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Background: Visceral leishmaniasis is endemic in Ethiopia and caused by Leishmania donovani. Although the disease manifests with significant clinical variability, a substantial number of individuals are asymptomatic. These individuals can serve as reservoirs, complicating control efforts. However, comprehensive data on asymptomatic L. donovani infections in Ethiopia are lacking, highlighting the need for a systematic review and meta-analysis to consolidate evidence and understand the distribution and determinants of this infection. Methods: PRISMA guidelines followed and registered with PROSPERO (CRD42024531454). Systematically searched electronic databases and grey literature sources up to April 13, 2024. Original research articles in English considered. Statistical analyses performed using STATA version 16. Publication bias evaluated using funnel plots and Egger's regression tests. Pooled estimate of asymptomatic L. donovani infection derived using a random effects model. Study heterogeneity assessed using Chi-square (χ²)-based Q test (p < 0.1) and I² subgroup analysis and meta-regression conducted with significance set at p < 0.05. Result: A total of 1,288 articles were identified, with 11 studies met inclusion criteria. These studies, published between 2012 and 2024, reported data from 17 districts across six regions. Sample sizes ranged from 185 to 1,682, with a total of 7,288. Six types of laboratory testing methods were employed. Prevalence of asymptomatic L. donovani infection per individual study ranged from 0.9 to 15.8%, while district-level prevalence varied from 0 to 31.1%. The overall pooled estimate of asymptomatic L. donovani infection in Ethiopia was 9.0% (95% CI: 6.0-11.0%). The pooled estimate in the Amhara region was 9.0% (95% CI: 8.0-11.0%), compared to 7.0% (95% CI: 3.0-12.0%) in other regions. Living in a household with domestic animals (OR: 2.54; 95% CI: 1.43–3.64) and being male (OR: 2.22; 95% CI: 1.21–3.23) were significantly associated with higher asymptomatic L. donovani infection. Conclusion: A considerable number of asymptomatic L. donovani infections were reported in Ethiopia. Close contact with domestic animals and being male were identified as significant risk factors. Regular screening of people living in close contact with animals. This will minimize role of man as reservoir host of asymptomatic L. donovani infection VL and hence aid in disease control and management. [ABSTRACT FROM AUTHOR]

Trypanosomatids are the etiologic agents of numerous parasitic diseases that cause significant morbidity and mortality in millions of people and animals around the world. Approved antitrypanosomatid agents are limited by several drawbacks, such as severe toxicity, lengthy treatment, need for hospitalization, and susceptibility to drug resistance. Consequently, parasitic diseases remain a substantial public health problem, and new drugs are required, especially drugs suitable for rural health systems that have limited resources. In an attempt to find antitrypanosomatid agents to address this problem, we report here on the synthesis and biological efficacy of ferrocene derivatives of nifuroxazide and nitrofurazone, which were designed by replacing the nitrofuran scaffold within their structures with the ferrocene moiety. The 1,2‐disubstituted ferrocene intermediates 8 and 9, featuring amine and carboxaldehyde groups, exhibited the best in vitro antiamastigote activity against Leishmania major strain NIH S and Leishmania donovani strain 9515, respectively. Ferroxazide derivative 15 was revealed as a mammalian cell nontoxic hit compound against Trypanosoma congolense strain IL3000 trypomastigotes; however, no in vivo treatment efficacy was observed against T. congolense strain IL3000‐infected BALB/c mice during a preliminary animal study. The synthesized ferrocene derivatives were poorly soluble in the in vitro and in vivo testing media, hindering uniform sampling and dosing. This study's outcome indicates that replacing the 5‐nitrofuran moiety with ferrocene did not increase antitrypanosomatid activity compared to the nitrofuran parent drugs nifuroxazide and nitrofurazone. [ABSTRACT FROM AUTHOR]

Background Ethiopia has a high burden of visceral leishmaniasis. Recently, there was a significant increase in cases in the South Omo Zone. This study aims to assess the prevalence of Leishmania donovani infection and its associated factors. Methods A household-based cross-sectional study was carried out in January 2023 in the South Omo Zone in Ethiopia. Dried blood spot samples were collected from 382 randomly selected study participants. Direct agglutination test (DAT) and kinetoplast DNA real-time PCR tests were performed to detect L. donovani infection. Participants' sociodemographic, clinical and risk factors for L. donovani infection data were collected using questionnaires. Bivariate and multivariate logistic regressions were used to analyze the data. Febrile cases were checked for malaria with a multiplex PCR assay. Results Overall prevalence of L. donovani infection among the sampled population was 32.5% (n=124), of which 41.1% (n=51) was detected by PCR, 33.9% (n=42) by DAT and 25.0% (n=31) by both tests. The majority of the positives were from the Logira (28.2%; n=35) and Dilbayne (29.0%; n=36) villages. Participants residing in Logira (adjusted OR [AOR]: 5.80; 95% CI 1.85 to 18.15) and Dilbayne (AOR: 3.38; 95% CI 1.15 to 9.96) villages and owning cows (AOR: 2.31; 95% CI 1.03 to 5.15) showed an association with Leishmania infection. Plasmodium falciparum was detected in 3.4% (n=2) of 59 febrile participants. Conclusions The prevalence of L. donovani infection in the South Omo Zone is high. Further research on the role of cows in the transmission cycle is needed to design the best strategy to control Leishmania infection in the South Omo Zone. Such interventions should focus on the Logira and Dilbayne villages, where most of the infections were identified. [ABSTRACT FROM AUTHOR]

Visceral Leishmaniasis, caused by Leishmania donovani, is the second most deadly parasitic disease, causing over 65,000 deaths annually. Synthetic drugs available in the market, to combat this disease, have numerous side effects. In this backdrop, we aim to find safer antileishmanial alternatives with minimal side effects from mushrooms, which harbour various secondary metabolites with promising efficacy. Robust screening of sixteen extracts from eight different wild mushrooms reveals that the hydroalcoholic extract of Amanita princeps has outstanding antileishmanial activity against Leishmania donovani. Metabolomic profiling of this lead extract identifies 50 bioactive mycocompounds and among them, 10 were selected for in-silico study against five major targets—arginase, spermidine synthase, ornithine decarboxylase, trypanothione reductase and SOD, crucial for thiol-redox balance in parasites in the polyamine synthesis pathway. Molecular docking analysis against our prioritised targets identified two mycompounds Ergosterol and Taraxacolide 1-O-b-D-glucopyranoside from Amanita princeps having the highest binding affinity of -15.8 and -11.8 kcal/mol respectively against the ornithine decarboxylase of polyamine synthesis pathway. However, MD simulations and free energy calculation using MM-GBSA analysis revealed the better stability of ergosterol with PASP receptors suggesting its promising role as an anti-leishmanial compound. Further results of in vitro arginase, SOD, and NO enzyme assays also corroborated with in-silico findings, reinforcing the anti-leishmanial efficacy of the Amanita princeps extract. Thus, both in silico and in vitro analyses suggest the efficacy of both Ergosterol and Taraxacolide 1-O-b-D-glucopyranoside compounds resourced from Amanita princeps as potent antileishmanial agents. [ABSTRACT FROM AUTHOR]

Visceral leishmaniasis (VL), caused by Leishmania donovani, remains challenging to treat due to severe side effects and increasing drug resistance associated with current chemotherapies. Our study investigates the anti-leishmanial potential of Rubus ellipticus from Uttarakhand, India, with extracts prepared from leaves and stems using ethanol and hexane. Advanced GC–MS analysis identified over 100 bioactive compounds, which were screened using molecular docking to assess their binding to LdHEL-67, a DDX3-DEAD box RNA helicase of L. donovani. Our results spotlighted nine major compounds with high binding energy, which were then further analyzed for ADMET properties and toxicity predictions, demonstrating their promising pharmacokinetic profiles. Among these, clionasterol emerged as the standout compound, displaying superior results in all in silico analyses compared to Amphotericin B (the control). Notably, clionasterol was present in significant proportions across all the mentioned extracts. Subsequent treatment with these extracts led to a remarkable reduction in the intracellular amastigote and axenic amastigote, and promastigote forms of L. donovani and non-toxic to THP-1-derived macrophages. Moreover, the extracts induced apoptotic effects, as evidenced by the fragmentation of parasitic genomic DNA. This study marks a significant leap in developing herbal-based, target-specific inhibitors against VL. Hence, our findings highlight the immense potential of R. ellipticus as a natural treatment for VL. [ABSTRACT FROM AUTHOR]

Background: Visceral leishmaniasis (VL), known as Kala-azar on the Indian subcontinent, is a parasitic disease caused by the flagellated protozoa Leishmania donovani and can be fatal if left untreated. The sand fly Phlebotomus argentipes is the only proven vector of VL in the Southeast Asia region, and VL control in this region has relied on the use of synthetic insecticides for indoor residual spraying (IRS). The use of DDT in VL control programmes has led to the development of resistance to this insecticide in sand flies, resulting in DDT being replaced with the insecticide alpha-cypermethrin. However, alpha-cypermethrin has a similar mode of action as DDT and, therefore, the risk of resistance development in sand flies increases under the pressure of regular exposure to this insecticide. In the present study we assessed the susceptibility status of wild-caught sand flies and F1 progeny using the CDC bottle bioassay. Methods: Sand flies were collected from 10 villages in Muzaffarpur District, Bihar, India. Eight of these villages are receiving continuous IRS with alpha-cypermethrin, one village had discontinued IRS with alpha-cypermethrin and one village had never received IRS with alpha-cypermethrin. The collected sand flies were exposed to a pre-determined diagnostic dose for a specific time duration (3 µg/ml for 40 min), and knockdown and mortality at 24 h post-exposure were recorded. Results: Knockdown ranged from 91.19% to 99.47% for wild-caught sand flies and from 91.70% to 98.89% for their F1 progeny. At 24 h post-exposure, mortality ranged from 89.34% to 98.93% for wild-caught sand flies and from 90.16% to 98.33% for F1 progeny. Conclusions: The results of this study showed that P. argentipes is potentially developing resistance, signalling the need for continuous monitoring and vigilance to sustain the validation of elimination once achieved. [ABSTRACT FROM AUTHOR]

Uraria picta is used as a folk medicine to cure various ailments. Regardless of ethnobotanical application, a therapeutic study of the plant parts has yet to be reported. Aqueous leaf extract was enriched with secondary metabolites like phenols, alkaloids, and terpenoids. Total phenol (60.97 mgG−1 GAE), total flavonoid (52.36 mgG−1 RE), and antioxidant activity (IC50 2666.95 µgmL−1) of the extract were measured. Bio-based silver nanoparticles (LEUP-AgNPs) were fabricated using a secondary metabolite-enriched leaf extract of U. picta (LEUP), and characterization of LEUP-AgNPs was done. The LEUP-AgNPs were crystalline, circular (13.04 ± 5.97 nm), monodisperse (pdi 0.205), and stable (-17.8 mV). The LEUP-AgNPs surface was composed of carbon, nitrogen, oxygen, and silver. A comparative study was performed to evaluate the potential of LEUP and LEUP-AgNPs against promastigotes and intra-RAW264.7 macrophage amastigotes of Leishmania donovani. A high dose of LEUP and LEUP-AgNPs significantly inhibited the growth of promastigotes up to 53% and 68%, with an IC50 value of 47.90 µgmL−1 and 6.79 µgmL−1, respectively. LEUP and LEUP-AgNPs higher doses also inhibited intracellular amastigotes up to 53% and 80% with an IC50 value of 6.72 µgmL−1 and 1.16 µgmL−1, respectively. The microscopic examination revealed that LEUP-AgNPs lead to size reduction and aggregations of promastigotes. The LEUP-AgNPs efficiently declined the number of amastigotes per RAW 264.7 macrophages compared to LEUP. LEUP-AgNPs had no cytotoxic effects on RAW 264.7 macrophages based on the CC50 value. Findings showed LEUP-AgNPs were more efficient than LEUP in controlling L. donovani, which induces visceral leishmaniasis. [ABSTRACT FROM AUTHOR]

Leishmaniasis, a protozoan disease with significant global morbidity, manifests as Cutaneous, Mucocutaneous, and Visceral forms caused by Leishmania species. Visceral Leishmaniasis (VL), caused by Leishmania donovani, poses particular fatality due to its infiltration of the central nervous system (CNS). The emergence of multidrug resistance (MDR) in L. donovani underscores the need for alternative therapeutic strategies. Plant secondary metabolites, acting as inhibitors against L. donovani's survival pathways, present a promising avenue for drug development. The cysteine synthase pathway, crucial for L. donovani's survival, can be targeted for inhibition, focusing on the O-acetyltransferase (OASS) enzyme. OASS, pivotal in this pathway and absent in humans, becomes an attractive drug target. Initiating with the selection and optimization of OASS's 3D structure (PDB Id-3TBH), virtual screening against a plant metabolite library identified lead compounds with high binding affinities. Four potential candidates were shortlisted based on estimated free energy of binding and drug likeliness. These candidates underwent molecular dynamics simulations, providing insights into protein–ligand interactions via structural analyses. Additionally, Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA) analysis calculated binding free energies. Results indicated Skimmin (IMPHY007363) as a potential lead molecule for inhibiting OASS in Leishmania donovani, showing promise for further drug development against this devastating disease. [ABSTRACT FROM AUTHOR]

Background: Post Kala-azar Dermal Leishmaniasis (PKDL) is a dermal sequel of visceral leishmaniasis (VL), poses a significant threat to the success of ongoing kala-azar elimination program, due to its potential role in sustaining transmission cycles and complicating disease management strategies. In VL, neutrophils have been identified as the 'first line of defence', having multiple roles in disease pathogenesis, but their role in PKDL, if any, still remains elusive; presenting a critical gap in knowledge, and was the aim of this study. Methodology/Principal findings: In a cohort of PKDL patients, CD66b+ neutrophils were quantified in skin biopsies, followed by immunostaining of FFPE sections to identify activated neutrophils (CD66b+/CD64+) and degranulated (CD66b+/MPO+), along with expression of neutrophil elastase (NE), matrix metalloprotease 9 (MMP9) and collagen I. Plasma levels of neutrophil chemo-attractants CXCL8/1/2/5, CCL2 and 20 and cytokines, (IL-6, IFN-γ, IL-4, IL-10, TNF-α, IL-17 and IL-22, 23) were evaluated by a multiplex assay, while lesional expression of IL-8, IL-10 and IL-17 was evaluated by immunohistochemistry. As compared to healthy individuals (control skin samples), PKDL cases at the lesional sites had an increased number of activated CD66b+ neutrophils (positive for CD64+, MPO+ and NE+). The plasma levels of neutrophil chemo-attractants, pro-inflammatory and regulatory cytokines were raised as was circulating and lesional IL-8, along with an enhanced lesional expression of IL-10 and IL-17A. An increase in circulatory and lesional MMP9 was accompanied by decreased collagen I, suggesting disintegration of matrix integrity. Conclusions/Significance: Taken together, in PKDL, activated neutrophils possibly contribute towards modulating the lesional landscape. Understanding this involvement of neutrophils in patients with PKDL, particularly in the absence of an animal model, could offer better understanding of the disease pathogenesis and provide insights into novel therapeutic strategies for the ongoing elimination program. Author summary: Visceral leishmaniasis (VL), also known as kala-azar, is a fatal form of leishmaniasis caused by the digenetic parasite Leishmania donovani. In South Asia, around 10–20% of the cured VL cases develop a chronic dermal manifestation known as post-kala-azar dermal leishmaniasis (PKDL). Patients with PKDL serve as 'active disease reservoirs', perpetuating the transmission cycle and thereby pose a significant threat to the success of the ongoing kala-azar elimination program. Moreover, the absence of an animal model in PKDL poses a great challenge in elucidating the pathogenesis of the disease, thereby restricting studies exclusively to clinical cases. Neutrophils are recognized as crucial players in the initial phase of VL, acting as the 'first line of defence' and actively influence the outcome of infection, but their significance in PKDL has been overlooked, with previous research primarily focussing on macrophages and lymphocytes. This study addresses the critical gap in understanding the role of neutrophils in PKDL. This study revealed that neutrophils infiltrating at the lesional sites in PKDL played a functional role in modulating the disease pathology, shedding light on their involvement beyond the initial phase of infection. Conclusively, the findings in this study highlighted the importance of considering neutrophils as the 'new kid in the block' in PKDL immunology. In addition, this study contributed to a broader understanding of the disease pathogenesis by elucidating the extended roles of neutrophils in chronic phase of infection providing valuable insights that could potentiate targeted interventions, crucial for elimination of this debilitating neglected tropical disease. [ABSTRACT FROM AUTHOR]

AbstractVisceral leishmaniasis still remains a leading cause of parasitic deaths, with modern pentavalent antimonials showing limited efficacy and health risks. The methanolic bark extract of the Northeastern Indian plant, Garcinia cowa, demonstrated potent leishmanicidal effects against the parasite Leishmania donovani, demonstrating IC50 values of 20–36 µg/ml, with selective toxicity for parasites over healthy cells. It induced parasite death through elevated oxidative and nitrosative stress elements, reduced arginase activity, nuclear fragmentation, cell cycle arrest, and apoptosis. A GC-MS study and molecular docking identified stigmasterol as a primary component, an antileishmanial compound that inhibits Leishmania donovani parasite efficiently. [ABSTRACT FROM AUTHOR]

Visceral leishmaniasis (VL) caused by L. donovani in South-East Asian endemic countries including India, Nepal and Bangladesh has been the primary focus of the ongoing VL elimination program. With a major reduction in VL cases resulting from the elimination program during the last two decades, the efforts are now focused on the challenges posed by potential reservoirs within the asymptomatic cases, HIV-co-infection VL cases and Post Kala-azar Dermal Leishmaniasis (PKDL) cases that continue to sustain the parasite transmission cycle in known and newer endemic zones. This article brings attention to a new potential parasite reservoir in the form of atypical cutaneous leishmaniasis (ACL) cases caused by novel L. donovani genetic variants. L. donovani mediated ACL is an emerging phenomenon in recent endemic sites that now justify a need for implementing molecular surveillance tools to identify region-specific L. donovani variants with dermotropic capabilities and potential to revert to visceral disease. A timely detection of novel ACL causing L. donovani genetic lineages in South-East Asian endemic regions is necessary to halt the spread of ACL and is potentially crucial for the sustainability of the advances made by the VL elimination. [ABSTRACT FROM AUTHOR]

Background: Collectively, leishmaniasis and Chagas disease cause approximately 8 million cases and more than 40,000 deaths annually, mostly in tropical and subtropical regions. The current drugs used to treat these diseases have limitations and many undesirable side effects; hence, new drugs with better clinical profiles are needed. Fungal endophytes associated with plants are known to produce a wide array of bioactive secondary metabolites, including antiprotozoal compounds. In this study, we analyzed endophytic fungal isolates associated with Theobroma cacao and Coffea arabica crop plants, which yielded extracts with antitrypanosomatid activity. Methods: Crude extracts were subjected to bioassay-guided isolation by HPLC, followed by spectrometric and spectroscopic analyses via mass spectrometry (MS) and nuclear magnetic resonance (NMR), Results: Compounds 1–9 were isolated and displayed novel antitrypanosomal and antileishmanial activities ranging from 0.92 to 32 μM. Tandem liquid chromatography–mass spectrometry (LC–MS) analysis of the organic extracts from different strains via the feature-based Global Natural Products Social (GNPS) molecular networking platform allowed us to dereplicate a series of metabolites (10–23) in the extracts. Molecular docking simulations of the active compounds, using the 3-mercaptopyruvate sulfurtransferase protein from L. donovani (Ld3MST) and the cruzipain enzyme from T. cruzi as putative molecular targets, allowed us to suggest possible mechanisms for the action of these compounds. Conclusions: The isolation of these antiprotozoal compounds confirms that crop plants like coffee and cacao harbor populations of endophytes with biomedical potential that confer added value to these crops. [ABSTRACT FROM AUTHOR]

Visceral leishmaniasis derived from Leishmania donovani is transmitted by sand flies (Phlebotomus argentipes) throughout the Indian subcontinent. Although considered anthroponotic, L. donovani infects other mammals susceptible to sand fly bites, including dogs. Aggressive strategies to reduce sand fly populations in India have led to flies seeking nonhuman hosts, so understanding the role of dogs in L. donovani transmission has become critical. Our study investigated L. donovani infection in dogs and the potential for such infections to be transmitted back to sand flies. We performed xenodiagnosis by using P. argentipes on dogs (n = 73) with quantitative PCR–detectible parasitemia in both endemic and outbreak villages. We found that 12% (9/73) of dogs were infectious to sand flies during winter and rainy seasons. Patients with visceral leishmaniasis remain primary sources of L. donovani transmission, but our findings suggest a possible link between canine infection and human exposure.

Abstract India is accelerating efforts to eliminate kala-azar by aligning its National Kala-Azar Elimination Program with the World Health Organization’s (WHO) roadmap for Neglected Tropical Diseases (NTDs) 2021–2030. Elimination relies on comprehensive vector surveillance and integrated vector management. This study aimed to conduct nationwide entomological surveillance to detect Leishmania donovani in phlebotomine sand flies. A cross-sectional survey was conducted from January 2022 to December 2023 in five different biogeographical zones in India. Mechanical aspirator, light traps were used for sampling. The collected sand flies were identified to species level. Molecular xenomonitoring was conducted using kDNA qPCR, and parasite characterization targeting ITS1 gene sequencing and RFLP. Sand fly species was confirmed by DNA barcode. Molecular xenomonitoring revealed that Phlebotomus argentipes from Bihar, West Bengal, and Kerala exhibited high levels of L. donovani parasitic DNA. In Rajasthan, P. sergenti and P. papatasi and in Himachal Pradesh, P. longiductus, P. major, and P. bruneyi were positive. The high levels of L. donovani parasitic DNA detected in various Phlebotomus species, along with its presence in other sand fly species beyond the established vectors, underscore the urgent need for the National Kala-Azar Elimination Program to prioritize comprehensive and rigorous vector surveillance. Strengthening these efforts is crucial for achieving the program’s goal of eliminating the disease.

Abstract Background Visceral leishmaniasis (VL) remains a significant public health concern in West Pokot County, Kenya, where a large outbreak between 2020 and 2022 emphasised the need for improved VL control strategies. However, these measures are partially hampered by limited insight into the geographical distribution of cases and localised outbreaks of the disease. This study aimed to describe the epidemiology and spatiotemporal patterns of VL in West Pokot between 2018 and 2022, in order to map the spread of VL transmission and identify regions that should be prioritised for control interventions. Methods VL patient demographics and village of residence were retrieved from admission records of Kacheliba Sub-County Hospital in West Pokot, Kenya. The temporal trend in VL admissions between 2018 and 2022 was analysed using seasonal decomposition analysis. To describe the spatial distribution of VL cases, geographic coordinates of villages of residence were collected from pre-established databases, and VL incidence was mapped at the sub-location level. Hotspot analysis was performed per study year to identify villages with high VL incidence, and scan statistics were applied to detect spatiotemporal clusters of VL cases during the study period. Results A total of 1948 VL patients were reported between 2018 and 2022. The annual number of cases increased from 245 in 2019 to 598 in 2022, and VL admissions were generally higher at the start of the wet seasons. 70% of the VL cases could be georeferenced, and mapping of VL incidence revealed high case rates in the east of West Pokot during the complete study period. The eastern villages Lotongot and Chepaywat were marked as VL hotspots at a 99% confidence level in all study years. In addition, five significant spatiotemporal clusters were detected in the east and north, suggestive of local VL outbreaks in these regions. Conclusions The increase in VL hospital admissions during the study period stresses the need for enhanced VL control and outbreak mitigation in West Pokot. These control measures should be focused on the hotspot regions in the east of the county.

Cutaneous leishmaniasis is atypical in Sri Lanka because Leishmania donovani, which typically causes visceral disease, is the causative agent. The origins of recently described hybrids between L. donovani and other Leishmania spp. usually responsible for cutaneous leishmaniasis remain unknown. Other endemic dermotropic Leishmania spp. have not been reported in Sri Lanka. Genome analysis of 27 clinical isolates from Sri Lanka and 32 Old World Leishmania spp. strains found 8 patient isolates clustered with L. tropica and 19 with L. donovani. The L. tropica isolates from Sri Lanka shared markers with strain LtK26 reported decades ago in India, indicating they were not products of recent interspecies hybridization. Because L. tropica was isolated from patients with leishmaniasis in Sri Lanka, our findings indicate L. donovani is not the only cause of cutaneous leishmaniasis in Sri Lanka and potentially explains a haplotype that led to interspecies dermotropic L. donovani hybrids.

Background & objectives: The human blood parasite Leishmania donovani causes visceral leishmaniasis or grayish discoloration of the skin (black fever/kala-azar). Antitumor drugs such as daunorubicin and etoposide can help to treat such diseases. The computational approach is used to find a better interaction of drugs with the active site of the protein and help to design new drugs. Methods: In this study, we have optimized two antitumor drugs, daunorubicin and etoposide. We studied frontier molecular orbitals, electrostatic potential (MEP) maps, and the natural bond order analysis of these anticancer drugs, followed by molecular docking with Leishmania donovani protein. Results: The three-dimensional structure of MapK from Leishmania donovani is LDBPK-331470. Our computational calculations reveal that daunorubicin and etoposide drugs can have an affinity with MapK from Leishmania donovani. Interpretation & conclusion: Our study predicted that both daunorubicin and etoposide could have a similar affinity with the protein (UvrD) Leishmania donovani.

Leishmaniasis is a neglected disease with a global spread that affects both domestic and wild animals in addition to people. Leishmania donovani is the suspected anthroponotic cause of visceral leishmaniasis (VL) in India, where it is an endemic disease. The reservoir hosts play a crucial role in the life cycle of the Leishmania parasite. The complicated connection between the pathogen, vector, and reservoir exhibits geographical and temporal diversity. Human-to-human and, to a lesser extent, human-to-animal transmission are the principal mechanisms for the maintenance of anthroponotic diseases. A number of animals were examined for the presence of Leishmania parasites and the findings were reviewed in order to examine the role of animal reservoirs in domestic transmission of cutaneous leishmaniasis in endemic regions of India. The analysis objective was to assess the research conducted on domestic animals’ propensity to spread L. donovani in endemic areas, with a particular emphasis on how proximity and animal density may impact the prevalence of human leishmaniasis. Species of the L. donovani complex have distinct enzootic, zoonotic, and anthroponotic life cycles that depend on the environment. The majority of Leishmania spp. are zoonotic, spreading from non-human mammals to humans. Many nations have leishmaniasis as an endemic disease, and the Indian subcontinent (ISC) has an estimated two to three lakh people who are at risk. This systematic review evaluates the gaps in our understanding of disease transmission that contradict conventional wisdom about the reservoir(s) of visceral leishmaniasis and efforts to manage it on the Indian subcontinent. Fundamental concerns in VL epidemiology and ecology will be clarified by a better understanding of L. donovani infection in domestic animals and its transfer to sandflies. A deliberate, systematic search was conducted on PubMed, Science Direct, and Google Scholar using keywords such as “Leishmania donovani”, “zoonotic visceral leishmaniasis”, and “wild animal reservoir for Leishmania donovani”. A total of 530 potentially relevant references were obtained from these databases, and 507 were not considered due to copy avoidance, irrelevant titles, research publications from nations other than India, or modified compositions. Among the remaining 23 investigations, 20 were rejected, and only 3 were included in the present study. Finally, three research papers with 867 goats, 161 cattle, 106 chickens, 26 sheep, three buffaloes, 406 dogs, and 309 rats were reported. Along with these data, studies across Asian and African countries that are considered VL-endemic areas have been discussed. According to the review, goats are the epidemic’s primary host and possible reservoir in several regions of India. In the endemic regions of the disease, some species of rodents, along with the canines, appear to be maintaining the L. donovani transmission cycle.

Phlebotomus argentipes is the established vector of leishmaniasis in the Indian sub-continent. Antibodies to sand fly salivary antigens are biomarkers for vector-host exposure in leishmaniasis-endemic regions. Ph. argentipes transmits Leishmania donovani in Sri Lanka, primarily causing cutaneous leishmaniasis (CL). Our study compared the performance of salivary gland homogenate (SGH) from a lab-reared local strain of Ph. argentipes females to a composite recombinant salivary biomarker (rPagSP02 + rPagSP06) in a CL-endemic population. Sera from 546 healthy individuals, 30 CL patients, and 15 non-endemic individuals were collected. Western blot analysis of Ph. argentipes SGH identified immunogenic bands between 15 kDa and 67 kDa, with bands of predicted molecular weight ∼of 15 kDa (SP02) and ∼28–30 kDa (SP06) as the major antibody targets. Indirect ELISAs using SGH or rPagSP02 + rPagSP06 antigens showed high sensitivity (96.7%) and specificity (100%), detecting comparable seropositivity in endemic populations. rPagSP02 + rPagSP06 exhibited enhanced discriminatory ability, supported by a strong positive correlation (r = 0.869) with SGH. Our findings indicate that the composite rPagSP02 + rPagSP06 salivary biomarker effectively identifies Ph. argentipes exposure in individuals living in Sri Lanka, showing promising potential for use in surveillance. These findings should be further validated to confirm the epidemiological applications in leishmaniasis-endemic regions. [ABSTRACT FROM AUTHOR]

Adenylosuccinate synthetase (AdSS), which catalyses the GTP‐dependent conversion of inosine monophosphate (IMP) and aspartic acid to succinyl‐AMP, plays a major role in purine biosynthesis. In some bacterial AdSS, it is implicated that IMP binding is important to organize the active site, but in certain plant AdSS, GTP performs this role. Here, we report that in Leishmania donovani AdSS, IMP binding favoured dimerization, induced greater conformational change and improved the protein stability more than GTP binding. IMP binding, which resulted in a network of hydrogen bonds, stabilized the conformation of active site loops and brought the switch loop to a closed conformation, which then facilitated GTP binding. Our results provide a basis for designing better inhibitors of leishmanial AdSS. [ABSTRACT FROM AUTHOR]

Sterol biosynthesis requires the oxidative removal of two methyl groups from the C-4 position by sterol C-4-demethylase and one methyl group from the C-14 position by sterol C-14-demethylase. In Leishmania donovani, a CYP5122A1 (Cytochrome P450 family 5122A1) protein was recently identified as the bona fide sterol C-4 methyl oxidase catalyzing the initial steps of C-4-demethylation. Besides CYP5122A1, Leishmania parasites possess orthologs to ERG25 (ergosterol pathway gene 25), the canonical sterol C-4 methyl oxidase in Saccharomyces cerevisiae. To determine the contribution of CYP5122A1 and ERG25 in sterol biosynthesis, we assessed the essentiality of these genes in Leishmania major, which causes cutaneous leishmaniasis. Like in L. donovani, CYP5122A1 in L. major could only be deleted in the presence of a complementing episome. Even with strong negative selection, L. major chromosomal CYP5122A1-null mutants retained the complementing episome in both promastigote and amastigote stages, demonstrating its essentiality. In contrast, the L. major ERG25-null mutants were fully viable and replicative in culture and virulent in mice. Deletion and overexpression of ERG25 did not affect the sterol composition, indicating that ERG25 is not required for C-4-demethylation. These findings suggest that CYP5122A1 is the dominant and possibly only sterol C-4 methyl oxidase in Leishmania, and inhibitors of CYP5122A1 may have strong therapeutic potential against multiple Leishmania species. [ABSTRACT FROM AUTHOR]

Background: Cutaneous leishmaniasis (CL) in Ethiopia and some parts of Kenya is predominantly caused by Leishmania aethiopica. While skin-slit (SS) microscopy is routinely used for CL diagnosis, more sensitive molecular tests are available. The Loopamp™ Leishmania detection kit (Loopamp) is a robust loop-mediated isothermal amplification (LAMP) assay with the potential for implementation in primary healthcare facilities. In this study, we comparatively assessed the diagnostic accuracy of four methods currently used to diagnose CL: Loopamp, kinetoplast DNA (kDNA) PCR, spliced leader RNA (SL-RNA) PCR and SS microscopy. Methods: A study on 122 stored tape disc samples of suspected CL patients was conducted in Gondar, northwestern Ethiopia. Routine SS microscopy results were obtained from all patients. Total nucleic acids were extracted from the tapes and subjected to PCR testing targeting kDNA and SL-RNA, and Loopamp. Diagnostic accuracy was calculated with SS microscopy as a reference test. The limit of detection (LoD) of Loopamp and kDNA PCR were determined for cultured L. aethiopica and Leishmania donovani. Results: Of the 122 patients, 64 (52.5%) were identified as CL cases based on SS microscopy. Although the PCR tests showed a sensitivity of 95.3% (95% confidence interval [CI] 91.6–99.1), Loopamp only had 48.4% (95% CI 39.6–57.3) sensitivity and 87.9% (95% CI 82.1–93.7) specificity. The LoD of Loopamp for L. donovani was 100-fold lower (20 fg/µl) than that for L. aethiopica (2 pg/µl). Conclusions: The Loopamp™ Leishmania detection kit is not suitable for the diagnosis of CL in Ethiopia, presumably due to a primer mismatch with the L. aethiopica 18S rRNA target. Further research is needed to develop a simple and sensitive point-of-care test that allows the decentralization of CL diagnosis in Ethiopia. [ABSTRACT FROM AUTHOR]

Background: Visceral leishmaniasis (VL) remains a significant public health concern in West Pokot County, Kenya, where a large outbreak between 2020 and 2022 emphasised the need for improved VL control strategies. However, these measures are partially hampered by limited insight into the geographical distribution of cases and localised outbreaks of the disease. This study aimed to describe the epidemiology and spatiotemporal patterns of VL in West Pokot between 2018 and 2022, in order to map the spread of VL transmission and identify regions that should be prioritised for control interventions. Methods: VL patient demographics and village of residence were retrieved from admission records of Kacheliba Sub-County Hospital in West Pokot, Kenya. The temporal trend in VL admissions between 2018 and 2022 was analysed using seasonal decomposition analysis. To describe the spatial distribution of VL cases, geographic coordinates of villages of residence were collected from pre-established databases, and VL incidence was mapped at the sub-location level. Hotspot analysis was performed per study year to identify villages with high VL incidence, and scan statistics were applied to detect spatiotemporal clusters of VL cases during the study period. Results: A total of 1948 VL patients were reported between 2018 and 2022. The annual number of cases increased from 245 in 2019 to 598 in 2022, and VL admissions were generally higher at the start of the wet seasons. 70% of the VL cases could be georeferenced, and mapping of VL incidence revealed high case rates in the east of West Pokot during the complete study period. The eastern villages Lotongot and Chepaywat were marked as VL hotspots at a 99% confidence level in all study years. In addition, five significant spatiotemporal clusters were detected in the east and north, suggestive of local VL outbreaks in these regions. Conclusions: The increase in VL hospital admissions during the study period stresses the need for enhanced VL control and outbreak mitigation in West Pokot. These control measures should be focused on the hotspot regions in the east of the county. [ABSTRACT FROM AUTHOR]

Leishmaniasis poses a significant health burden, particularly among immunocompromised patients. In Thailand, Leishmania infection caused by Leishmania martiniquensis and Leishmania orientalis lacks information about the incidence and risk factors among HIV-infected populations. This longitudinal cohort study aimed to investigate the incidence and persistence of Leishmania infection among HIV-infected individuals in an affected area, Trang Province, Southern Thailand. The study also identified risk factors associated with the incidence of Leishmania infection. The study enrolled 373 participants in the HIV clinic, Trang Hospital, who initially tested negative for Leishmania infection during 2015–2016, and 133 individuals initially tested positive for Leishmania infection. Thus, follow-up visits of 506 participants occurred during 2018–2019. Direct Agglutination Test (DAT) and nested PCR (nPCR) identified incidents and persistent cases of Leishmania infection. Cox proportional-hazards regression analyses were performed to assess risk factors for the incidence of Leishmania infection. Among the initially negative group, 12 incident cases comprised one L. orientalis infection and 11 seropositive cases using DAT, resulting in a cumulative incidence of 3.2% and an incidence density of 10.38 per 1000 person-years. Increasing age was a significant predictor of the incidence of Leishmania infection. Five persistent cases comprised one Leishmania donovani complex and four seropositive cases using DAT in the initially positive group, with a cumulative persistence rate of 3.7% and a persistence density of 12.85 per 1000 person-years. All patients were asymptomatic. This study sheds light on the incidence and persistence of Leishmania infection among HIV-infected individuals in Trang Province, Southern Thailand, underscoring the importance of continued monitoring and tailored interventions to mitigate the impact of this co-infection. Author summary: In Thailand, Leishmania martiniquensis and Leishmania orientalis are the causative agents of cutaneous (CL) and visceral leishmaniasis (VL) reported in immunocompetent and immunocompromised individuals. VL poses a significant health threat, especially to those with HIV infection. Our study conducted a cohort study among HIV-infected patients in Trang Hospital, Trang Province, Southern Thailand, to explore the incidence and persistence of Leishmania infection, a topic not extensively studied in this region. Our findings are crucial for multiple reasons. Firstly, this study reveals a significant incidence rate of 3.2% among HIV patients, and increasing age was a significant predictor of incident Leishmania infection. Secondly, the persistence of Leishmania infection in 3.7% of initially positive cases underscores the challenges in managing this co-infection. It has immediate implications for healthcare providers, policymakers, and public health officials, aiding them in implementing targeted interventions and preventive measures to reduce the impact of leishmaniasis among HIV-infected individuals. By shedding light on this understudied issue, we hope to contribute to better health outcomes for this vulnerable population. [ABSTRACT FROM AUTHOR]

Introduction: Hemophagocytic lymphohistiocytosis characterized by hemophagocytosis leading to uncontrolled inflammation; the most common etiology in secondary cases of hemophagocytic lymphohistiocytosis is viral infections, especially Epstein–Barr virus. Visceral leishmaniasis is a vectorborne protozoal disease caused by Leishmania donovani complex. It is common in tropical and subtropical regions, with 50,000–90,000 new cases annually. Case presentation: A 15-month-old Arab female was admitted to our hospital with 15 days of fever and decreased weight. On clinical examination, she had a markedly enlarged liver and spleen that were palpable 4 cm and 6 cm below the costal margin, respectively. The peripheral blood smear showed hypochromic microcytic anemia, poikilocytosis, reactive lymphocytosis, and mild thrombocytopenia. Bone marrow aspiration did not show malignancy or any other pathological findings. The patient was put on antibiotic therapy without improvement. Repeated bone marrow aspiration showed erythrophagocytosis; intracellular small round organisms looked like the amastigote form of Leishmania (Donovan bodies) with no evidence of malignancies. Her lab values showed ferritin greater than 500 ug/L, pancytopenia, and hypertriglyceridemia. The patient was diagnosed with hemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis. Conclusion: Hemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis is an extensively rare phenomenon in the medical literature that causes challenges in diagnosis and management. Steroids should be used wisely to not cover the symptoms of infections or malignancy, and amphotericin B resistance should be kept in mind in unresponsive Leishmania cases. [ABSTRACT FROM AUTHOR]

Human visceral leishmaniasis (VL) is an endemic disease in eastern Sudan, particularly in Al Gadarif State, causing significant morbidity and fatality rates. This disease is induced by Leishmania donovani and Leishmania infantum. Several studies have suggested that dogs (Canis familiaris), which are known for being the primary reservoir hosts of L. infantum (causing canine leishmaniasis), may play a vital role in transmitting human VL caused by L. donovani. This study aimed to determine the prevalence of leishmaniasis in general and L. donovani, particularly in dogs, and to investigate the potential risk factors associated with the disease in Al Gadarif State. Blood samples were collected from 151 dogs from five localities and examined using Giemsa-stained blood smears and PCR. The overall prevalence was 44.4% based on microscopic examination. Significant variation in the prevalence of leishmaniasis was observed among the localities (p = 0.000), where the highest prevalence was reported in Algurreisha (85%) and the lowest was observed in Alhawata (4.2%). Dog type was another risk factor that was shown to be significantly associated with infection (p = 0.041). The highest prevalence was reported in household dogs (47.7%) compared to stray dogs (23.8%). The analysis revealed that factors such as the use of dogs, sex, and age were not statistically linked to the disease. However, among household dogs, the highest prevalence was reported in pet dogs (59.7%), males (49.1%) compared to females (32.6%), and young dogs (50%) compared to older dogs (40.9%). All blood samples tested negative for L. donovani by PCR, thus requiring further investigation to identify the causative species in dogs and their possible roles in the epidemiology of zoonotic leishmaniasis in Sudan. [ABSTRACT FROM AUTHOR]

The aim of this work was to obtain and evaluate, as antiprotozoals, new derivatives of benzoate imidazo-1,3,4-thiadiazole 18–23 based on the concepts of molecular repositioning and hybridization. In the design of these compounds, two important pharmacophoric subunits of the fexnidazole prototype were used: metronidazole was used as a repositioning molecule, p-aminobenzoic acid was incorporated as a bridge group, and 1,3,4-thiadiazole group was incorporated as a second pharmacophore, which at position 5 has an aromatic group with different substituents incorporated. The final six compounds were obtained through a five-step linear route with moderate to good yields. The biological results demonstrated the potential of this new class of compounds, since three of them 19–21 showed inhibitory activity on proliferation, in the order of 50%, in the in vitro assay against epimastigotes of T. cruzi (Strain Y sensitive to nifurtimox and benznidazole) and promastigotes of L. donovani, at a single concentration of 50 μM. [ABSTRACT FROM AUTHOR]

Purpose: The parasitic disease leishmaniasis is responsible for high mortality and morbidity rates worldwide. The visceral form is the most severe form of leishmaniasis (or leishmaniosis), which is caused predominantly by Leishmania donovani. Currently, clinically recommended antileishmanial drugs are not convenient because of several medical complications and resistance issues. Phytocompounds are the best candidates in this regard. The present study aimed to evaluate the antileishmanial activity of Averrhoa carambola leaf extract. Methods: The antipromastigote activity and cytotoxicity were assessed using the MTT assay. Morphological distortions were determined using phase contrast microscopy and scanning electron microscopy (SEM). Reactive oxygen species (ROS) production, nonprotein thiol depletion and apoptotic death in promastigotes were determined via flow cytometry. UV–visible spectroscopy and energy dispersive X-ray (EDX) spectroscopy was performed for elemental analysis. Fourier-transform infrared spectroscopy (FTIR) and liquid chromatography‒mass spectrometry (LCMS) were used to characterize the phytocomponent(s) present in the extract. Results: The chloroform extract of Averrhoa carambola leaf (ACCEX) (IC50 = 50.76 ± 1.7 µg/mL) exhibited the highest activity, followed by the ethyl acetate, hexane, and methanol extracts. ACCEX has also exhibited lower toxicity towards host macrophages. ACCEX also induced morphological distortions in promastigotes, with significant generation of ROS and the concomitant apoptosis initiation followed by a decrease in the nonprotein thiol level. The major phytometabolites present in ACCEX were identified from the National Institute of Standards and Technology (NIST) database and from a literature review. Conclusions: This study suggested that Averrhoa carambola leaf extracts are rich in some classes of biologically active phytocompounds and exhibit good antileishmanial activity. [ABSTRACT FROM AUTHOR]

Background: Leishmaniasis is a deadly protozoan parasitic disease and a significant health problem in underdeveloped and developing countries. The global spread of the parasite, coupled with the emergence of drug resistance and severe side effects associated with existing treatments, has necessitated the identification of new and potential drugs. Objective: This study aimed to identify promising compounds for the treatment of leishmaniasis by targeting two essential enzymes of Leishmania donovani: trypanothione reductase (Try-R) and trypanothione synthetase (Try-S). Methods: High-throughput virtual and in vitro screening of in-house and commercial databases was conducted. A pharmacophore model with seven features was developed and validated using the Guner-Henery method. The pharmacophore-based virtual screening yielded 690 hits, which were further filtered through Lipinski's rule, ADMET analysis, and molecular docking against Try-R and Try-S. Molecular dynamics studies were performed on selected compounds, and in vitro experiments were conducted to evaluate their activity against the promastigote and amastigote forms of L. donovani. Results: The virtual screening and subsequent analysis identified 33 promising compounds. Molecular dynamics studies of two compounds (comp-1 and comp-2) demonstrated stable binding interactions with the target enzymes and high affinity. In vitro experiments revealed that 13 compounds exhibited moderate activity against both the promastigote (IC50, 41 µM–76 µM) and the amastigote (IC50, 44 µM–72 µM) forms of L. donovani. Compounds 1 and 2 showed the highest percent inhibition and the lowest IC50 values. Conclusion: The identified compounds demonstrated significant inhibitory activity against Leishmania donovani and stable interactions with target enzymes. These findings suggest that the compounds could serve as promising leads for developing new treatments for leishmaniasis. [ABSTRACT FROM AUTHOR]

Cutaneous leishmaniasis is atypical in Sri Lanka because Leishmania donovani, which typically causes visceral disease, is the causative agent. The origins of recently described hybrids between L. donovani and other Leishmania spp. usually responsible for cutaneous leishmaniasis remain unknown. Other endemic dermotropic Leishmania spp. have not been reported in Sri Lanka. Genome analysis of 27 clinical isolates from Sri Lanka and 32 Old World Leishmania spp. strains found 8 patient isolates clustered with L. tropica and 19 with L. donovani. The L. tropica isolates from Sri Lanka shared markers with strain LtK26 reported decades ago in India, indicating they were not products of recent interspecies hybridization. Because L. tropica was isolated from patients with leishmaniasis in Sri Lanka, our findings indicate L. donovani is not the only cause of cutaneous leishmaniasis in Sri Lanka and potentially explains a haplotype that led to interspecies dermotropic L. donovani hybrids. [ABSTRACT FROM AUTHOR]

Nanostructured lipid carriers have gained popularity due to their exceptional physicochemical and biocompatible properties and also have been proven to deliver valuable drugs without compromising safety and efficacy. In this study, nanostructured lipid carriers brimmed with amphotericin B were prepared using a novel one-pot, single-step microwave-assisted method. Maneuvering a 2-factor 3-level central composite design. The characterization of preparation of optimized batch was done by Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. Further, evaluation was done for in vitro drug release, ex vivo skin permeation, histopathology, stability studies, and antileishmanial activity. The optimized batch of formulation was found to be monodispersed having PdI 0.209 and particle size of 123.9 nm with drug entrapment efficiency of 91.2% that remained stable on storage. Histopathological evaluation confirmed the preparation to be safe on the skin. Antileishmanial study confirmed the cytotoxicity of the formulation towards the L. donovani infected THP1 cells. In vitro drug release investigation revealed 61.716 ± 0.02% release of amphotericin B in 8 h, following the Higuchi model of release kinetics, and drug release was governed by Fickian diffusion (n < 0.5). Here, nanostructured lipid carriers prepared by microwave assisted technique demonstrated the enhanced solubility, permeability, stability and also prospected the significant antileishmanial activity. Thus, it could be a promising alternative for treating other parasitic infections also. Graphical depiction of formulation, characterization and evaluation of AmpB-NLC [ABSTRACT FROM AUTHOR]

Leishmaniasis is a neglected disease with a global spread that affects both domestic and wild animals in addition to people. Leishmania donovani is the suspected anthroponotic cause of visceral leishmaniasis (VL) in India, where it is an endemic disease. The reservoir hosts play a crucial role in the life cycle of the Leishmania parasite. The complicated connection between the pathogen, vector, and reservoir exhibits geographical and temporal diversity. Human-to-human and, to a lesser extent, human-to-animal transmission are the principal mechanisms for the maintenance of anthroponotic diseases. A number of animals were examined for the presence of Leishmania parasites and the findings were reviewed in order to examine the role of animal reservoirs in domestic transmission of cutaneous leishmaniasis in endemic regions of India. The analysis objective was to assess the research conducted on domestic animals' propensity to spread L. donovani in endemic areas, with a particular emphasis on how proximity and animal density may impact the prevalence of human leishmaniasis. Species of the L. donovani complex have distinct enzootic, zoonotic, and anthroponotic life cycles that depend on the environment. The majority of Leishmania spp. are zoonotic, spreading from non-human mammals to humans. Many nations have leishmaniasis as an endemic disease, and the Indian subcontinent (ISC) has an estimated two to three lakh people who are at risk. This systematic review evaluates the gaps in our understanding of disease transmission that contradict conventional wisdom about the reservoir(s) of visceral leishmaniasis and efforts to manage it on the Indian subcontinent. Fundamental concerns in VL epidemiology and ecology will be clarified by a better understanding of L. donovani infection in domestic animals and its transfer to sandflies. A deliberate, systematic search was conducted on PubMed, Science Direct, and Google Scholar using keywords such as "Leishmania donovani", "zoonotic visceral leishmaniasis", and "wild animal reservoir for Leishmania donovani". A total of 530 potentially relevant references were obtained from these databases, and 507 were not considered due to copy avoidance, irrelevant titles, research publications from nations other than India, or modified compositions. Among the remaining 23 investigations, 20 were rejected, and only 3 were included in the present study. Finally, three research papers with 867 goats, 161 cattle, 106 chickens, 26 sheep, three buffaloes, 406 dogs, and 309 rats were reported. Along with these data, studies across Asian and African countries that are considered VL-endemic areas have been discussed. According to the review, goats are the epidemic's primary host and possible reservoir in several regions of India. In the endemic regions of the disease, some species of rodents, along with the canines, appear to be maintaining the L. donovani transmission cycle. [ABSTRACT FROM AUTHOR]

Obligate intracellular protozoan parasite, Leishmania donovani, causative agent of visceral leishmaniasis, led to impaired macrophage functions. It is well documented that many of these changes were induced by parasite‐mediated reduction in macrophage cholesterol content. Leishmania‐mediated alteration in the other lipids has not been explored in detail yet. Here, we found that the expression of key cholesterol biosynthetic genes and total cellular cholesterol were reduced during L. donovani infection. Further, we have also identified that this reduction in the cholesterol led to increased membrane fluidity and inhibition of antigen‐presenting potential of macrophages. In addition to this, we studied the relative changes in different lipids in THP‐1‐derived macrophages during L. donovani infection through liquid chromatography‐mass spectrometry. We found that Sphingomyelin (16:0) and ceramide (20:1, 26:0 and 26:1) were significantly reduced in infected macrophages. We further observed that the majority of different sub‐classes of phospholipids were downregulated significantly. Overall ratio of phosphatidylcholine versus phosphotidylethanolamine was decreased which indicated the compensatory mechanism of cell in response to cholesterol reduction. The observed Leishmania‐mediated alteration in macrophage‐lipidome provided the novel insights into mechanism of host‐pathogen interactions. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a spectrum of conditions caused by infection with the protozoan Leishmania spp. parasites. Leishmaniasis is endemic in 98 countries around the world, and resistance to current anti-leishmanial drugs is rising. Our work has identified and characterised a previously unstudied galactokinase-like protein (GalK) in Leishmania donovani , which catalyses the MgATP-dependent phosphorylation of the C-1 hydroxyl group of d -galactose to galactose-1-phosphate. Here, we report the production of the catalytically active recombinant protein in E. coli , determination of its substrate specificity and kinetic constants, as well as analysis of its molecular envelope using in solution X-ray scattering. Our results reveal kinetic parameters in range with other galactokinases with an average apparent Km value of 76 μM for galactose, V max and apparent K cat values with 4.46376 × 10−9 M/s and 0.021 s−1, respectively. Substantial substrate promiscuity was observed, with galactose being the preferred substrate, followed by mannose, fructose and GalNAc. Ld GalK has a highly flexible protein structure suggestive of multiple conformational states in solution, which may be the key to its substrate promiscuity. Our data presents novel insights into the galactose salvaging pathway in Leishmania and positions this protein as a potential target for the development of pharmaceuticals seeking to interfere with parasite substrate metabolism. • Galactose, mannose, fructose and GalNAc are substrates for Ld GalK. • Kinetic parameters are in range with other galactokinases. • Structural flexibility indicates conformational changes upon ligand binding. • Development of anti-leishmanial therapeutics exploiting galactose metabolism. [ABSTRACT FROM AUTHOR]

Purpose: Leishmaniasis, caused by the parasite of the genus Leishmania, is a neglected tropical disease which is endemic in more than 60 countries. In South-East Asia, Brazil, and East Africa, it mainly occurs as kala-azar (visceral leishmaniasis, VL), and subsequently as post kala-azar dermal leishmaniasis (PKDL) in a smaller portion of cases. As stated per WHO roadmap, accessibility to accurate diagnostic methods is an essential step to achieve elimination. This study aimed to test the accuracy of a portable minoo device, a small battery-driven, multi-use fluorimeter operating with isothermal technology for molecular diagnosis of VL and PKDL. Methods: Fluorescence data measured by the device within 20 min are reported back to the mobile application (or app) via Bluetooth and onward via the internet to a backend. This allows anonymous analysis and storage of the test data. The test result is immediately returned to the app displaying it to the user. Results: The limit of detection was 11.2 genome copies (95% CI) as determined by screening a tenfold dilution range of whole Leishmania donovani genomes using isothermal recombinase polymerase amplification (RPA). Pathogens considered for differential diagnosis were tested and no cross-reactivity was observed. For its diagnostic performance, DNA extracted from 170 VL and PKDL cases, comprising peripheral blood samples (VL, n = 96) and skin biopsies (PKDL, n = 74) from India (n = 108) and Bangladesh (n = 62), was screened. Clinical sensitivity and specificity were 88% and 91%, respectively. Conclusion: Minoo devices can offer a convenient, cheaper alternative to other molecular diagnostics. Its easy handling makes it ideal for use in low-resource settings to identify parasite burden. [ABSTRACT FROM AUTHOR]

Visceral leishmaniasis (VL) caused by L. donovani in South-East Asian endemic countries including India, Nepal and Bangladesh has been the primary focus of the ongoing VL elimination program. With a major reduction in VL cases resulting from the elimination program during the last two decades, the efforts are now focused on the challenges posed by potential reservoirs within the asymptomatic cases, HIV-co-infection VL cases and Post Kala-azar Dermal Leishmaniasis (PKDL) cases that continue to sustain the parasite transmission cycle in known and newer endemic zones. This article brings attention to a new potential parasite reservoir in the form of atypical cutaneous leishmaniasis (ACL) cases caused by novel L. donovani genetic variants. L. donovani mediated ACL is an emerging phenomenon in recent endemic sites that now justify a need for implementing molecular surveillance tools to identify region-specific L. donovani variants with dermotropic capabilities and potential to revert to visceral disease. A timely detection of novel ACL causing L. donovani genetic lineages in South-East Asian endemic regions is necessary to halt the spread of ACL and is potentially crucial for the sustainability of the advances made by the VL elimination.

The clinical manifestation of leishmaniasis has historically been determined by the Leishmania species involved. However, recent emergence of novel Leishmania lineages has caused atypical pathologies. We isolated and characterized 2 new Leishmania donovani parasites causing cutaneous leishmaniasis in Himachal Pradesh, India.

Leishmaniasis is a chronic inflammatory disease caused by a flagellate protozoan from the genus Leishmania, transmitted by an insect vector belonging to either the genus Phlebotomus spp. or Lutzomyia spp. This disease is considered one of the most prevalent infectious diseases worldwide due to its high detection rate and the morbidity it causes. A 70-year-old woman from a low-income background, with no significant medical or drug history and no other general constitutional symptoms, presented with an asymptomatic, exophytic, granulomatous growth that has a reddish hue. The growth is located on the lingual aspect of the mandibular anterior teeth region and has been progressing over the past six months. Radiographic features suggested associated chronic periodontitis along with hyperdense calcified deposits. On excisional biopsy and histopathology, the excised specimen revealed characteristic Leishmania amastigotes and pseudoepitheliomatous hyperplasia. An abdominal ultrasound was advised to rule out any visceral involvement, but no significant findings were observed. The present case is particularly intriguing due to oral mucosal involvement by Leishmania sp. without associated primary visceral or cutaneous lesions, especially given the male predilection (M:F=7:5) and the most common site involved being the posterior palatal region for Leishmaniasis. The present case represents a rare instance. Considering the difficult socio-economic circumstances, the involvement of the World Health Organization (WHO) demonstrates an understanding of the need for collaboration in supporting underprivileged communities.

Ente Li,1,2,&ast; Qingfeng Zhu,3,&ast; Ziman Lv,1,2,&ast; Songsong Xie,3 Chunju Zhang,4 Wei Li,5 Ligu Mi,1,2 Quan Liu,6 Yuanzhi Wang,1,2 Xiaobo Lu2 1Department of Basic Medicine, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region, 832002, People’s Republic of China; 2Key Laboratory for Prevention and Control of Emerging Infectious Diseases and Public Health Security, the Xinjiang Production and Construction Corps, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region, 832002, People’s Republic of China; 3The First Affiliated Hospital of Shihezi University Medical College, Shihezi City, Xinjiang Uygur Autonomous Region, 832002, People’s Republic of China; 4Tumxuk Center for Disease Prevention and Control, Tumxuk City, Xinjiang Uygur Autonomous Region, 843806, People’s Republic of China; 5Department of Basic Medicine, School of Medicine, Tarim University, Alaer City, Xinjiang Uygur Autonomous Region, 843300, People’s Republic of China; 6Department of Infectious Diseases and Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, Key Laboratory of Zoonotic Diseases, The First Hospital of Jilin University, Changchun City, Jilin Province, 30061, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Yuanzhi Wang; Xiaobo Lu, Email wangyuanzhi621@126.com; xjykdluxiaobo@126.comAbstract: Visceral leishmaniasis (VL), also known as kala-azar. It is characterized by prolonged intermittent fever, anemia, splenomegaly, hepatomegaly, and skin darkening. VL is primarily endemic in regions, such as Brazil, East Africa, and India. However, Northern Xinjiang, which is located in northwestern China, is considered a low-incidence area for VL, contributing to its status as a neglected infectious disease. In this report, we present a case of VL caused by Leishmania donovani that was diagnosed using metagenomic next-generation sequencing (mNGS). This case underscores the diagnostic value of mNGS, particularly in regions with low incidence of VL. Keywords: Visceral leishmaniasis, Leishmania donovani, metagenomic next-generation sequencing, northwestern China

Abstract Centrin1 gene deleted Leishmania donovani parasite (LdCen1 −/− ) was developed and extensively tested experimentally as an intracellular stage-specific attenuated and immunoprotective live parasite vaccine candidate ex vivo using human PBMCs and in vivo in animals. Here we report manufacturing and pre-clinical evaluation of current Good-Laboratory Practice (cGLP) grade LdCen1 −/− parasites, as a prerequisite before proceeding with clinical trials. We screened three batches of LdCen1 −/− parasites manufactured in bioreactors under cGLP conditions, for their consistency in genetic stability, attenuation, and safety. One such batch was preclinically tested using human PBMCs and animals (hamsters and dogs) for its safety and protective immunogenicity. The immunogenicity of the CGLP grade LdCen1 −/− parasites was similar to one grown under laboratory conditions. The cGLP grade LdCen1 −/− parasites were found to be safe and non-toxic in hamsters and dogs even at 3 times the anticipated vaccine dose. When PBMCs from healed visceral leishmaniasis (VL) cases were infected with cGLP LdCen1 −/− , there was a significant increase in the stimulation of cytokines that contribute to protective responses against VL. This effect, measured by multiplex ELISA, was greater than that observed in PBMCs from healthy individuals. These results suggest that cGLP grade LdCen1 −/− manufactured under cGMP complaint conditions can be suitable for future clinical trials.

Visceral leishmaniasis (VL) is among the most neglected tropical diseases in the world. Drug cell permeability is essential for killing the intracellular residing parasites responsible for VL, making cell-permeating peptides a logical choice to address VL. Unfortunately, the limited biological stability of peptides restricts their usage. Sequence-specific oligo-N-substituted glycines ('peptoids') are a class of peptide mimics that offers an excellent alternative to peptides in terms of ease of synthesis and good biostability. We tested peptoids against the parasite Leishmania donovani in both forms, that is, intracellular amastigotes and promastigotes. N-alkyl hydrophobic chain addition (lipidation) and bromination of oligopeptoids yielded compounds with good antileishmanial activity against both forms, showing the promise of these antiparasitic peptoids as potential drug candidates to treat VL.

Background: Cutaneous leishmaniasis (CL) is understudied in sub-Saharan Africa. The epidemiology of CL is determined by the species involved in its transmission. Our objectives were to systematically review available data on the species of Leishmania, along with vectors and reservoirs involved in the occurrence of human cases of CL in sub-Saharan Africa, and to discuss implications for case management and future research. Methods: We systematically searched PubMed, Scopus, Cochrane and African Index Medicus. There was no restriction on language or date of publication. The review was conducted according to PRISMA guidelines and was registered on PROSPERO (CRD42022384157). Results: In total, 188 published studies and 37 reports from the grey literature were included. An upward trend was observed, with 45.7% of studies published after 2010. East Africa (55.1%) represented a much greater number of publications than West Africa (33.3%). In East Africa, the identification of reservoirs for Leishmania tropica remains unclear. This species also represents a therapeutic challenge, as it is often resistant to meglumine antimoniate. In Sudan, the presence of hybrids between Leishmania donovani and strictly cutaneous species could lead to important epidemiological changes. In Ghana, the emergence of CL in the recent past could involve rare species belonging to the Leishmania subgenus Mundinia. The area of transmission of Leishmania major could expand beyond the Sahelian zone, with scattered reports in forested areas. While the L. major–Phlebotomus duboscqi–rodent complex may not be the only cycle in the dry areas of West Africa, the role of dogs as a potential reservoir for Leishmania species with cutaneous tropism in this subregion should be clarified. Meglumine antimoniate was the most frequently reported treatment, but physical methods and systemic agents such as ketoconazole and metronidazole were also used empirically to treat L. major infections. Conclusions: Though the number of studies on the topic has increased recently, there is an important need for intersectional research to further decipher the Leishmania species involved in human cases of CL as well as the corresponding vectors and reservoirs, and environmental factors that impact transmission dynamics. The development of molecular biology in sub-Saharan Africa could help in leveraging diagnostic and research capacities and improving the management of human cases through personalized treatment strategies. [ABSTRACT FROM AUTHOR]

Concerns regarding toxicity and resistance of current drugs in visceral leishmaniasis have been reported. Antimicrobial peptides are considered to be promising candidates and among them human cathelicidin hCAP18/LL-37 showed significant parasite killing on drug-sensitive and resistant Leishmania promastigotes, in addition to its apoptosis-inducing role. Administration of hCAP18/LL-37 to infected macrophages also decreased parasite survival and increased the host favorable cytokine interleukin 12. However, 1,25-dihydroxyvitamin D3 (vitamin D3)-induced endogenous hCAP18/LL-37 production was hampered in infected THP-1 cells. Infection also suppressed the vitamin D3 receptor (VDR), transcription factor of hCAP18/LL-37. cAMP response element modulator (CREM), the repressor of VDR, was induced in infection, resulting in suppression of both VDR and cathelicidin expression. PGE2/cAMP/PKA axis was found to regulate CREM induction during infection and silencing CREM in infected cells and BALB/c mice led to decreased parasite survival. This study documents the antileishmanial potential of cathelicidin and further identifies CREM as a repressor of cathelicidin in Leishmania infection. [ABSTRACT FROM AUTHOR]

Liposomal amphotericin B is an important frontline drug for the treatment of visceral leishmaniasis, a neglected disease of poverty. The mechanism of action of amphotericin B (AmB) is thought to involve interaction with ergosterol and other ergostane sterols, resulting in disruption of the integrity and key functions of the plasma membrane. Emergence of clinically refractory isolates of L. donovani and L. infantum is an ongoing issue and knowledge of potential resistance mechanisms can help to alleviate this problem. Here we report the characterisation of four independently selected L. donovani clones that are resistant to AmB. Whole genome sequencing revealed that in three of the moderately resistant clones, resistance was due solely to the deletion of a gene encoding C24-sterol methyltransferase (SMT1). The fourth, hyper-resistant resistant clone (>60-fold) was found to have a 24 bp deletion in both alleles of a gene encoding a putative cytochrome P450 reductase (P450R1). Metabolic profiling indicated these parasites were virtually devoid of ergosterol (0.2% versus 18% of total sterols in wild-type) and had a marked accumulation of 14-methylfecosterol (75% versus 0.1% of total sterols in wild-type) and other 14-alpha methylcholestanes. These are substrates for sterol 14-alpha demethylase (CYP51) suggesting that this enzyme may be a bona fide P450R specifically involved in electron transfer from NADPH to CYP51 during catalysis. Deletion of P450R1 in wild-type cells phenocopied the metabolic changes observed in our AmB hyper-resistant clone as well as in CYP51 nulls. Likewise, addition of a wild type P450R1 gene restored sterol profiles to wild type. Our studies indicate that P450R1 is essential for L. donovani amastigote viability, thus loss of this gene is unlikely to be a driver of clinical resistance. Nevertheless, investigating the mechanisms underpinning AmB resistance in these cells provided insights that refine our understanding of the L. donovani sterol biosynthetic pathway. Author summary: The antifungal drug, amphotericin B, is also used in the treatment of visceral leishmaniasis, a potentially lethal parasitic disease infecting the specialised immune cells (macrophages) in the liver, spleen, and bone marrow. Treatment failures due to emerging drug resistance are a significant concern. Using a combination of genetic and biochemical approaches, we have confirmed the mechanisms by which these parasites become less sensitive to treatment with amphotericin B. In addition, we have identified a novel mechanism involving loss of a key enzyme (cytochrome P450 reductase 1) in the biosynthetic pathway to ergosterol, an important lipid component of the parasite's plasma membrane. These studies increase our fundamental understanding of this important metabolic pathway and provide information that may be exploited to develop novel therapeutic strategies to combat this killer disease. [ABSTRACT FROM AUTHOR]

Background: Characterization of the host response in cutaneous leishmaniasis (CL) through proteome profiling has gained limited insights into leishmaniasis research compared to that of the parasite. The primary objective of this study was to comprehensively analyze the proteomic profile of the skin lesions tissues in patients with CL, by mass spectrometry, and subsequent validation of these findings through immunohistochemical methods. Methods: Eight lesion specimens from leishmaniasis-confirmed patients and eight control skin biopsies were processed for proteomic profiling by mass spectrometry. Formalin-fixed paraffin-embedded lesion specimens from thirty patients and six control skin specimens were used for Immunohistochemistry (IHC) staining. Statistical analyses were carried out using SPSS software. The chi-square test was used to assess the association between the degree of staining for each marker and the clinical and pathological features. Results: Sixty-seven proteins exhibited significant differential expression between tissues of CL lesions and healthy controls (p < 0.01), representing numerous enriched biological processes within the lesion tissue, as evident by both the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome databases. Among these, the integrated endoplasmic reticulum stress response (IERSR) emerges as a pathway characterized by the up-regulated proteins in CL tissues compared to healthy skin. Expression of endoplasmic reticulum (ER) stress sensors, inositol-requiring enzyme-1 (IRE1), protein kinase RNA-like ER kinase (PERK) and activating transcription factor 6 (ATF6) in lesion tissue was validated by immunohistochemistry. Conclusions: In conclusion, proteomic profiling of skin lesions carried out as a discovery phase study revealed a multitude of probable immunological and pathological mechanisms operating in patients with CL in Sri Lanka, which needs to be further elaborated using more in-depth and targeted investigations. Further research exploring the intricate interplay between ER stress and CL pathophysiology may offer promising avenues for the development of novel diagnostic tools and therapeutic strategies in combating this disease. [ABSTRACT FROM AUTHOR]

Background: Visceral leishmaniasis (VL) is a parasitic disease that affects public health. It is described by weight reduction, irregular fever bouts, anemia, and amplification of the spleen and liver. Materials and Methods: Three concentrations (15.6, 31.2, and 62.5 μg/mL) were used to find the potency of an aqueous extract of Chara vulgaris algae in the treatment of VL. A cytotoxicity assay was performed to show the cytotoxic effect of this extract on human cells. High-performance liquid chromatography (HPLC) test was done to determine the active compounds in the extract. Histopathological sections for infected liver and spleen were performed, as were liver function tests (alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase), which were assessed after 1 month of treatment. Results: As cytotoxicity assay, results showed that there were no significant differences between the cells treated and those not treated with the extract. HPLC test demonstrated that phenolic and terpene compounds are the main active compounds in the extract. P-coumaric acid and ursolic acid present the highest percent among other phenolic and terpene compounds (21.84%, 17.82%), respectively. Histopathological sections showed that this extract had a significant effect in the treatment of infected tissues, and this effect was very clear after the end of the treatment period. As for the liver function tests, a significant increase (P < 0.01) in the studied liver enzymes was found in the infected group of mice compared to the healthy group, whereas in the infected and treated groups, a clear and gradual decrease in the level of enzymes was observed. [ABSTRACT FROM AUTHOR]

Background. Fungi produce many compounds have pharmaceutical usage. The current study was aimed to extract therapeutic compounds from fungi that grow in critical conditions and fungi that can be produced commercially which may have potential therapeutic activities against Leishmania donovani. The current study was aimed to extract therapeutic compounds from fungi that grow in critical conditions and fungi that can be produced commercially which may have potential therapeutic activities against Leishmania donovani. Methods. Two fungal isolates were used to evaluate antileishmanial activities of their extracts, the first due to Aspergillus terreus was isolated from salty sediments, while another represented local edible mushroom of Agaricus bisporus. The experiment was conducted in vivo after four weeks infection of Leishmania donovani. Infected mice were treated intraperitonially with 2 and 4 mg/kg daily for 10 days. Result. All compound has a significant effect on the viability and decrease the number of parasites in animal in comparison with pentostam, as well as, the M19 was appeared with highest effect in both concentrations. The method of examining infected tissues had a role in determining the number of parasites without affecting the percentage of presence in different treatments, as the numbers of parasites calculated in the tissue sections are more realistic than the number of parasites calculated in the printing method, as counting the parasite with tissue sections gives an impression of the spatial distribution of the parasite, whether within tissues or body fluids, unlike the printing method, which shows the presence of the parasite in body fluids and immune cells thus be suitable for the diagnosis of parasite amastigote in vivo. Conclusion. The compound extracted during study and diagnoses by GC-Mass technique are promising applicants for research on new drugs with anti-Leishmania activity derived from natural products. [ABSTRACT FROM AUTHOR]

Background The pathogenic risk caused by the Leishmania donovani (L. donovani) parasite has long been known, and it has become necessary to find a suitable treatment other than traditional medications and their many side effects, among the best medicines in China, Artemisinin (ART) is not only an anti-inflammatory medicine, but also an anti-allergy medicine and and antibiotics. Objective To investigate the effect of the ART in inhibiting the activity of the L. donovani parasite through studying its impact on alanine transaminase (ALT), aspartate transaminase (AST), cholesterol (CL) and triglyceride (TG). Methods The ART drug was compared with Pentostam drug (the traditional drug used in the treatment of leishmaniasis), a concentration of 20 mg/ml (0.01 ml/day) of the ART was prepared and was tested in vivo by observation the levels of liver enzyme ALT, AST, CL and TG in serum of infected mice and comparing with control positive group after 7, 14 and 21 days of treatment. Results The results showed that there were statistically significant differences between the groups treated with ART drug and Pentostam compared to the positive control group, in addition to the statistical differences between these groups over the three weeks. The AST and ALT values increased in positive control mice over the three weeks, while they returned to normal levels in mice treated with ART drug and Pentostam. As for the CL value, it decreased significantly and statistically significantly in the group of positive control mice. As for the treated groups, there were also statistical differences during the three weeks. While the TG value had statistical differences between the different groups for one week, the TG value for the same group was not affected much. Conclusion The results indicate the 20 mg/ml of ART had the approximately same positive effects of Pentostam in returning ALT, AST, CL and TG to normal level in mice infested with L. donovani promastigotes parasite. [ABSTRACT FROM AUTHOR]