Prediction score for antimony treatment failure in patients with ulcerative leishmaniasis lesions

Background

Increased rates for failure in leishmaniasis antimony treatment have been recently recognized worldwide. Although several risk factors have been identified there is no clinical score to predict antimony therapy failure of cutaneous leishmaniasis.

Methods

A case control study was conducted in Peru from 2001 to 2004. 171 patients were treated with pentavalent antimony and followed up to at least 6 months to determine cure or failure. Only patients with ulcerative cutaneous leishmaniasis (N = 87) were considered for data analysis. Epidemiological, demographical, clinical and laboratory data were analyzed to identify risk factors for treatment failure. Two prognostic scores for antimonial treatment failure were tested for sensitivity and specificity to predict antimony therapy failure by comparison with treatment outcome.

Results

Among 87 antimony-treated patients, 18 (21%) failed the treatment and 69 (79%) were cured. A novel risk factor for treatment failure was identified: presence of concomitant distant lesions. Patients presenting concomitant-distant lesions showed a 30.5-fold increase in the risk of treatment failure compared to other patients. The best prognostic score for antimonial treatment failure showed a sensitivity of 77.78% and specificity of 95.52% to predict antimony therapy failure.

Conclusions

A prognostic score including a novel risk factor was able to predict antimonial treatment failure in cutaneous leishmaniasis with high specificity and sensitivity. This prognostic score presents practical advantages as it relies on clinical and epidemiological characteristics, easily obtained by physicians or health workers, and makes it a promising clinical tool that needs to be validated before their use for developing countries.     

Epidemiology of leishmaniasis in Ecuador: current status of knowledge -- a review

Although leishmaniasis is regarded as a significant health problem in Ecuador by the Ministry of Health, and the incidence has increased over the last years, an official map on the geographic distribution of disease and sand fly vectors or a control strategy do not exist yet. This article reviews the current situation based on published information to improve our knowledge and understand the epidemiological situation of leishmaniasis in Ecuador in order to help future research and to develop a national control strategy. The disease is endemic in most provinces throughout Pacific coastal region, Amazonian lowlands, and some inter-Andean valleys with a total 21,805 cases reported during 1990-2003. Whereas cutaneous leishmaniasis (CL) is found throughout Ecuador, mucocutaneous leishmaniasis (MCL) appears to be restricted to the Amazon region; one, parasitologically unconfirmed case of visceral form was reported in 1949. Most human infections are caused by Leishmania (Viannia) spp., which is distributed in the subtropical and tropical lowlands; infections due to L. (Leishmania) spp. are found in the Andean highlands and in the Pacific lowlands as well. The proven vectors are Lutzomyia trapidoi and Lu. ayacuchensis. Canis familiaris, Sciurus vulgaris, Potos flavus, and Tamandua tetradactyla have been found infected with Leishmania spp. It is estimated that around 3000-4500 people may be infected every year, and that 3.1 to 4.5 millions people are estimated to be at risk of contracting leishmaniasis.     

Indirect immunofluorescence test in New World leishmaniasis: serological and clinical relationship

The indirect immunofluorescence test (IF) for anti-Leishmania antibodies (IgG and IgM) was performed with sera from the following groups of individuals: 214 cutaneous leishmaniasis patients, 28 healthy subjects with positive Montenegro's skin test (MST), 29 healthy subjects with negative MST and 16 visceral leishmaniasis patients. The first four groups came from a suburban area of Rio de Janeiro (Jacarepaguá) where cutaneous leishmaniasis caused by Leishmania braziliensis braziliensis is endemic. It was observed that IF-IgM titers were significantly higher amongst the cutaneous leishmaniasis patients with less than four months of disease as compared to those with longer periods and that IF-IgG titers were significantly higher in patients with multiple lesions as compared to those with single lesions. The visceral leishmaniasis patients had IF-IgG titers significantly higher than those from cutaneous leishmaniasis patients. A group of 28 individuals selected amongst the 214 cutaneous leishmaniasis patients had their IF-titers (IgG and IgM) compared to those of the two control groups of healthy subjects from the endemic area, respectively with positive and negative MST. Significantly higher titers of IF-IgG and IF-IgM were found in the group with active disease. The same group of patients showed IF-IgG titers significantly lower at the end of the antimonial therapy than those observed during this treatment.     

Cloning,expression, purification and spectrophotometric analysis of lanosterol 14-alpha demethylase from <Emphasis Type="Italic">Leishmania braziliensis</Emphasis> (<Emphasis Type="Italic">Lb</Emphasis>CYP51)

Leishmaniasis, a neglected tropical disease, is a major cause of morbidity and mortality worldwide. Of the three main clinical forms, cutaneous leishmaniasis (CL) is the most common and 40 million people are at risk in the endemic areas. Currently, the available drugs to fight leishmaniasis have high toxicity and poor efficiency. Then, it is very important to search for effective and safe drugs that would target essential enzymes from the parasite, such as lanosterol 14-alpha demethylase (CYP51, EC 1.14.13.70) from Leishmania braziliensis. Because most drug design efforts have been directed for Leishmania non-braziliensis species, there is no structural or kinetic data regarding L. braziliensis CYP51. Herein, we present for the first time molecular biology efforts and purification protocol to obtain the enzyme LbCYP51. These results lay the ground for future investigation of drugs against this target.     

Clinical and immunopathological spectrum of American cutaneous leishmaniasis with special reference to the disease in Amazonian Brazil: a review

The wide variety of Leishmania species responsible for human American cutaneous leishmaniasis combined with the immune mechanisms of the host results in a large spectrum of clinical, histopathological, and immunopathological manifestations. At the middle of this spectrum are the most frequent cases of localized cutaneous leishmaniasis (LCL) caused by members of the subgenera Leishmania and Viannia, which respond well to conventional therapy. The two pathogenicity extremes of the spectrum generally recognized are represented at the hypersensitivity pole by mucocutaneous leishmaniasis (MCL) and at the hyposensitivity pole by anergic diffuse cutaneous leishmaniasis (ADCL). Following the present study on the clinical, histopathological and immunopathological features of cutaneous leishmaniasis in Amazonian Brazil, we propose the use of the term "borderline disseminated cutaneous leishmaniasis" for the disseminated form of the disease, due to parasites of the subgenera Leishmania and Viannia, which might be regarded as intermediate between LCL and the extreme pathogenicity poles MCL and ADCL.     

Serum neopterin concentrations during treatment of leishmaniasis: useful as test of cure?

Neopterin, a product of gamma-interferon-activated macrophages, was measured in sera from 28 patients (12 patients with cutaneous leishmaniasis and 16 patients with visceral leishmaniasis) to determine the utility as a marker of disease activity and therapeutic efficacy. Patients originated from Kenya (n=5) and from the Academic Medical Center, Amsterdam, The Netherlands (n=23). In seven patients follow-up sera after treatment were available. Two patients at the time of diagnosis of visceral leishmaniasis were co-infected with HIV. The 12 patients with cutaneous leishmaniasis had serum neopterin levels below the upper limit of the normal range. All 16 patients with visceral leishmaniasis had elevated levels of serum neopterin before treatment. In six out of seven patients with visceral leishmaniasis followed during treatment neopterin levels decreased to values below the upper limit of the normal range (10 nmol l(-1)). Sequential measurements of serum neopterin levels may be useful for monitoring therapeutic efficacy in patients with visceral leishmaniasis.     

Mechanisms of acquired immunity in leishmaniasis

Self-curing cutaneous leishmaniasis depends on T cell-mediated immune activation of infected macrophages. Failure of immune control in inbred mouse models of metastasizing mucocutaneous and visceralizing forms of the disease involves, respectively, insusceptibility of the parasite and the generation of T cells that suppress a potentially curative response. Prophylactic immunization in man has so far been restricted to cutaneous leishmaniasis and based on inducing infection under controlled conditions with virulent Leishmania tropica major promastigotes. The feasibility of immunization against visceral leishmaniasis merits reconsideration. BALB/c mice are genetically vulnerable to L. tropica major, which produces a fatal visceralizing type of disease involving specific suppression of cell-mediated immunity. Potent and lasting protection can be induced by repeated intravenous immunization with irradiated promastigotes. The efficacy of this 'vaccine' is relatively heat-stable (1 h at 56 degrees C). Immunity is not attributable to antibody but to the generation of Lyt-1+2- T cells which, although possessing helper and macrophage-activating functions, do not express classical delayed-type hypersensitivity. The immunological features of this system and its relevance to the possibility of protection against human Leishmania donovani infection are considered.     

Asymmetric dimethylarginine and long-term adverse cardiovascular events in patients with type 2 diabetes: relation with the glycemic control

Patients with type 2 diabetes are at a high risk for acute cardiovascular events, which usually arise from the rupture of a vulnerable coronary lesion characterized by specific morphological plaque features. Thus, the identification of vulnerable plaques is of utmost clinical importance in patients with type 2 diabetes. However, there is currently no scoring system available to identify vulnerable lesions based on plaque characteristics. Thus, we aimed to characterize the diagnostic value of optical coherence tomography (OCT) - derived lesion characteristics to quantify plaque vulnerability both as individual parameters and when combined to a score in patients with type 2 diabetes. OCT was performed in the coronary culprit lesions of 112 patients with type 2 diabetes. The score, which quantifies plaque vulnerability, was defined as the predicted probability that a lesion is the cause for an acute coronary syndrome (ACS) (vs. stable angina (SAP)) based on its specific plaque morphology. Multivariable logistic regression analysis demonstrated that plaque vulnerability was independently predicted by the minimal fibrous cap thickness overlying a lesion’s lipid core (odds ratio (OR) per 10 μm 0.478, p = 0.002), the medium lipid arc (OR per 90° 13.997, p < 0.001), the presence of macrophages (OR 4.797, p = 0.015) and the lipid plaque length (OR 1.290, p = 0.098). Receiver-operating-characteristics (ROC) analyses demonstrated that these parameters combined to a score demonstrate an excellent diagnostic efficiency to identify culprit lesions of patients with ACS (vs. SAP, AUC 0.90, 95% CI 0.84-0.96). This is the first study to present a score to quantify lesion vulnerability in patients with type 2 diabetes. This score may be a valuable adjunct in decision-making and useful in guiding coronary interventions.     

Assessing the vulnerability of an assemblage of subtropical rainforest vertebrate species to climate change in south‐east Queensland

Global climate change is a threat to ecosystems that are rich in biodiversity and endemism, such as the World Heritage‐listed subtropical rainforests of central eastern Australia. Possible effects of climate change on the biota of tropical rainforests have been studied, but subtropical rainforests have received less attention. We analysed published data for an assemblage of 38 subtropical rainforest vertebrate species in four taxonomic groups to evaluate their relative vulnerability to climate change. Focusing on endemic and/or threatened species, we considered two aspects of vulnerability: (i) resistance, defined by indicators of rarity (geographical range, habitat specificity and local abundance); and (ii) resilience, defined by indicators of a species potential to recover (reproductive output, dispersal potential and climatic niche). Our analysis indicated that frogs are most vulnerable to climate change, followed by reptiles, birds, then mammals. Many species in our assemblage are regionally endemic montane rainforest specialists with high vulnerability. Monitoring of taxa in regenerating rainforest showed that many species with high resilience traits also persisted in disturbed habitat, suggesting that they have capacity to recolonize habitats after disturbance, that is climate change‐induced events. These results will allow us to prioritize adaptation strategies for species most at risk. We conclude that to safeguard the most vulnerable amphibian, reptile and bird species against climate change, climatically stable habitats (cool refugia) that are currently without protection status need to be identified, restored and incorporated in the current reserve system. Our study provides evidence that montane subtropical rainforest deserves highest protection status as habitat for vulnerable taxa.     

Spatial relations among environmental factors and phlebotomine sand fly populations (Diptera: Psychodidae) in central and southern Morocco

Phlebotomine sand flies (Diptera: Psychodidae, Phlebotominae) are of considerable public health importance because of their ability to transmit several human parasites, mainly as vectors of Leishmania spp. Over the past decade, the epidemiological situation of cutaneous leishmaniasis (CL) has significantly increased with its geographic expansion to previously free areas and the emergence of overlapping foci of cutaneous leishmaniasis and visceral leishmaniasis (VL) in several provinces of Morocco. A total of 15,313 specimens was collected during this entomological survey. The genera Phlebotomus (57.38%) and Sergentomyia (42.62%) were identified. Sergentomyia minuta (22.01%) was the most prevalent species, followed by S. fallax (18.21%), Phlebotomus perniciosus (14.35%), P. papatasi (14.06%), P. sergenti (12.85%), P. longicuspis (10.74%), P. ariasi (2.68%), S. dreyfussi (1.53%), P. alexandri (1.31%), P. bergeroti (1.14%), S. christophersi (0.62%), S. africana (0.25%), P. chabaudi (0.14%), P. chadlii (0.05%), and P. kazeruni (0.04%). We aimed to determine current distribution of leishmaniases vectors, their ecological characteristics, and the significance of the predominant species at any bioclimate stage, altitude range, and soil texture in terms of the risk of leishmaniasis transmission.     

Leishmania mexicana mexicana: genetic heterogeneity of mexican isolates revealed by restriction length polymorphism analysis of kinetoplast DNA

Leishmania mexicana mexicana isolates from 23 patients with localized, diffuse, and an atypical "pseudodiffuse" form of cutaneous leishmaniasis were obtained in various endemic regions of Mexico. Restriction fragment length polymorphism analysis of kinetoplast DNA was done with nine different endonucleases in addition to an in vitro growth pattern analysis. We found that the 23 L. mexicana mexicana isolates could be consistently classified into six groups, according to the endonuclease digestion patterns obtained with HaeIII, HpaII, and MseI. Whereas localized cutaneous leishmaniasis isolates could have any of five patterns, diffuse cutaneous leishmaniasis showed only two patterns and pseudodiffuse cutaneous leishmaniasis consistently showed only one pattern. Thus, a clear correlation among digestion pattern, clinical disease, and geographical localization was obtained for the pseudodiffuse cutaneous leishmaniasis group. Additionally, the L. mexicana mexicana isolates could be differentiated into fast- and slow-growing groups. Diffuse cutaneous leishmaniasis isolates were found to be fast growing, whereas localized cutaneous leishmaniasis isolates fell into both categories. In contrast, all pseudo diffuse cutaneous leishmaniasis isolates were slow growing. Here we report the first study in which distinct and persistent genotypic characteristics of kinetoplast DNA heterogeneity within the L. mexicana mexicana species could be directly correlated with clinical disease and its growth behavior, suggesting that a distinctive restriction pattern could have important biological implications. Additionally, this study sheds new light on the biological significance of parasite kinetoplast DNA, since the heterogeneity seems not to be random but to form a distinct pattern.     

Humoral immune responses among mucosal and cutaneous leishmaniasis patients caused by Leishmania braziliensis

Mucosal leishmaniasis is arguably the most morbid sequelae of cutaneous leishmaniasis. The importance of early diagnosis for effective therapy, coupled with the difficulty of diagnosing the disease parasitologically, prompted this investigation of humoral immune markers of mucosal disease. Promastigote soluble antigens of Leishmania braziliensis, isolated from cutaneous and mucosal lesions, were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis; antigens were identified by immunoblotting with parasite-specific IgG antibody-positive sera of patients with mucosal disease (n = 18) and cutaneous disease (n = 23). For antigens of the cutaneous parasite WR 2095, mucosal sera generally reacted intensely to antigens of 75, 66, and 45 kDa and weakly to 48-50-kDa antigens, whereas cutaneous sera generally detected weakly the first 3 antigens and intensely the latter doublet. The data suggest that the transition from the cutaneous antigenic profile to a mucosal antigenic profile could be used to predict mucosal disease in approximately half of mucosal patients. An additional finding was that antibodies present in the sera of patients with mucosal disease labeled a 66-kDa peptide of normal human lip mucosa more intensely than did cutaneous sera. Autoimmune processes stimulated by the reaction of IgG, originally directed against the 66-kDa of L. braziliensis, to the 66-kDa antigen of mucosal tissue may contribute to the clinical presentation of mucosal leishmaniasis.     

生态脆弱区农户返贫脆弱性评估及其影响因素——以陇南山区为例

生态脆弱区既是生态环境最敏感区域,也是返贫问题较为集中的区域,返贫脆弱性作为评价农户返贫状况的重要指标,可为生态脆弱区农户的防返贫提供有效借鉴。以地处西秦岭的陇南山区为例,构建农户的返贫脆弱性评价指标体系,并利用微观调查数据,测度农户的返贫脆弱性水平,并利用分位数回归模型揭示其影响因素。结果发现:(1)陇南山区农户返贫脆弱性指数均值为0.103,整体处于中度脆弱水平,等级分布呈"两头小中间大"的橄榄形态势。(2)不同类型农户的返贫脆弱性水平存在分化特征,高山区、农业收入占比高、抚养比高的农户返贫脆弱性较高,且农业收入占比高、抚养比高农户的高脆弱群体占比也高。(3)不同抚养比农户的暴露度与适应能力差异最为显著,敏感性水平则在不同生计方式和抚养比农户中差异最大。(4)家庭规模的扩大可显著增强农户的返贫脆弱性,而交通便利度、网络覆盖率、未来生活预期、帮扶措施多样化和政策帮扶强度的提高可有效减缓农户的返贫脆弱性;政策帮扶强度削弱了高度脆弱农户因交通便利度低所致的返贫脆弱性,帮扶措施多样化则减弱了户主受教育水平高所发挥的降脆效果。     

FC-TRIPLEX Chagas/Leish IgG1: A Multiplexed Flow Cytometry Method for Differential Serological Diagnosis of Chagas Disease and Leishmaniasis

Differential serological diagnosis of Chagas disease and leishmaniasis is difficult owing to cross-reactivity resulting from the fact that the parasites that cause these pathologies share antigenic epitopes. Even with optimized serological assays that use parasite-specific recombinant antigens, inconclusive test results continue to be a problem. Therefore, new serological tests with high sensitivity and specificity are needed. In the present work, we developed and evaluated the performance of a new flow cytometric serological method, referred to as FC-TRIPLEX Chagas/Leish IgG1, for the all-in-one classification of inconclusive tests. The method uses antigens for the detection of visceral leishmaniasis, localized cutaneous leishmaniasis, and Chagas disease and is based on an inverted detuned algorithm for analysis of anti-Trypanosomatidae IgG1 reactivity. First, parasites were label with fluorescein isothiocyanate or Alexa Fluor 647 at various concentrations. Then serum samples were serially diluted, the dilutions were incubated with suspensions of mixed labeled parasites, and flow cytometric measurements were performed to determine percentages of positive fluorescent parasites. Using the new method, we obtained correct results for 76 of 80 analyzed serum samples (95% overall performance), underscoring the outstanding performance of the method. Moreover, we found that the fluorescently labeled parasite suspensions were stable during storage at room temperature, 4°C, and –20°C for 1 year. In addition, two different lots of parasite suspensions showed equivalent antigen recognition; that is, the two lots showed equivalent categorical segregation of anti-Trypanosomatidae IgG1 reactivity at selected serum dilutions. In conclusion, we have developed a sensitive and selective method for differential diagnosis of Chagas disease, visceral leishmaniasis, and localized cutaneous leishmaniasis.     

Using fuzzy logic to determine the vulnerability of marine species to climate change

Marine species are being impacted by climate change and ocean acidification, although their level of vulnerability varies due to differences in species' sensitivity, adaptive capacity and exposure to climate hazards. Due to limited data on the biological and ecological attributes of many marine species, as well as inherent uncertainties in the assessment process, climate change vulnerability assessments in the marine environment frequently focus on a limited number of taxa or geographic ranges. As climate change is already impacting marine biodiversity and fisheries, there is an urgent need to expand vulnerability assessment to cover a large number of species and areas. Here, we develop a modelling approach to synthesize data on species‐specific estimates of exposure, and ecological and biological traits to undertake an assessment of vulnerability (sensitivity and adaptive capacity) and risk of impacts (combining exposure to hazards and vulnerability) of climate change (including ocean acidification) for global marine fishes and invertebrates. We use a fuzzy logic approach to accommodate the variability in data availability and uncertainties associated with inferring vulnerability levels from climate projections and species' traits. Applying the approach to estimate the relative vulnerability and risk of impacts of climate change in 1074 exploited marine species globally, we estimated their index of vulnerability and risk of impacts to be on average 52 ± 19 SD and 66 ± 11 SD, scaling from 1 to 100, with 100 being the most vulnerable and highest risk, respectively, under the ‘business‐as‐usual' greenhouse gas emission scenario (Representative Concentration Pathway 8.5). We identified 157 species to be highly vulnerable while 294 species are identified as being at high risk of impacts. Species that are most vulnerable tend to be large‐bodied endemic species. This study suggests that the fuzzy logic framework can help estimate climate vulnerabilities and risks of exploited marine species using publicly and readily available information.     

Cutaneous leishmaniasis in western Sicily (Italy) and preliminary survey of phlebotomine sandflies (Diptera: Psychodidae)

A survey of phlebotomine sandflies was carried out in two provinces of western Sicily (Italy), where 65 cases of cutaneous leishmaniasis (CL) had been diagnosed by the Dermatology Department of the University of Palermo, between 1977 and 1987. Eight collecting stations, distributed throughout the CL foci of the Agrigento and Palermo provinces produced a total of 2,410 specimens (12.78% males). Of these, 77.59% were Phlebotomus perfiliewi, 12.78% P. perniciosus, 0.74% P. major and 2.07% Sergentomyia minuta. P. perfiliewi, the probable vector of CL, was present in 7 out of the 8 collecting stations with very high densities in two localities.     

A case of high altitude cutaneous leishmaniasis in a non-endemic region in Nepal

A case of cutaneous leishmaniasis was discovered in a 32-year old man with a persistent erythematous plaque. The patient resides in a high altitude (~2000 m above sea level) area that is not endemic for cutaneous leishmaniasis in the Dunai village of Dolpa, Nepal. The patient's lesion was initially misdiagnosed as lupus vulgaris. After response failure to initial treatment, additional testing by histological microscopy revealed the presence of Leishmania amastigotes in tissue from the lesion, and the diagnosis of cutaneous leishmaniasis was confirmed by nested PCR DNA assay of tissue from the lesion, and by a positive rK39 test in blood. Sequencing of the kinetoplast region confirmed the presence of Leishmania donovani complex. The patient responded well to treatments for cutaneous leishmaniasis and the skin lesions regressed after 6 months. This is the first known case of cutaneous leishmaniasis in a patient in Nepal who resides at high altitude in a non-endemic region. Increasing temperatures in this region of Nepal may be expanding the range of vectors that transmit cutaneous leishmaniasis.     

Local increase of arginase activity in lesions of patients with cutaneous leishmaniasis in Ethiopia

Background

Cutaneous leishmaniasis is a vector-borne disease that is in Ethiopia mainly caused by the parasite Leishmania aethiopica. This neglected tropical disease is common in rural areas and causes serious morbidity. Persistent nonhealing cutaneous leishmaniasis has been associated with poor T cell mediated responses; however, the underlying mechanisms are not well understood.

Methodology/Principal Findings

We have recently shown in an experimental model of cutaneous leishmaniasis that arginase-induced L-arginine metabolism suppresses antigen-specific T cell responses at the site of pathology, but not in the periphery. To test whether these results translate to human disease, we recruited patients presenting with localized lesions of cutaneous leishmaniasis and assessed the levels of arginase activity in cells isolated from peripheral blood and from skin biopsies. Arginase activity was similar in peripheral blood mononuclear cells (PBMCs) from patients and healthy controls. In sharp contrast, arginase activity was significantly increased in lesion biopsies of patients with localized cutaneous leishmaniasis as compared with controls. Furthermore, we found that the expression levels of CD3ζ, CD4 and CD8 molecules were considerably lower at the site of pathology as compared to those observed in paired PBMCs.

Conclusion

Our results suggest that increased arginase in lesions of patients with cutaneous leishmaniasis might play a role in the pathogenesis of the disease by impairing T cell effector functions.     

Second-generation vaccines against leishmaniasis

Several species of Leishmania cause human diseases that range from self-healing cutaneous lesions to fatal visceral leishmaniasis, mucosal leishmaniasis and diffuse cutaneous leishmaniasis. Drug resistance and toxicities associated with chemotherapy emphasize the need for a safe, effective vaccine. Studies of the immunopathogenesis and mechanisms of protective immunity define several features that should be met by an effective vaccine. The leishmaniases are unique among parasitic diseases because a single vaccine has the potential to protect against more than one species (disease) and be successful at both treating and preventing disease. In addition, several antigens have been identified and characterized that might be potential vaccine candidates. In this article, we focus on advances made with second-generation vaccines against leishmaniasis.