RESUMEN

Interleukin 27 (IL-27) is a cytokine that regulates susceptibility to Leishmania infantum infection in humans and experimental models. This cytokine has not yet been described in canine leishmaniasis (CanL). Therefore, we investigated whether IL-27 has a regulatory role in CanL. The EBI3 and p28 subunits of IL-27 were measured in splenic leukocytes culture supernatant from dogs with CanL and compared to control dogs. We also correlated EBI3 and p28 levels with IL-21, anti-L. infantum antibodies and parasite loads. We performed functional assays followed by IL-27 blockade and measured parasite loads, production of cytokines in splenic leukocytes culture supernatant, and the expression of PD-1, CTLA-4, phospho-Stat-1/3, T-bet, GATA3 and nitric oxide production (NO). Both IL-27 subunits increased in the supernatant of dogs with CanL compared to control dogs. EBI3 and p28 levels showed a moderate positive correlation with IL-21 (r = 0.67, p < 0.0001 and r = 0.45, p < 0.012, respectively), and the EBI3 subunit was positively associated with anti-L. infantum IgG antibodies (r = 0.38, p < 0.040) and parasite load (r = 0.47, p < 0.009). IL-27 and IL-21 participate of immune responses in CanL. IL-27 may be associated with the failure of immunity to control parasite replication via upregulation of the expression of PD-1, CTLA-4, T-bet and NO in splenic leukocytes from dogs with CanL. These findings suggest that the pathways regulated by IL-27 are involved in CanL pathogenesis in the host, and may be targets for new therapies.

Asunto(s)

Enfermedades de los Perros , Interleucina-27 , Leishmania infantum , Leishmaniasis Visceral , Carga de Parásitos , Animales , Perros , Enfermedades de los Perros/inmunología , Enfermedades de los Perros/parasitología , Leishmania infantum/inmunología , Leishmaniasis Visceral/inmunología , Leishmaniasis Visceral/veterinaria , Leishmaniasis Visceral/parasitología , Interleucina-27/metabolismo , Inmunidad Adaptativa , Anticuerpos Antiprotozoarios/sangre , Anticuerpos Antiprotozoarios/inmunología , Masculino , Bazo/inmunología , Bazo/parasitología , Interleucinas/metabolismo , Interleucinas/inmunología , Femenino , Citocinas/metabolismo , Leucocitos/inmunología , Leucocitos/parasitología

RESUMEN

Visceral leishmaniasis (VL), caused by protozoa of the genus Leishmania, remains a significant public health concern due to its potentially lethal nature if untreated. Current chemotherapy options are limited by severe toxicity and drug resistance. Derivatives of 1,2,4-oxadiazole have emerged as promising drug candidates due to their broad biological activity. This study investigated the effects of novel 1,2,4-oxadiazole derivatives (Ox1-Ox7) on Leishmania infantum, the etiological agent of VL. In silico predictions using SwissADME suggest that these compounds have high oral absorption and good bioavailability. Among them, Ox1 showed the most promise, with higher selectivity against promastigotes and lower cytotoxicity towards L929 fibroblasts and J774.G8 macrophages. Ox1 exhibited selectivity indices of 18.7 and 61.7 against L. infantum promastigotes and amastigotes, respectively, compared to peritoneal macrophages. Ultrastructural analyses revealed severe morphological damage in both parasite forms, leading to cell death. Additionally, Ox1 decreased the mitochondrial membrane potential in promastigotes, as shown by flow cytometry. Molecular docking and dynamic simulations indicated a strong affinity of Ox1 for the L. infantum CYP51 enzyme. Overall, Ox1 is a promising and effective compound against L. infantum.

Asunto(s)

Antiprotozoarios , Leishmania infantum , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Oxadiazoles , Proteínas Protozoarias , Leishmania infantum/efectos de los fármacos , Oxadiazoles/química , Oxadiazoles/farmacología , Antiprotozoarios/farmacología , Antiprotozoarios/química , Animales , Proteínas Protozoarias/metabolismo , Proteínas Protozoarias/química , Ratones , Leishmaniasis Visceral/tratamiento farmacológico , Leishmaniasis Visceral/parasitología , Línea Celular , Potencial de la Membrana Mitocondrial/efectos de los fármacos

RESUMEN

Visceral leishmaniasis, caused by Leishmania infantum in New World countries, is the most serious and potentially fatal form of leishmaniasis, if left untreated. There are currently no effective prophylactic measures, and therapeutic options are limited. Therefore, we investigated whether the aromatase inhibitor letrozole (LET), which is already used to treat breast cancer, has an antileishmanial activity and/or immunomodulatory potential and therefore may be used to treat L. infantum infection. LET was active against L. infantum promastigote and amastigote life cycle stages in an in vitro infection model using human THP-1 cell-derived macrophages. In human peripheral blood leukocytes ex vivo, LET reduced the internalized forms of L. infantum by classical monocytes and activated neutrophils. Concomitantly, LET stimulated the production of IL-12/TNF-α and decreased the production of IL-10/TGF-ß by peripheral blood phagocytes, while in T and B cells, it promoted the production of TNF-α/IFN-γ and decreased that of IL-10. In a murine infection model, LET significantly reduced the parasite load in the liver after just 5 days and in the spleen after 15 days. During in vivo treatment with LET, the production of TNF-α/IFN-γ also increased. In addition, the proportion of developing granulomas decreased and that of mature granulomas increased in the liver, while there was no significant change in organ architecture in the spleen. Based on these data, repositioning of LET may be promising for the treatment of visceral leishmaniasis in humans.

Asunto(s)

Reposicionamiento de Medicamentos , Interleucina-10 , Leishmania infantum , Leishmaniasis Visceral , Letrozol , Factor de Necrosis Tumoral alfa , Leishmaniasis Visceral/tratamiento farmacológico , Leishmaniasis Visceral/parasitología , Animales , Leishmania infantum/efectos de los fármacos , Humanos , Ratones , Letrozol/uso terapéutico , Letrozol/farmacología , Interleucina-10/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Antiprotozoarios/farmacología , Antiprotozoarios/uso terapéutico , Macrófagos/efectos de los fármacos , Macrófagos/parasitología , Femenino , Células THP-1 , Ratones Endogámicos BALB C , Interferón gamma , Interleucina-12/metabolismo , Monocitos/efectos de los fármacos , Monocitos/parasitología , Carga de Parásitos , Bazo/parasitología , Bazo/efectos de los fármacos , Factor de Crecimiento Transformador beta/metabolismo

RESUMEN

Here we described a case of fatal canine visceral leishmaniasis (VL) in French Guiana, a non-endemic VL Amazonian area. The dog was a 2-year-old pug imported from Brazil to French Guiana. Initially seen for a pruriginous lesion on the muzzle which healed after treatment, the dog was in a deteriorated condition and had sublingual, foreleg and eye ulcers, one month later. A visceral leishmaniasis was suspected by the veterinarian. The dog was hospitalized awaiting results, which revealed the presence of L. infantum. However, the dog succumbed suddenly before the results were returned. Few imported and scarce autochthonous canine VL cases have been previously reported in French Guiana, raising the need for local epidemiological surveillance, considering the possibility of unusual transmission routes of the parasite.

Asunto(s)

Enfermedades de los Perros , Leishmania infantum , Leishmaniasis Visceral , Animales , Leishmaniasis Visceral/veterinaria , Leishmaniasis Visceral/diagnóstico , Leishmaniasis Visceral/parasitología , Leishmaniasis Visceral/tratamiento farmacológico , Perros , Guyana Francesa , Enfermedades de los Perros/parasitología , Enfermedades de los Perros/diagnóstico , Leishmania infantum/aislamiento & purificación , Resultado Fatal , Brasil , Masculino , Enfermedades Transmisibles Importadas/parasitología , Enfermedades Transmisibles Importadas/veterinaria , Enfermedades Transmisibles Importadas/diagnóstico

RESUMEN

Visceral leishmaniasis (VL) is a neglected tropical disease that is potentially fatal when untreated. Current diagnostic methods have limitations that contribute to ongoing transmission and poor prognosis. Thus, new tests are needed to provide quick, accurate diagnoses and evaluate clinical progression and treatment efficacy. The monokine induced by interferon-gamma (MIG) and interferon-gamma-inducible protein 10 (IP-10) has been associated with the host susceptibility to VL with potential diagnostic and prognostic purposes. We performed a systematic review using four search databases (Scopus, PubMed, Web of Science, and MEDLINE) to identify studies assessing MIG and IP-10 as potential biomarkers in patients with VL across various clinical conditions. A total of 13 studies were potentially eligible and included in this review. The articles, in general, reveal that the chemokines MIG and IP-10 are elevated in response to infection by Leishmania spp., acting on the host's resistance to the development of the disease. They are associated with asymptomatic conditions and after VL treatment, and this relationship can be observed in both immunocompetent and immunocompromised individuals. Consequently, these chemokines hold relevance in the diagnoses and appropriate management of individuals with VL.

RESUMEN

The effectiveness of a visceral leishmaniasis (VL) control strategy based on the application of 4 % deltamethrin impregnated collars (DIC) exclusively in seropositive dogs was assessed between 2018 and 2019, through a prospective study. The effectiveness of DIC-collaring was evaluated by comparing the incidence rate of anti-leishmanial antibodies among dogs from two endemic districts in Brazil. In one of the areas, the conventional control measure which is based on the non-compulsory euthanasia of LV seropositive dogs, was practiced by the official healthy service as a regular procedure, whereas strategic collaring, conceived in this study, was carried out in the other. Results of serological tests applied to serum samples collected from all domiciled dogs were evaluated in three consecutive times, spaced by around 200 days. Incidence rates of VL seroreactivity were compared between districts in the same period of time as well as within the same district, in consecutive periods. Based on the results, the risk of infection in the population under conventional control measure was up to four times higher than the risk of infection where DIC-collaring was used. The strategic use of collar proposed here emerged as a promising measure for VL control in dogs from endemic areas. Strategic collaring does not rely on the euthanasia of infected animals, an extremely controversial procedure, and instead of being used in all dogs, as collaring is normally recommended; only seropositive dogs are intervened. Strategic use of DIC has the potential to drastically reduce costs, if compared to mass collaring canine population.

Asunto(s)

Enfermedades de los Perros , Insecticidas , Leishmaniasis Visceral , Nitrilos , Piretrinas , Animales , Perros , Leishmaniasis Visceral/veterinaria , Leishmaniasis Visceral/prevención & control , Leishmaniasis Visceral/epidemiología , Piretrinas/administración & dosificación , Piretrinas/farmacología , Enfermedades de los Perros/prevención & control , Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/parasitología , Nitrilos/administración & dosificación , Nitrilos/farmacología , Brasil/epidemiología , Insecticidas/administración & dosificación , Incidencia , Estudios Prospectivos , Anticuerpos Antiprotozoarios/sangre , Masculino , Femenino

RESUMEN

PURPOSE: This case report examines the clinical presentation, diagnosis, treatment, and outcomes of mucocutaneous leishmaniasis with primary oral involvement in HIV-positive and HIV-negative patients diagnosed in Brazil. METHODS: We discuss the clinical manifestations, diagnostic methods, and therapeutic strategies, highlighting the clinical and histopathologic diagnostic features and distinct progression patterns based on HIV status. Our findings are compared with patterns observed in other countries, emphasizing the differences between the Americas and Europe, Asia, and Africa. RESULTS: In the Americas, particularly in Brazil, mucocutaneous leishmaniasis often presents with localized oral lesions, even in the presence of systemic immunosuppression, whereas in the Europe, Asia, and Africa, oral involvement is typically associated with visceral leishmaniasis in immunocompromised patients. These differences were due to variations in the parasite species involved. CONCLUSION: This comparison underscores the importance of regional and immunological factors in diagnosing and managing this neglected infectious disease.

Asunto(s)

Leishmaniasis Mucocutánea , Humanos , Masculino , Leishmaniasis Mucocutánea/patología , Leishmaniasis Mucocutánea/diagnóstico , Leishmaniasis Mucocutánea/tratamiento farmacológico , Adulto , Infecciones por VIH/complicaciones , Femenino , Persona de Mediana Edad , Enfermedades de la Boca/patología , Enfermedades de la Boca/parasitología

RESUMEN

OBJECTIVES: In the American regions, Brazil accounts for 97% of visceral leishmaniasis (VL) cases, with a case fatality rate of approximately 10%. This study aimed to investigate the VL mortality distribution in Brazil and identify high-priority and high-risk areas for intervention strategies. STUDY DESIGN: This was an ecological study that analysed the spatial-temporal patterns of VL mortality in Brazilian municipalities. METHODS: Age-standardised VL mortality rates from the Global Burden of Disease study from 2001 to 2018 were used. The distribution of mortality in the municipalities was assessed, and subsequently the Local Index of Spatial Autocorrelation (LISA) analysis was conducted to identify contiguous areas with high mortality rates. Scan analysis identified clusters of high spatial-temporal risks. RESULTS: The highest mortality rates and clusters were in municipalities located in the Northeast region and in the states of Tocantins and Roraima (North region), Mato Grosso do Sul (Central-West region), and Minas Gerais (Southeast region). According to LISA, there was an increase in the number of municipalities classified as high priority from the first 3-year period (n = 434) to the last 3-year period (n = 644). The spatio-temporal analysis identified 21 high-risk clusters for VL mortality. CONCLUSION: Areas with a high risk of VL mortality should prioritise preventing transmission, invest in early diagnosis and treatment, and promote the training of healthcare professionals.

Asunto(s)

Ciudades , Carga Global de Enfermedades , Leishmaniasis Visceral , Análisis Espacio-Temporal , Leishmaniasis Visceral/mortalidad , Leishmaniasis Visceral/epidemiología , Humanos , Brasil/epidemiología , Ciudades/epidemiología , Masculino , Adulto , Femenino

RESUMEN

Leishmaniases, caused by Leishmania parasites, are widespread and pose significant health risks globally. Visceral leishmaniasis (VL) is particularly prevalent in Brazil, with high morbidity and mortality rates. Traditional treatments, such as pentavalent antimonials, have limitations due to toxicity and resistance. Therefore, exploring new compounds like lectins is crucial. Concanavalin A (ConA) has shown promise in inhibiting Leishmania growth. This study aimed to evaluate its leishmanicidal effect on L. infantum promastigotes and understand its mechanism of action. In vitro tests demonstrated inhibition of promastigote growth when treated with ConA, with IC50 values ranging from 3 to 5 µM over 24-72 h. This study suggests that ConA interacts with L. infantum glycans. Additionally, ConA caused damage to the membrane integrity of parasites and induced ROS production, contributing to parasite death. Scanning electron microscopy confirmed morphological alterations in treated promastigotes. ConA combined with the amphotericin B (AmB) showed synergistic effects, reducing the required dose of AmB, and potentially mitigating its toxicity. ConA demonstrated no cytotoxic effects on macrophages, instead stimulating their proliferation. These findings reinforce that lectin exhibits promising leishmanicidal activity against L. infantum promastigotes, making ConA a potential candidate for leishmaniasis treatment.

Asunto(s)

Antiprotozoarios , Canavalia , Concanavalina A , Leishmania infantum , Leishmania infantum/efectos de los fármacos , Concanavalina A/farmacología , Animales , Antiprotozoarios/farmacología , Antiprotozoarios/química , Semillas/química , Especies Reactivas de Oxígeno/metabolismo , Ratones , Anfotericina B/farmacología , Lectinas/farmacología , Lectinas/química , Lectinas/metabolismo , Lectinas de Plantas/farmacología , Lectinas de Plantas/química , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Macrófagos/parasitología

RESUMEN

Visceral Leishmaniasis (VL) is a serious public health issue, documented in more than ninety countries, where an estimated 500,000 new cases emerge each year. Regardless of novel methodologies, advancements, and experimental interventions, therapeutic limitations, and drug resistance are still challenging. For this reason, based on previous research, we screened natural products (NP) from Nuclei of Bioassays, Ecophysiology, and Biosynthesis of Natural Products Database (NuBBEDB), Mexican Compound Database of Natural Products (BIOFACQUIM), and Peruvian Natural Products Database (PeruNPDB) databases, in addition to structural analogs of Miglitol and Acarbose, which have been suggested as treatments for VL and have shown encouraging action against parasite's N-glycan biosynthesis. Using computer-aided drug design (CADD) approaches, the potential inhibitory effect of these NP candidates was evaluated by inhibiting the Mannosyl-oligosaccharide Glucosidase Protein (MOGS) from Leishmania infantum, an enzyme essential for the protein glycosylation process, at various pH to mimic the parasite's changing environment. Also, computational analysis was used to evaluate the Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) profile, while molecular dynamic simulations were used to gather information on the interactions between these ligands and the protein target. Our findings indicated that Ocotillone and Subsessiline have potential antileishmanial effects at pH 5 and 7, respectively, due to their high binding affinity to MOGS and interactions in the active center. Furthermore, these compounds were non-toxic and had the potential to be administered orally. This research indicates the promising anti-leishmanial activity of Ocotillone and Subsessiline, suggesting further validation through in vitro and in vivo experiments.

RESUMEN

BACKGROUND: The sand fly Nyssomyia neivai is one of the most abundant species in Southern Brazil. It is frequently found in areas that are foci of visceral leishmaniasis in the state of Santa Catarina, caused by Leishmania infantum. In this region, the main vector of L. infantum, Lutzomyia longipalpis, has not been detected. In the absence of L. longipalpis, this study aimed to identify the sand fly fauna and diagnose any potential Leishmania spp. infection in sand flies and in dogs in a region of Southern Brazil that experienced a recent canine visceral leishmaniasis outbreak. METHODS: This report includes a survey of the sand fly fauna at the Zoonosis Control Center of the Municipality of Tubarão (Santa Catarina, Brazil). Molecular tests were conducted to investigate Leishmania spp. natural infection in sand flies using polymerase chain reaction (PCR). In positive females, in addition to morphological identification, molecular analysis through DNA barcoding was performed to determine the sand fly species. Additionally, the dogs were tested for the presence of Leishmania spp. using a non-invasive technique for the collection of biological material, to be assessed by PCR. RESULTS: A total of 3419 sand flies, belonging to five genera, were collected. Nyssomyia neivai was the most abundant species (85.8%), followed by Migonemyia migonei (13.3%), Pintomyia fischeri (0.8%), Evandromyia edwardsi (< 0.1%), and species of the genus Brumptomyia. (0.1%). Out of the 509 non-engorged females analyzed by PCR, two (0.4%) carried L. infantum DNA. The naturally infected females were identified as Ny. neivai, in both morphological and molecular analysis. In addition, two out of 47 conjunctival swabs from dogs tested positive for L. infantum, yielding an infection rate of 4.2%. CONCLUSIONS: These results confirm the presence of Ny. neivai naturally infected with L. infantum in an area where dogs were also infected by the parasite, suggesting its potential role as a vector in Southern Brazil.

Asunto(s)

Enfermedades de los Perros , Insectos Vectores , Leishmania infantum , Leishmaniasis Visceral , Psychodidae , Animales , Perros , Leishmania infantum/genética , Leishmania infantum/aislamiento & purificación , Brasil/epidemiología , Psychodidae/parasitología , Psychodidae/clasificación , Enfermedades de los Perros/parasitología , Enfermedades de los Perros/epidemiología , Leishmaniasis Visceral/veterinaria , Leishmaniasis Visceral/epidemiología , Leishmaniasis Visceral/parasitología , Leishmaniasis Visceral/transmisión , Femenino , Insectos Vectores/parasitología , Reacción en Cadena de la Polimerasa , Masculino

RESUMEN

Visceral leishmaniasis (VL) results from protozoa Leishmania infantum and L. donovani infection. This study investigated whether host factors would explain the relapses. First, susceptibility to amphotericin B of L. infantum isolates was evaluated in vitro. Then, clinical data and the lipid profile of patients with relapsing and non-relapsing VL were assessed. Susceptibility to amphotericin B was similar between the isolates. CD4+ lymphocytes were reduced in both groups of patients in the first episode and with relapsing VL. Still, the strongest blood cell indicator associated with relapses was low total lymphocyte counts. Total plasma cholesterol, high-density lipoprotein, low-density lipoprotein, and, uniquely, triglycerides of the six individuals in the first episode and twenty-three with relapsing VL were lower in relapsing patients than those in the first episode. Deceased patients had extremely low low-density lipoprotein. After CD4+ decreases, lymphocyte CD8+ reduction is the final stage of immunological failure. The lower lipid concentrations appear to be secondary to the depletion of fat stores by inflammation-induced cachexia and fat exhaustion provoked by the co-occurrence of both diseases, which can finally lead to death.

RESUMEN

Visceral leishmaniasis is a disease caused by protozoa of the species Leishmania (Leishmania) infantum (syn = Leishmania chagasi) and Leishmania (Leishmania) donovani, which are transmitted by hematophagous insects of the genera Lutzomyia and Phlebotomus. The domestic dog (Canis familiaris) is considered the main urban reservoir of the parasite due to the high parasite load on its skin, serving as a source of infection for sandfly vectors and, consequently, perpetuating the disease in the urban environment. Some factors are considered important in the perpetuation and spread of canine visceral leishmaniasis (CVL) in urban areas, such as stray dogs, with their errant behavior, and houses that have backyards with trees, shade, and organic materials, creating an attractive environment for sandfly vectors. CVL is found in approximately 50 countries, with the number of infected dogs reaching millions. However, due to the difficulty of controlling and diagnosing the disease, the number of infected animals could be even greater. In the four continents endemic for CVL, there are reports of disease expansion in endemic countries such as Brazil, Italy, Morocco, and Tunisia, as well as in areas where CVL is not endemic, for example, Uruguay. Socio-environmental factors, such as migration, drought, deforestation, and global warming, have been pointed out as reasons for the expansion into areas where it had been absent. Thus, the objective of this review is to address (i) the distribution of CVL in endemic areas, (ii) the role of the dog in the visceral leishmaniasis epidemiology and the factors that influence dog infection and the spread of the disease, and (iii) the challenges faced in the control of CVL.

RESUMEN

In the New World, dogs are considered the main reservoir of visceral leishmaniasis (VL). Due to inefficacies in existing treatments and the lack of an efficient vaccine, dog culling is one of the main strategies used to control disease, making the development of new therapeutic interventions mandatory. We previously showed that Tanespimycin (17-AAG), a Hsp90 inhibitor, demonstrated potential for use in leishmaniasis treatment. The present study aimed to test the safety of 17-AAG in dogs by evaluating plasma pharmacokinetics, dose-proportionality, and the tolerability of 17-AAG in response to a dose-escalation protocol and multiple administrations at a single dose in healthy dogs. Two protocols were used: Study A: four dogs received variable intravenous (IV) doses (50, 100, 150, 200, or 250 mg/m2) of 17-AAG or a placebo (n = 4/dose level), using a cross-over design with a 7-day "wash-out" period; Study B: nine dogs received three IV doses of 150 mg/m2 of 17-AAG administered at 48 h intervals. 17-AAG concentrations were determined by a validated high-performance liquid chromatographic (HPLC) method: linearity (R2 = 0.9964), intra-day precision with a coefficient of variation (CV) ≤ 8%, inter-day precision (CV ≤ 20%), and detection and quantification limits of 12.5 and 25 ng/mL, respectively. In Study A, 17-AAG was generally well tolerated. However, increased levels of liver enzymes-alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT)-and bloody diarrhea were observed in all four dogs receiving the highest dosage of 250 mg/m2. After single doses of 17-AAG (50-250 mg/m2), maximum plasma concentrations (Cmax) ranged between 1405 ± 686 and 9439 ± 991 ng/mL, and the area under the curve (AUC) plotting plasma concentration against time ranged between 1483 ± 694 and 11,902 ± 1962 AUC 0-8 h µg/mL × h, respectively. Cmax and AUC parameters were dose-proportionate between the 50 and 200 mg/m2 doses. Regarding Study B, 17-AAG was found to be well tolerated at multiple doses of 150 mg/m2. Increased levels of liver enzymes-ALT (28.57 ± 4.29 to 173.33 ± 49.56 U/L), AST (27.85 ± 3.80 to 248.20 ± 85.80 U/L), and GGT (1.60 ± 0.06 to 12.70 ± 0.50 U/L)-and bloody diarrhea were observed in only 3/9 of these dogs. After the administration of multiple doses, Cmax and AUC 0-48 h were 5254 ± 2784 µg/mL and 6850 ± 469 µg/mL × h in plasma and 736 ± 294 µg/mL and 7382 ± 1357 µg/mL × h in tissue transudate, respectively. In conclusion, our results demonstrate the potential of 17-AAG in the treatment of CVL, using a regimen of three doses at 150 mg/m2, since it presents the maintenance of high concentrations in subcutaneous interstitial fluid, low toxicity, and reversible hepatotoxicity.

RESUMEN

The treatment for visceral leishmaniasis (VL) causes toxicity in patients, entails high cost and/or leads to the emergence of resistant strains. No human vaccine exists, and diagnosis presents problems related to the sensitivity or specificity of the tests. Here, we tested two phage clones, B1 and D11, which were shown to be protective against Leishmania infantum infection in a murine model as immunotherapeutics to treat mice infected with this parasite species. The phages were used alone or with amphotericin B (AmpB), while other mice received saline, AmpB, a wild-type phage (WTP) or WTP/AmpB. Results showed that the B1/AmpB and D11/AmpB combinations induced polarised Th1-type cellular and humoral responses, which were primed by high levels of parasite-specific IFN-γ, IL-12, TNF-α, nitrite and IgG2a antibodies, which reflected in significant reductions in the parasite load in distinct organs of the animals when analyses were performed 1 and 30 days after the treatments. Reduced organic toxicity was also found in these animals, as compared with the controls. In conclusion, preliminary data suggest the potential of the B1/AmpB and D11/AmpB combinations as immunotherapeutics against L. infantum infection.

Asunto(s)

Anfotericina B , Anticuerpos Antiprotozoarios , Inmunoterapia , Leishmania infantum , Leishmaniasis Visceral , Ratones Endogámicos BALB C , Leishmaniasis Visceral/inmunología , Leishmaniasis Visceral/tratamiento farmacológico , Animales , Anfotericina B/uso terapéutico , Anfotericina B/administración & dosificación , Anticuerpos Antiprotozoarios/sangre , Leishmania infantum/inmunología , Leishmania infantum/efectos de los fármacos , Ratones , Inmunoterapia/métodos , Femenino , Antiprotozoarios/uso terapéutico , Antiprotozoarios/administración & dosificación , Inmunoglobulina G/sangre , Carga de Parásitos , Modelos Animales de Enfermedad , Técnicas de Visualización de Superficie Celular , Citocinas/metabolismo , Células TH1/inmunología

RESUMEN

Diagnosing canine visceral leishmaniasis (CVL) in Brazil faces challenges due to the limitations regarding the sensitivity and specificity of the current diagnostic protocol. Therefore, it is urgent to map new antigens or enhance the existing ones for future diagnostic techniques. Immunoinformatic tools are promising in the identification of new potential epitopes or antigen candidates. In this study, we evaluated peptides selected by epitope prediction for CVL serodiagnosis in ELISA assays. Ten B-cell epitopes were immunogenic in silico, but two peptides (peptides No. 45 and No. 48) showed the best performance in vitro. The selected peptides, both individually and in combination, were highly diagnostically accurate, with sensitivities ranging from 86.4% to 100% and with a specificity of approximately 90%. We observed that the combination of peptides showed better performance when compared to peptide alone, by detecting all asymptomatic dogs, showing lower cross-reactivity in sera from dogs with other canine infections, and did not detect vaccinated animals. Moreover, our data indicate the potential use of immunoinformatic tools associated with ELISA assays for the selection and evaluation of potential new targets, such as peptides, applied to the diagnosis of CVL.

RESUMEN

We studied some fibrotic aspects of chronic interstitial pneumonitis in the lungs of dogs infected with Leishmania infantum. The lungs of eleven naturally infected dogs, twelve experimentally infected with two distinct strains of L. infantum (BH401 and BH46), and six uninfected (controls) dogs, were analyzed by histological, parasitological, and immunohistochemical studies. Conventional histology (HE), collagen deposition (Gomori's silver staining for reticulin collagen fibers), and immunohistochemistry for myofibroblast characterization were carried out based on the cellular expression of alpha-smooth muscle actin, vimentin, cytokeratin, E-cadherin, snail antigen homologue 1 (SNAI1) (Snail), and the cytokine expression of transforming growth factor-beta (TGF-ß). Parasitological screening was carried out using conventional polymerase chain reaction (PCR) and the immunohistochemical reaction of streptavidin-peroxidase for visualizing Leishmania amastigotes. Dogs naturally infected with L. infantum and experimentally infected with L. infantum BH401 strains showed intense interstitial pneumonitis characterized by thickening of the alveolar septa as a consequence of an intense diffuse and focal (plaques) chronic exudate of mononuclear cells associated with fibrogenesis. The expression of alpha-actin, vimentin, and TGF-ß was higher in the lung interstitium of all infected dogs than in the other two groups (BH46 strain and controls). Moreover, in both the naturally and experimentally infected dog (BH401 strain) groups, the expression of Snail was moderate to intense in contrast to the other groups. Based on these immunohistochemical results, we concluded that mesenchymal cells are active in promoting changes in the extracellular matrix in the lungs of dogs naturally and experimentally infected with L. infantum, but it depends on the virulence of the parasite.

RESUMEN

Canine visceral leishmaniasis (CVL), caused by the protozoan Leishmania infantum, affects several organs, including the skin. Dogs are considered the major domestic reservoir animals for leishmaniasis, and through their highly parasitized skin, they can serve as a source of infection for sandfly vectors. Therefore, studies of the skin parasite-host relationship can contribute to the understanding of the infectious dissemination processes of parasites in the dermis and help to identify targets for diagnosis and treatment. Thus, the aim of this study was to evaluate the association of anatomical vascular differences and Leishmania-induced vascular morphological changes with clinical signs and parasite load by analyzing the ear and abdominal skin from dogs naturally infected with L. infantum. Paired samples of ear and abdominal skin from L. infantum-positive dogs (n = 26) were submitted for histological and immunohistochemistry analyses. The ear skin samples showed a more intense and more diffusely distributed granulomatous inflammatory reaction, a higher number and larger diameter of blood vessels, increased parasite load, higher expression of VEGF+ (vascular endothelial growth factor) and MAC 387+ (calprotectin) recently infiltrating cells, and more intense collagen disruption compared to the abdominal skin samples. Intracellular amastigotes were observed in blood vessels and inside endothelial cells and were diffusely distributed throughout the dermis in the ear skin samples. The NOS2/MAC387+ cell ratio was lower in the ear skin samples than in those of the abdomen, suggesting that in the ear dermis, the inflammatory infiltrate was less capable of producing NO and thereby control the parasite load. Together, these findings indicate how parasites and immune cells are distributed in the skin and suggest an important role for dermal vascularization in cellular influx and thereby in parasite dissemination through the skin of naturally infected dogs.

RESUMEN

This study was carried out to identify the spatial distribution and characterize the clinical-epidemiological profile of Visceral Leishmaniasis (VL) in Maranhão state, Brazil, from 2009 to 2020. This descriptive ecological study collected sociodemographic and clinical data of VL cases from the Brazilian Notifiable Diseases Information System database. A spatial autocorrelation analysis (Moran statistics) was performed. From 2009 to 2020, 5699 cases of VL were reported, with incidence of 6.5 cases/100,000 and prevalence of 7.1 cases/100,000. The temporal analysis showed a significant growth in incidence from 2009 to 2018, followed by a significant decrease between 2019 and 2020. The Moran map shows hotspots of high values in the central-west and central-east regions, and hotspots of low values in the northern region of Maranhão. The profile of patients affected by VL comprises males (OR = 1.8; IC95% = 1.72-1.92), aged under 14 years, brown, and with incomplete elementary schooling. The main symptoms reported were fever, fatigue, and edema. The main diagnostic method was laboratory. The mortality rate was 6.8%, and co-infection with HIV was reported by 8.5% of patients. The results of this study indicated the increase in incidence and lethality, as well as the expansion, of leishmaniasis in the state of Maranhão.

RESUMEN

The zoonotic visceral leishmaniasis is caused by the protozoan Leishmania infantum and dogs are reservoirs for this parasite. For the diagnosis of Leishmania at the species level in dogs in formalin-fixed, paraffin-embedded skin (FFPES) samples, colorimetric in situ hybridization (CISH) and quantitative real-time polymerase chain reaction (qPCR) are options, but their sensitivities are not well established. Therefore, the aim of this study was to determine the sensitivity of these two techniques in FFPES for the diagnosis of the L. infantum infection in dogs using culture as the reference standard. The FFPES of 48 dogs with cutaneous infection by L. infantum confirmed by culture and by multilocus enzyme electrophoresis were examined by CISH and qPCR using specific probes for L. infantum. The sensitivities of qPCR, CISH and their combination were, respectively, 77.0%, 58.0% and 83.3%. The sensitivities of qPCR in dogs with and without clinical signs were, respectively, 74.2% and 82.4%. The sensitivities of CISH in dogs with and without clinical signs were, respectively, 61.3% and 52.9%. The CISH and qPCR showed satisfactory sensitivities for the diagnosis of L. infantum in the FFPES of dogs, even in dogs without clinical signs, and their combination increases the sensitivity for this diagnosis.