed against T. brucei and L. infantum and the toxicity against THP-1 human macrophages. Notably, the 5,6-dimethyl-2-guanidinobenzimidazole 2g resulted to be the most potent (Ki = 9 nM) and highly selective TbDHFR inhibitor, 6000-fold over TbPTR1 and 394-fold over hDHFR. The 5,6-dimethyl tricyclic analogue 1g, despite showing a lower potency and selectivity profile than 2g, shared a comparable antiparasitic activity against T. brucei in the low micromolar domain. The dichloro-substituted 2-guanidino benzimidazoles 2c and 2d revealed their potent and broad-spectrum antitrypanosomatid activity affecting the growth of T. brucei and L. infantum parasites. Therefore, both chemotypes could represent promising templates that could be valorized for further drug development.

Asunto(s)

Antagonistas del Ácido Fólico , Tetrahidrofolato Deshidrogenasa , Triazinas , Trypanosoma brucei brucei , Trypanosoma brucei brucei/efectos de los fármacos , Trypanosoma brucei brucei/enzimología , Humanos , Tetrahidrofolato Deshidrogenasa/metabolismo , Tetrahidrofolato Deshidrogenasa/química , Antagonistas del Ácido Fólico/farmacología , Antagonistas del Ácido Fólico/química , Triazinas/farmacología , Triazinas/química , Tripanocidas/farmacología , Tripanocidas/química , Proguanil/farmacología , Proguanil/química , Timidilato Sintasa/antagonistas & inhibidores , Timidilato Sintasa/química , Timidilato Sintasa/metabolismo , Leishmania infantum/efectos de los fármacos , Leishmania infantum/enzimología , Bencimidazoles/farmacología , Bencimidazoles/química , Relación Estructura-Actividad , Antiprotozoarios/farmacología , Antiprotozoarios/química , Proteínas Protozoarias/antagonistas & inhibidores , Proteínas Protozoarias/metabolismo , Proteínas Protozoarias/química , Oxidorreductasas