Global Dilemma and Needs Assessment Toward Achieving Sustainable Development Goals in Controlling Leishmaniasis.

Leishmaniasis is a disease of poverty that imposes a devastating medical, social, and economic burden on over 1 billion people nationwide. To date, no in-depth study to analyze the major global challenges and needs assessment has been carried out. This investigation aimed to explore a comprehensive narrative review of leishmaniasis's main challenges and initially highlight obstacles that might impede the implementation of control measures. Also, we propose a specific list of priorities for needs assessment. The presence of socioeconomic factors, multiple clinical and epidemiological forms, various Leishmania species, the complexity of the life cycle, the absence of effective drugs and vaccines, and the lack of efficient vector and reservoir control make this organism unique and sophisticated in playing a tangled role to react tricky with its surrounding environments, despite extensive efforts and implementation of all-inclusive former control measures. These facts indicate that the previous strategic plans, financial support, and basic infrastructures connected to leishmaniasis surveillance are still insufficient. Strengthening the leishmaniasis framework in a context of accelerated programmatic action and intensification of cross-cutting activities along with other neglected tropical diseases (NTDs) is confidently expected to result in greater effectiveness, cost-benefit, and fruitful management. Sensitive diagnostics, effective therapeutics, and efficacious vaccines are vital to accelerating advancement toward elimination, and reducing morbidity/mortality and program costs. Collective actions devoted by all sectors and policy-makers can hopefully overcome technical and operational barriers to guarantee that effective and coordinated implementation plans are sustained to meet the road map for NTDs 2021- 2030 goals.

Ensuring access to essential health products: Lessons from Colombia's leishmaniasis control and elimination initiative.

BACKGROUND: This paper identifies opportunities and challenges for leishmaniasis control and elimination in Colombia, emphasizing the role of pooled procurement of essential medicines and supplies. Colombia is among the countries most affected by leishmaniasis globally, and also faces the dual challenge of procuring critically needed medicines in the context of limited national resources. It recently renewed its commitment to the control and elimination of leishmaniasis under its 2022-2031 Public Health Plan (PDSP) through a comprehensive public health approach. METHODOLOGY/PRINCIPAL FINDINGS: The methodology comprises a comprehensive literature review and key informant interviews with leishmaniasis experts from the Colombian national control program and PAHO/WHO, focusing on cutaneous, mucocutaneous, and visceral leishmaniasis. Leishmaniasis is endemic throughout Colombia, with over 11 million people at risk, many of whom live in poverty-stricken, remote and isolated rural areas with limited access to health services. Leishmaniasis care, including medicines, is provided free of charge, but many barriers were nonetheless identified at environmental, population, and health system levels, including the supply of quality-assured medicines. Opportunities to alleviate these barriers were identified, including the support of the PAHO Strategic Fund. Within the context of the sustainable development goals and international leishmaniasis control and elimination targets, Colombian officials have established their own priorities, the highest of which is the reduction of deaths from visceral leishmaniasis. CONCLUSIONS/SIGNIFICANCE: The elimination of leishmaniasis as a public health problem presents significant challenges, given its biological complexity and diversity, physical and clinical manifestations, social and economic impacts, frequently burdensome treatment regimens, and insufficient supply of necessary medicines. However, rigorous prevention and control efforts through strong political commitment and a highly motivated workforce can dramatically reduce its burden. Colombia's new PDSP, which highlights leishmaniasis control, is an opportunity for a revitalized health system response through committed leadership, intersectoral actions, and partnerships with international organizations that share a common vision.

The immune response in canine and human leishmaniasis and how this influences the diagnosis- a review and assessment of recent research.

Leishmaniasis is a widespread but still underdiagnosed parasitic disease that affects both humans and animals. There are at least 20 pathogenic species of Leishmania, most of them being zoonotic. The diagnosis of leishmaniasis remains a major challenge, with an important role being played by the species of parasites involved, the genetic background, the immunocompetence of the host. This paper brings to the fore the sensitivity of the balance in canine and human leishmaniasis and addresses the importance of the host's immune response in establishing a correct diagnosis, especially in certain cases of asymptomatic leishmaniasis, or in the situation the host is immunosuppressed or acquired leishmaniasis through vertical transmission. The methods considered as a reference in the diagnosis of leishmaniasis no longer present certainty, the diagnosis being influenced mostly by the immune response of the host, which differs according to the presence of other associated diseases or even according to the breed in dogs. Consequently, the diagnosis and surveillance of leishmaniasis cases remains an open topic, requiring new diagnostic methods adapted to the immunological state of the host.

Burden of dengue, leishmaniasis and lymphatic filariasis in India and its states from 1990-2019: Analysis from the Global Burden of Disease study (GBD 2019).

Vector-borne diseases such as dengue, leishmaniasis, and lymphatic filariasis, constitute significant sources of illness, disability, and mortality among the poor and vulnerable in many countries around the world, including India. Based on the global burden of diseases, injuries, and risk factors study 2019, we analyse the burden of dengue, leishmaniasis, and lymphatic filariasis, in India from 1990 to 2019. Over this period, there was a reduction in the burden of lymphatic filariasis and leishmaniasis. Notably, dengue emerged as the most common vector-borne disease, exhibiting high fatality rate above 15 years of age and the highest DALY within 15-49 age group. Additionally, dengue cases surged substantially between 1990 and 2019. Leishmaniasis related mortality and DALY declined in the year 2019 compared to the year 1990, with high mortality and DALY in the 0-49-year-old age group. For lymphatic filariasis, DALY was more pronounce among those in the 15-49-year age group, which underwent reduction in 2019. Males had a higher burden in other vector-borne diseases than females, although females had a slightly elevated dengue burden. These findings highlight the evolving epidemiological trends related to vector-borne diseases in India, over the last three decades and underline the critical significance of sustained efforts for the elimination and control of vector-borne diseases.

Assessment of pan-Leishmania detection by recombinase polymerase amplification assay.

The spread of vector habitats along with increasing human mobility can introduce atypical Leishmania species and hence can challenge existing diagnostic practices for rapid detection of active infection with species outside the narrow target range. Here we assessed the pan-Leishmania detection ability of isothermal recombinase polymerase amplification (RPA) assays targeting 18S rRNA gene, cathepsin L-like cysteine proteinase B (Cpb) gene, and kinetoplast minicircle DNA (kDNA) regions. While the lowest limit of detection of the 18S rRNA-RPA and Cpb-RPA assays were estimated as 12 and 17 standard DNA molecules, respectively, both assays could amplify genomic DNA of 7 pathogenic Leishmania species. Evaluation of 18S rRNA-RPA and our previously developed kDNA-RPA assays on 70 real-time PCR-positive leishmaniasis samples of varying pathologies resulted in sensitivity rates of 35.71% and 88.57%, respectively, while the combined sensitivity was 98.57%. Combinatorial application of 18S rRNA-RPA and kDNA-RPA assays can be recommended for further diagnostic assessments.

Assessment of circulating immune complexes in canine leishmaniosis and dirofilariosis.

Canine leishmaniosis (CanL) by Leishmania infantum (L.i.) and heartworm disease by Dirofilaria immitis (D.i.) are common zoonotic vector-borne diseases (VBDs) characterized by a variety of pathological and clinical signs. The immunopathology in both VBDs is extremely complex, and their clinical manifestations are strongly dependent on the type of immune response elicited by the parasites. In particular, the formation of circulating immune complexes (CICs) plays an important role in the pathogenesis of these VBDs. Based on the international guidelines, dogs with high anti-L. infantum antibody titres and one or more clinical and/or laboratory signs related to CanL require anti-Leishmania treatment. Consequently, the CICs measurement could be used for improving the clinical staging process of CanL. The aim of the study was to assess the CICs level by a competitive inhibition enzyme immunoassay, in healthy or sick dogs seropositive to L.i. and in healthy dogs positive to D.i.. Out of 51 enrolled dogs, 11 were included in Group A (seronegative to L.i., D.i. negative and healthy), 15 in Group B (exposed to L.i., D.i. negative and healthy), 12 in Group C (seropositive to L.i., D.i. negative and sick) and 13 in Group D (seronegative to L.i, D.i. positive and healthy). The comparison of CIC level in canine sera revealed a significant difference among groups (P < 0.001), with the highest concentration (i.e., median = 104.6 µg/mL) in dogs with CanL. The findings of the study highlight the CICs measurement as a useful tool in the clinical staging of CanL for avoiding misclassification of dogs as leishmaniotic, thus not requiring anti-Leishmania therapy, as well as the possibility of results misuse in geographical areas where both leishmaniosis and heart-worm disease are endemic.

Muito além de uma história das leishmanioses no Novo Mundo / Far more than a history of leishmaniasis in the New World

Nesta obra, os autores não se limitaram à análise do objeto central da obra, isto é, a história das leishmanioses, mas também lançaram luz sobre pesquisas desenvolvidas acerca de várias enfermidades como malária, filariose, tripanossomíases, arboviroses, entre outras. No novo volume, é dada atenção especial ao papel desempenhado pela London School of Hygiene and Tropical Medicine e pelo parasitologista britânico Percy Cyril Claude Garnham na construção de uma nova rede centrada em nova abordagem, menos antropocêntrica e com maior interesse pelas zoonoses. A obra examina em detalhes a relação entre urbanização, surtos e expansão geográfica das leishmanioses tegumentares e a criação da Zona Franca de Manaus, a exploração de minério em Carajás e Pitinga, o projeto de produção de celulose em Jari e a construção das rodovias Transamazônica e Belém-Brasília, da hidrelétrica de Balbina e do gasoduto Coari-Manaus.O livro, portanto, apresenta uma perspectiva dinâmica sobre a pesquisa científica na região amazônica e as complexas interações entre saúde pública, desenvolvimento econômico e transformações socioambientais

Thiazolidine derivatives: In vitro toxicity assessment against promastigote and amastigote forms of Leishmania infantum and ultrastructural study.

Neglected diseases, such as Leishmaniasis, constitute a group of communicable diseases that occur mainly in tropical countries. Considered a public health problem with limited treatment. Therefore, there is a need for new therapies. In this sense, our proposal was to evaluate in vitro two series of thiazolidine compounds (7a-7e and 8a-8e) against Leishmania infantum. We performed in vitro evaluations through macrophage cytotoxicity assays (J774) and nitric oxide production, activity against promastigotes and amastigotes, as well as ultrastructural analyzes in promastigotes. In the evaluation of cytotoxicity, the thiazolidine compounds presented CC50 values between 8.52 and 126.83 µM. Regarding the evaluation against the promastigote forms, the IC50 values ranged between 0.42 and 142.43 µM. Compound 7a was the most promising, as it had the lowest IC50. The parasites treated with compound 7a showed several changes, such as cell body shrinkage, shortening and loss of the flagellum, intense mitochondrial edema and cytoplasmic vacuolization, leading the parasite to cell inviability. In assays against the amastigote forms, the compound showed a low IC50 (0.65 µM). These results indicate that compound 7a was efficient for both evolutionary forms of the parasite. In silico studies suggest that the compound has good oral bioavailability. These results show that compound 7a is a potential drug candidate for the treatment of Leishmaniasis.

Impact assessment of different DNA extraction methods for non-invasive molecular diagnosis of tegumentary leishmaniasis.

The aim of this study was to evaluate two methods of nucleic acid extraction (spin-column-based method - commercial kit and direct boil - DB) from swab sampling compared to biopsy sampling for the diagnosis of tegumentary leishmaniasis (TL), (cutaneous - CL and mucocutaneous - MCL forms). The impact of these nucleic acid extraction protocols on different types of PCR and LAMP techniques were compared regarding nucleic acid quality, molecular assays accuracy, indirect quantitation, and costs. The evaluated patients were 57 TL cases (36 CL and 21 MCL) and 34 non-cases. Swab samples extracted by the DB method showed a higher DNA degradation rate and worse DNA quality in comparison to the commercial kit. Molecular tests performed on biopsy samples showed identical or higher performance in all analysis, as compared to their own performance on swab samples for TL (CL and MCL). However, only the SSU rRNA TaqMan™ RT-PCR test showed a significant difference between the performance of biopsy and swab samples extracted by commercial kit. The kDNA-cPCR coupled with swab extracted by commercial kit showed the highest accuracy (95.6%) for TL diagnosis. The sensitivity of the LAMP-RT 18S method in swab samples extracted with a commercial kit (82.5%) was close to that found in biopsy samples (86%) for TL diagnosis. The DB extraction method presented the lowest cost. The use of swab as a minimally-invasive sampling method, associated with an efficient nucleic acid extraction protocol, may represent a low-cost alternative for the diagnosis of CL and MCL.

Preclinical Assessment of the Immunogenicity of Experimental Leishmania Vaccines.

Leishmaniases are neglected diseases caused by Leishmania parasites and affect millions of people worldwide. The induction of protective immunity against infection by some species of Leishmania has stimulated the development of vaccine candidates against the disease. In this chapter we describe protocols for immunizing mice with a recombinant chimera vaccine containing selected epitopes that specifically stimulate a Th1-type immune response. We describe protocols for challenging mice with live Leishmania parasite and for measuring parameters of the immune response to vaccination and parasite infection, including the production of cytokines, nitric oxide, and IgG antibodies, and the contribution of CD4+ and CD8+ T cells. We also provide protocols for isolating mouse organs for cell culture and for quantifying parasite loads in unvaccinated control animals and in vaccine-protected animals. These protocols can form the basis of immunological studies of candidate Leishmania vaccines in the mouse, as a step toward further vaccine development for human use.

Toxicity assessment of synthetic chalcones with antileishmanial potential in BALB/c mice. / Evaluación de la toxicidad de chalconas sintéticas con potencial anti-Leishmania en ratones BALB/c.

OBJECTIVE: To evaluate the toxicity of three synthetic chalcones administered intraperitoneally to BALB/c mice. MATERIALS AND METHODS: The median lethal dose (LD50) was estimated by Dixon's Up-and-Down method. Subchronic toxicity of chalcones was evaluated at 20 and 40 mg/kg for 21 days. Behavioral, physiological, biochemical, and histological toxic effects were evaluated. RESULTS: Chalcone 43 produced mucus in feces, visceral damage (liver) and alterations in organ coefficient (kidney, p = 0.037 and brain, p = 0.008) when compared to the control group. In addition, histological analysis showed that this chalcone produced edema, inflammation and necrosis in the evaluated organs, although there was no significant difference with the control. None of the biochemical parameters differed significantly between the treatment groups at 40 mg/kg dose and the control. CONCLUSIONS: The LD50 for all three chalcones was greater than 550 mg/kg of body weight. Chalcones 40 and 42 were found to be relatively non-toxic. Both can be considered safe for intraperitoneal application in BALB/c mice and, consequently, are potential candidates for use in the treatment of leishmaniasis.

OBJETIVO: Evaluar la toxicidad de tres chalconas sintéticas administradas por vía intraperitoneal en ratones BALB/c. MATERIALES Y MÉTODOS: La dosis letal media (DL50) se estimó por el método Up-and-Down de Dixon. La toxicidad subcrónica de las chalconas se evaluó a 20 y 40   mg/kg por 21 días. Se evaluó el efecto tóxico a nivel de comportamiento, fisiológico, bioquímico e histológico. RESULTADOS: La chalcona 43 generó moco en las heces, daño visceral (hígado) y alteración en el coeficiente de órganos (riñón, p   =   0,037 y cerebro, p   =   0,008) en comparación con el grupo control. Además, en el análisis histológico se observó que esta chalcona produjo edema, inflamación y necrosis en los órganos evaluados, aunque no hubo diferencia significativa con el control. Todos los parámetros bioquímicos no difirieron significativamente entre los grupos de tratamiento a dosis de 40   mg/kg y el control. CONCLUSIONES: La DL50 para las tres chalconas fue superior a 550   mg/kg de peso corporal. Las chalconas 40 y 42 son relativamente no tóxicas. Ambas pueden considerarse seguras para la aplicación vía intraperitoneal en ratones BALB/c y, en consecuencia, son posibles candidatas para ser usadas en el tratamiento contra las leishmaniosis.

Assessment of liver function test and associated factors among visceral leishmaniasis patients attending university of gondar leishmaniasis research and treatment center, Northwest Ethiopia.

BACKGROUND: Visceral leishmaniasis (VL) is one of the major public health burden, mainly distributed throughout tropical and subtropical regions of the world. Among the Sub-Saharan African countries, Ethiopia is the second most affected country with VL. An Alteration of liver function is a typical manifestation of the disease. OBJECTIVE: The purpose of conducting this study was to assess liver function tests and associated risk factors among VL patients at Leishmaniasis Research and Treatment Center of University of Gondar Comprehensive Specialized Hospital, North West Ethiopia. METHOD: Hospital based comparative cross-sectional study design was conducted. A total of 102 study participants were involved in this study. Newly diagnosed VL patients who were attended at Leishmaniasis Research and Treatment Center of University of Gondar Comprehensive Specialized Hospital from 21st February 2020 to 30th September 2020 were included under case group category. On the other hand, age-sex matched apparently healthy study subjects were categorized as control group. Written consent was obtained willingness of patients to participate after ethical clearance was obtained from the Institutional Review Board of School of Medicine, University of Gondar. After overnight fasting, 5ml venous blood was drawn from both VL patients and controls to evaluate liver function tests, including AST, ALT, total bilirubin, albumin, and total protein. Thus, senior health professionals (laboratory technologist) investigate the results using Cobas Integra 400 Plus clinical chemistry analyzer. Data was entered into Epi-data version 4.6 and exported to STATA 14 for analysis of liver function tests and associated risk factors. RESULT: The result of this study showed that significant mean difference was exhibited in aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin, serum albumin, and total protein level among VL patients and controls. It showed that there was a statistically significant elevation in the level of AST, ALT, and total bilirubin among cases as compared to control. The serum AST level was significantly (p<0.001) elevated among cases as compared to controls. Serum ALT was significantly (p<0.001) elevated among cases compared to controls. Additionally, the total serum bilirubin level was significantly increased (P<0.001) among cases as compared to controls. There was a statistically significant (P<0.001) reduction of serum albumin level among VL patients as compared to controls. Similarly, serum total protein was significantly (P<0.001) reduced in VL patients than control groups. CONCLUSION: There were significantly higher mean levels of serum AST, ALT, and total bilirubin among VL patients as compared to controls. On the other hand, VL patients showed significantly lowered level of albumin and total protein as compared to controls.

Human leishmaniasis vaccines: Use cases, target population and potential global demand.

The development of vaccines against one or all forms of human leishmaniasis remains hampered by a paucity of investment, at least in part resulting from the lack of well-evidenced and agreed estimates of vaccine demand. Starting from the definition of 4 main use cases (prevention of visceral leishmaniasis, prevention of cutaneous leishmaniasis, prevention of post-kala-azar dermal leishmaniasis and treatment of post-kala-azar dermal leishmaniasis), we have estimated the size of each target population, focusing on those endemic countries where incidence levels are sufficiently high to justify decisions to adopt a vaccine. We assumed a dual vaccine delivery strategy, including a wide age-range catch-up campaign before the start of routine immunisation. Vaccine characteristics and delivery parameters reflective of a target product profile and the likely duration of the clinical development effort were considered in forecasting the demand for each of the four indications. Over a period of 10 years, this demand is forecasted to range from 300-830 million doses for a vaccine preventing visceral leishmaniasis and 557-1400 million doses for a vaccine preventing cutaneous leishmaniasis under the different scenarios we simulated. In a scenario with an effective prophylactic visceral leishmaniasis vaccine, demand for use to prevent or treat post-kala-azar dermal leishmaniasis would be more limited (over the 10 years ~160,000 doses for prevention and ~7,000 doses for treatment). Demand would rise to exceed 330,000 doses, however, in the absence of an effective vaccine for visceral leishmaniasis. Because of the sizeable demand and potential for public health impact, a single-indication prophylactic vaccine for visceral or cutaneous leishmaniasis, and even more so a cross-protective prophylactic vaccine could attract the interest of commercial developers. Continuous refinement of these first-of-their kind estimates and confirmation of country willingness and ability to pay will be paramount to inform the decisions of policy makers and developers in relation to a leishmaniasis vaccine. Positive decisions can provide a much-needed contribution towards the achievement of global leishmaniasis control.

Density assessment and reporting for Phlebotomus perniciosus and other sand fly species in periurban residential estates in Spain.

Green periurban residential areas in Mediterranean countries have flourished in the last decades and become foci for leishmaniasis. To remedy the absence of information on vector ecology in these environments, we examined phlebotomine sand fly distribution in 29 sites in Murcia City over a 3-year period, including the plots of 20 detached houses and nine non-urbanized sites nearby. We collected 5,066 specimens from five species using "sticky" interception and light attraction traps. The relative frequency of the main Leishmania infantum vector Phlebotomus perniciosus in these traps was 32% and 63%, respectively. Sand fly density was widely variable spatially and temporally and greatest in non-urbanized sites, particularly in caves and abandoned buildings close to domestic animal holdings. Phlebotomus perniciosus density in house plots was positively correlated with those in non-urbanized sites, greatest in larger properties with extensive vegetation and non-permanently lived, but not associated to dog presence or a history of canine leishmaniasis. Within house plots, sand fly density was highest in traps closest to walls. Furthermore, the study provides a guideline for insect density assessment and reporting and is envisioned as a building block towards the development of a pan-European database for robust investigation of environmental determinants of sand fly distribution.

Potential of Piper spp. as a source of new compounds for the leishmaniases treatment.

Current treatment guidelines for leishmaniasis is based on chemotherapy with drugs that show a set of limitations such as high cost, toxicity, difficult route of administration, and lack of efficacy in endemic areas. In this context, phytopharmaceutical products and herbal medicines emerge as promising alternatives for developing new treatment against leishmaniasis. This review discusses the perspectives of leishmaniasis treatment based on natural products and phytotherapy highlighting the Piper genus, especially P. aduncun and P. mollicomum Kunth covering the period of 1998 to 2020. Leishmanicidal activity of pure compounds of Piper spp. [3-(3,4,5-trimethoxyphenyl) propanoic acid, 3-chlorosintenpyridone, 2'-hydroxy-3',4',6'-trimethoxy-chalcone, cardamonin, conocarpan, cubebin, eupomatenoid, flavokavain B, ( +)-(7R,8S)-epoxy-5,6-didehydrokavain, N-[7-(3',4'-methylenedioxypheny l-2(E),4(E)-heptadienoyl-pyrrolidine, N-[7-(3',4'-methylenedioxyphenyl)-2(Z),4(Z)-heptadienoyl-pyrrolidine, piperovatine, pellitorine, and piplartine (piperlongumine)] were proved against the promastigote and amastigote forms of parasite related with cutaneous (L. (L.) amazonensis, L. (V.) braziliensis, and L. (V.) guyanensis) and visceral (L. (L.) donovani, L. (L.) chagasi, and L. (L.) infantum). We also discussed the perspective of leishmaniasis treatment, considering the potential synergism between different promising species of Piper, presenting some interesting interaction possibilities for future studies between plants. Finally, the necessary steps for technological development of phytomedicines and herbal medicines with the desirable quality requirements for medicines are highlighted. The data presented here highlight the use of Piper spp. as source of pharmacological compounds that can lead to effective, safe, and inexpensive treatments for leishmaniasis.

Host immune response against leishmaniasis and parasite persistence strategies: A review and assessment of recent research.

Leishmaniasis, a neglected parasitic disease caused by a unicellular protozoan of the genus Leishmania, is transmitted through the bite of a female sandfly. The disease remains a major public health problem and is linked to tropical and subtropical regions, with an endemic picture in several regions, including East Africa, the Mediterranean basin and South America. The different causative species display a diversity of clinical presentations; therefore, the immunological data on leishmaniasis are both scarce and controversial for the different forms and infecting species of the parasite. The present review highlights the main immune parameters associated with leishmaniasis that might contribute to a better understanding of the pathogenicity of the parasite and the clinical outcomes of the disease. Our aim was to provide a concise overview of the immunobiology of the disease and the factors that influence it, as this knowledge may be helpful in developing novel chemotherapeutic and vaccine strategies.