Development of a novel squalene/α-tocopherol-based self-emulsified nanoemulsion incorporating Leishmania peptides for induction of antigen-specific immune responses.

Vaccination has emerged as the most effective strategy to confront infectious diseases, among which is leishmaniasis, that threat public health. Despite laborious efforts there is still no vaccine for humans to confront leishmaniasis. Multi-epitope protein/peptide vaccines present a number of advantages, however their use along with appropriate adjuvants that may also act as antigen carriers is considered essential to overcome subunit vaccines' low immunogenicity. In the present study, a stable self-emulsified nanoemulsion was developed and double-adjuvanted with squalene and α-tocopherol. The prepared nanoemulsion droplets exhibited low cytotoxicity in a certain range of concentrations, while they were efficiently taken up by macrophages and dendritic cells in vitro as well as in vivo in secondary lymphoid organs. To further characterize nanoformulation's potent antigen delivery capability, three multi-epitope Leishmania peptides were incorporated into the nanoemulsion. Peptide encapsulation resulted in dendritic cells' functional differentiation characterized by elevated levels of maturation markers and intracellular cytokine production. Intramuscular administration of the nanoemulsion incorporating Leishmania peptides induced antigen-specific spleen cell proliferation as well as elicitation of CD4+ central memory cells, supporting the potential of the developed nanoformulation to successfully act also as an antigen delivery vehicle and thus encouraging further preclinical studies on its vaccine candidate potency.

Adjuvantation of whole-killed Leishmania vaccine with anti-CD200 and anti-CD300a antibodies potentiates its efficacy and provides protection against wild-type parasites.

One of the major reasons behind the limited success of vaccine candidates against all forms of leishmaniasis is the inability of parasitic antigens to induce robust cell-mediated immunity and immunological memory. Here we find, for the first time, that the adjuvantation of whole-killed Leishmania vaccine (Leishvacc) with anti-CD200 and anti-CD300a antibodies enhances CD4+ T cells mediated immunity in vaccinated mice and provides protection against wild-type parasites. The antibody adjuvantation, either alone or with a TLR4 agonist monophosphoryl A (MPL-A), induced the production of pro-inflammatory cytokines viz., IFN-γ, TNF-α, and IL-2 by antigen experienced CD4+ T cells, and also enhanced their rate of conversion into their memory phenotypes against Leishvacc antigens. The antibody adjuvanted vaccine also promoted the generation of IgG2a-mediated protective humoral immunity in vaccinated mice. Further, the mice vaccinated with antibodies adjuvanted vaccine showed strong resilience against metacyclic forms of L. donovani parasites as we observed reduced clinical features such as splenomegaly, hepatomegaly, granulomatous tissues in the liver, and parasitic load in their spleen. The findings of this study demonstrate that the anti-CD200 and anti-CD300a antibodies have potential to increase the protective efficacy of the whole-killed Leishmania vaccine, and opens up a new gateway to diversify the roles of immune checkpoints in vaccine development against leishmaniasis.

Development of chimeric protein as a multivalent vaccine for human Kinetoplastid infections: Chagas disease and leishmaniasis.

Leishmania spp. and Trypanosoma cruzi are parasitic kinetoplastids of great medical and epidemiological importance since they are responsible for thousands of deaths and disability-adjusted life-years annually, especially in low- and middle-income countries. Despite efforts to minimize their impact, current prevention measures have failed to fully control their spread. There are still no vaccines available. Taking into account the genetic similarity within the Class Kinetoplastida, we selected CD8+ T cell epitopes preserved among Leishmania spp. and T. cruzi to construct a multivalent and broad-spectrum chimeric polyprotein vaccine. In addition to inducing specific IgG production, immunization with the vaccine was able to significantly reduce parasite burden in the colon, liver and skin lesions from T. cruzi, L. infantum and L. mexicana challenged mice, respectively. These findings were supported by histopathological analysis, which revealed decreased inflammation in the colon, a reduced number of degenerated hepatocytes and an increased proliferation of connective tissue in the skin lesions of the corresponding T. cruzi, L. infantum and L. mexicana vaccinated and challenged mice. Collectively, our results support the protective effect of a polyprotein vaccine approach and further studies will elucidate the immune profile associated with this protection. Noteworthy, our results act as conceptual proof that a single multi-kinetoplastida vaccine can be used effectively to control different infectious etiologies, which in turn can have a profound impact on the development of a new generation of vaccines.

Recombinant endonuclease III protein from Leishmania infantum associated with Th1-type adjuvants is immunogenic and induces protection against visceral leishmaniasis.

Vaccination against visceral leishmaniasis (VL) should be considered as a safe and effective measure to disease control; however, few vaccines are available against canine VL and there is no an approved human vaccine. In this context, in the present study, we evaluated the endonuclease III (ENDO) protein, which was recently showed to be antigenic for human disease, as a vaccine candidate against Leishmania infantum infection. The recombinant protein (rENDO) was administered in BALB/c mice alone or associated with saponin (rENDO/Sap) or micelles (rENDO/Mic) as adjuvants. Controls received saline, saponin or empty micelles. Results showed that both rENDO/Sap and rENDO/Mic compositions induced higher levels of IFN-γ, IL-12, TNF-α, and GM-CSF cytokines, besides nitrite and IgG2a isotype antibodies, before and after challenge infection, which were related to both CD4+ and CD8+ T cell subtypes. The immunological results contributed to significant reductions in the parasite load found in the spleens, livers, bone marrows and draining lymph nodes of the vaccinated animals. In general, mice immunized with rENDO/Mic presented a slightly higher Th1-type cellular and humoral immune response, as compared to those receiving rENDO/Sap. In addition, saponin caused a slight to moderate inflammatory edema in their vaccinated footpads, which was not observed when micelles were used with rENDO. In addition, a preliminary analysis showed that the recombinant protein was immunogenic to human cells cultures, since PBMCs from treated VL patients and healthy subjects showed higher lymphoproliferation and IFN-γ production in the culture supernatants. In conclusion, data suggest that rENDO could be considered as a candidate to be evaluated in future studies as vaccine to protect against VL.

Directrices para el tratamiento de las leishmaniasis en la región de las américas - 2 ed / Guidelines for the treatment of leishmaniasis in the region of the Americas - 2 ed

Las leishmaniasis son enfermedades infecciosas desatendidas de gran importancia en la Región de las Américas debido a su morbilidad, mortalidad y amplia distribución geográfica. De las tres formas clínicas principales, la cutánea es la más común y la visceral es la forma más grave, ya que puede causar la muerte de hasta 90% de las personas que no reciban tratamiento. En el 2013, la Organización Panamericana de la Salud (OPS) elaboró recomendaciones para el tratamiento de las leishmaniasis en la Región de las Américas utilizando la metodología de clasificación de la valoración, la elaboración y la evaluación de las recomendaciones (GRADE, por su sigla en inglés). No obstante, dada la evidencia acumulada desde entonces, se hizo necesario revisar esas recomendaciones. En esta segunda edición se presentan las recomendaciones actualizadas sobre el tratamiento de las leishmaniasis, y se detallan los esquemas y los criterios de indicación del tratamiento en el contexto regional. Estas directrices presentan modificaciones sustanciales con respecto a la primera edición. En el caso de la leishmaniasis cutánea, se ha eliminado el ketoconazol de las opciones terapéuticas, el número de especies de Leishmania para las que hay evidencia sólida de la eficacia de la miltefosina ha aumentado de dos a cuatro y la recomendación de administrar antimoniales intralesionales ahora es fuerte. Con respecto a la leishmaniasis mucosa, se incluye una recomendación fuerte sobre el uso de antimoniales pentavalentes con o sin pentoxifilina oral. Por lo que respecta a la leishmaniasis visceral, la recomendación fuerte sobre el uso de antimoniales pentavalentes y desoxicolato de anfotericina B ahora es condicional. También hay evidencia contundente en contra del uso de miltefosina en pacientes con leishmaniasis causada por Leishmania infantum. Otros cambios importantes son el desglose de las recomendaciones según si se trata de pacientes adultos o pediátricos, la inclusión de las especies de Leishmania y, en el caso de los pacientes inmunocomprometidos, la introducción de una recomendación fuerte contra el uso de antimoniales pentavalentes. Esta segunda edición es una versión revisada de la publicación Leishmaniasis en las Américas: recomendaciones para el tratamiento: https://iris.paho.org/handle/10665.2/7704

A recombinant Leishmania amastigote-specific protein, rLiHyG, with adjuvants, protects against infection with Leishmania infantum.

Vaccination against visceral leishmaniasis (VL) should be considered as a control measure to protect against disease, and amastigote-specific proteins could help to develop such vaccines, since this parasite form is in contact with the host immune system during the active disease. In this study, a Leishmania amastigote-specific protein, LiHyG, was evaluated as recombinant protein (rLiHyG) as vaccine candidate against Leishmania infantum infection in BALB/c mice. The protein was associated with saponin (rLiHyG/Sap) or Poloxamer 407-based polymeric micelles (rLiHyG/Mic) as adjuvants, and animals receiving saline, saponin or micelle as controls. Immunological and parasitological analyses were performed before (n = 8 per group; as primary endpoint) and after (n = 8 per group; as secondary endpoint) infection. Results showed that, in both endpoints, rLiHyG/Sap and rLiHyG/Mic induced higher levels of IFN-γ, IL-12 and GM-CSF in spleen cell cultures from vaccinated animals, besides elevated presence of IgG2a isotype antibodies. Decreased hepatotoxicity and 'positive lymphoproliferative response were also found after challenge. Such findings reflected in significantly lower levels of parasite load found in their spleens, livers, bone marrows and draining lymph nodes. In conclusion, rLiHyG associated with Th1-type adjuvant could be considered for future studies as vaccine candidate to protect against VL.

The knowns and unknowns of the efficacy of neem oil (Azadirachta indica) used as a preventative measure against Leishmania sand fly vectors (Phlebotomus genus).

Since domestic dogs are the main reservoir hosts of Leishmania infantum throughout the world, they are the main focus in terms of controlling zoonotic visceral leishmaniosis. To protect dogs from leishmaniosis, chemical repellents of durable efficacy are available in the form of collars, spot-on and sprays. However, the negative effects of chemical pesticides on the environment are well established as they affect animals and plants. This phenomenon has created the need for safer and more environmentally friendly substitutes. Plant extract-based insecticides and/or repellents have therefore been increasingly used by pet owners and veterinarians. Several botanical products have been tested as insecticides and/or repellents against a variety of bloodsucking arthropods that transmit human diseases. Among the products tested against Leishmania vectors, neem oil containing azadirachtin is the most studied. This study reviews the scientific literature concerning the efficacy of neem oil (azadirachtin-based products) against phlebotomine sand fly bites. A questionnaire was also administered to assess Italian veterinarians' attitudes to the use of neem oil. The survey was anonymous and consisted of three closed-ended questions. According to the data reported in the literature, the efficacy of neem oil in reducing the risk of sand fly bites has been tested against Phlebotomus papatasi, Phlebotomus perniciosus, Phlebotomus argentipes, Phlebotomus orientalis and Phlebotomus bergeroti. The efficacy of the products tested was expressed in percentages, ranging from 74.9% to 100%. The protection time was only available for six out of eight studies, ranging from "only during the first hour" (minimum protection time) to "all night" (expected maximum protection time). As regards the attitude to recommending the use of neem oil, 208 veterinarians participated in the online survey. Of the 126 veterinarians who recommended natural products, 119 (94.44%) reported that they recommended the use of neem oil-based products. Considering the limited data on the duration of protection and the dose of the active ingredient, more studies are required on the efficacy of neem oil-based products in reducing the risk of contracting canine leishmaniosis. These studies should also refer specifically to the concentration of the active ingredient as well as the interval of administration. Until such results are available, the use of azadirachtin-based products as the only topical products for the prevention of leishmaniosis in dogs is not recommended.

Estrategias digitales de educación en salud sobre leishmaniasis / Digital strategies for health education on leishmaniasis

La leishmaniasis es una enfermedad desatendida y endémica en localidades remotas de Perú, y existe evidencia de un alto índice de inexperiencia por parte del personal de salud que labora en zonas endémicas; asociada al diagnóstico, tratamiento y desconocimiento de protocolos nacionales e internacionales respecto a la enfermedad; lo que se traduce en un incremento de eventos adversos o una cura incompleta para los pacientes. Por otro lado, la pandemia por COVID-19, ha originado interrupción en los sistemas educativos, estimulando la aplicación de enfoques educativos a distancia. Se elaboró un programa académico de educación superior bajo la modalidad virtual, dirigido a profesionales sanitarios que laboran en áreas de riesgo o endémicas de leishmania, en el marco del eLearning, empleando tecnologías de información y comunicación (TIC) como herramientas para el aprendizaje; y se aplicó la metodología MEDESME en la planificación de herramientas digitales educativas. El producto incluyó la ficha académica del programa "leishmaniasis tegumentaria y visceral", diversos recursos de autoaprendizaje y estrategias de evaluación digitales. La aplicación del programa educativo permitiría capacitar y actualizar conocimientos a los profesionales de la salud y, en consecuencia, optimizar el diagnóstico, tratamiento y seguimiento de los pacientes afectados por las distintas manifestaciones de la leishmaniasis(AU)

Leishmaniasis is a neglected and endemic disease in remote locations in Peru, and there is evidence of a high rate of inexperience on the part of health personnel working in endemic areas; associated with the diagnosis, treatment and ignorance of national and international protocols regarding the disease; which translates into an increase in adverse events or an incomplete cure for patients. On the other hand, the COVID-19 pandemic has caused disruption in educational systems, stimulating the application of distance educational approaches. An academic program of higher education was developed under the virtual modality, aimed at health professionals who work in risky or endemic areas of leishmania, within the framework of eLearning, using information and communication technologies (ICT) as tools for learning; and the MEDESME methodology was applied in the planning of educational digital tools. The product included the academic record of the program "integumentary and visceral leishmaniasis", various self-study resources and digital assessment strategies. The application of the educational program would allow health professionals to be trained and updated and, consequently, to optimize the diagnosis, treatment and follow-up of patients affected by the different manifestations of leishmaniasis(AU)

Potential biomarkers of immune protection in human leishmaniasis.

Leishmaniasis is a vector-borne neglected tropical disease endemic in over 100 countries around the world. Available control measures are not always successful, therapeutic options are limited, and there is no vaccine available against human leishmaniasis, although several candidate antigens have been evaluated over the last decades. Plenty of studies have aimed to evaluate the immune response development and a diverse range of host immune factors have been described to be associated with protection or disease progression in leishmaniasis; however, to date, no comprehensive biomarker(s) have been identified as surrogate marker of protection or exacerbation, and lack of enough information remains a barrier for vaccine development. Most of the current understanding of the role of different markers of immune response in leishmaniasis has been collected from experimental animal models. Although the data generated from the animal models are crucial, it might not always be extrapolated to humans. Here, we briefly review the events during Leishmania invasion of host cells and the immune responses induced against Leishmania in animal models and humans and their potential role as a biomarker of protection against human leishmaniasis.

Immunotherapy in treatment of leishmaniasis.

Leishmaniasis caused by various species of protozoan transmitted by sand fly vectors occurs as a spectrum of clinical features including cutaneous, mucocutaneous and visceral forms. It is a geographically distributed parasitic disease and a major public health problem in the world. The clinical syndromes are highly variable depending on the parasite species, host genetics, vectors and environment. To date, there is no effective vaccine and traditional treatments are toxic, expensive with long administration duration and many adverse side effects and/or drug resistance. Instead of treatments based on chemotherapy, certain strategies aim to recover leishmaniasis and reduce the parasitic burden. Immunotherapy has focused on the induction of effective immune response to rapidly control the disease. Recent studies have indicated that a single dose of a suitable therapeutic vaccine induces a quick and lasting recovery in patients. Immunotherapy reduces the toxicity of drug and the emergence of resistance dramatically. It could be an effective addition to chemotherapy with a safe and potent drug compared with monotherapy, resulting in a prophylactic and therapeutic cure of leishmaniasis. This review has focused on treatment of leishmaniasis with particular emphasis on immunotherapy as an alternative to conventional drug treatment.

The host mTOR pathway and parasitic diseases pathogenesis.

The mechanistic (or mammalian) target of rapamycin (mTOR) is considered as a critical regulatory enzyme involved in essential signaling pathways affecting cell growth, cell proliferation, protein translation, regulation of cellular metabolism, and cytoskeletal structure. Also, mTOR signaling has crucial roles in cell homeostasis via processes such as autophagy. Autophagy prevents many pathogen infections and is involved on immunosurveillance and pathogenesis. Immune responses and autophagy are therefore key host responses and both are linked by complex mTOR regulatory mechanisms. In recent years, the mTOR pathway has been highlighted in different diseases such as diabetes, cancer, and infectious and parasitic diseases including leishmaniasis, toxoplasmosis, and malaria. The current review underlines the implications of mTOR signals and intricate networks on pathogen infections and the modulation of this master regulator by parasites. Parasitic infections are able to induce dynamic metabolic reprogramming leading to mTOR alterations in spite of many other ways impacting this regulatory network. Accordingly, the identification of parasite effects and interactions over such a complex modulation might reveal novel information regarding the biology of the abovementioned parasites and might allow the development of therapeutic strategies against parasitic diseases. In this sense, the effects of inhibiting the mTOR pathways are also considered in this context in the light of their potential for the prevention and treatment of parasitic diseases.

Immunotherapeutic Potential of Interleukin-32 and Trained Immunity for Leishmaniasis Treatment.

Neglected tropical diseases annually account for several million infections worldwide. Efficacious treatment for these poorly understood infectious diseases is often limited to ineffective, expensive, and toxic therapies such as the SbV used for leishmaniasis patients. Here, we review the latest discoveries and literature on the molecular pathways, cell types, and immune mediators involved in the immune response to infection with New World Leishmania spp. in humans and their interaction with the adaptive and innate immune system. Novel developments in the field of trained innate immunity and the recently described role of IL-32 are emphasized as potential immunotherapeutic treatments for the management of leishmaniasis.

Immunogenicity of HLA-DR1 and HLA-A2 peptides derived from Leishmania major Gp63 in golden hamsters.

AIMS: This study aimed to evaluate the toxicity and humoral and cellular immune response of three heterologous vaccines against Leishmania infantum, yet containing synthetic peptides from Leishmania major in the experimental model in hamsters. METHODS AND RESULTS: Through bioinformatics analyses, two Leishmania major Gp63 peptides were predicted and selected for vaccine formulations. Hamsters were divided into four groups, with each group receiving doses of three vaccine formulations containing HLA-DR1 or HLA-A2 peptides plus MontanideTM or both associated with the adjuvant. The animals received three vaccine doses and were evaluated for toxicity after each dose, in addition to being analysed for the production of antibodies and lymphoproliferation on day 211 after the last vaccine dose. Peptides predicted in association with oily adjuvant induced a humoral response and strong lymphoproliferation to Leishmania infantum antigen-specific stimulation.

Lipophosphoglycan-3 recombinant protein vaccine controls hepatic parasitism and prevents tissue damage in mice infected by Leishmania infantum chagasi.

AIMS: In this work, we aimed to evaluate the effects of the Leishmania infantum chagasi infection on the liver of vaccinated mice, considering parameters of tissue damage and the inflammatory response elicited by vaccination. MAIN METHODS: We used recombinant LPG3 protein (rLPG3) as immunogen in BALB/c mice before challenge with promastigote forms of L. infantum chagasi. The animals were separated into five groups: NI: non-infected animals; NV: non-vaccinated; SAP: treated with saponin; rLPG3: immunized with rLPG3; rLPG3 + SAP: immunized with rLPG3 plus SAP. The experiment was conducted in replicate, and the vaccination protocol consisted of three subcutaneous doses of rLPG3 (40 µg + two boosters of 20 µg). The mice were challenged two weeks after the last immunization. KEY FINDINGS: Our results showed that rLPG3 + SAP immunization decreased the parasite burden in 99 %, conferring immunological protection in the liver of the infected animals. Moreover, the immunization improved the antioxidant defenses, increasing CAT and GST activity, while reducing the levels of oxidative stress markers, such as H2O2 and NO3/NO2, and carbonyl protein in the organ. As a consequence, rLPG3 + SAP immunization preserved tissue integrity and reduced the granuloma formation, inflammatory infiltrate and serum levels of AST, ALT, and ALP. SIGNIFICANCE: Taken together, these results showed that rLPG3 vaccine confers liver protection against L. infantum chagasi in mice, while maintaining the liver tissue protected against the harmful inflammatory effects caused by the vaccine followed by the infection.

Environmental risk factors of leishmaniasis in Bahia State, Brazil using NASA Earth observation satellites / Fatores de risco ambientais para leishmanioses no estado da Bahia, Brasil, utilizando satélites da NASA de observação da Terra

NASA’s Earth Observing Satellites (EOS) were used to calculate three vegetation indices, extract precipitation and elevation data, and then evaluate their applicability for assessing risk of visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL) in Bahia State, Brazil. Regression models showed that either form of leishmaniasis can be predicted by NDVI, NDMI, NDWI data products and TRMM) precipitation data (R2 = 0.370; p<0.001). Elevation was not significantly associated with the distribution of either VL or CL. In areas of high annual precipitation, CL was 3.6 times more likely to occur than VL. For vegetative moisture (NDMI), CL was 2.11 times more likely to occur than VL. Odds of CL occurrence increased to 5.5 times when vegetation (NDVI) and 13.5 times when liquid water content of vegetation canopies (NDWI) was considered. Areas at risk of CL and VL were mapped based on the selected explanatory variables. Accuracy of models were assessed using area under the receiver operating characteristic curve (AUC=0.72). We propose that statewide scale risk models based on use of EOS products will be a useful tool at 1 km2 spatial resolution to enable health workers to identify and target high risk areas to prevent transmission of leishmaniasis.

Os satélites de observação da Terra (SOT) da NASA foram usados para calcular três índices de vegetação, extrair dados de precipitação e elevação e avaliar sua aplicabilidade para identificar o risco para leishmaniose visceral (LV) e leishmaniose tegumentar (LT) no Estado da Bahia, Brasil. Modelos de regressão mostraram que ambas as formas de leishmaniose podem ser preditas pelos NDVI, NDMI, NDWI e precipitação TRMM (R2 = 0,370; p<0,001). A elevação não foi significativamente associada à distribuição de LV ou LT. Em áreas de alta precipitação anual, a LT foi 3,6 vezes mais provável de ocorrer do que a LV. Para a umidade vegetativa (NDMI), a LT apresentou 2,11 maior probabilidade de ocorrer do que a LV. As chances de ocorrência de LT aumentaram para 5,5 vezes em relação com a vegetação (NDVI) e 13,5 vezes quando o conteúdo de água líquida dos dosséis da vegetação (NDWI) foi considerado. Áreas em risco de LT e LV foram mapeadas com base nas variáveis explicativas selecionadas. A precisão dos modelos foi avaliada usando a área sob curva característica de operação do receptor (Curva COR=0,72). Propusemos que os modelos de risco em escala estadual baseados no uso de produtos SOT são uma ferramenta útil na resolução espacial de 1 km2 por permitir que profissionais de saúde identifiquem e direcionem áreas de alto risco para evitar a transmissão da leishmaniose.

Contribuciones de la epidemiología al control de la leishmaniosis / Contributions of epidemiology to the control of leishmaniasis

RESUMEN La leishmaniosis continúa siendo un importante problema de salud pública pese a los esfuerzos gubernamentales, de grupos e individuos. Se estima que a nivel mundial se producen entre 50 000 y 90 000 casos nuevos de leishmaniosis visceral y entre 0.5 y 1 millón de leishmaniosis tegumentaria. Además, en algunas regiones esta parasitosis tiene carácter endemoepidémico, y en los últimos años ha incrementado su frecuencia y distribución. El objeto del presente escrito es mostrar algunas contribuciones de la epidemiología al control de la leishmaniosis, como resultado de la descripción y del análisis de la distribución y de los determinantes de esta parasitosis, extremadamente compleja en cuanto a transmisor, agente etiológico, reservorio y susceptible. Con base en la revisión de la literatura científica en el contexto de un estudio descriptivo, documental y retrospectivo se alcanzó el objetivo del presente escrito. Se concluye que es clara la utilidad de la epidemiología en el control de la leishmaniosis o, en todo caso, se reafirma el carácter válido y práctico de la epidemiología en el quehacer programático y operativo de la intervención en salud en el caso de la leishmaniosis.(AU)

ABSTRACT Leishmaniasis despite government efforts, groups and individuals continues to be a major public health problem, it is estimated that globally occur between 50 000 and 90 000 new cases of visceral leishmaniasis and between 0.5 and 1 million tegumentary leishmaniasis, plus in some regions, this parasitism has an endemo-epidemic nature, and in recent years its frequency and distribution have increased. The purpose of this paper is to show some contributions of epidemiology to the control of leishmaniasis, as a result of the description and analysis of the distribution and determinants of this parasitism, extremely complex in terms of transmitter, etiological agent, reservoir and susceptible. Based on the review of the scientific literature in the context of a descriptive, documentary and retrospective study, the objective of this paper was achieved. It is concluded that the usefulness of epidemiology in the control of leishmaniasis is clear or in any case reaffirms the validity and practicality of epidemiology in the programmatic and operational task of health intervention in the case of leishmaniasis.(AU)

A Laboratory Strain of Leishmania major: Protective Effects on Experimental Leishmaniasis.

PURPOSE: Leishmaniasis, as one of the most important vector-borne and zoonotic diseases, can be seen in different forms and is more prevalent in developing countries worldwide. Due to the absence of effective strategies in its prevention, treatment, and control, investigation of effective control strategies against the disease is necessary. In this research, we evaluated the immunogenicity of a cold-adapted laboratory strain of Leishmania major (LMC) in the mouse model. METHODS: Twenty BALB/c mice were divided into two groups. LMC group received 4 × 106 of LMC strain in 0.5 ml DMEM, and VLM group, as the control group, received 0.5 ml Dulbecco's modified Eagle's medium. Both groups were challenged with virulent L. major 3 weeks after inoculation. RESULTS: The data obtained from the analysis of immune responses and histopathological changes interestingly revealed protection against L. major in immunized mice. Compared with the VLM group, the mice immunized with LMC strain of L. major in the LMC group showed a significant increase in IFN-γ and IgG2a levels (P < 0.05) which are important indexes for Th1-related immune responses. Additionally, significant differences in concentration of IgG1 and IgG total before and after the challenge was observed in LMC group (P < 0.05). Furthermore, the immunized mice showed a significant reduction in mean sizes of skin lesion and liver damage compared to the VLM group. CONCLUSION: Based on the present findings on immunogenicity of LMC strain, it seems this strain is able to induce both humoral and cellular immunity and a significant protection against L. major in the mouse model.

Protocolo del Sistema Nacional de Vigilancia Epidemiológica: enfermedades vectoriales de origen parasitario. No. 04 / Protocol of the National Epidemiological Surveillance System: vector diseases of parasitic origin. No. 04

Estos protocolos están dirigido a personal médico, paramédico y otros profesionales que realizan acciones gerenciales y operativas de vigilancia epidemiológica en los servicios de salud del país, y están divididos en varios tomos para dar a conocer y actualizar la identificación y medidas de control para diversos padecimientos a fin de continuar con el mejoramiento de las capacidades técnicas de los trabajadores de salud, que permita planificar la prestación de servicios con decisiones partiendo de un enfoque epidemiológico comprobado, para responder a los cambios de tendencias epidemiológicas y con ello contribuir al fortalecimiento de prácticas asertivas de la salud pública de nuestro país.

Comparative Evolution of Sand Fly Salivary Protein Families and Implications for Biomarkers of Vector Exposure and Salivary Vaccine Candidates.

Sand fly salivary proteins that produce a specific antibody response in humans and animal reservoirs have been shown to be promising biomarkers of sand fly exposure. Furthermore, immunity to sand fly salivary proteins were shown to protect rodents and non-human primates against Leishmania infection. We are missing critical information regarding the divergence amongst sand fly salivary proteins from different sand fly vectors, a knowledge that will support the search of broad or specific salivary biomarkers of vector exposure and those for vaccines components against leishmaniasis. Here, we compare the molecular evolution of the salivary protein families in New World and Old World sand flies from 14 different sand fly vectors. We found that the protein families unique to OW sand flies are more conserved than those unique to NW sand flies regarding both sequence polymorphisms and copy number variation. In addition, the protein families unique to OW sand flies do not display as many conserved cysteine residues as the one unique to the NW group (28.5% in OW vs. 62.5% in NW). Moreover, the expression of specific protein families is restricted to the salivary glands of unique sand fly taxon. For instance, the ParSP15 family is unique to the Larroussius subgenus whereas phospholipase A2 is only expressed in member of Larroussius and Adlerius subgenera. The SP2.5-like family is only expressed in members of the Phlebotomus and Paraphlebotomus subgenera. The sequences shared between OW and NW sand flies have diverged at similar rates (38.7 and 45.3% amino acid divergence, respectively), yet differences in gene copy number were evident across protein families and sand fly species. Overall, this comparative analysis sheds light on the different modes of sand fly salivary protein family divergence. Also, it informs which protein families are unique and conserved within taxon for the choice of taxon-specific biomarkers of vector exposure, as well as those families more conserved across taxa to be used as pan-specific vaccines for leishmaniasis.