Safety and Effectiveness of Sodium Stibogluconate and Paromomycin Combination for the Treatment of Visceral Leishmaniasis in Eastern Africa: Results from a Pharmacovigilance Programme

In Silico and in vitro assessment of anti-leishmania infantum activity of a novel cyclohexyl-1,2,4-oxadiazole derivative

Globally, an estimated 1 billion people reside in endemic areas, and over 12 million individuals are infected with leishmaniasis. Despite its prevalence, leishmaniasis continues to be a neglected disease, mainly affecting underdeveloped countries. In Brazil, the available treatments are pentavalent antimonials and amphotericin B, which are outdated, toxic, require prolonged parenteral administration and have limited efficacy. The heterocyclic ring oxadiazole has been documented in the literature to possess various biological activities, including leishmanicidal properties, thus positioning it as a potential candidate for further investigation. This study aims to evaluate the in vitro leishmanicidal activity of an oxadiazole compound (2i), explore its mechanism of action through enzymatic inhibition and molecular docking, assess its antioxidant activity, and conduct an in silico pharmacokinetic prediction. Pharmacokinetic predictions via ADME/TOX modeling revealed that the 2i molecule exhibits good intestinal absorption (92 %), is water-insoluble (-4 log.mol/L) and demonstrates high permeability in Caco-2 cells (1.35 log.Papp10-6cm/s), suggesting potential for oral administration. Metabolic studies indicated that oxadiazole 2i is an inhibitor of cytochrome P450 enzymes CYP1A2 and CYP2C19, necessitating further evaluation of potential drug interactions. Additionally, it did not exhibit hepatotoxicity or cardiotoxicity; however, it demonstrated mutagenic potential in the salmonella reverse mutation test (AMES), which is a genetic method that detects mutagenic chemical agents, thus justifying more complex confirmatory studies. In vitro assays showed that oxadiazole 2i has DPPH (2,2-diphenyl-1-picrylhydrazyl) radical reducing activity, indicating potential antioxidant properties with an IC50 of 12.10 µg/mL. Concerning its leishmanicidal mechanism of action, molecular docking simulations at the active site of acetylcholinesterase demonstrated that the 2i molecule had superior binding energy values compared to the reference drug physostigmine (-7.39 kcal/mol versus -6.66 kcal/mol, respectively). However, the pharmacophore map revealed that physostigmine had more molecular interactions than oxadiazole 2i. In acetylcholinesterase inhibition assays, the 2i molecule exhibited significant inhibitory activity with an IC50 of 11.91 µg/mL, suggesting a mechanism of action that compromises the parasitic membrane. Moreover, the 2i molecule demonstrated significant leishmanicidal activity against L. infantum with an IC50 of 30.86 μM. Cytotoxicity assays on RAW 264.7 macrophages revealed a high CC50 value of 485.5 µM and a selectivity index (SI) of 17.86. Based on these findings, oxadiazole 2i emerges as a promising candidate for further study, offering prospects for more affordable, selective, and less toxic leishmanicidal agents.

Progress in antileishmanial drugs: Mechanisms, challenges, and prospects

Leishmaniasis, a neglected tropical disease caused by Leishmania parasites, continues to pose global health challenges. Current treatments face issues like resistance, safety, efficacy, and cost. This review covers the discovery, mechanisms of action, clinical applications, and limitations of key antileishmanial agents: pentavalent antimonials, amphotericin B, miltefosine, paromomycin, and pentamidine. Despite toxicity and resistance (antimonials), hospitalization needs and side effects (amphotericin B), regional efficacy variability (miltefosine), inconsistent outcomes (paromomycin), and severe side effects (pentamidine), these drugs are vital. Novel strategies to overcome the deficiencies of current therapies are highlighted, including combination regimens, advanced drug delivery systems, and immunomodulatory approaches. Comprehensive and cooperative efforts are crucial to fully realize the potential of advancements in antileishmanial pharmacotherapy and to reduce the unacceptable worldwide burden imposed by this neglected disease.

Vaccine Designing Technology against Leishmaniasis: Current Challenges and Implication

Leishmaniasis, a debilitating disease caused by protozoan parasites of the genus Leishmania and transmitted by the bite of a female sandfly, continues to present significant challenges despite ongoing research and collaboration in vaccine development. The intricate interaction between the parasite's life cycle stages and the host's immunological response, namely the promastigote and amastigote forms, adds complexity to vaccine design. The quest for a potent vaccine against Leishmaniasis demands a comprehensive understanding of the immune mechanisms that confer long-lasting protection, which necessitates extensive research efforts. In this pursuit, innovative approaches such as reverse vaccinology and computer-aided design offer promising avenues for unraveling the intricacies of host-pathogen interactions and identifying effective vaccine candidates. However, numerous obstacles, including limited treatment options, the need for sustained antigenic presence, and the prevalence of co-infections, particularly with HIV, impede progress. Nevertheless, through persistent research endeavours and collaborative initiatives, the goal of developing a highly efficacious vaccine against Leishmaniasis can be achieved, offering hope through the latest Omics data development with immunoinformatics approaches for effective vaccine design for the prevention of this disease.

Disease-Specific Differences in Pharmacokinetics of Paromomycin and Miltefosine Between Post-Kala-Azar Dermal Leishmaniasis and Visceral Leishmaniasis Patients in Eastern Africa

Treatment regimens for post-kala-azar dermal leishmaniasis (PKDL) are usually extrapolated from those for visceral leishmaniasis (VL), but drug pharmacokinetics (PK) can differ due to disease-specific variations in absorption, distribution, and elimination. This study characterized PK differences in paromomycin and miltefosine between 109 PKDL and 264 VL patients from Eastern Africa. VL patients showed 0.55-fold (95% confidence interval [CI], .41-.74) lower capacity for paromomycin saturable reabsorption in renal tubules, and required a 1.44-fold (95% CI, 1.23-1.71) adjustment when relating renal clearance to creatinine-based estimated glomerular filtration rate. Miltefosine bioavailability in VL patients was lowered by 69% (95% CI, 62%-76%) at treatment start. Comparing PKDL to VL patients on the same regimen, paromomycin plasma exposures were 0.74- to 0.87-fold, while miltefosine exposure until the end of treatment day was 1.4-fold. These pronounced PK differences between PKDL and VL patients in Eastern Africa highlight the challenges of directly extrapolating dosing regimens from one leishmaniasis presentation to another.

Cytokine profiles, blood parasite load and clinical features of visceral leishmaniasis in West Pokot County, Kenya

Visceral leishmaniasis (VL) is a severe infectious disease caused by protozoan parasites of the Leishmania donovani complex. Blood cytokine concentrations in VL patients can inform us about underlying immunopathogenesis and may serve as a biomarker for treatment effectiveness. However, cytokine levels have not yet been studied in VL patients from Kenya, where case load is high. This study measured the serum cytokine profile, blood parasite load and clinical and haematological features of VL patients from West Pokot County, Kenya, over the course of treatment with sodium stibogluconate and paromomycin (SSG-PM). VL patients recruited at the hospital presented with splenomegaly and weight loss, and frequently had pancytopenia and anaemia. Median Leishmania parasite load in blood, determined with real-time polymerase chain reaction, was 2.6 × 104 parasite equivalents mL−1. Compared to endemic healthy controls, serum interferon gamma (IFN-γ), interleukin 5 (IL-5), IL-6, IL-10, IL-12p70, IL-17A and IL-27 were significantly elevated in untreated VL patients. Severe VL was associated with higher IL-10 and lower IFN-γ levels. After 17 daily injections with SSG-PM, disease symptoms disappeared, leukocyte and thrombocyte counts significantly increased, and blood parasite load decreased to undetectable levels in all VL patients. There was a significant decrease in IL-10 and IL-6, whereas IL-17A levels increased; the remaining cytokines showed no significant concentration change during treatment. In conclusion, the results suggest that SSG-PM treatment of VL patients from West Pokot was effective. Moreover, both inflammatory and regulatory immune responses appeared to decrease during treatment, although the increase in IL-17A could reflect a partial continuation of immune activation.

The status of combination therapy for visceral leishmaniasis: an updated review

For the past 15 years, trials of combination therapy options for visceral leishmaniasis have been conducted with the aim of identifying effective, and safe treatment regimens that were shorter than existing monotherapy regimens and could also prevent or delay the emergence of drug resistance. Although first-line treatment currently relies on combination therapy in east Africa, this is not true in Latin America owing to disappointing trial results, with lower than expected efficacy seen for the combination treatment group. By contrast, several effective combination therapy regimens have been identified through trials on the Indian subcontinent; yet, first-line therapy is still AmBisome monotherapy as the drug is part of a free donation programme and is highly effective in this region. Achieving a short all-oral combination treatment will require new chemical entities, several of which are currently under evaluation. Future studies should systematically include pharmacological substudies to ensure optimal dosing for all patient groups. To achieve maximal impact of new combination treatments, mechanisms to ensure drug availability and access after trials should be established. Enhancing the longevity of current and novel treatments will require effective systems for early detection of emerging drug resistance.

Exploration of Antileishmanial Compounds Derived from Natural Sources

AIMS

Leishmaniasis is a deadly tropical disease that is neglected in many countries. World Health Organization, along with a few other countries, has been working together to protect against these parasites. Many novel drugs from the past few years have been discovered and subjected against leishmaniasis, which have been effective but they are quite expensive for lower-class people. Some drugs showed no effect on the patients, and the longer use of these medicines has made resistance against these deadly parasites. Researchers have been working for better medication by using natural products from medicinal plants (oils, secondary metabolites, plant extracts) and other alternatives to find active compounds as an alternative to the current synthetic drugs.

MATERIALS AND METHODS

To find more potential natural products to treat Leishmania spp, a study has been conducted and reported many plant metabolites and other natural alternatives from plants and their extracts. Selected research papers with few term words such as natural products, plant metabolites, Leishmaniasis, in vivo, in vitro, and treatment against leishmaniasis; in the Google Scholar, PubMed, and Science Direct databases with selected research papers published between 2015 and 2021 have been chosen for further analysis has been included in this report which has examined either in vivo or in vitro analysis.

RESULTS

This paper reported more than 20 novel natural compounds in 20 research papers that have been identified which report a leishmanicidal activity and shows an action against promastigote, axenic, and intracellular amastigote forms.

CONCLUSION

Medicinal plants, along with a few plant parts and extracts, have been reported as a possible novel anti-leishmanial medication. These medicinal plants are considered nontoxic to Host cells. Leishmaniasis treatments will draw on the isolated compounds as a source further and these compounds compete with those already offered in clinics.

Inhibition and structural insights of leishmanial glutamyl-tRNA synthetase for designing potent therapeutics

Aminoacyl-tRNA synthetases (aaRSs), essential components of the protein synthesizing machinery, have been often chosen for devising therapeutics against parasitic diseases. Due to their relevance in drug development, the current study was designed to explore functional and structural aspects of Leishmania donovani glutamyl-tRNA synthetase (LdGluRS). Hence, LdGluRS was cloned into an expression vector and purified to homogeneity using chromatographic techniques. Purified protein showed maximum enzymatic activity at physiological pH, with more binding capacity towards its cofactor (Adenosine triphosphate, 0.06 ± 0.01 mM) than the cognate substrate (L-glutamate, 9.5 ± 0.5 mM). Remarkably, salicylate inhibited LdGluRS competitively with respect to L-glutamate and exhibited druglikeness with negligible effect on human macrophages. The protein possessed more α-helices (43 %) than β-sheets (12 %), whereas reductions in thermal stability and cofactor-binding affinity, along with variation in mode of inhibition after mutation signified the role of histidine (H60) as a catalytic residue. LdGluRS could also generate a pro-inflammatory milieu in human macrophages by upregulating cytokines. The docking study demonstrated the placement of salicylate into LdGluRS substrate-binding site, and the complex was found to be stable during molecular dynamics (MD) simulation. Altogether, our study highlights the understanding of molecular inhibition and structural features of glutamyl-tRNA synthetase from kinetoplastid parasites.

Hematological and Clinical Features Associated with Initial Poor Treatment Outcomes in Visceral Leishmaniasis Patients with and without HIV Coinfection in Gondar, Northwest Ethiopia

Ethiopia is among the countries with a high leishmaniasis burden. In this retrospective review, we aimed to determine hematological and clinical features associated with initial poor treatment outcomes of visceral leishmaniasis (VL) patients. The majority of VL cases in this study had leucopenia (94.3%), thrombocytopenia (87.1%), and anemia (85.9%). HIV coinfection was present in 7.0% (n = 23) of VL cases. At the center, VL patients without HIV coinfection were treated with sodium stibogluconate and paromomycin combination, whereas HIV coinfected cases were treated with AmBisome and miltefosine combination therapy. End-of-treatment cure rates among HIV-positive and HIV-negative visceral leishmaniasis cases, respectively, were 52.2% and 96.9%. Case fatality rates were 34.8% and 2.7% in HIV-positive and HIV-negative cases, respectively. Overall, non-survivors in this study were more likely to have HIV (55.0% vs. 4.1%, p < 0.001), sepsis (15.0% vs. 1.4%, p = 0.019), and dyspnea (40.0% vs. 2.7%, p < 0.001) at admission. In this regard, particular attention to the management of superimposed disease conditions at admission, including sepsis, HIV, and dyspnea, is needed to improve VL patients’ treatment outcomes. The inadequacy of the current treatments, i.e., AmBisome and miltefosine combination therapy, for HIV coinfected visceral leishmaniasis patients requires further attention as it calls for new treatment modalities.

Design, synthesis and evaluation of novel β-carboline ester analogues as potential anti-leishmanial agents

Leishmaniasis is one of today's most neglected diseases. The emergence of new anti-leishmanial therapies emphasizes several study groups funded by the World Health Organization. The present investigation will focus on the research to determine a few new potential derivatives of β-carboline ester derivatives against leishmaniasis. The in-silico predicted ADMET properties of most of the titled compounds are in an acceptable range and having drug like properties. Among all the tested analogs, compound ES-3 (EC₅₀ 3.36 μM; SI > 29.80) showed comparable and equipotent anti-leishmanial activity as that of standard drug miltefosine (EC₅₀ 4.80 μM; SI > 20.80) against amastigote forms of the tested L. infantum strain. Two compounds ES-6 and ES-10 exhibited significant activity with EC₅₀ 10.16, 13.56 μM; SI > 4.90, 7.37, respectively. In-silico based molecular docking and dynamics study of the significantly active analog also performed to study the putative binding mode, interaction pattern at the active site of the target leishmanial trypanothione reductase enzyme as well as stability of the target-ligand complex. The changes in the conformation of molecules during MD (frame wise trajectory analysis) provided new insights for the development of novel potent molecules. These findings will further give insight that will help modify the compound ES-3 for better potency and the design of novel inhibitors for leishmaniasis.Communicated by Ramaswamy H. Sarma.

Epidemiological and clinical factors associated with lethality from Human Visceral Leishmaniasis in Northeastern Brazil, 2007 to 2018

Human Visceral Leishmaniasis (HVL) presents a subacute clinical evolution with systemic involvement, which can result in high case fatality, especially among untreated individuals or those with low socioeconomic status. This study aimed to identify epidemiological and clinical factors associated with HVL case fatality in the Ceara State, from 2007 to 2018. This is an analytical cross-sectional study. The bivariate analysis was performed by Stata 15.1 using Pearson’s Chi-square or Fisher’s exact test; and Poisson regression for age-controlled multivariate analysis. From 2007 to 2018, there were 4,863 new confirmed cases and 343 deaths from HVL (case fatality rate=7.05%). The risk factors associated with case fatalities were: age group (RR=8.69; 95%CI:3.56-21.20); black population (RR=2.21; 95%CI:1.45-3.35); jaundice symptoms (RR=1.72; 95%CI:1.38-2.14); edema (RR=2.62; 95%CI:2.10-3.26) and hemorrhagic phenomena (RR=1.63; 95%CI:1.26-2.10); and no prescription drug intake (RR=4.03; 95%CI:2.98-5.46). Treatment with pentavalent antimonial was a protective factor (RR=0.35; 95%CI:0.27-0.45). The number of deaths increased among the elderly, illiterate, urban residents, and black skin color individuals. The drugs pentavalent antimonial and amphotericin B showed an association with death, but were not considered causal factors. Treatment failure led to a high risk of death. In multivariate analysis, the risk factors for fatal cases were age group, black skin, symptoms of jaundice, edema and hemorrhagic phenomena; and failure to take the prescription drugs. Treatment with pentavalent antimonial was shown to be a protective factor. Knowing the factors associated with the fatality of VL-HIV cases may help to improve public policies, in order to refine the epidemiological surveillance program and, consequently, prevent deaths related to the disease in Ceara.

The increasing incidence of visceral leishmaniasis relapse in South Sudan: A retrospective analysis of field patient data from 2001-2018

BACKGROUND

Visceral Leishmaniasis (VL) is endemic in South Sudan, manifesting periodically in major outbreaks. Provision of treatment during endemic periods and as an emergency response is impeded by instability and conflict. Médecins Sans Frontières (MSF) has provided health care in South Sudan since the late 1980's, including treatment for 67,000 VL patients. In recent years, MSF monitoring data have indicated increasing numbers of VL relapse cases. A retrospective analysis of these data was performed in order to provide insight into the possible causes of this increase.

METHODOLOGY/PRINCIPAL FINDINGS

Programme monitoring data from the MSF hospital in Lankien, Jonglei State, South Sudan, for the period 2001-2018 were analysed to detect trends in VL relapse as a proportion of all VL cases presenting to MSF treatment centres. Routinely collected patient-level data from relapse and primary VL cases treated at all MSF sites in South Sudan over the same period were analysed to describe patient characteristics and treatments received. VL relapse as a proportion of all VL cases increased by 6.5% per annum (95% CI 0.3% to 13.0%, p = 0.04), from 5.2% during 2001-2003 to 14.4% during 2016-2018. Primary VL and VL relapse patients had similar age, sex and anthropometric characteristics, the latter indicating high indices of undernutrition which were relatively constant over time. Clinical factors (Hb, spleen size, and VL severity score) also did not vary substantially over time. SSG/PM was the main treatment regimen from 2001-2018, used in 68.7% of primary and 70.9% of relapse VL cases; AmBisome was introduced in 2013, received by 22.5% of primary VL and 32.6% of VL relapse cases from 2013-2018.

CONCLUSION

Increasing incidence of VL relapse in South Sudan does not appear to be explained by changes in patient characteristics or other factors. Our data are concerning and may indicate an emergence of treatment-resistant parasite strains, decreasing the effectiveness of treatment regimens. This warrants further investigation as a causal factor. New chemical entities that will enable safe and highly effective short-course oral treatments for VL are urgently needed.

Design, synthesis and evaluation of novel phenanthridine triazole analogs as potential antileishmanial agents

Aim: To synthesize and screen phenanthridine and 1,2,3-triazole derivatives for antileishmanial activity. Methodology: Synthesized analogs were tested for antileishmanial activity against transgenic strain of Leishmania infantum promastigotes and ex vivo infections. Results: Compounds T01, T08 and T11 revealed significant activity with EC₅₀ <30 μm and lacked toxicity in mouse spleen and HepG2 cells. T01 with EC₅₀ 3.07 μm is four-fold more potent than the drug miltefosine (EC₅₀ 12.6 μM) against L. infantum promastigotes. In silico studies indicate that the analogs are nontoxic. A molecular docking analysis was also carried out on the T01 and T08 to investigate the binding pattern at the active site of the chosen target trypanothione reductase. Conclusion: The results of this study reveal that phenanthridine triazoles exhibit antileishmanial activity.

Prevalence of cutaneous leishmaniasis in the largest populated city Karachi, Pakistan

The study was undertaken from September 2018 to April 2019 to determine the prevalence of cutaneous leishmaniasis in human beings living in six districts of Karachi. Suspected persons were screened for the disease and positive cases were identified on the basis of skin lesions and blood samples. Samples were observed by mounting their smear. A total of 207 subjects of different ages and sex groups were investigated, however, only 192 (92%) of the suspected cases were found to have the disease 64% of cases were male which were significantly high (p 0.05), than female 36%. The lesion was more frequently detected among the youth ages of 21-30 years (31%) as compared to other groups. In both sexes, legs were found to be more infected (25% male + 20% female) followed by arms (20% male + 0% female) and face (15% male +11% female). The mixed body parts had shown the lowest infections such as (4% in males + 5%) in females. In conclusion, the highest and lowest leishmaniasis infections were observed in District West (23% male + 9% female) followed by District East (15% male + 7% female), District Malir (11% male+ 4% female), District Central (7% male + 5% female), District Korangi (4% male + 7% female) and District South (4% male + 4% female) respectively.

Lymphatic filariasis and visceral leishmaniasis coinfection: A review on their epidemiology, therapeutic, and immune responses

Coinfection is less commonly observed in individuals around the world, yet it is more common than the single infection. Around 800 million people worldwide are infected with helminths as a result of various diseases. Lymphatic filariasis (LF) and visceral leishmaniasis (VL) are chronic, deadly, crippling, and debilitating neglected tropical diseases (NTDs) that are endemic in tropical and subtropical regions of the world. Due to poor hygienic conditions, poverty, and genetic predisposition, those living in endemic areas are more likely to develop both leishmaniasis and filariasis. One of the key challenges in the management of LF/VL coinfection is the development of an effective therapeutic strategy that not only treats the first episode of VL but also prevents LF. However, there is a scarcity of knowledge and data on the relationship between LF and VL coinfection. While reviewing it was apparent that only a few studies relevant to LF/VL coinfections have been reported from southeastern Spain, Sudan, and the Indian subcontinents, highlighting the need for greater research in the most affected areas. We also looked at LF and VL as a single disease and also as a coinfection. Some features of the immune response evolved in mammalian hosts against LF and VL alone or against coinfection are also discussed, including epidemiology, therapeutic regimens, and vaccines. In addition to being potentially useful in clinical research, our findings imply the need for improved diagnostic methodology and therapeutics, which could accelerate the deployment of more specific and effective diagnosis for treatments to lessen the impact of VL/LF coinfections in the population.

Assay development in leishmaniasis drug discovery: a comprehensive review

INTRODUCTION

Cutaneous, muco-cutaneous and visceral leishmaniasis occur due to an infection with the protozoan parasite Leishmania. The current therapeutic options are limited mainly due to extensive toxicity, emerging resistance and variation in efficacy based on species and strain of the Leishmania parasite. There exists a high unmet medical need to identify new chemical starting points for drug discovery to tackle the disease.

AREAS COVERED

The authors have highlighted the recent progress, limitations and successes achieved in assay development for leishmaniasis drug discovery.

EXPERT OPINION

It is true that sophisticated and robust phenotypic in vitro assays have been developed during the last decade, however limitations and challenges remain with respect to variation in activity reported between different research groups and success in translating in vitro outcomes in vivo. The variability is not only due to strain and species differences but also a lack of well-defined criteria and assay conditions, e.g. culture media, host cell type, assay formats, parasite form used, multiplicity of infection and incubation periods. Thus, there is an urgent need for more physiologically relevant assays that encompass multi-species phenotypic approaches to identify new chemical starting points for leishmaniasis drug discovery.

Assessment of serum amylase, lipase and associated factors among patients with visceral leishmaniasis treated with sodium stibogluconate/paromomycin at University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia

BACKGROUND

Visceral leishmaniasis (VL) is a life-threatening parasitic disease next to malaria, which is responsible for the death of 50,000 patients annually. It has three major clinical stages, including visceral, cutaneous, and mucocutaneous leishmaniasis. Ethiopia is one of the east African countries commonly affected with leishmanisis disease. There are many drugs for leishmaniasis, including sodium stibogluconate and paromomycin combined therapy. However, the adverse effect of those combined drugs is not well-defined. Therefore, the purpose of this study was to assess serum amylase, lipase, and associated factors among patients with VL treatment with those combined drugs.

METHODS

Hospital-based cross-sectional study was conducted at the University of Gondar Comprehensive Specialized Hospital Leishmaniasis Research and Treatment Center from February to September 2020 G.C. Simple random sampling technique was utilized to select study participants. The study participants who fulfill the inclusion criteria were included in the study with written informed consent. 5 ml of blood was withdrawn by an experienced health professional to analyze serum amylase and lipase level. Descriptive data was presented by tables, charts and graphs. Data was cleared, entered by Epi-data version 3.1 then transfer to STATA 14.1 SE version and for analysis paired t-test was used, for factors correlation and regression was used. Those factor variable who have p-value <0.25 was filtered and goes to multivariate regression and p-value <0.05 was considered as significant variables.

RESULTS

The result of this study showed that there was a significant mean difference between serum pancreatic amylase and lipase before and after treatment. The mean ± SD level of serum amylase after treatment showed a statistically significant elevation (P<0.001) as compared to its level before treatment. Similarly, the mean ± SD level of serum lipase after treatment showed a statistically significant elevation (P<0.001) as compared to its level before treatment. There was also significant association between age and baseline serum amylase as compared to serum amylase after treatment. Similarly, there was also significant relation of age and serum lipase with serum lipase after treatment.

CONCLUSION

In this study, the level of serum amylase and lipase at treatment of cure was higher and there was an increase in mean serum amylase and lipase after a patient taking sodium stibogluconate and paromomycin combined drugs. Consequently, the elevated result of these biochemical profiles mainly associated with drug induced adverse effect and associated risk factors in VL patients.

Visceral Leishmaniasis in pregnancy and vertical transmission: A systematic literature review on the therapeutic orphans

Background

Reports on the occurrence and outcome of Visceral Leishmaniasis (VL) in pregnant women is rare in published literature. The occurrence of VL in pregnancy is not systematically captured and cases are rarely followed-up to detect consequences of infection and treatment on the pregnant women and foetus.

Methods

A review of all published literature was undertaken to identify cases of VL infections among pregnant women by searching the following database: Ovid MEDLINE; Ovid Embase; Cochrane Database of Systematic Reviews; Cochrane Central Register of Controlled Trials; World Health Organization Global Index Medicus: LILACS (Americas); IMSEAR (South-East Asia); IMEMR (Eastern Mediterranean); WPRIM (Western Pacific); ClinicalTrials.gov; and the WHO International Clinical Trials Registry Platform. Selection criteria included any clinical reports describing the disease in pregnancy or vertical transmission of the disease in humans. Articles meeting pre-specified inclusion criteria and non-primary research articles such as textbook, chapters, letters, retrospective case description, or reports of accidental inclusion in trials were also considered.

Results

The systematic literature search identified 272 unique articles of which 54 records were included in this review; a further 18 records were identified from additional search of the references of the included studies or from personal communication leading to a total of 72 records (71 case reports/case series; 1 retrospective cohort study; 1926–2020) describing 451 cases of VL in pregnant women. The disease was detected during pregnancy in 398 (88.2%), retrospectively confirmed after giving birth in 52 (11.5%), and the time of identification was not clear in 1 (0.2%). Of the 398 pregnant women whose infection was identified during pregnancy, 346 (86.9%) received a treatment, 3 (0.8%) were untreated, and the treatment status was not clear in the remaining 49 (12.3%). Of 346 pregnant women, Liposomal amphotericin B (L-AmB) was administered in 202 (58.4%) and pentavalent antimony (PA) in 93 (26.9%). Outcomes were reported in 176 pregnant women treated with L-AmB with 4 (2.3%) reports of maternal deaths, 5 (2.8%) miscarriages, and 2 (1.1%) foetal death/stillbirth. For PA, outcomes were reported in 88 of whom 4 (4.5%) died, 24 (27.3%) had spontaneous abortion, 2 (2.3%) had miscarriages. A total of 26 cases of confirmed, probable or suspected cases of vertical transmission were identified with a median detection time of 6 months (range: 0–18 months).

Conclusions

Outcomes of VL treatment during pregnancy is rarely reported and under-researched. The reported articles were mainly case reports and case series and the reported information was often incomplete. From the studies identified, it is difficult to derive a generalisable information on outcomes for pregnant women and babies, although reported data favours the usage of liposomal amphotericin B for the treatment of VL in pregnant women.

Visceral Leishmaniasis (VL) is a neglected tropical disease with an estimated incidence of 50,000 to 90,000 cases in 2019. Women who are susceptible to becoming pregnant or those who are pregnant and lactating are regularly excluded from clinical studies of VL. A specific concern of public health relevance is the little knowledge of the consequences of VL and its treatment on the mother and the foetus. We did a systematic review of all published literature with an overarching aim of identifying cases of VL in pregnancy and assessing the risk-benefit balance of antileishmanial treatment to the pregnant women and the child. We identified a total of 72 records (1926–2020) describing 451 VL cases in pregnant women. In 398, infection was identified during pregnancy of whom 202 received Liposomal Amphotericin B (L-AmB) and 93 received pentavalent antimony (PA). In studies that reported maternal outcomes, reports of maternal death abortion/spontaneous abortion, and miscarriages were proportionally lower among those who received L-AmB compared to PA (no formal test of significance carried out). A total of 26 cases of confirmed, probable or suspected cases of vertical transmission were identified and the median time to detection was 6 months (range: 0–18 months). Our review brings together scattered observations of VL in pregnant women in the clinical literature and clearly highlights that the disease in pregnancy is under-reported and under-studied. The collated evidence derived mainly from case reports and case series indicate that L-AmB has a favourable safety profile than the antimony regimen and should be the preferred treatment for VL during pregnancy.

Efficacy and safety of a combined treatment of sodium stibogluconate at 20mg/kg/day with upper maximum daily dose limit of 850mg and Paromomycin 15mg/kg/day in HIV negative visceral leishmaniasis patients. A retrospective study, northwest Ethiopia

BACKGROUND

Visceral leishmaniasis (VL) is one of the most neglected tropical infectious diseases. It is fatal if left untreated. The objective of this study was to assess the efficacy and safety of 17-day injections of combined regimen of sodium stibogluconate and paromomycin (SSG/PM) in HIV-negative VL patients.

METHODS

A retrospective analysis of medical records of VL patients treated in the University of Gondar Hospital during period 2012-2019 was carried out.

RESULTS

A total of 2836 patients were treated for VL from 2012 to 2019. Of these 1233 were treated with SSG-PM, and 1000 of them were included in the study. Initial cure was achieved in 922 (92.2%) patients. The frequency of treatment failure, treatment interruptions, default and deaths respectively were 30 (3%), 20 (2%), 13 (1.3%) and 15 (1.5%). Among 280 patients who completed 6-month follow up, the final cure was 93.9% (263/280), 4 (1.4%) relapsed and 13 (4.6%) developed post-kala-azar dermal leishmaniasis (PKDL). The most common adverse events (AEs) were raised liver transaminases (35.1%; 351 patients), injection site pain (29.1%, 291 patients) and raised serum alpha-amylase (29.1%, 291 patients). Factors associated with poor treatment outcomes were sepsis, pneumonia, and adverse events.

CONCLUSION

A combination of SSG at 20mg/kg with upper daily maximum dose of 850mg and PM was effective for achieving initial cure at end of treatment and safe for treatment of HIV negative VL patients in northwestern Ethiopia. Our data are consistent with previous reports and confirms effectiveness of SSG/PM treatment regimen in the Eastern African countries. Efficacy at 6-months (93.9%) was estimated on data derived from patients who completed follow up and needs to be interrogated by future studies.

Parasitic sirtuin 2 as an opportunity in drug discovery

Infections caused by protozoans remain a public health issue, especially in tropical countries. Serious adverse events, lack of efficacy at the different stages of the infection and routes of administration that have a negative impact on treatment adherence are some of the problems with currently available therapy against these diseases. Here we describe an epigenetic target, sirtuin 2 and its related proteins, that is promising given the results in phenotypic assays and in vivo models against Sir2 of Plasmodium falciparum, Leishmania donovani, Leishmania infantum, Schistosoma mansoni, Trypanosoma brucei and Trypanosoma cruzi parasites. The results we present highlight how this target can be extensively explored and how its inhibitors might be employed in the clinic.

Acute kidney injury in patients with Visceral Leishmaniasis in Northwest Ethiopia

BACKGROUND

Visceral Leishmaniasis (VL) is a neglected tropical disease endemic to several countries including Ethiopia. Outside of Africa, kidney involvement in VL is frequent and associated with increased mortality. There is however limited data on acute kidney injury (AKI) in VL patients in East-Africa, particularly in areas with high rates of HIV co-infection. This study aims to determine the prevalence, characteristics and associated factors of AKI in VL patients in Northwest Ethiopia.

METHODS

A hospital based retrospective patient record analysis was conducted including patients treated for VL from January 2019 to December 2019 at the Leishmaniasis Research and Treatment Center (LRTC), Gondar, Ethiopia. Patients that were enrolled in ongoing clinical trials at the study site and those with significant incomplete data were excluded. Data was analyzed using SPSS version 20. P values were considered significant if < 0.05.

RESULTS

Among 352 VL patients treated at LRTC during the study period, 298 were included in the study. All were male patients except two; the median age was 23 years (IQR: 20-27). The overall prevalence of AKI among VL patients was 17.4% (confidence interval (CI): 13.6%-22.2%). Pre-renal azotemia (57%) and drug-induced AKI (50%) were the main etiologies of AKI at admission and post-admission respectively. Proteinuria and hematuria occurred in 85% and 42% of AKI patients respectively. Multivariate logistic regression revealed HIV co-infection (adjusted odds ratio (AOR): 6.01 95% CI: 1.99-18.27, p = 0.001) and other concomitant infections (AOR: 3.44 95% CI: 1.37-8.65, p = 0.009) to be independently associated with AKI.

CONCLUSION

AKI is a frequent complication in Ethiopian VL patients. Other renal manifestations included proteinuria, hematuria, and pyuria. HIV co-infection and other concomitant infections were significantly associated with AKI. Further studies are needed to quantify proteinuria and evaluate the influence of AKI on the treatment course, morbidity and mortality in VL patients.

Serious adverse events following treatment of visceral leishmaniasis: A systematic review and meta-analysis

Background

Despite a historical association with poor tolerability, a comprehensive review on safety of antileishmanial chemotherapies is lacking. We carried out an update of a previous systematic review of all published clinical trials in visceral leishmaniasis (VL) from 1980 to 2019 to document any reported serious adverse events (SAEs).

Methods

For this updated systematic review, we searched the following databases from 1^st Jan 2016 through 2^nd of May 2019: PUBMED, Embase, Scopus, Web of Science, Cochrane, clinicaltrials.gov, WHO ICTRP, and the Global Index Medicus. We included randomised and non-randomised interventional studies aimed at assessing therapeutic efficacy and extracted the number of SAEs reported within the first 30 days of treatment initiation. The incidence rate of death (IRD) from individual treatment arms were combined in a meta-analysis using random effects Poisson regression.

Results

We identified 157 published studies enrolling 35,376 patients in 347 treatment arms. Pentavalent antimony was administered in 74 (21.3%), multiple-dose liposomal amphotericin B (L-AmB) in 52 (15.0%), amphotericin b deoxycholate in 51 (14.7%), miltefosine in 33 (9.5%), amphotericin b fat/lipid/colloid/cholesterol in 31 (8.9%), and single-dose L-AmB in 17 (4.9%) arms. There was a total of 804 SAEs reported of which 793 (including 428 deaths) were extracted at study arm level (11 SAEs were reported at study level only). During the first 30 days, there were 285 (66.6%) deaths with the overall IRD estimated at 0.068 [95% confidence interval (CI): 0.041–0.114; I² = 81.4%; 95% prediction interval (PI): 0.001–2.779] per 1,000 person-days at risk; the rate was 0.628 [95% CI: 0.368–1.021; I² = 82.5%] in Eastern Africa, and 0.041 [95% CI: 0.021–0.081; I² = 68.1%] in the Indian Subcontinent. In 21 study arms which clearly indicated allowing the inclusion of patients with HIV co-infections the IRD was 0.575 [95% CI: 0.244–1.355; I² = 91.9%] compared to 0.043 [95% CI: 0.020–0.090; I² = 62.5%] in 160 arms which excluded HIV co-infections.

Conclusion

Mortality within the first 30 days of VL treatment initiation was a rarely reported event in clinical trials with an overall estimated rate of 0.068 deaths per 1,000 person-days at risk, though it varied across regions and patient populations. These estimates may serve as a benchmark for future trials against which mortality data from prospective and pharmacovigilance studies can be compared. The methodological limitations exposed by our review support the need to assemble individual patient data (IPD) to conduct robust IPD meta-analyses and generate stronger evidence from existing trials to support treatment guidelines and guide future research.

Visceral leishmaniasis, also known as Kala-Azar, is a neglected infectious disease of poverty affecting countries in the Indian Subcontinent and Eastern Africa. Existing treatments have concerning safety profiles and are far from ideal, with documented reports of serious adverse events (SAEs) following therapy. We did a systematic review of all published clinical trials in VL (1980–2019) to document SAEs following treatment administration reported in clinical literature and carried out a meta-analysis to quantify the incidence rate of mortality within 30 days of treatment initiation. We found that safety outcomes are poorly reported in published literature with substantial missing information regarding timing and frequency of the events. We also observed that mortality following treatment with antileishmanial drugs, as reported in the literature, is a rare event. There was substantial variability in mortality rates across geographical regions and patient sub-groups. Results from this review can provide benchmark estimates for comparing data from prospective trials and pharmacovigilance studies and support the need to assemble individual patient data (IPD) to conduct a robust IPD meta-analyses to overcome some of the underlying limitations.

Trypanosomatid-Caused Conditions: State of the Art of Therapeutics and Potential Applications of Lipid-Based Nanocarriers

Trypanosomatid-caused conditions (African trypanosomiasis, Chagas disease, and leishmaniasis) are neglected tropical infectious diseases that mainly affect socioeconomically vulnerable populations. The available therapeutics display substantial limitations, among them limited efficacy, safety issues, drug resistance, and, in some cases, inconvenient routes of administration, which made the scenarios with insufficient health infrastructure settings inconvenient. Pharmaceutical nanocarriers may provide solutions to some of these obstacles, improving the efficacy-safety balance and tolerability to therapeutic interventions. Here, we overview the state of the art of therapeutics for trypanosomatid-caused diseases (including approved drugs and drugs undergoing clinical trials) and the literature on nanolipid pharmaceutical carriers encapsulating approved and non-approved drugs for these diseases. Numerous studies have focused on the obtention and preclinical assessment of lipid nanocarriers, particularly those addressing the two currently most challenging trypanosomatid-caused diseases, Chagas disease, and leishmaniasis. In general, in vitro and in vivo studies suggest that delivering the drugs using such type of nanocarriers could improve the efficacy-safety balance, diminishing cytotoxicity and organ toxicity, especially in leishmaniasis. This constitutes a very relevant outcome, as it opens the possibility to extended treatment regimens and improved compliance. Despite these advances, last-generation nanosystems, such as targeted nanocarriers and hybrid systems, have still not been extensively explored in the field of trypanosomatid-caused conditions and represent promising opportunities for future developments. The potential use of nanotechnology in extended, well-tolerated drug regimens is particularly interesting in the light of recent descriptions of quiescent/dormant stages of Leishmania and Trypanosoma cruzi, which have been linked to therapeutic failure.

Recent advances and new strategies on leishmaniasis treatment

Leishmaniasis is one of the most important tropical neglected diseases according to the World Health Organization. Even after more than a century, we still have few drugs for the disease therapy and their great toxicity and side effects put in check the treatment control program around the world. Moreover, the emergence of strains resistant to conventional drugs, co-infections such as HIV/Leishmania spp., the small therapeutic arsenal (pentavalent antimonials, amphotericin B and formulations, and miltefosine), and the low investment for the discovery/development of new drugs force researchers and world health agencies to seek new strategies to combat and control this important neglected disease. In this context, the aim of this review is to summarize new advances and new strategies used on leishmaniasis therapy addressing alternative and innovative treatment paths such as physical and local/topical therapies, combination or multi-drug uses, immunomodulation, drug repurposing, and the nanotechnology-based drug delivery systems.Key points• The treatment of leishmaniasis is a challenge for global health agencies.• Toxicity, side effects, reduced therapeutic arsenal, and drug resistance are the main problems.• New strategies and recent advances on leishmaniasis treatment are urgent.• Immunomodulators, nanotechnology, and drug repurposing are the future of leishmaniasis treatment.

Epidemiological features of cutaneous leishmaniasis endemic in hilly areas of district Karak, Khyber-Pakhtunkhwa province of Pakistan

Cutaneous leishmaniasis is a vector borne infection caused by flagellated parasitic protozoans of the genus Leishmania. This is an emergent threat and endemic in areas of tropic and sub-tropics and has a wider geographical distribution. This study was aimed to find the epidemiological aspects of cutaneous leishmaniasis during the recent epidemic in district Karak in 2018-2019. The suspected patients of leishmaniasis from different areas of district Karak were examined. We came across 803 cases during six-month period from August 2018 to January 2019. A major portion (> 37%; n = 299) of these patients were in age 11-20 years. The infection rate was higher in female (55.3%; n = 803) compared to males (44.6%; n = 803). Both gender and age showed a significant effect on the occurrence of infection. It is concluded that cutaneous leishmaniasis has appeared as a major health issue in district Karak. The current study report CL outbreak in Karak district which need immediate response from the healthcare authorities. In addition, extensive awareness campaigns are needed for timely prevention of such outbreaks.

Prognostic factors for mortality among patients with visceral leishmaniasis in East Africa: Systematic review and meta-analysis

BACKGROUND

Visceral leishmaniasis (VL) is a vector-borne disease that is deadly if left untreated. Understanding which factors have prognostic value may help to focus clinical management and reduce case fatality. However, information about prognostic factors is scattered and conflicting. We conducted a systematic review and meta-analysis to identify prognostic factors for mortality among VL patients in East Africa.

METHODOLOGY/PRINCIPAL FINDINGS

The review protocol was registered in PROSPERO (CRD42016043112). We included studies published in English after 1970 describing VL patients treated in East African health facilities. To be included, studies had to report on associations between clinical or laboratory factors and mortality during admission or during VL treatment, with a minimal study size of ten patients. Conference abstracts and evaluations of genetic or immunological prognostic factors were excluded. We searched for studies in MEDLINE and four other databases in December 2018. To assess the risk of bias in observational studies and clinical trials, we used the Quality in Prognostic Studies (QUIPS) tool. We included 48 studies in the systematic review, describing 150,072 VL patients of whom 7,847 (5.2%) died. Twelve prognostic factors were evaluated in five or more studies and these results were submitted to meta-analysis producing one pooled crude odds ratio (OR) per prognostic factor. The following factors were strongly (OR>3) and significantly (P-value<0.05) associated with mortality: jaundice (OR = 8.27), HIV (OR = 4.60), tuberculosis (OR = 4.06), age >45 years (OR = 3.69), oedema (OR = 3.52), bleeding (OR = 3.37), and haemoglobin ≤6.5 g/dl (OR = 3.26). Factors significantly and moderately (OR between one and three) associated with death were severe malnutrition, long duration of illness, young age (<5 years), and large spleen size.

CONCLUSIONS/SIGNIFICANCE

These prognostic factors can be identified by health professionals in resource-constrained settings. They should be considered as "core" prognostic factors in future studies that aim at improving the prognosis of VL patients.

Genomic and Metabolomic Polymorphism among Experimentally Selected Paromomycin-Resistant Leishmania donovani Strains

Understanding the mechanism(s) underpinning drug resistance could lead to novel treatments to reverse the increased tolerance of a pathogen. In this study, paromomycin (PMM) resistance (PMM^r) was induced in three Nepalese clinical strains of Leishmania donovani with different inherent susceptibilities to antimony (Sb) drugs by stepwise exposure of promastigotes to PMM.

Understanding the mechanism(s) underpinning drug resistance could lead to novel treatments to reverse the increased tolerance of a pathogen. In this study, paromomycin (PMM) resistance (PMM^r) was induced in three Nepalese clinical strains of Leishmania donovani with different inherent susceptibilities to antimony (Sb) drugs by stepwise exposure of promastigotes to PMM. Exposure to PMM resulted in the production of mixed populations of parasites, even though a single cloned population was used at the start of selection. PMM 50% inhibitory concentration (IC₅₀) values for PMM^r parasites varied between 104 and 481 μM at the promastigote stage and 32 and 195 μM at the intracellular amastigote stage. PMM resistance was associated with increased resistance to nitric oxide at the amastigote stage but not the promastigote stage (P < 0.05). This effect was most marked in the Sb-resistant (Sb^r) PMM^r clone, in which PMM resistance was associated with a significant upregulation of glutathione compared to that in its wild type (P < 0.05), although there was no change in the regulation of trypanothione (detected in its oxidized form). Interestingly, PMM^r strains showed an increase in either the keto acid derivative of isoleucine (Sb intermediate PMM^r) or the 2-hydroxy acids derived from arginine and tyrosine (Sb susceptible PMM^r and Sb^r PMM^r). These results are consistent with the recent finding that the upregulation of the branched-chain amino acid aminotransferase and d-lactate dehydrogenase is linked to PMM^r. In addition, we found that PMM^r is associated with a significant increase in aneuploidy during PMM selection in all the strains, which could allow the rapid selection of genetic changes that confer a survival advantage.

Visceral Leishmaniasis: Recent Advances in Diagnostics and Treatment Regimens

Diagnostic advances in visceral leishmaniasis include the development of the rK39 and rK28 rapid diagnostic test. The direct agglutination test is also increasingly used, as well as conventional and real-time polymerase chain reaction, which also performs well on peripheral blood. The choice of treatment for visceral leishmaniasis depends on the geographic region where the infection is acquired. Liposomal amphotericin B is generally found to be safe and effective in most endemic regions of the world; antimonials still remain to be the most effective in eastern Africa despite its high toxicity. Combination therapy is increasingly explored. Immunosuppressed patients require adapted diagnostic and therapeutic strategies.

Elucidation of role of an acetyltransferase like protein in paromomycin resistance in Leishmania donovani using in silico and in vitro approaches

Paromomycin, an aminoglycoside antibiotic, is an effective treatment for VL (visceral leishmaniasis) in India. The modification of aminoglycoside antibiotics by enzymes such as aminoglycoside acetyltransferases is the predominant mechanism of resistance to antibiotics in bacterial system. In the present study, we identified and characterized LdATLP (an acetyltransferase-like protein) and elucidated its role in paromomycin resistance in Leishmania donovani. Gene encoding LdATLP was consistently up-regulated (>2fold) in three distinct paromomycin resistant in comparison with sensitive parasites, although the gene sequence was identical in the two. In silico analysis revealed that LdATLP consisted of conserved GNAT (GCN5-related N-Acetyltransferase) domain which is characteristic of aminoglycoside N-acetyltransferases. Evolutionary relationship among LdATLP of Leishmania and aminoglycoside acetyltransferases of bacteria was established by phylogenetic analysis. The 3D structure of LdATLP, predicted by ab-initio modeling, constituted 6 α-helices and 6 β-sheets. A few residues, such as R175, R177, E196, R197, V198, V200, K202, R205, C206, D208, G210, R211, R215, A234, S237, S238, K239, D240, F241 and Y242 of GNAT domain were predicted to be present at active site. Molecular docking of LdATLP with paromomycin or indolicidin (broad spectrum inhibitor of aminoglycoside modifying enzymes), followed by molecular dynamics simulation of docked complex suggested that both paromomycin and indolicidin bind to LdATLP with comparable free energy of binding. In vitro studies revealed that in the presence of indolicidin, paromomycin resistant parasites exhibited reversion of phenotype into sensitive parasites with marked increase in paromomycin susceptibility, suggesting the role of LdATLP in paromomycin resistance.Communicated by Ramaswamy H. Sarma.

Topoisomerase IB poisons induce histone H2A phosphorylation as a response to DNA damage in Leishmania infantum

DNA topoisomerases are considered consolidated druggable targets against diseases produced by trypanosomatids. Several reports indicated that indenoisoquinolines, a family of non-camptothecinic based topoisomerase poisons, have a strong leishmanicidal effect both in vitro and in vivo in murine models of visceral leishmaniasis. The antileishmanial effect of the indenoisoquinolines implies several mechanisms that include the stabilization of the cleavage complex, histone H2A phosphorylation and DNA fragmentation.

A series of 20 compounds with the indenoisoquinoline scaffold and several substituents at positions N6, C3, C8 and C9, were tested both in promastigotes and in intramacrophage splenic amastigotes obtained from an experimental murine infection. The antileishmanial effect of most of these compounds was within the micromolar or submicromolar range. In addition, the introduction of an N atom in the indenoisoquinoline ring (7-azaindenoisoquinolines) produced the highest selectivity index along with strong DNA topoisomerase IB inhibition, histone H2A phosphorylation and DNA-topoisomerase IB complex stabilization.

This report shows for the first time the effect of a series of synthetic indenoisoquinolines on histone H2A phosphorylation, which represents a primary signal of double stranded DNA break in genus Leishmania.

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N-6 indenoisoquinoline derivatives show strong antileishmanial activity.

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Indenoisoquinolines arrest Leishmania cell-cycle in S phase.

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Inhibition of leishmanial TopIB by indenoisoquinolines induces DNA fragmentation.

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Leishmanial H2A histone is phosphorylated at the Thr128 in response to DNA damage.

Visceral Leishmaniasis Treatment Outcome and Associated Factors in Northern Ethiopia

BACKGROUND

Visceral leishmaniasis (VL), one of the most neglected tropical diseases, is placing a huge burden on Ethiopia. Despite the introduction of antileishmanial drugs, treatment outcomes across regions are variable due to drug resistance and other factors. Thus, understanding of VL treatment outcomes and its contributing factors helps decisions on treatment. However, the magnitude and the risk factors of poor treatment outcome are not well studied in our setting. Therefore, our study was designed to assess treatment outcomes and associated factors in patients with VL.

MATERIALS AND METHODS

A cross-sectional study was conducted in VL patients admitted between June 2016 and April 2018 to Ayder Comprehensive Specialized Hospital, Tigray, Northern Ethiopia. Data was collected through chart review of patient records. Logistic regression analysis was used to identify factors associated with poor treatment outcome.

RESULTS

A total of 148 VL patients were included in the study. The mean age (SD) of the patients was 32.86 (11.9) years; most of them (94.6%) were male patients. The proportion of poor treatment outcome was 12.1%. Multivariable logistic regression analysis showed that long duration of illness (> four weeks) (adjusted odds ratio (AOR): 6.1 [95% confidence interval (CI); 1.3-28.6], p=0.02) and concomitant tuberculosis (TB) infection (AOR 4.6 [95% CI; 1.1-19.1], p=0.04) were the independent predictors of poor treatment outcome.

CONCLUSIONS

Poor treatment outcome was observed in a considerable proportion of VL patients. Long duration of illness and coinfection with TB were associated with poor VL treatment outcome. Hence, early diagnosis and effective prompt treatment are important to improve treatment outcomes among VL patients. Special attention should also be given in the treatment of VL/TB coinfected patients in our setting.

Potential Use of Gluconate in Cancer Therapy

We have recently discovered that cancer cells take up extracellular citrate through plasma membrane citrate transporter (pmCiC) and advantageously use citrate for their metabolism. Citrate uptake can be blocked with gluconate and this results in decreased tumor growth and altered metabolic characteristics of tumor tissue. Interestingly, gluconate, considered to be physiologically neutral, is incidentally used in medicine as a cation carrier, but not as a therapeutically active substance. In this review we discuss the results of our recent research with available literature and suggest that gluconate may be useful in the treatment of cancer.

Current and promising novel drug candidates against visceral leishmaniasis

Leishmaniasis is a group of zoonotic diseases caused by a trypanosomatid parasite mostly in impoverished populations of low-income countries. In their different forms, leishmaniasis is prevalent in more than 98 countries all over the world and approximately 360-million people are at risk. Since no vaccine is currently available to prevent any form of the disease, the control strategy of leishmaniasis mainly relies on early case detection followed by adequate pharmacological treatment that may improve the prognosis and can reduce transmission. A handful of compounds and formulations are available for the treatment of leishmaniasis in humans, but only few of them are currently in use since most of these agents are associated with toxicity problems such as nephrotoxicity and cardiotoxicity in addition to resistance problems. In recent decades, very few novel drugs, new formulations of standard drugs or combinations of them have been approved against leishmaniasis. This review highlights the current drugs and combinations that are used medical practice and recent advances in new treatments against leishmaniasis that were pointed out in the recent 2nd Conference, Global Challenges in Neglected Tropical Diseases, held in San Juan, Puerto Rico in June 2018, emphasizing the plethora of new families of molecules that are bridging the gap between preclinical and first-in-man trials in next future.

Treatment outcomes of visceral leishmaniasis in Ethiopia from 2001 to 2017: a systematic review and meta-analysis

Background

Ethiopia has the highest number of visceral leishmaniasis (VL) cases after Sudan in Sub-Saharan Africa. However, there was lack of comprehensive data on VL treatment outcome despite the huge burden of the diseases in the country. Hence, we aimed to perform a systematic review and meta-analysis on this topic to obtain stronger evidence on treatment outcomes of VL from the existing literature in Ethiopia.

Methods

The Cochrane guidelines to conduct meta-analysis following the Preferred Reporting Items for Systematic review and Meta-Analysis statement was used to conduct a computerized systematic search of the PubMed, Google Scholar, and ScienceDirect databases. Random effects model was used to combine studies showing heterogeneity of Cochrane Q P < 0.10 and I² > 50. Treatment outcomes were assessed at end of treatment and at 6 months follow-up. Subgroup analyses were performed on treatment outcomes based on the different antileishmanial treatment options and patients’ HIV status.

Results

Fifteen studies were included in the final analyses. At end of treatment, an overall treatment success rate of 82.6% was noticed. At 6 months follow-up, the overall treatment success rate was 72.2%. For patients treated with sodium stibogluconate (SSG), the treatment success rates at the end of treatment and at six-month follow-up were 81.5% and 80.7%, respectively. Multiple doses of liposomal-amphotericin B (L-AMB) had treatment success rates of 96.7 and 71–100% at the end of treatment and at 6 months follow-up, respectively. The combination of SSG with paromomycin (PM) gave treatment success rates of up to 90.1% at the end of treatment. HIV-infected individuals were found to have a higher mortality (odds ratio = 4.77, 95% CI: 1.30–17.43, P = 0.009) rate at 6 months follow-up.

Conclusions

SSG alone has shown lower treatment efficacy in the management of VL when compared to combination of SSG with PM and multiple doses of L-AMB. The combination of SSG with PM gave good treatment success rates with shorter duration of treatment. Hence, the combination of SSG with PM should be used preferentially over SSG monotherapy. Multiple doses of L-AMB showed great efficacy especially among patients with complications, severe disease, HIV co-infection, and intolerance to the adverse effects of antimonials. HIV-infected individuals had a worse prognosis than their HIV-negative counterparts.

Electronic supplementary material

The online version of this article (10.1186/s40249-018-0491-7) contains supplementary material, which is available to authorized users.

Leishmaniasis

Leishmaniasis is a poverty-related disease with two main clinical forms: visceral leishmaniasis and cutaneous leishmaniasis. An estimated 0·7-1 million new cases of leishmaniasis per year are reported from nearly 100 endemic countries. The number of reported visceral leishmaniasis cases has decreased substantially in the past decade as a result of better access to diagnosis and treatment and more intense vector control within an elimination initiative in Asia, although natural cycles in transmission intensity might play a role. In east Africa however, the case numbers of this fatal disease continue to be sustained. Increased conflict in endemic areas of cutaneous leishmaniasis and forced displacement has resulted in a surge in these endemic areas as well as clinics across the world. WHO lists leishmaniasis as one of the neglected tropical diseases for which the development of new treatments is a priority. Major evidence gaps remain, and new tools are needed before leishmaniasis can be definitively controlled.

Recent Development of Visceral Leishmaniasis Treatments: Successes, Pitfalls, and Perspectives

Research in visceral leishmaniasis in the last decade has been focused on how better to use the existing medicines as monotherapy or in combination. Systematic research by geographical regions has shown that a universal treatment is far from today's reality. Substantial progress has been made in the elimination of kala-azar in South Asia, with a clear strategy on first- and second-line therapy options of single-dose liposomal amphotericin B and a combination of paromomycin and miltefosine, respectively, among other interventions. In Eastern Africa, sodium stibogluconate (SSG) and paromomycin in combination offer an advantage compared to the previous SSG monotherapy, although not exempted of limitations, as this therapy requires 17 days of painful double injections and bears the risk of SSG-related cardiotoxicity. In this region, attempts to improve the combination therapy have been unsuccessful. However, pharmacokinetic studies have led to a better understanding of underlying mechanisms, like the underexposure of children to miltefosine treatment, and an improved regimen using an allometric dosage. Given this global scenario of progress and pitfalls, we here review what steps need to be taken with existing medicines and highlight the urgent need for oral drugs. Furthermore, it should be noted that six candidates belonging to five new chemical classes are reaching phase I, ensuring an optimistic near future.

Cutaneous Leishmaniasis in the Metropolitan City of Multan, Pakistan, a Neglected Tropical Disease

Cutaneous leishmaniasis is a vector-borne infection caused by flagellated parasitic protozoans in the genus Leishmania. Promastigotes are the infective stage, which are transmitted by the bite of female sand flies of the genera Phlebotomus or Lutzomyia. Three clinical forms of Leishmania infection are recognized in humans, and they are caused by different Leishmania species. They are cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (ML), and visceral leishmaniasis (VL). Up to 2 million cases of leishmaniasis are reported annually worldwide. In Pakistan, CL is widely distributed in endemic areas. In the current study, a survey was conducted to investigate the occurrence of CL in an endemic area of the metropolitan city of Multan, Pakistan. The material for diagnosis of CL was obtained from 461 patients from 239 clinical laboratories and health care centers in Multan. Of these patients, 42.9% (198 of 461) having positive findings of amastigotes in Giemsa stained tissue impression smears. The distribution of CL skin lesions was highly variable. Most patients (76.2%) had a single lesion. Most CL lesions were found on a single hand (23.7%). The prevalence of two CL lesions per patient was 21.7%, while three or more positive CL lesions were observed in 2.0% of patients. The 198 CL-positive patients ranged in age 10-40 yr old, 101 were males, and 97 were females. Logistic regression analysis of leishmaniasis versus age and gender showed that both the age and gender had a significant (P < 0.05) effect on the occurrence of infection. Outbreaks of CL were reported in 14 of the 68 Union Councils of Multan.

The initial effectiveness of liposomal amphotericin B (AmBisome) and miltefosine combination for treatment of visceral leishmaniasis in HIV co-infected patients in Ethiopia: A retrospective cohort study

BACKGROUND

North-west Ethiopia faces the highest burden world-wide of visceral leishmaniasis (VL) and HIV co-infection. VL-HIV co-infected patients have higher (initial) parasitological failure and relapse rates than HIV-negative VL patients. Whereas secondary prophylaxis reduces the relapse rate, parasitological failure rates remain high with the available antileishmanial drugs, especially when administered as monotherapy. We aimed to determine the initial effectiveness (parasitologically-confirmed cure) of a combination of liposomal amphotericin B (AmBisome) and miltefosine for treatment of VL in HIV co-infected patients.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a retrospective cohort study at a Médecins Sans Frontières-supported health center in north-west Ethiopia. We included VL-HIV co-infected adults, treated for VL between January 2011 and August 2014, with AmBisome infusion (30 mg/kg total dose) and miltefosine orally for 28 days (100 mg/day). Proportions of initial treatment outcome categories were calculated. Predictors of initial parasitological failure and of death were determined using multivariable logistic regression. Of the 173 patients included, 170 (98.3%) were male and the median age was 32 years. The proportion of patients with primary VL (48.0%) and relapse VL (52.0%) were similar. The majority had advanced HIV disease (n = 111; 73.5%) and were on antiretroviral therapy prior to VL diagnosis (n = 106; 64.2%). Initial cure rate was 83.8% (95% confidence interval [CI], 77.6-88.6); death rate 12.7% (95% CI, 8.5-18.5) and parasitological failure rate 3.5% (95% CI, 1.6-7.4). Tuberculosis co-infection at VL diagnosis was predictive of parasitological failure (adjusted odds ratio (aOR), 8.14; p = 0.02). Predictors of death were age >40 years (aOR, 5.10; p = 0.009), hemoglobin ≤6.5 g/dL (aOR, 5.20; p = 0.002) and primary VL (aOR, 8.33; p = 0.001).

CONCLUSIONS/SIGNIFICANCE

Initial parasitological failure rates were very low with AmBisome and miltefosine combination therapy. This regimen seems a suitable treatment option. Knowledge of predictors of poor outcome may facilitate better management. These findings remain to be confirmed in clinical trials.

Chemotherapeutics of visceral leishmaniasis: present and future developments

Treatment of Visceral Leishmaniasis (VL), a neglected tropical disease, is very challenging with few treatment options. Long duration of treatment and drug toxicity further limit the target of achieving VL elimination. Chemotherapy remains the treatment of choice. Single dose of liposomal amphotericin B (LAmB) and multidrug therapy (LAmB + miltefosine, LAmB + paromomycin (PM), or miltefosine + PM) are recommended treatment regimen for treatment of VL in Indian sub-continent. Combination therapy of pentavalent antimonials (Sbv) and PM in East Africa and LAmB in the Mediterranean region/South America remains the treatment of choice. Various drugs having anti-leishmania properties are in preclinical phase and need further development. An effective treatment and secondary prophylaxis of HIV-VL co-infection should be developed to decrease treatment failure and drug resistance.

Development of (6 R)-2-Nitro-6-[4-(trifluoromethoxy)phenoxy]-6,7-dihydro-5 H-imidazo[2,1- b][1,3]oxazine (DNDI-8219): A New Lead for Visceral Leishmaniasis

Discovery of the potent antileishmanial effects of antitubercular 6-nitro-2,3-dihydroimidazo[2,1-b][1,3]oxazoles and 7-substituted 2-nitro-5,6-dihydroimidazo[2,1-b][1,3]oxazines stimulated the examination of further scaffolds (e.g., 2-nitro-5,6,7,8-tetrahydroimidazo[2,1-b][1,3]oxazepines), but the results for these seemed less attractive. Following the screening of a 900-compound pretomanid analogue library, several hits with more suitable potency, solubility, and microsomal stability were identified, and the superior efficacy of newly synthesized 6R enantiomers with phenylpyridine-based side chains was established through head-to-head assessments in a Leishmania donovani mouse model. Two such leads (R-84 and R-89) displayed promising activity in the more stringent Leishmania infantum hamster model but were unexpectedly found to be potent inhibitors of hERG. An extensive structure–activity relationship investigation pinpointed two compounds (R-6 and pyridine R-136) with better solubility and pharmacokinetic properties that also provided excellent oral efficacy in the same hamster model (>97% parasite clearance at 25 mg/kg, twice daily) and exhibited minimal hERG inhibition. Additional profiling earmarked R-6 as the favored backup development candidate.