Cluster randomised trial to evaluate the effectiveness of a vaccine against cutaneous leishmaniasis in the Caratinga microregion, south-east Brazil.
ABSTRACT BACKGROUND: The eco-epidemiological complexity of American cutaneous leishmaniasis (ACL) has made it difficult to devise an efficient strategy for management of the disease, and development of an effective vaccine remains the most promising approach. The objective of the study was to determine the reduction in incidence of ACL following intramuscular administration of two doses of a killed Leishmania (Leishmania) amazonensis vaccine. METHODS: A cluster randomised trial was conducted from 2002 to 2011 in 108 localities in an endemic area of southeast Brazil. Communities were stratified according to population size, and randomly allocated to receive vaccine (n = 50) or placebo (n = 58). The post-vaccination ACL incidence rates in the two groups were compared through covariance analysis. RESULTS: A cyclic fluctuation in the number of cases recorded during the 18-year pre-vaccination period was similar in both groups. Following the vaccination campaign, a significant reduction in the number of cases of ACL was observed in the vaccine group compared with the placebo group. This group also included the individuals who refused to participate in the trial. CONCLUSION: This study demonstrated that the vaccine has been able to confer protection against ACL up to the present time. It is necessary to continue epidemiological surveillance to determine the duration of the vaccine's effectiveness.
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ABSTRACT: Leishmaniasis is a major protozoal disease threatening the lives of 350 million people throughout the world. However, the therapeutic options for the disease are limited. In the present study, the antiprotozoal activity of the latex obtained from the Ethiopian plant Aloe calidophila Reynolds was evaluated by in vitro testing against Leishmania aethiopica and Leishmania major. It was found that the latex possesses moderate activity against both parasites with IC50 values of 64.05 and 82.29 µg/mL, respectively. Phytochemical investigation resulted in the isolation of three anthrones identified as aloinoside, aloin, and microdontin on the basis of IR, MS, 1H NMR, and 13C NMR spectral data. The isolated compounds showed strong antileishmanial activity with IC50 values ranging from 1.76 to 6.32 µg/mL against L. aethiopica and from 2.09 to 8.85 µg/mL against L. major. Although these values were higher than those of amphotericin B (IC50 = 0.109 and 0.067 µg/mL), the selectivity indices (813.35 and 694.90, respectively, against L. aethiopica and L. major) of aloinoside were much better than those of the standard drug (423.49 and 688.96). The results indicate that the isolated compounds have the potential to be used as a scaffold for the development of safe and cost-effective antileishmanial agents. Copyright © 2014 John Wiley & Sons, Ltd.Phytotherapy Research 07/2014; 28(12). DOI:10.1002/ptr.5204 · 2.40 Impact Factor
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ABSTRACT: Background/Purpose A proper adjuvant has a relevant role in vaccine formulations to generate an effective immune response. In this study, total Leishmania antigen (TLA) formulated with Montanide ISA 763 or R848 as adjuvants were evaluated as a first generation Leishmania vaccine in a murine model. Methods Immunization protocols were tested in BALB/c mice with a subcutaneous prime/boost regimen with an interval of 3 weeks. Mice immunized with unadjuvanted TLA and phosphate-buffered saline (PBS) served as control groups. On Day 21 and Day 36 of the protocol, we evaluated the humoral immune response induced by each formulation. Fifteen days after the boost, the immunized mice were challenged with 1 × 105 promastigotes of Leishmania (Leishmania) amazonensis in the right footpad (RFP). The progress of the infection was followed for 10 weeks; at the end of this period, histopathological studies were performed in the RFP. Results Vaccines formulated with Montanide ISA 763 generated an increase in the production of immunoglobulin G (IgG; p < 0.05) compared with the control group. There were no statistically significant differences in IgG1 production between the study groups. However, immunization with TLA-Montanide ISA 763 resulted in an increase in IgG2a compared to the unadjuvanted control (p < 0.001). Also noteworthy was the fact that a significant reduction in swelling and histopathological damage of the RFP was recorded with the Montanide ISA 763 formulation. Conclusion We conclude that the immunization of BALB/c mice with a vaccine formulated with TLA and Montanide ISA 763 generated a protective immune response against L. (L.) amazonensis, characterized by an intense production of IgG2a.Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi 03/2014; DOI:10.1016/j.jmii.2014.01.006 · 1.63 Impact Factor
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ABSTRACT: Leishmaniasis is an infectious disease caused by Leishmania species. Leishmania amazonensis is a New World Leishmania species belonging to the Mexicana complex, which is able to cause all types of leishmaniasis infections. The L. amazonensis reference strain MHOM/BR/1973/M2269 was sequenced identifying 8,802 codifying sequences (CDS), most of them of hypothetical function. Comparative analysis using six Leishmania species showed a core set of 7,016 orthologs. L. amazonensis and Leishmania mexicana share the largest number of distinct orthologs, while Leishmania braziliensis presented the largest number of inparalogs. Additionally, phylogenomic analysis confirmed the taxonomic position for L. amazonensis within the “Mexicana com-plex”, reinforcing understanding of the split of New and Old World Leishmania. Potential non-homologous isofunctional enzymes (NISE) were identified between L. amazonensis and Homo sapiens that could provide new drug targets for development.Evolutionary bioinformatics online 02/2014; 8:131. DOI:10.4137/EBo.s13759 · 1.17 Impact Factor