Transcriptomics analysis highlights potential ways in human pathogenesis in Leishmania braziliensis infected with the viral endosymbiont LRV1.

The parasite Leishmania (Viannia) braziliensis is widely distributed in Brazil and is one of the main species associated with human cases of different forms of tegumentary leishmaniasis (TL) such as cutaneous leishmaniasis (CL) and mucosal leishmaniasis (ML). The mechanisms underlying the pathogenesis of TL are still not fully understood, but it is known that factors related to the host and the parasite act in a synergistic and relevant way to direct the response to the infection. In the host, macrophages have a central connection with the parasite and play a fundamental role in the defense of the organism due to their ability to destroy intracellular parasites and present antigens. In the parasite, some intrinsic factors related to the species or even the strain analyzed are fundamental for the outcome of the disease. One of them is the presence of Leishmania RNA Virus 1 (LRV1), an endosymbiont virus that parasitizes some species of Leishmania that triggers a cascade of signals leading to a more severe TL phenotype, such as ML. One of the strategies for understanding factors associated with the immune response generated after Leishmania/host interaction is through the analysis of molecular patterns after infection. Thus, the gene expression profile in human monocyte-derived macrophages obtained from healthy donors infected in vitro with L. braziliensis positive (LbLRV1+) and negative (LbLRV1-) for LRV1 was evaluated. For this, the microarray assay was used and 162 differentially expressed genes were identified in the comparison LbLRV1+ vs. LbLRV1-, 126 upregulated genes for the type I and II interferons (IFN) signaling pathway, oligoadenylate synthase OAS/RNAse L, non-genomic actions of vitamin D3 and RIG-I type receptors, and 36 down-regulated. The top 10 downregulated genes along with the top 10 upregulated genes were considered for analysis. Type I interferon (IFNI)- and OAS-related pathways results were validated by RT-qPCR and Th1/Th2/Th17 cytokines were analyzed by Cytometric Bead Array (CBA) and enzyme-linked immunosorbent assay (ELISA). The microarray results validated by RT-qPCR showed differential expression of genes related to IFNI-mediated pathways with overexpression of different genes in cells infected with LbLRV1+ compared to LbLRV1- and to the control. No significant differences were found in cytokine levels between LbLRV1+ vs. LbLRV1- and control. The data suggest the activation of gene signaling pathways associated with the presence of LRV1 has not yet been reported so far. This study demonstrates, for the first time, the activation of the OAS/RNase L signaling pathway and the non-genomic actions of vitamin D3 when comparing infections with LbLRV1+ versus LbLRV1- and the control. This finding emphasizes the role of LRV1 in directing the host's immune response after infection, underlining the importance of identifying LRV1 in patients with TL to assess disease progression.

A review on potential therapeutic targets for the treatment of leishmaniasis.

Leishmania, a protozoan parasite, is responsible for the occurrence of leishmaniasis, a disease that is prevalent in tropical regions. Visceral Leishmaniasis (VL), also known as kala-azar in Asian countries, is one of the most significant forms of VL, along with Cutaneous Leishmaniasis (CL) and Mucocutaneous Leishmaniasis (ML). Management of this condition typically entails the use of chemotherapy as the sole therapeutic option. The current treatments for leishmaniasis present several drawbacks, including a multitude of side effects, prolonged treatment duration, disparate efficacy across different regions, and the emergence of resistance. To address this urgent need, it is imperative to identify alternative treatments that are both safer and more effective. The identification of appropriate pharmacological targets in conjunction with biological pathways constitutes the initial stage of drug discovery. In this review, we have addressed the key metabolic pathways that represent potential pharmacological targets as well as prominent treatment options for leishmaniasis.

The changing epidemiology of human leishmaniasis in the non-endemic country of Austria between 2000 to 2021, including a congenital case.

BACKGROUND: Leishmaniasis is caused by infection with intracellular protozoans of the genus Leishmania. Transmission occurs predominantly by the bite of phlebotomine sandflies, other routes, including congenital transmission, are rare. The disease manifests as either cutaneous, visceral or mucosal/mucocutaneous leishmaniasis. In recent years, changes in the epidemiological pattern have been reported from Europe. PRINCIPAL FINDINGS: A total of 311 new and 29 published leishmaniasis cases occurring between 01/01/2000 and 12/31/2021 in Austria were collected and analyzed. These encompassed 146 cutaneous (CL), 14 visceral (VL), 4 mucosal, and 3 cases with concurrent VL and CL. In addition, asymptomatic infections, comprising 11 unspecified cases with Leishmania DNA detectable only in the blood and 162 cases with anti-Leishmania antibodies were reported. Particularly since 2016, the incidence of leishmaniasis has steadily risen, mainly attributable to increasing numbers of CL and cases with positive serology against Leishmania species, whereas the incidence of VL has slowly decreased. Analysis revealed that a shift in the causative species spectrum had occurred and that a substantial number of CL cases were caused by members of the Leishmania donovani/infantum complex. Simultaneous occurrence of VL and CL was identified in immunocompromised individuals, but also in a not yet reported case of an immunocompetent child after vertical transmission. CONCLUSIONS: The incidence of leishmaniasis has risen in the recent years. The numbers are anticipated to keep rising due to increasing human mobility, including travel and forced migration, growing reservoir host populations as well as expansion and dispersal of vector species caused by climate and habitat changes, urbanization and globalization. Hence, elevated awareness for the disease, including possible transmission in previously non-endemic regions and non-vector transmission modes, support of sandfly surveillance efforts and implementation and establishment of public health interventions in a One Health approach are pivotal in the global efforts to control and reduce leishmaniasis.

Case Report: In Situ and Systemic Immune Response to Mucosal Leishmaniasis in an HIV-Infected Patient.

In situ and systemic evaluations of the immune responses of HIV-infected patients to mucosal leishmaniasis have been poorly described. We describe a recently diagnosed HIV-infected patient with mucosal leishmaniasis who was characterized by a CD4 count of 85 cells/mm3 and nasal septum destruction resulting from pruritic and ulcerated nasal mucosa with crust formation and progression over 2 years. In situ and systemic immune evaluations of T cell activation, memory, and exhaustion were conducted using cytofluorometric assays, and sequencing of the Leishmania species was performed. The immune profile of HIV-infected patient with mucosal leishmaniasis shows a mixed Th1/Th2 pattern and an activated and exhausted status.

Stigma associated with cutaneous and mucocutaneous leishmaniasis: A systematic review.

BACKGROUND: Cutaneous (CL) and mucocutaneous leishmaniasis (MCL) are parasitic diseases caused by parasites of the genus leishmania leading to stigma caused by disfigurations. This study aimed to systematically review the dimensions, measurement methods, implications, and potential interventions done to reduce the CL- and MCL- associated stigma, synthesising the current evidence according to an accepted stigma framework. METHODS: This systematic review followed the PRISMA guidelines and was registered in PROSPERO (ID- CRD42021274925). The eligibility criteria included primary articles discussing stigma associated with CL and MCL published in English, Spanish, or Portuguese up to January 2023. An electronic search was conducted in Medline, Embase, Scopus, PubMed, EBSCO, Web of Science, Global Index Medicus, Trip, and Cochrane Library. The mixed methods appraisal tool (MMAT) was used for quality checking. A narrative synthesis was conducted to summarise the findings. RESULTS: A total of 16 studies were included. The studies report the cognitive, affective, and behavioural reactions associated with public stigma. Cognitive reactions included misbeliefs about the disease transmission and treatment, and death. Affective reactions encompass emotions like disgust and shame, often triggered by the presence of scars. Behavioural reactions included avoidance, discrimination, rejection, mockery, and disruptions of interpersonal relationships. The review also highlights self-stigma manifestations, including enacted, internalised, and felt stigma. Enacted stigma manifested as barriers to forming proper interpersonal relationships, avoidance, isolation, and perceiving CL lesions/scars as marks of shame. Felt stigma led to experiences of marginalisation, rejection, mockery, disruptions of interpersonal relationships, the anticipation of discrimination, fear of social stigmatisation, and facing disgust. Internalised stigma affected self-identity and caused psychological distress. CONCLUSIONS: There are various manifestations of stigma associated with CL and MCL. This review highlights the lack of knowledge on the structural stigma associated with CL, the lack of stigma interventions and the need for a unique stigma tool to measure stigma associated with CL and MCL.

The leishmaniases in Kenya: A scoping review.

BACKGROUND: The leishmaniases are a group of four vector-borne neglected tropical diseases caused by 20 species of protozoan parasites of the genus Leishmania and transmitted through a bite of infected female phlebotomine sandflies. Endemic in over 100 countries, the four types of leishmaniasis-visceral leishmaniasis (VL) (known as kala-azar), cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), and post-kala-azar dermal leishmaniasis (PKDL)-put 1.6 billion people at risk. In Kenya, the extent of leishmaniasis research has not yet been systematically described. This knowledge is instrumental in identifying existing research gaps and designing appropriate interventions for diagnosis, treatment, and elimination. METHODOLOGY/PRINCIPAL FINDINGS: This study used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology to determine the state of leishmaniases research in Kenya and identify research gaps. We searched seven online databases to identify articles published until January 2022 covering VL, CL, MCL, and/or PKDL in Kenya. A total of 7,486 articles were found, of which 479 underwent full-text screening, and 269 met our eligibility criteria. Most articles covered VL only (n = 141, 52%), were published between 1980 and 1994 (n = 108, 39%), and focused on the theme of "vectors" (n = 92, 34%). The most prevalent study types were "epidemiological research" (n = 88, 33%) tied with "clinical research" (n = 88, 33%), then "basic science research" (n = 49, 18%) and "secondary research" (n = 44, 16%). CONCLUSION/SIGNIFICANCE: While some studies still provide useful guidance today, most leishmaniasis research in Kenya needs to be updated and focused on prevention, co-infections, health systems/policy, and general topics, as these themes combined comprised less than 4% of published articles. Our findings also indicate minimal research on MCL (n = 1, <1%) and PKDL (n = 2, 1%). We urge researchers to renew and expand their focus on these neglected diseases in Kenya.

Co-expression analysis of lncRNA and mRNA suggests a role for ncRNA-mediated regulation of host-parasite interactions in primary skin lesions of patients with American tegumentary leishmaniasis.

Leishmaniasis, caused by different Leishmania species, manifests as cutaneous or visceral forms. In the American continent, the cutaneous form is called American tegumentary leishmaniasis (ATL) and is primarily caused by Leishmania (Viannia) braziliensis. Mucosal leishmaniasis (ML), the most severe form of ATL, arises in approximately 20% of patients from a primary cutaneous lesion. Evidence indicates changes in overall expression patterns of mRNAs and lncRNAs of the host in response to Leishmania infection, with the parasite capable of modulating host immune response, which may contribute to disease progression. We evaluated whether the co-expression of lncRNAs and their putative target mRNAs in primary cutaneous lesions of patients with ATL could be associated with the development of ML. Previously available public RNA-Seq data from primary skin lesions of patients infected with L. braziliensis was employed. We identified 579 mRNAs and 46 lncRNAs differentially expressed in the primary lesion that subsequently progressed to mucosal disease. Co-expression analysis revealed 1324 significantly correlated lncRNA-mRNA pairs. Among these, we highlight the positive correlation and trans-action between lncRNA SNHG29 and mRNA S100A8, both upregulated in the ML group. S100A8 and its heterodimeric partner S100A9 form a pro-inflammatory complex expressed by immune cells and seems to participate in host innate immune response processes of infection. These findings expand the knowledge of the Leishmania-host interaction and indicate that the expression of lncRNAs in the primary cutaneous lesion could regulate mRNAs and play roles in disease progression.

The stigma associated with cutaneous leishmaniasis (CL) and mucocutaneous leishmaniasis (MCL): A protocol for a systematic review.

Leishmaniasis is a neglected tropical disease with three main clinical types; cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), and visceral leishmaniasis (VL). CL and MCL are considered to be highly stigmatizing due to potentially disfiguring skin pathology. CL and MCL-associated stigma are reported across the world in different contexts assimilating different definitions and interpretations. Stigma affects people with CL, particularly in terms of quality of life, accessibility to treatment, and psycho-social well-being. However, evidence on CL- and MCL-associated stigma is dispersed and yet to be synthesized. This systematic review describes the types, measurements, and implications of the stigma associated with CL and MCL and identifies any preventive strategies/interventions adopted to address the condition. This study was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) statement which is registered in the International Platform of Registered Systematic Review and Meta-analysis Protocols PROSPERO (ID- CRD42021274925). We will perform an electronic search in MEDLINE, Embase, Scopus, PubMed, EBSCO, Web of Science, Global Index Medicus, Trip, and Cochrane Library databases, and in Google Scholar, using a customized search string. Any article that discusses any type of CL- and/or MCL-associated stigma in English, Spanish and Portuguese will be included. Articles targeting veterinary studies, sandfly vector studies, laboratory-based research and trials, articles focusing only on visceral leishmaniasis, and articles on diagnostic or treatment methods for CL and MCL will be excluded. Screening for titles and abstracts and full articles and data extraction will be conducted by two investigators. The risk of bias will be assessed through specific tools for different study types. A narrative synthesis of evidence will then follow. This review will identify the knowledge gap in CL-associated stigma and will help plan future interventions.

Detection of Leishmania RNA Virus 1 in Leishmania (Viannia) panamensis Isolates, Panama.

We detected Leishmania RNA virus 1 (LRV1) in 11 isolates of Leishmania (Viannia) panamensis collected during 2014-2019 from patients from different geographic areas in Panama. The distribution suggested a spread of LRV1 in L. (V.) panamensis parasites. We found no association between LRV1 and an increase in clinical pathology.

Clinicopathological characteristics of cutaneous and mucocutaneous leishmaniasis in patients treated with TNF-α inhibitors.

BACKGROUND AND OBJECTIVES: The increasing use of biologics in the treatment of inflammatory diseases has led to more cases of leishmaniasis in patients subjected to iatrogenic immunosuppression. The main objective was to describe the characteristics of the patients with cutaneous (CL) or mucocutaneous (MCL) leishmaniasis who were receiving a biological therapy at the time of diagnosis. PATIENTS AND METHODS: A multicenter retrospective study was design based on a cohort of patients diagnosed with CL or MCL. All patients who were being treated with biologicals were included. For each case, two matched non-exposed patients were included for comparison. RESULTS: 38 patients were diagnosed with CL or MCL while being treated with tumor necrosis factor alpha (TNF-α) inhibitors. Leishmaniasis presented more frequently as a plaque (58.3%) with a larger median lesion size (2.5 cm), ulceration (92.1%), and required a greater median number of intralesional meglumine antimoniate infiltrations (3 doses) (P < 0.05) than in non-exposed patients. We found no systemic involvement in patients being treated with anti-TNF-α. We did not find differences regarding the treatment characteristics whether biologic therapy was modified or not. CONCLUSIONS: Although management should be individualized, maintenance of biologic therapy does not seem to interfere with treatment of CL or MCL.

Fever with perinasal and tongue lesions: A diagnostic challenge.

The diagnosis may be challenging, and high suspicion index should be maintained in immunosuppressed patients with unusual mucocutaneous lesions, even in non-endemic areas for mucocutaneous leishmaniasis.

Leishmania RNA Virus Is Not Detected in All Species of the Leishmania Viannia Subgenus: The Case of L. (V.) panamensis in Colombia.

The endosymbiotic Leishmania RNA virus 1 (LRV1) has been associated with severity and clinical manifestations of American tegumentary leishmaniasis caused by species of the Leishmania (Viannia) subgenus. Between and within Leishmania species, and among endemic countries, the prevalence of LRV is highly variable. The LRV virus has not been detected in L. (V.) panamensis, the second-most prevalent species in Central America and Colombia. However, no systematic screening of LRV has been conducted in L. (V.) panamensis, and thus it is still controversial whether this virus is truly absent from the species. We sought to determine the prevalence of LRV1 in L. (V.) panamensis clinical strains isolated from patients with cutaneous leishmaniasis (CL), from different geographic areas of Colombia. We analyzed 219 clinical strains; 78% were L. (V.) panamensis, 18% were L. (V.) braziliensis, and 4% were L. (V.) guyanensis. Screening for LRV1 was performed by quantitative reverse transcription-polymerase chain reaction. The LRV1 was detected in 18% (7 of 40) of L. (V) braziliensis strains, and was not detected in any of the L. (V.) guyanensis or L. (V.) panamensis strains. The LRV1-positive L. (V). braziliensis strains came from the Amazon Basin. Of the seven LRV1-positive strains, two were isolated from patients with mucocutaneous leishmaniasis, and the remaining from patients with CL. Our results confirm the absence of LRV1 in L. (V.) panamensis in Colombia.

Mucosal Leishmaniasis of the lip: Report of an Exuberant case in a Young man.

BACKGROUND: Leishmaniasis is a tropical disease caused by protozoan parasites of the genus Leishmania. Mucosal leishmaniasis has been described as secondary to the cutaneous form; however, isolated mucosal involvement can also occur. Specifically, mucosal leishmaniasis of the lip is poorly described and its diagnosis challenges clinicians. METHODS: We herein report a case of mucosal leishmaniasis affecting the lower lip without cutaneous involvement in a 20-year-old Venezuelan man. The patient had no relevant past medical history. Clinically, a mass-like lesion with ulcerations and crusts was observed. RESULTS: Microscopically, the lesion was composed of granulomatous inflammation along with macrophages containing intracytoplasmic inclusions similar to round-shaped Leishmania. The species Leishmania (Viannia) braziliensis was confirmed. Treatment with meglumine antimonate was effective. The lesion healed satisfactorily, and no side effects or recurrences were observed. CONCLUSION: Clinicians should be aware of isolated forms of mucosal leishmaniasis of the lip, even in cases where the cutaneous lesion is undetected or clinically manifests as self-limiting. Knowing the endemic areas in the scenario of the dynamics of the ecoepidemiology of leishmaniasis is also essential for surveillance and counselling of the population.

American Cutaneous Leishmaniasis in Eastern Minas Gerais: veiled reality of a neglected disease / Leishmaniose Tegumentar Americana no Leste de Minas Gerais: realidade velada de uma doença negligenciada

Objective: to analyze the notified and confirmed cases of ACL in a municipality in east Minas Gerais, from 2007 to 2020. Methods: a combined study was carried out as a cross-sectional and an ecological approach of time series type, using notified and confirmed ACL cases, from 2007 to 2020. Primary and secondary data were used. Data were analyzed using descriptive and inferential statistics (simple linear regression, T-test, Mann-Whitney, chi-square (χ2) at a 5% significance level). Results: a total of 219 cases were reported with a decreasing temporal trend, with a higher frequency observed for the cutaneous form (82.6%), age group 40 to 59 years (32.1%), black race (56.4%), and completed elementary school (47.7%). Individuals with the mucosal clinical form had lesions for a longer time, a greater chance of not progressing to cure, and used more vials of meglumine antimoniate when compared to patients with the cutaneous form. Conclusions: different correlations were observed between the variables studied and the profile of involvement described in the scientific literature, with the clinical form predominantly cutaneous and with a good prognosis.

Objetivo: analisar os casos notificados e confirmados de LTA em um município do leste de Minas Gerais, no período de 2007 a 2020. Métodos: foi realizado um estudo combinado com abordagem transversal e ecológica do tipo série temporal, utilizando casos notificados e confirmados de LTA, de 2007 a 2020. Foram utilizados dados primários e secundários. Os dados foram analisados por meio de estatística descritiva e inferencial (regressão linear simples, teste T, Mann-Whitney, qui-quadrado (χ2) com nível de significância de 5%). Resultados: foram notificados 219 casos com tendência temporal decrescente, com maior frequência observada para a forma cutânea (82,6%), faixa etária de 40 a 59 anos (32,1%), raça negra (56,4%) e ensino fundamental completo (47,7%). Indivíduos com a forma clínica mucosa apresentaram maior tempo de lesão, maior possibilidade de não evoluir para cura e utilizaram mais ampolas de antimoniato de meglumina quando comparados aos pacientes com a forma cutânea. Conclusões: foram observadas diferentes correlações entre as variáveis estudadas e o perfil de acometimento descrito na literatura científica, com a forma clínica predominantemente cutânea e com bom prognóstico.

The cure rate after different treatments for mucosal leishmaniasis in the Americas: A systematic review.

BACKGROUND: Mucosal or mucocutaneous leishmaniasis is the most severe form of tegumentary leishmaniasis due to its destructive character and potential damage to respiratory and digestive tracts. The current treatment recommendations are based on low or very low-quality evidence, and pentavalent antimonial derivatives remain strongly recommended. The aim of this review was to update the evidence and estimate the cure rate and safety profile of the therapeutic options available for mucosal leishmaniasis (ML) in the Americas. METHODOLOGY: A systematic review was conducted in four different databases and by different reviewers, independently, to evaluate the therapeutic efficacy and toxicity associated with different treatments for ML. All original studies reporting cure rates in more than 10 patients from American regions were included, without restriction of design, language, or publication date. The risk of bias was assessed by two reviewers, using different tools according to the study design. The pooled cure rate based on the latest cure assessment reported in the original studies was calculated grouping all study arms addressing the same intervention. The protocol for this review was registered at the International Prospective Register of Systematic Reviews, PROSPERO: CRD42019130708. PRINCIPAL FINDINGS: Twenty-seven original studies from four databases fulfilled the selection criteria. A total of 1,666 patients with ML were treated predominantly with pentavalent antimonials in Brazil. Other interventions, such as pentamidine, miltefosine, imidazoles, aminosidine sulfate, deoxycholate and lipidic formulations of amphotericin B (liposomal, lipid complex, colloidal dispersion), in addition to combinations with pentoxifylline, allopurinol or sulfa were also considered. In general, at least one domain with a high risk of bias was identified in the included studies, suggesting low methodological quality. The pooled cure rate based on the latest cure assessment reported in the original studies was calculated grouping all study arms addressing the same intervention. It was confirmed that antimony is still the most used treatment for ML, with only moderate efficacy (possibly increased by combining with pentoxifylline). There is already evidence for the use of miltefosine for ML, with a cure rate similar to antimony, as observed in the only direct meta-analysis including 57 patients (OR: 1.2; 0.43-3.49, I2 = 0). It was possible to gather all descriptions available about adverse events reported during ML treatment, and the toxicity reflected the pattern informed in the manufacturers' technical information. CONCLUSIONS: This study provides an overview of the clinical experience in the Americas related to ML treatment and points out interventions and possible combinations that are eligible to be explored in future well-designed studies.