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1.
PLoS Negl Trop Dis ; 15(2): e0009126, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33524030

RESUMO

The increasing use of immunosuppressants in areas where visceral leishmaniasis (VL) is endemic has increased the number of people susceptible to developing more severe forms of the disease. Few studies have examined the quality of the immune response in immunosuppressed patients or experimental animals with VL. The present work characterises the parasite load developed in, and immune response to, Leishmania infantum-induced VL in C57BL/6 mice that, prior to and during infection, received immunosuppressant treatment with methylprednisolone (MPDN), anti-tumour necrosis factor (anti-TNF) antibodies, or methotrexate (MTX). The latter two treatments induced a significant reduction in the number of CD4+ T lymphocytes over the infection period. The anti-TNF treatment was also associated with a higher parasite load in the liver and a lower parasite load in the spleen. This, plus a possibly treatment-induced reduction in the number of cytokine-producing Th1 cells in the spleen, indicates the development of more severe VL. Interestingly, the MPDN and (especially) MTX treatments provoked a greater presence of soluble Leishmania antigen-specific multi-cytokine-producing T cells in the spleen and a lower liver parasite load than in control animals. These results highlight the need to better understand how immunosuppressant treatments might influence the severity of VL in human patients.

2.
J Immunol Res ; 2020: 8385672, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32377538

RESUMO

Visceral leishmaniasis (VL) is a lethal disease if left untreated. Current treatments produce variable rates of treatment failure and toxicity without sterile cure, rendering treatment efficacy monitoring essential. To avoid repeated invasive tissue aspirates as well as empirical treatment, there is a need for new tools that allow a less-invasive and early assessment of treatment efficacy in the field. Cross-sectional studies have suggested levels of cytokines/chemokines after whole blood stimulation as good markers of cure, but longitudinal studies are lacking. In this study, we followed 13 active VL cases in an endemic area in Ethiopia by measuring the production of IFN-γ, TNF-α, IP-10, IL-2, IL-10, MCP-1, and MIG before, during, and at the end of treatment. After 24 hours of stimulation of whole blood with soluble Leishmania antigen, we observed an early, robust, and incremental increase of IFN-γ, TNF-α, and IP-10 levels in all patients during treatment. Moreover, based on the IFN-γ levels that showed an average 13-fold increase from the time of diagnosis until the end of treatment, we could almost perfectly discriminate active from cured status. Similar concentrations and patterns were found in stimulation assays with the two main Leishmania species. The levels of IFN-γ, IP-10, or TNF-α also seemed to be inversely associated with the parasite load at baseline. Despite a 1/10 drop in concentrations, similar patterns were observed in IFN-γ and IP-10 levels when dried plasma spots were stored at 4°C for an average of 225 days. All the above evidence suggests a detectable restoration of cell-mediated immunity in VL and its association with parasite clearance. With a potential application in rural settings by means of dried plasma spots, we recommend to further explore the early diagnostic value of such assays for treatment efficacy monitoring in large cohort studies including treatment failure cases.

3.
PLoS Negl Trop Dis ; 14(4): e0008253, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32324738

RESUMO

BACKGROUND: In the Mediterranean basin, Leishmania infantum is the causative agent of visceral leishmaniasis (VL), a zoonosis in which the dog is the primary domestic reservoir, although wildlife may have a leading role in the sylvatic cycle of the disease in some areas. Infections without disease are very frequent. There is limited information regarding the role that VL patients and asymptomatic infected individuals could be playing in the transmission of L. infantum. Xenodiagnosis of leishmaniasis has been used in this descriptive study to explore the role of symptomatic and asymptomatic infected individuals as reservoirs in a recent focus of leishmaniasis in southwestern Madrid, Spain. METHODOLOGY AND MAIN FINDINGS: Asymptomatic blood donors (n = 24), immunocompetent patients who were untreated (n = 12) or treated (n = 11) for visceral leishmaniasis (VL), and immunocompromised patients with VL (n = 3) were enrolled in the study. Their infectivity to Phlebotomus perniciosus was studied by indirect xenodiagnosis on peripheral blood samples. Quantitative polymerase chain reaction of blood samples from immunocompetent patients untreated for VL and immunocompromised untreated, treated and under secondary prophylaxis for VL was performed. Antibodies against Leishmania were studied by indirect fluorescent antibody and rK39-immunochromatographic tests. A lymphoproliferative assay with a soluble Leishmania antigen was used to screen for leishmaniasis infection in the healthy population. Sixty-two xenodiagnostic tests were carried out and 5,080 sand flies were dissected. Positive xenodiagnosis was recorded in four patients, with different sand fly infection rates: 1 immunosuppressed HIV / L. infantum coinfected asymptomatic patient, 1 immunosuppressed patient with multiple myeloma and symptomatic active VL, and 2 immunocompetent patients with untreated active VL. All blood donors were negative for both xenodiagnosis and conventional PCR. CONCLUSIONS / SIGNIFICANCE: There is no consensus amongst authors on the definition of an 'asymptomatic case' nor on the tools for screening; we, therefore, have adopted one for the sake of clarity. Immunocompetent subjects, both infected asymptomatics and those treated for VL, are limited in number and appear to have no epidemiological relevance. The impact is limited for immunocompetent patients with untreated active VL, whilst immunosuppressed individuals undergoing immunosuppressive therapy and immunosuppressed individuals HIV / L. infantum coinfected were the most infectious towards sand flies. It is noteworthy that the HIV / L. infantum coinfected patient with asymptomatic leishmaniasis was easily infectious to sand flies for a long time, despite being under continuous prophylaxis for leishmaniasis. Accordingly, screening for latent Leishmania infection in HIV-infected patients is recommended in scenarios where transmission occurs. In addition, screening for VL in HIV-infected patients who have spent time in VL-endemic areas should also be implemented in non-endemic areas. More research is needed to better understand if some asymptomatic coinfected individuals contribute to transmission as 'super-spreaders'.


Assuntos
Reservatórios de Doenças , Transmissão de Doença Infecciosa , Leishmania infantum/isolamento & purificação , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/transmissão , Adulto , Animais , Anticorpos Antiprotozoários/sangue , Doenças Assintomáticas/epidemiologia , DNA de Protozoário/sangue , Feminino , Humanos , Leucócitos Mononucleares/imunologia , Masculino , Pessoa de Meia-Idade , Psychodidae/parasitologia , Espanha/epidemiologia
4.
Semin Immunopathol ; 42(3): 231-246, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32189034

RESUMO

Progress has been made in the control or elimination of tropical diseases, with a significant reduction of incidence. However, there is a risk of re-emergence if the factors fueling transmission are not dealt with. Although it is essential to understand these underlying factors for each disease, asymptomatic carriers are a common element that may promote resurgence; their impact in terms of proportion in the population and role in transmission needs to be determined. In this paper, we review the current evidence on whether or not to treat asymptomatic carriers given the relevance of their role in the transmission of a specific disease, the efficacy and toxicity of existing drugs, the Public Health interest, and the benefit at an individual level, for example, in Chagas disease, to prevent irreversible organ damage. In the absence of other control tools such as vaccines, there is a need for safer drugs with good risk/benefit profiles in order to change the paradigm so that it addresses the complete infectious process beyond manifest disease to include treatment of non-symptomatic infected persons.

5.
Trends Parasitol ; 36(1): 29-38, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31718888

RESUMO

Effective diagnosis and treatment of visceral leishmaniasis, together with the study of vectors and reservoirs, can lead to a better understanding of the parasite transmission dynamics and the development of more efficient control measures. Recent studies have applied new methodologies and biomarkers, and these have contributed to the early and rapid diagnosis of the disease; assessment of success of pharmacological treatments; efficient monitoring of immunosuppressed individuals; and to population screening for field trials of vaccine efficacy. This opinion article proposes an update to the diagnostic tools for visceral leishmaniasis and their rational and combined use to establish the real prevalence of infection or of exposure to Leishmania in endemic areas.


Assuntos
Biomarcadores/sangue , Quimiocinas/sangue , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/prevenção & controle , Animais , Humanos
6.
Front Vet Sci ; 6: 373, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31709270

RESUMO

Canine leishmaniosis (CanL) prevention in the Mediterranean basin is considered essential to stop human zoonotic visceral leishmaniasis. In this context, vaccination of dogs is expected to have a significant impact in disease control. CaniLeish® (Virbac Animal Health) is one of a few CanL vaccines that are at this moment licensed in Europe. This vaccine contains purified excreted-secreted proteins of Leishmania having several antigens/immunogens with potential to influence serological response. Therefore, it is important to know if CaniLeish vaccination increased the diagnostic challenges associated with conventional serology, limiting the value of some antigens. To address this 20 dogs from a cohort of 35 healthy dogs that were vaccinated, maintained indoor for 1 month and then returned to their natural domiciles for 2 years. After this period, they were re-called to evaluate their clinical/parasitological condition and assess the evolution of seroreactivity against different antigens: soluble promastigote Leishmania antigens (SPLA), recombinant protein Leishmania infantum cytosolic peroxiredoxin, recombinant protein K39 (rK39), recombinant protein K28 and recombinant kinesin degenerated derived repeat using ELISA. Two years after vaccination all vaccinated non-infected animals were seropositive for SPLA. For the other antigens the serological profile was indistinguishable from non-infected animals. Moreover, vaccinated animals presented a characteristic relative serological profile, with higher normalized serological response to SPLA than rK39. This fact enabled to distinguish with sensitivity 92.3% and specificity 95.4%, vaccinated non-infected dogs from infected and non-infected dogs. Ultimately, relative serological profile enabled the detection of healthy vaccinated animals enabling more accurate serological surveys.

8.
Parasit Vectors ; 12(1): 359, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31340851

RESUMO

BACKGROUND: An outbreak of leishmaniasis caused by Leishmania infantum was declared in the southwest of the Madrid region (Spain) in June 2009. This provided a unique opportunity to compare the management of visceral leishmaniasis (VL) in immunocompetent adults (IC-VL), patients with HIV (HIV-VL) and patients receiving immunosuppressants (IS-VL). METHODS: A cohort of adults with VL, all admitted to the Hospital Universitario de Fuenlabrada between June 2009 and June 2018, were monitored in this observational study, recording their personal, epidemiological, analytical, diagnostic, treatment and outcome variables. RESULTS: The study population was made up of 111 patients with VL (10% HIV-VL, 14% IS-VL, 76% IC-VL). Seventy-one percent of the patients were male; the mean age was 45 years (55 years for the IS-VL patients, P = 0.017). Fifty-four percent of the IC-VL patients were of sub-Saharan origin (P = 0.001). Fever was experienced by 98% of the IC-VL patients vs 73% of the LV-HIV patients (P = 0.003). Plasma ferritin was > 1000 ng/ml in 77% of the IC-VL patients vs 17% of the LV-HIV patients (P = 0.007). Forty-two percent of patients fulfilled the criteria for haemophagocytic lymphohistiocytosis. RDT (rK39-ICT) serological analysis returned sensitivity and specificity values of 45% and 99%, respectively, and ELISA/iIFAT returned 96% and 89%, respectively, with no differences in this respect between patient groups. Fourteen (13.0%) patients with VL experienced treatment failure, eight of whom were in the IC-VL group. Treatment with < 21 mg/kg (total) liposomal amphotericin B (LAB) was associated with treatment failure in the IC-VL patients [P = 0.002 (OR: 14.7; 95% CI: 2.6-83.3)]. CONCLUSIONS: IS-VL was more common than HIV-VL; the lack of experience in dealing with IS-VL is a challenge that needs to be met. The clinical features of the patients in all groups were similar, although the HIV-VL patients experienced less fever and had lower plasma ferritin concentrations. RDT (rK39-ICT) analysis returned a good specificity value but a much poorer sensitivity value than reported in other scenarios. The patients with HIV-VL, IS-VL and IC-VL returned similar serological results. Current guidelines for treatment seem appropriate, but the doses of LAB required to treat patients with HIV-VL and IS-VL are poorly defined.


Assuntos
Surtos de Doenças/estatística & dados numéricos , Infecções por HIV/parasitologia , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/epidemiologia , Adulto , Idoso , Antígenos de Protozoários/imunologia , Coinfecção/tratamento farmacológico , Coinfecção/epidemiologia , Coinfecção/parasitologia , Coinfecção/virologia , Diagnóstico Tardio , Surtos de Doenças/prevenção & controle , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Imunocompetência , Imunossupressores/uso terapêutico , Leishmania infantum , Leishmaniose Visceral/tratamento farmacológico , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Minorias Sexuais e de Gênero , Espanha/epidemiologia , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
9.
Sci Rep ; 9(1): 9932, 2019 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-31289323

RESUMO

Visceral leishmaniasis (VL) is one of the leading infectious diseases affecting developing countries. Colloidal gold-based diagnostic tests are rapid tools to detect blood/serum antibodies for VL diagnosis. Lack of uniformity in the performance of these tests in different endemic regions is a hurdle in early disease diagnosis. This study is designed to validate a serum-based dipstick test in eight centres of six countries, India, Nepal, Sri Lanka, Brazil, Ethiopia and Spain with archived and fresh sera from 1003 subjects. The dipstick detects antibodies against Leishmania donovani membrane antigens (LAg). The overall sensitivity and specificity of the test with 95% confidence intervals were found to be 97.10% and 93.44%, respectively. The test showed good sensitivity and specificity in the Indian subcontinent (>95%). In Brazil, Ethiopia, and Spain the sensitivity and specificity of the dipstick test (83.78-100% and 79.06-100%) were better as compared to the earlier reports of the performance of rK39 rapid test in these regions. Interestingly, less cross-reactivity was found with the cutaneous form of the disease in Spain, Brazil, and Sri Lanka demonstrating 91.58% specificity. This dipstick test can therefore be a useful tool for diagnosing VL from other symptomatically similar diseases and against cutaneous form of leishmaniasis.


Assuntos
Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Leishmania donovani/imunologia , Leishmaniose Visceral/sangue , Leishmaniose Visceral/diagnóstico , Proteínas de Protozoários/imunologia , Testes Sorológicos/métodos , Brasil/epidemiologia , Estudos de Casos e Controles , Etiópia/epidemiologia , Humanos , Índia/epidemiologia , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/parasitologia , Nepal/epidemiologia , Espanha/epidemiologia , Sri Lanka/epidemiologia
10.
PLoS Negl Trop Dis ; 13(6): e0007461, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31158223

RESUMO

Concomitant infection with human immunodeficiency virus (HIV) and the Leishmania parasite is a growing public health problem, the result of the former spreading to areas where the latter is endemic. Leishmania infection is usually asymptomatic in immunocompetent individuals, but the proportion of HIV+ individuals in contact with the parasite who remain asymptomatic is not known. The aim of the present work was to examine the use of cytokine release assays in the detection of asymptomatic immune responders to Leishmania among HIV+ patients with no previous leishmaniasis or current symptomatology. Eighty two HIV+ patients (all from Fuenlabrada, Madrid, Spain, where a leishmaniasis outbreak occurred in 2009) were examined for Leishmania infantum infection using molecular and humoral response-based methods. None returned a positive molecular or serological result for the parasite. Thirteen subjects showed a positive lymphoproliferative response to soluble Leishmania antigen (SLA), although the mean CD4+ T lymphocyte counts of these patients was below the normal range. Stimulation of peripheral blood mononuclear cells (PBMC) or whole blood with SLA (the lymphoproliferative assay and whole blood assay respectively), led to the production of specific cytokines and chemokines. Thus, despite being immunocompromised, HIV+ patients can maintain a Th1-type cellular response to Leishmania. In addition, cytokine release assays would appear to be useful tools for detecting these individuals via the identification of IFN-γ in the supernatants of SLA-stimulated PBMC, and of IFN-γ, MIG and IL-2 in SLA-stimulated whole blood. These biomarkers appear to be 100% reliable for detecting asymptomatic immune responders to Leishmania among HIV+ patients.


Assuntos
Doenças Assintomáticas/epidemiologia , Infecções por HIV/complicações , Leishmania infantum/imunologia , Leishmaniose Visceral/epidemiologia , Adulto , Idoso , Proliferação de Células , Citocinas/metabolismo , Feminino , HIV , Humanos , Leucócitos Mononucleares/imunologia , Masculino , Pessoa de Meia-Idade , Espanha/epidemiologia , Adulto Jovem
11.
Euro Surveill ; 24(22)2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31164191

RESUMO

BackgroundA large outbreak of leishmaniasis with 758 cutaneous and visceral leishmaniasis cases occurred in 2009 in Fuenlabrada, in the south-west of the Madrid region of Spain.AimWe aimed to determine the prevalence of asymptomatic Leishmania infection after this outbreak, and its associated risk factors.MethodsA cross-sectional study of 804 healthy individuals living in Fuenlabrada who had no history of leishmaniasis, was conducted between January and July 2015. Asymptomatic infections were sought by either a combination of PCR, immunofluorescent antibody titre, and direct agglutination tests, or by whole blood stimulation assay (WBA) with interleukin-2 (IL-2) quantification.ResultsUsing the first approach, prevalence of asymptomatic individuals was 1.1% (9/804), while the second returned a value of 20.7% (143/804). Older age, being male, proximity to the park where the focus of infection was identified, and living in a detached house, were all strongly associated with the prevalence of asymptomatic infection.ConclusionsThe true number of infected individuals may be underestimated if only serological methods are used. The combination of WBA with IL-2 quantification may allow to better determine the prevalence of asymptomatic Leishmania infection, which would be useful in establishing control measures and in quantifying their impact. In our study, the use of WBA with IL-2 quantification also helped establish the risk factors that influence exposure to and infection by Leishmania.


Assuntos
Infecções Assintomáticas/epidemiologia , Surtos de Doenças , Leishmaniose Cutânea/epidemiologia , Leishmaniose Visceral/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Criança , Pré-Escolar , Estudos Transversais , Surtos de Doenças/prevenção & controle , Feminino , Humanos , Lactente , Leishmaniose Cutânea/sangue , Leishmaniose Cutânea/diagnóstico , Leishmaniose Visceral/sangue , Leishmaniose Visceral/diagnóstico , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Espanha/epidemiologia , Adulto Jovem
12.
Artigo em Inglês | MEDLINE | ID: mdl-30483480

RESUMO

Increased numbers of peripheral blood mononucleocytes (PBMC) and increased IFN-γ secretion following in vitro challenge of blood samples with soluble Leishmania antigen (SLA), have been proposed as biomarkers of specific cell-mediated immunity, indicating that treatment of visceral leishmaniasis (VL) has been successful. However, Leishmania infantum infection may manifest as cutaneous leishmaniasis (CL), and less commonly as localized leishmanial lymphadenopathy (LLL) or mucosal leishmaniasis (ML). The present work examines the value of these biomarkers as indicators of cured leishmaniasis presenting in these different forms. Blood samples were collected before and after treatment from patients living in Fuenlabrada (Madrid, Spain), an L. infantum-endemic area recently the center of a leishmaniasis outbreak. All samples were subjected to Leishmania-specific PCR, serological tests (IFAT and rK39-ICT), and the SLA-cell proliferation assay (SLA-CPA), recording PBMC proliferation and the associated changes in IFN-γ production. Differences in the results recorded for the active and cured conditions were only significant for VL. PCR returned positive results in 67% of patients with active VL and in 3% of those with cured leishmaniasis. Similarly, rK39-ICT returned a positive result in 77% of active VL samples vs. 52% in cured VL samples, and IFAT in 90% vs. 56%; in the SLA-CPA, PBMC proliferation was seen in 16% vs. 90%, and an associated increase in IFN-γ production of 14 and 84%, respectively. The present findings reinforce the idea that PBMC proliferation and increased IFN-γ production in SLA-stimulated PBMC provide biomarkers of clinical cure in VL. Other tests are urgently needed to distinguish between the cured and active forms of the other types of clinical leishmaniasis caused by L. infantum.


Assuntos
Biomarcadores/sangue , Testes Diagnósticos de Rotina/métodos , Monitoramento de Medicamentos/métodos , Leishmania infantum/crescimento & desenvolvimento , Leishmaniose/diagnóstico , Leishmaniose/patologia , Proliferação de Células , Humanos , Interferon gama/metabolismo , Leishmaniose/tratamento farmacológico , Leucócitos Mononucleares/imunologia , Espanha
13.
Int J Antimicrob Agents ; 52(5): 682-687, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29969693

RESUMO

The present work assesses the effect in vitro of combining the antiretroviral drug nelfinavir (NFV), a drug used against HIV but also a strong in vitro inhibitor of the growth of Leishmania promastigotes and amastigotes, with amphotericin B or miltefosine on different strains of Leishmania infantum. The isobolograms revealed a synergistic effect for both combinations, with a fractional inhibitory concentration index (∑FIC) <0.5. The ∑FIC values obtained with reference strain MCAN/ES/98/LLM-724 were 0.25 ± 0.1 (95% CI: 0.178-0.322) for the combination NFV+AMB and 0.48 ± 0.2 (95% CI: 0.377-0.573) for the combination NFV+MTF. The effect of NFV on visceral leishmaniasis induced by L. infantum in BALB/c mice was also examined, and the results confirmed a leishmanicidal effect when administered alone, with approximately 60% (P<0.05) reductions in the liver and spleen parasite burdens. This is the first time this has been reported in an in vivo model. A significant reduction in the liver (77%; P<0.01) and spleen (76%; P<0.01) parasite burdens was also observed for NFV+MTF compared with those obtained when these drugs were used alone. This indicates that such combinations may be useful treatment options in patients with visceral leishmaniasis who are also infected with HIV.


Assuntos
Anfotericina B/farmacologia , Antiprotozoários/farmacologia , Sinergismo Farmacológico , Leishmania infantum/efeitos dos fármacos , Nelfinavir/farmacologia , Fosforilcolina/análogos & derivados , Anfotericina B/administração & dosagem , Animais , Antiprotozoários/administração & dosagem , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Leishmania infantum/isolamento & purificação , Leishmaniose Visceral/tratamento farmacológico , Fígado/parasitologia , Masculino , Camundongos Endogâmicos BALB C , Nelfinavir/administração & dosagem , Carga Parasitária , Fosforilcolina/administração & dosagem , Fosforilcolina/farmacologia , Baço/parasitologia , Resultado do Tratamento
14.
Front Immunol ; 9: 843, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29740446

RESUMO

Leishmania-activated C-kinase antigen (LACK) is a highly conserved protein among Leishmania species and is considered a viable vaccine candidate for human leishmaniasis. In animal models, prime-boost vaccination with LACK-expressing plasmids plus attenuated vaccinia viruses (modified vaccinia Ankara [MVA] and mutant M65) expressing LACK, has been shown to protect against cutaneous leishmaniasis (CL). Further, LACK demonstrated to induce the production of protective cytokines in patients with active CL or cured visceral leishmaniasis, as well as in asymptomatic individuals from endemic areas. However, whether LACK is capable to trigger cytokine release by peripheral blood mononuclear cells from patients cured of CL due to Leishmania infantum (L. infantum) or induce protection in L. infantum-infected hamsters [visceral leishmaniasis (VL) model], has not yet been analyzed. The present work examines the ex vivo immunogenicity of LACK in cured VL and CL patients, and asymptomatic subjects from an L. infantum area. It also evaluates the vaccine potential of LACK against L. infantum infection in hamsters, in a protocol of priming with plasmid pCI-neo-LACK (DNA-LACK) followed by a booster with the poxvirus vectors MVA-LACK or M65-LACK. LACK-stimulated PBMC from both asymptomatic and cured subjects responded by producing IFN-γ, TNF-α, and granzyme B (Th1-type response). Further, 78% of PBMC samples that responded to soluble Leishmania antigen showed IFN-γ secretion following stimulation with LACK. In hamsters, the protocol of DNA-LACK prime/MVA-LACK or M65-LACK virus boost vaccination significantly reduced the amount of Leishmania DNA in the liver and bone marrow, with no differences recorded between the use of MVA or M65 virus vector options. In summary, the Th1-type and cytotoxic responses elicited by LACK in PBMC from human subjects infected with L. infantum, and the parasite protective effect of prime/boost vaccination in hamsters with DNA-LACK/MVA-LACK and DNA-LACK/M65-LACK, revealed the significance of LACK in activating human and hamster immune responses and support LACK to be a valuable candidate for inclusion in a vaccine against human VL.


Assuntos
Antígenos de Protozoários/imunologia , Imunização Secundária , Imunogenicidade da Vacina , Leucócitos Mononucleares/imunologia , Proteínas de Protozoários/imunologia , Vacinas Protozoárias/imunologia , Animais , Cricetinae , Citocinas/imunologia , Testes Imunológicos de Citotoxicidade , DNA de Protozoário/análise , Vetores Genéticos , Humanos , Interferon gama/imunologia , Leishmania infantum/imunologia , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/prevenção & controle , Masculino , Vacinas Protozoárias/genética , Células Th1/imunologia , Vacinas de DNA/genética , Vacinas de DNA/imunologia , Vírus Vaccinia/genética
15.
Parasit Vectors ; 11(1): 250, 2018 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-29665825

RESUMO

BACKGROUND: Nucleic acid amplification tests (NAATs) have proven to be advantageous in the diagnosis of leishmaniases, allowing sensitive diagnosis of: (i) cutaneous leishmaniasis in long duration lesions and (ii) visceral leishmaniasis using a less-invasive sample like peripheral blood, in opposition to tissue aspiration required for parasite demonstration by microscopy. Despite their benefits, the implementation of NAATs for leishmaniasis diagnosis at the point-of-care has not been achieved yet, mostly due to the complexity and logistical issues associated with PCR-based methods. METHODS: In this work, we have evaluated the performance of a ready-to-use loop-mediated isothermal amplification (LAMP) kit using two real time fluorimeters to amplify leishmanial DNA obtained by silica column-based and Boil & Spin protocols. RESULTS: The different approaches used to run and interpret the LAMP reactions showed a performance equivalent to PCR and real-time PCR, using spiked and clinical samples. The time to positivity obtained with real-time fluorimetry showed an excellent correlation with both Ct values and parasite load from real-time quantitative PCR. CONCLUSIONS: The results obtained open the possibility of using a highly stable, ready-to-use LAMP kit for the accurate diagnosis of leishmaniasis at the point-of-care. Furthermore, the feasibility of relating time to positivity, determined with a portable real-time fluorimeter, with the parasite burden could have a wider application in the management of leishmaniasis, such as in treatment efficacy monitoring or as a pharmacodynamics tool in clinical trials.


Assuntos
Fluorometria/métodos , Leishmania/isolamento & purificação , Leishmaniose/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Colorimetria/métodos , Humanos , Leishmania/genética , Testes Imediatos
16.
Parasit Vectors ; 11(1): 50, 2018 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-29357901

RESUMO

BACKGROUND: The use of contact lenses has increased in recent years as has the incidence of Dry Eye Syndrome, partly due to their use. Artificial tears are the most common treatment option. Since these changes can facilitate Acanthamoeba infection, the present study has been designed to evaluate the effect of three artificial tears treatments in the viability of Acanthamoeba genotype T4 trophozoites. Optava Fusion™, Oculotect®, and Artelac® Splash were selected due to their formulation. METHODS: Viability was assessed using two staining methods, Trypan Blue stain and CTC stain at different time intervals (2, 4, 6, 8 and 24 h). Trypan Blue viability was obtained by manual count with light microscopy while the CTC stain was determined using flow cytometry. RESULTS: Trypan Blue staining results demonstrated a decrease in viability for Optava Fusion™ and Artelac® Splash during the first 4 h of incubation. After, this effect seems to lose strength. In the case of Oculotect®, complete cell death was observed after 2 h. Using flow cytometry analysis, Optava Fusion™ and Oculotect® exhibited the same effect observed with Trypan Blue staining. However, Artelac® Splash revealed decreasing cell respiratory activity after four hours, with no damage to the cell membrane. CONCLUSIONS: The present study uses, for the first time, CTC stain analyzed by flow cytometry to establish Acanthamoeba viability demonstrating its usefulness and complementarity with the traditional stain, Trypan Blue. Artelac® Splash, with no preservatives, and Optava Fusion TM, with Purite®, have not shown any useful amoebicidal activity. On the contrary, promising results presented by Ocultect®, with BAK, open up a new possibility for Acanthamoeba keratitis prophylaxis and treatment although in vivo studies should be carried out.


Assuntos
Ceratite por Acanthamoeba/prevenção & controle , Acanthamoeba castellanii/efeitos dos fármacos , Lubrificantes Oftálmicos/análise , Lubrificantes Oftálmicos/química , Trofozoítos/efeitos dos fármacos , Ceratite por Acanthamoeba/tratamento farmacológico , Ceratite por Acanthamoeba/parasitologia , Acanthamoeba castellanii/metabolismo , Acanthamoeba castellanii/ultraestrutura , Amebicidas/análise , Amebicidas/química , Amebicidas/farmacologia , Humanos , Técnicas In Vitro , Lubrificantes Oftálmicos/efeitos adversos , Lubrificantes Oftálmicos/farmacologia , Conservantes Farmacêuticos/farmacologia , Trofozoítos/ultraestrutura , Azul Tripano/farmacologia
17.
PLoS Negl Trop Dis ; 11(11): e0005951, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29176865

RESUMO

The notion that previous infection by Leishmania spp. in endemic areas leads to robust anti-Leishmania immunity, supports vaccination as a potentially effective approach to prevent disease development. Nevertheless, to date there is no vaccine available for human leishmaniasis. We optimized and assessed in vivo the safety and immunogenicity of an innovative vaccine candidate against human visceral leishmaniasis (VL), consisting of Virus-Like Particles (VLP) loaded with three different recombinant proteins (LJL143 from Lutzomyia longipalpis saliva as the vector-derived (VD) component, and KMP11 and LeishF3+, as parasite-derived (PD) antigens) and adjuvanted with GLA-SE, a TLR4 agonist. No apparent adverse reactions were observed during the experimental time-frame, which together with the normal hematological parameters detected seems to point to the safety of the formulation. Furthermore, measurements of antigen-specific cellular and humoral responses, generally higher in immunized versus control groups, confirmed the immunogenicity of the vaccine formulation. Interestingly, the immune responses against the VD protein were reproducibly more robust than those elicited against leishmanial antigens, and were apparently not caused by immunodominance of the VD antigen. Remarkably, priming with the VD protein alone and boosting with the complete vaccine candidate contributed towards an increase of the immune responses to the PD antigens, assessed in the form of increased ex vivo CD4+ and CD8+ T cell proliferation against both the PD antigens and total Leishmania antigen (TLA). Overall, our immunogenicity data indicate that this innovative vaccine formulation represents a promising anti-Leishmania vaccine whose efficacy deserves to be tested in the context of the "natural infection".


Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Imunogenicidade da Vacina , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/prevenção & controle , Saliva/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Humanos , Imunidade Celular , Imunidade Humoral , Leishmania donovani , Leishmaniose Visceral/imunologia , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Psychodidae/imunologia , Psychodidae/parasitologia , Proteínas Recombinantes/imunologia
18.
Parasit Vectors ; 10(1): 454, 2017 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-28969710

RESUMO

BACKGROUND: Leishmaniasis remains a major public health problem in African nations, including Morocco, where little is known about the vertebrate reservoirs involved in the causal parasites' transmission cycles. The present study investigates the role of rodent species as potential reservoirs of Leishmania spp. in central Morocco, where both L. tropica and L. infantum have been reported. METHODS: Rodents were caught from 22 sites in central Morocco, by using Sherman metal traps, and identified morphologically. For each specimen, genomic DNA was extracted from different tissues using the Speed Tools DNA extraction Kit. Then, samples were PCR-analyzed, targeting the SSU rRNA gene to detect Leishmania spp. DNA, followed by amplification of the internal transcribed spacer 1 (ITS1) and its sequencing to identify the species. RESULTS: A total of 197 rodents belonging to ten species were captured and identified: Rattus rattus (40.61%), Mus musculus (25.38%), Apodemus sylvaticus (8.63%), Mus spretus (7.11%), Meriones shawi (5.58%), Rattus norvegicus (4.57%), Meriones libycus (3.05%), Mastomys erythroleucus (2.03%), Gerbillus campestris (2.03%) and Lemniscomys barbarus (1.01%). Molecular analysis revealed the presence of Leishmania species in 18 specimens: six R. rattus (out of 80 captured; 7.5%), 11 M. musculus (out of 50 captured; 22%), and one R. norvegicus (out of 9 captured; 11.11%). CONCLUSIONS: To the best of our knowledge, L. infantum and L. tropica were identified in rodent species for the first time in Morocco. These findings suggest that rodent species may be involved in L. infantum and L. tropica transmission cycles in this country but that further studies are needed to confirm their role as reservoirs of Leishmania species in Morocco.


Assuntos
Reservatórios de Doenças/parasitologia , Leishmania infantum/isolamento & purificação , Leishmania tropica/isolamento & purificação , Leishmaniose Cutânea/parasitologia , Leishmaniose Visceral/parasitologia , Animais , DNA de Protozoário/isolamento & purificação , Doenças Endêmicas , Feminino , Gerbillinae , Humanos , Leishmania infantum/genética , Leishmania tropica/genética , Leishmaniose Cutânea/epidemiologia , Leishmaniose Visceral/epidemiologia , Masculino , Camundongos , Marrocos/epidemiologia , Ratos , Roedores
19.
Front Immunol ; 8: 1208, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29033933

RESUMO

New biomarkers are needed to identify asymptomatic Leishmania infection as well as immunity following vaccination or treatment. With the aim of finding a robust biomarker to assess an effective cellular immune response, monocyte chemotactic protein 1 (MCP-1) was examined in plasma from soluble Leishmania antigen (SLA)-stimulated whole blood collected from subjects living in a Leishmania infantum-endemic area. MCP-1, expressed 110 times more strongly than IL-2, identified 87.5% of asymptomatic subjects and verified some asymptomatic subjects close to the cutoff. MCP-1 was also significantly elevated in all patients cured of visceral leishmaniasis (VL), unlike IL-2, indicating the specific memory response generated against Leishmania. These results show MCP-1 to be a robust candidate biomarker of immunity that could be used as a marker of cure and to both select and follow the population in vaccine phase I-III human clinical trials with developed rapid, easy-to-use field tools.

20.
PLoS One ; 12(10): e0186372, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29028841

RESUMO

Leishmaniasis is a vector-borne disease of worldwide distribution, currently present in 98 countries. Since late 2010, an unusual increase of human visceral and cutaneous leishmaniasis cases has been observed in the south-western Madrid region, totaling more than 600 cases until 2015. Some hosts, such as human, domestic dog and cat, rabbit (Oryctolagus cuniculus), and hare (Lepus granatensis), were found infected by the parasite of this disease in the area. Hares were described as the most important reservoir due to their higher prevalence, capacity to infect the vector, and presence of the same strains as in humans. Various measures were adopted to prevent and control the disease, and since 2013 there was a slight decline in the human sickness. We used a mathematical model to evaluate the efficacy of each measure in reducing the number of infected hosts. We identified in the present model that culling both hares and rabbits, without immediate reposition of the animals, was the best measure adopted, decreasing the proportion of all infected hosts. Particularly, culling hares was more efficacious than culling rabbits to reduce the proportion of infected individuals of all hosts. Likewise, lowering vector contact with hares highly influenced the reduction of the proportion of infected hosts. The reduction of the vector density per host in the park decreased the leishmaniasis incidence of hosts in the park and the urban areas. On the other hand, the reduction of the vector density per host of the urban area (humans, dogs and cats) decreased only their affected population, albeit at a higher proportion. The use of insecticide-impregnated collar and vaccination in dogs affected only the infected dogs' population. The parameters related to the vector contact with dog, cat or human do not present a high impact on the other hosts infected by Leishmania. In conclusion, the efficacy of each control strategy was determined, in order to direct future actions in this and in other similar outbreaks. The present mathematical model was able to reproduce the leishmaniasis dynamics in the Madrid outbreak, providing theoretical support based on successful experiences, such as the reduction of human cases in Southwest Madrid, Spain.


Assuntos
Surtos de Doenças/prevenção & controle , Leishmaniose/epidemiologia , Leishmaniose/prevenção & controle , Modelos Estatísticos , Animais , Vetores de Doenças , Humanos , Leishmaniose/transmissão , Espanha/epidemiologia
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