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Leishmaniasis is a parasitic disease with clinical presentations that vary from asymptomatic infection to cutaneous, mucocutaneous, or visceral disease. Global change, with migratory movements and travels, among others, has had an impact on the presentation of the clinical forms of leishmaniasis in a given area, hindering its diagnosis. The traditional parasitological techniques have limited sensitivity, and currently, there is no reference or gold-standard molecular diagnostic method. The aim of this study was to evaluate the effectivity of the VIASURE Leishmania Real-Time PCR Detection Kit prototype (CerTest Biotec, Zaragoza, Spain) for the diagnosis of autochthonous and imported leishmaniasis in comparison with two other commercialized molecular kits: STAT-NAT® Leishmania spp. (Sentinel, Milano, Italy) and Leishmania spp. Real-TM PCR Kit (Sacace Biotechnologies, Como, Italy). Four species of Leishmania, L. infantum, L. major, L. braziliensis, and L. panamensis, were targeted to assess analytical sensitivity, whereas diagnostic sensitivity was evaluated by studying a panel of 49 DNA samples from patients with suspected or confirmed Leishmania infection. The prototype could detect all the New and Old World species studied and achieved a limit of detection of 5 × 10−5 ng DNA/μL in all species. Also, it allowed the diagnosis of autochthonous and imported cases of cutaneous and visceral leishmaniasis (VL). Diagnostic sensitivity was 81.8% for the prototype and 100% for the Sacace kit (27 and 33 positive samples detected, respectively). The STAT-NAT® kit failed to detect Vianna species. The VIASURE Leishmania Real-Time PCR Detection Kit prototype was found to have good analytical and diagnostic sensitivity. Using a simple protocol and ready-to-use reagents, results are obtained quickly and are easy to interpret. The evaluation results indicate that the test is a promising candidate for routine diagnosis of cutaneous leishmaniasis and VL in endemic countries, but more studies are necessary to address its sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Background: Post-kala-azar dermal leishmaniasis (PKDL) is a dermatosis that occurs 2–3 years after an apparently successful treatment of visceral leishmaniasis (VL). In rare cases, PKDL occurs concurrently with VL and is characterized by fever, splenomegaly, hepatomegaly or lymphadenopathy, and poor nutritional status and is known as Para-kala-azar dermal leishmaniasis (Para-KDL). Co-association of active VL in PKDL patients is documented in Africa, but very few case reports are found in South Asia. Case summary: We present a case of Para-kala-azar Dermal Leishmaniasis (Para-KDL) in a 50-year-old male patient with a history of one primary Visceral Leishmaniasis (VL) and 2 times relapse of Visceral Leishmaniasis (VL). The patient presented with fever, skin lesions, and hepatosplenomegaly. Laboratory tests revealed LD bodies in the slit skin smear and splenic biopsy. The patient was treated with two cycles of Amphotericin B with Miltefosine in between cycles for 12 weeks to obtain full recovery. Conclusion: This case report serves as a reminder that Para-kala-azar dermal leishmaniasis can develop as a consequence of prior visceral leishmaniasis episodes, even after apparently effective therapy. Since para-kala-azar is a source of infectious spread, endemics cannot be avoided unless it is effectively recognized and treated. [ABSTRACT FROM AUTHOR]

Background: Leishmaniasis is a parasitic disease caused by obligate intracellular protozoa of the genus Leishmania. This infection is characterized by a wide range of clinical manifestations, with symptoms greatly dependent on the causal parasitic species. Here we present the design and application of a new 70-kDa heat shock protein gene (hsp70)-based marker of 771 bp (HSP70-Long). We evaluated its sensitivity, specificity and diagnostic performance employing an amplicon-based MinION™ DNA sequencing assay to identify different Leishmania species in clinical samples from humans and reservoirs with cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL). We also conducted a comparative analysis between our novel marker and a previously published HSP70 marker known as HSP70-Short, which spans 330 bp. Methods: A dataset of 27 samples from Colombia, Venezuela and the USA was assembled, of which 26 samples were collected from humans, dogs and cats affected by CL and one sample was collected from a dog with VL in the USA (but originally from Greece). DNA was extracted from each sample and underwent conventional PCR amplification utilizing two distinct HSP70 markers: HSP70-Short and HSP70-Long. The subsequent products were then sequenced using the MinION™ sequencing platform. Results: The results highlight the distinct characteristics of the newly devised HSP70-Long primer, showcasing the notable specificity of this primer, although its sensitivity is lower than that of the HSP70-Short marker. Notably, both markers demonstrated strong discriminatory capabilities, not only in distinguishing between different species within the Leishmania genus but also in identifying instances of coinfection. Conclusions: This study underscores the outstanding specificity and effectiveness of HSP70-based MinION™ sequencing, in successfully discriminating between diverse Leishmania species and identifying coinfection events within samples sourced from leishmaniasis cases. [ABSTRACT FROM AUTHOR]

Background: Leishmaniasis is a common neglected tropical disease in Ethiopia. Visceral leishmaniasis (VL) caused by Leishmania donovani presents in the lowlands, while cutaneous leishmaniasis (CL) affects people living in the highlands. Although CL is described as being caused by Leishmania aethiopica, there is also evidence of L. tropica and L. major isolated from a patient, sand flies and potential reservoirs. Information on species causing CL in Ethiopia is patchy, and no nation-wide study has ever been done. Understanding which species are causing CL in Ethiopia can have important implications for patient management and disease prevention. Methods: We analyzed stored routine samples and biobanked DNA isolates from previously conducted studies of CL patients from different centers in the north, center and south of Ethiopia. Species typing was performed using ITS-1 PCR with high-resolution melt (HRM) analysis, followed by HSP70 amplicon sequencing on a selection of the samples. Additionally, sociodemographic, clinical and laboratory data of patients were analyzed. Results: Of the 226 CL samples collected, the Leishmania species could be determined for 105 (45.5%). Leishmania aethiopica was identified in 101 (96.2%) samples from across the country. In four samples originating from Amhara region, northwestern Ethiopia, L. donovani was identified by ITS-1 HRM PCR, of which two were confirmed with HSP70 sequences. While none of these four patients had symptoms of VL, two originated from known VL endemic areas. Conclusions: The majority of CL was caused by L. aethiopica, but CL due to L. tropica and L. major cannot be ruled out. Our study is the first to our knowledge to demonstrate CL patients caused by L. donovani in Ethiopia. This should spark future research to investigate where, how and to which extent such transmission takes place, how it differs genetically from L. donovani causing VL and whether such patients can be diagnosed and treated successfully with the currently available tools and drugs. [ABSTRACT FROM AUTHOR]

A rapid, cost-effective, and simple nucleic acid isolation technique coupled with a point-of-need DNA amplification assay is a desirable goal for programmatic use. For diagnosis of Visceral Leishmaniasis (VL), Recombinase Polymerase Amplification (RPA) rapid tests for the detection of Leishmania DNA are versatile and have operational advantages over qPCR. To facilitate the delivery of the RPA test at point-of-need for VL diagnosis, we compared two rapid DNA extraction methods, SwiftDx (SX) and an in-house Boil and Spin (BS) method, coupled with RPA amplification, versus more widely used methods for DNA extraction and amplification, namely Qiagen (Q) kits and qPCR, respectively. A total of 50 confirmed VL patients and 50 controls, matched for age and gender, were recruited from Mymensingh, Bangladesh, a region highly endemic for VL. Blood samples were collected from each participant and DNA was extracted using Q, SX and BS methods. Following DNA extraction, qPCR and RPA assays were performed to detect L. donovani in downstream analysis. No significant differences in sensitivity of the RPA assay were observed between DNA extraction methods, 94.00% (95% CI: 83.45–98.75%), 90% (95% CI: 78.19–96.67%), and 88% (95% CI: 75.69–95.47%) when using Q, SX, and BS, respectively. Similarly, using qPCR, no significant differences in sensitivity were obtained when using Q or SX for DNA extraction, 94.00% (95% CI: 83.45–98.75%) and 92.00% (80.77–97.78%), respectively. It is encouraging that RPA and qPCR showed excellent agreement (k: 0.919–0.980) when different extraction methods were used and that the DNA impurities using BS had no inhibitory effect on the RPA assay. Furthermore, significantly higher DNA yields were obtained using SX and BS versus Q; however, a significantly higher parasite load was detected using qPCR when DNA was extracted using Q versus SX. Considering the cost, execution time, feasibility, and performance of RPA assay, rapid extraction methods such as the Boil and Spin technique appear to have the potential for implementation in resource-limited endemic settings. Further clinical research is warranted prior to broader application. [ABSTRACT FROM AUTHOR]

Background: Immunosuppression is a major risk factor for the development of visceral leishmaniasis (VL). The number of patients receiving immunosuppressant drugs such as TNF antagonist (anti-TNF) and methotrexate (MTX) is increasing. In these patients, VL is more severe, their response to treatment poorer, and they are at higher risk of relapse, a consequence (largely) of the poor and inappropriate immune response they develop. Objectives: To examine the effect of immunosuppressive treatment on the host immune response and thus gain insight into the reduced efficacy of pentavalent antimonials in these patients. Experiments were performed using BALB/c mice immunosuppressed with anti-TNF or MTX, infected with Leishmania infantum promastigotes, and then treated with Glucantime® at clinical doses. Results: Immunosuppression with both agents impeded parasite elimination from the spleen and bone marrow. Low pro-inflammatory cytokine production by CD4+ and CD8+ T cells was detected, along with an increase in PD-1 and IL-10 expression by B and T cells in the immunosuppressed groups after treatment. Conclusion: The immunosuppressed mice were unable to develop specific cellular immunity to the parasite, perhaps explaining the greater risk of VL relapse seen in pharmacologically immunosuppressed human patients. [ABSTRACT FROM AUTHOR]

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, affects millions of people in the Americas and across the world, leading to considerable morbidity and mortality. Current treatment options, benznidazole (BNZ) and nifurtimox, offer limited efficacy and often lead to adverse side effects because of long treatment durations. Better treatment options are therefore urgently required. Here, we describe a pyrrolopyrimidine series, identified through phenotypic screening, that offers an opportunity to improve on current treatments. In vitro cell-based washout assays demonstrate that compounds in the series are incapable of killing all parasites; however, combining these pyrrolopyrimidines with a subefficacious dose of BNZ can clear all parasites in vitro after 5 days. These findings were replicated in a clinically predictive in vivo model of chronic Chagas disease, where 5 days of treatment with the combination was sufficient to prevent parasite relapse. Comprehensive mechanism of action studies, supported by ligand-structure modeling, show that compounds from this pyrrolopyrimidine series inhibit the Qi active site of T. cruzi cytochrome b, part of the cytochrome bc1 complex of the electron transport chain. Knowledge of the molecular target enabled a cascade of assays to be assembled to evaluate selectivity over the human cytochrome b homolog. As a result, a highly selective and efficacious lead compound was identified. The combination of our lead compound with BNZ rapidly clears T. cruzi parasites, both in vitro and in vivo, and shows great potential to overcome key issues associated with currently available treatments. Editor's summary: Chagas disease (CD) and visceral leishmaniasis are considered neglected tropical diseases and are responsible for ~30,000 fatalities annually. Current treatments for these vector-borne parasitic infections are inadequate, and there is a pressing need for better therapeutics. In companion articles, González et al. and Braillard et al. describe the development of closely related pyrrolopyrimidine compounds that target the cytochrome bc1 complex of the parasite electron transport chain and show promise for the treatment of both diseases. DNDI-6174 demonstrates potent activity in Leishmania models of infection and has a suitable profile for clinical development. For CD, the combination of pyrrolopyrimidine compounds with a subefficacious dose of benznidazole delivers rapid clearance of parasites in an animal model of chronic CD, offering the prospect of safer and shorter treatment regimens. Collectively, these studies represent advances in the development of potential treatments for some of the world's most neglected patient populations. —Christiana Fogg [ABSTRACT FROM AUTHOR]

New drugs for visceral leishmaniasis that are safe, low cost, and adapted to the field are urgently required. Despite concerted efforts over the last several years, the number of new chemical entities that are suitable for clinical development for the treatment of Leishmania remains low. Here, we describe the discovery and preclinical development of DNDI-6174, an inhibitor of Leishmania cytochrome bc1 complex activity that originated from a phenotypically identified pyrrolopyrimidine series. This compound fulfills all target candidate profile criteria required for progression into preclinical development. In addition to good metabolic stability and pharmacokinetic properties, DNDI-6174 demonstrates potent in vitro activity against a variety of Leishmania species and can reduce parasite burden in animal models of infection, with the potential to approach sterile cure. No major flags were identified in preliminary safety studies, including an exploratory 14-day toxicology study in the rat. DNDI-6174 is a cytochrome bc1 complex inhibitor with acceptable development properties to enter preclinical development for visceral leishmaniasis. Editor's summary: Chagas disease (CD) and visceral leishmaniasis are considered neglected tropical diseases and are responsible for ~30,000 fatalities annually. Current treatments for these vector-borne parasitic infections are inadequate, and there is a pressing need for better therapeutics. In companion articles, González et al. and Braillard et al. describe the development of closely related pyrrolopyrimidine compounds that target the cytochrome bc1 complex of the parasite electron transport chain and show promise for the treatment of both diseases. DNDI-6174 demonstrates potent activity in Leishmania models of infection and has a suitable profile for clinical development. For CD, the combination of pyrrolopyrimidine compounds with a subefficacious dose of benznidazole delivers rapid clearance of parasites in an animal model of chronic CD, offering the prospect of safer and shorter treatment regimens. Collectively, these studies represent advances in the development of potential treatments for some of the world's most neglected patient populations. —Christiana Fogg [ABSTRACT FROM AUTHOR]

Miranda Municipality of Mato Grosso do Sul, borders the Pantanal wetland, a famous fishing destination visited by tourists from all over the world, and is a location where visceral leishmaniasis has been reported. To assess the risk of Leishmania infantum transmission, we studied the sandfly community, focusing on known vector and parasite presence. We conducted light trap collections twice per month at nine sites within the city (including two forested areas) for one year. We collected a total of 12,727 sand flies, 10,891 males and 1,836 females belonging to 11 species: Brumptomyia avellari, Evandromyia aldafalcaoae, Ev. evandroi, Ev. lenti, Ev. sallesi, Ev. walkeri, Lu. longipalpis, Nyssomyia whitmani, Psathyromyia bigeniculata, Pa. hermanlenti and Pa. punctigeniculata. Lutzomyia longipalpis, the proven vector of Leishmania infantum, was captured each month, and was the most abundant species observed, accounting for more than 99% of sand flies captured in most sites, especially where chicken coops were present. Evidence of Leishmania infantum infection was detected in 0.40% of Lu. longipalpis tested. We developed a generalized mixed multilevel model for Lu. longipalpis, that includes within-year seasonality, location of capture (indoors vs. outdoors), vector abundance, and sex ratio. The VL vector was abundant both inside and outside houses. Large numbers of Lu. longipalpis were observed in outdoor sites where domestic animals were present but were absent from forest sites. Our findings suggest high vector populations and Le. infantum presence in a city where tourists could be exposed to visceral leishmaniasis, with significant implications for more surveillance and control activities. Author summary: Several localities in Mato Grosso do Sul have already recorded human visceral leishmaniasis cases, including the city of Miranda, which is a famous fishing and tourism destination. Due to the high number of visitors, we decided to evaluate the risk of Leishmania infantum transmission in the area. Thus, we conducted vector collections over one year, detecting both the presence of the main vector (Lutzomyia longipalpis) and the Le. infantum parasite. We used nonlinear multilevel mixed models, under the Bayesian framework, to investigate the seasonal changes on transmission risk (i.e.; overall vector abundance and the proportion of females), taking into account the residence space. We found that the overall vector abundance outdoors was higher than in the indoors. Outdoors abundance was more consistent with two-peaks during the year, whereas indoors abundance was more seasonal with a single peak. Although, indoor abundance was lower than observed outdoors, the proportion of females captured was up to twice that observed outdoors. These findings highlighted the spatiotemporal component of leishmaniasis transmission risk, which can guide entomological surveillance and control measures. [ABSTRACT FROM AUTHOR]

A chromone-peptidyl hybrids series was synthesised and rationally repurposed towards identification of potential antileishmanial hits against visceral leishmaniasis. Three hybrids 7c, 7n, and 7h showed potential IC50 values (9.8, 10, and 12 µM, respectively) which were comparable to erufosine IC50 (9.8 µM) but lower potency than miltefosine IC50 (3.5 µM). Preliminary assessment of cytotoxicity using human THP-1 cells presented chromone-peptidyl hybrids 7c and 7n as non-cytotoxic up to 100 µM while erufosine and miltefosine had CC50 of 19.4 µM and >40 µM, respectively. In silico studies pinpointed the N-p-methoxyphenethyl substituent at the peptidyl moiety together with the oxygen-based substituted functions of the phenyl ring of the chromone moiety as crucial players in binding to LdCALP. Together, these findings present chromone-peptidyl hybrids 7c and 7n as potential and anticipated non-cytotoxic antileishmanial hit compounds for possible development of potential antileishmanial agents against visceral leishmaniasis. [ABSTRACT FROM AUTHOR]

Background: This paper identifies opportunities and challenges for leishmaniasis control and elimination in Colombia, emphasizing the role of pooled procurement of essential medicines and supplies. Colombia is among the countries most affected by leishmaniasis globally, and also faces the dual challenge of procuring critically needed medicines in the context of limited national resources. It recently renewed its commitment to the control and elimination of leishmaniasis under its 2022–2031 Public Health Plan (PDSP) through a comprehensive public health approach. Methodology/Principal findings: The methodology comprises a comprehensive literature review and key informant interviews with leishmaniasis experts from the Colombian national control program and PAHO/WHO, focusing on cutaneous, mucocutaneous, and visceral leishmaniasis. Leishmaniasis is endemic throughout Colombia, with over 11 million people at risk, many of whom live in poverty-stricken, remote and isolated rural areas with limited access to health services. Leishmaniasis care, including medicines, is provided free of charge, but many barriers were nonetheless identified at environmental, population, and health system levels, including the supply of quality-assured medicines. Opportunities to alleviate these barriers were identified, including the support of the PAHO Strategic Fund. Within the context of the sustainable development goals and international leishmaniasis control and elimination targets, Colombian officials have established their own priorities, the highest of which is the reduction of deaths from visceral leishmaniasis. Conclusions/Significance: The elimination of leishmaniasis as a public health problem presents significant challenges, given its biological complexity and diversity, physical and clinical manifestations, social and economic impacts, frequently burdensome treatment regimens, and insufficient supply of necessary medicines. However, rigorous prevention and control efforts through strong political commitment and a highly motivated workforce can dramatically reduce its burden. Colombia's new PDSP, which highlights leishmaniasis control, is an opportunity for a revitalized health system response through committed leadership, intersectoral actions, and partnerships with international organizations that share a common vision. Author summary: Leishmaniasis is a vector-borne disease transmitted by female sand flies to humans and animals, causing infections ranging from asymptomatic and self-healing cutaneous leishmaniasis to visceral leishmaniasis which is highly lethal if untreated. Although all forms of leishmaniasis are treatable and curable with early diagnosis and treatment, the disease presents many challenges for affected populations, many of whom live in remote rural areas of the developing world, with limited access to public health facilities. Health services also face major constraints in supplying critically needed, yet costly medicines, in the context of limited financial resources. This paper presents the case of Colombia which is among the countries most affected by leishmaniasis globally, and discusses its many challenges in responding to the disease, including the guaranteed supply of necessary medicines. Our results uncover new opportunities for a revitalized health system response through committed leadership, intersectoral actions, such as a One Health approach, and partnerships with like-minded international organizations. These include Colombia's new 10-Year Public Health Plan that contains specific time-bound goals for leishmaniasis control and elimination as a public health problem, prioritizing a reduction in deaths from visceral leishmaniasis, and potential cost-savings from the acquisition of essential medicines and supplies through the Strategic Fund of the Pan American Health Organization. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a neglected tropical disease that affects millions of people around the world. Available therapy causes severe side effects, has unacceptable prices for some specific formulations, and the existence of drug-resistant parasites limits the use of the currently available arsenal of antiparasitic drugs. Therefore, natural products serve as one of the main sources to develop new and effective alternative drugs against leishmaniasis. In this sense, the present study evaluated the potential of the triterpene Lupeol (Lu) entrapped in nanostructured lipid carriers (NLCs) for the treatment of experimental visceral leishmaniasis. The therapeutic efficacy of Lu or Lu entrapped in NLC (Lu-NLC) was investigated in golden hamsters infected with Leishmania (Leishmania) infantum. Lu-NLC presented a mean particle size of 265.3 ± 4.6 nm, a polydispersity index of <0.25 and a zeta potential of −37.2 ± 0.84 mV; the efficacy of encapsulation was 84.04 ± 0.57%. Studies on hamsters showed that Lu-NLC (5 mg/kg) administered intraperitoneally for 10 consecutive days caused a reduction of 99.9% in the number of parasites in the spleen and liver compared to the untreated infected control. On the contrary, Lu-treated animals (5 mg/kg) had 94.4 and 90.2% less parasites in the spleen and liver, respectively, than the infected group. Additionally, a significant preservation of splenic and hepatic tissues was observed in animals treated with Lu-NLC or Lu. Furthermore, Lu-NLC-treated animals produced high levels of anti-Leishmania IgG2 isotype. These data indicate that NLC potentialized Lu efficacy in experimental visceral leishmaniasis. This work suggests that Lu and nanoformulations carrying this compound may be considered as an important tool to be included in the alternative therapy of leishmaniasis. [ABSTRACT FROM AUTHOR]

Visceral leishmaniasis (VL, kala azar), caused by Leishmania donovani, transmitted by Phlebotomus orientalis, is a serious systemic disease that causes high morbidity and mortality rates in Sudan and other parts of East Africa and the world. Despite progress in understanding the epidemiology of the disease in East Africa, little is known about the host preference of P. orientalis in kala azar endemic villages of Sudan, which have some of the highest VL incidence rates in the world. The present study used host choice experiments and blood‐meal identification approaches to determine the host preference of P. orientalis in kala azar endemic villages in Gedarif state, eastern Sudan. In the host choice experiment, tent traps were used to compare the attractiveness of cows, donkeys, sheep and goats for host‐seeking P. orientalis. In the blood‐meal identification study, blood‐fed P. orientalis females, captured inside houses and peri‐domestic habitats, were subjected to molecular typing using cytochrome b gene (cyt b) amplification and sequence analysis. Cows and donkeys were the most attractive to blood‐seeking P. orientalis, followed by goats. Similarly, the blood‐meal analysis of P. orientalis showed that the vector preferentially feeds on cows, followed by donkeys, humans and goats. The human blood index of P. orientalis was 19.4% (42/216), indicating a high zoophilic habit of the vector, both inside and outside the houses. Although the order of host preference varied by location, it was clear that cows are the most preferred host of P. orientalis in the area. Results are discussed in relation to the role of domestic/livestock animals in VL zoopotentiation and zooprophylaxis. Inference is made on the potential impact of insecticide treatment of cows in control of the vector and the transmission of VL in Sudan and other parts of East Africa. [ABSTRACT FROM AUTHOR]

Tegumentary leishmaniasis (TL) is the main clinical manifestation of leishmaniasis, and it can cause the infected hosts to self-healing cutaneous lesions until mutilating scars in mucosal membranes, particularly in the nose and throat. The treatment against disease presents problems, and the diagnosis is hampered by variable sensitivity and/or specificity of the tests. In this context, the development of prophylactic vaccines could be considered as a strategy to control the disease. Previously, we showed that the recombinant LiHyp1 protein plus adjuvant protected mice from infection with Leishmania infantum, which causes visceral leishmaniasis. In the present study, we tested whether rLiHyp1 could induce protection against infection with L. amazonensis, a parasite species able to cause TL. We immunized BALB/c mice with rLiHyp1 plus saponin (rLiHyp1/S) or incorporated in micelles (rLiHyp1/M) as adjuvants and performed parasitological and immunological evaluations before and after infection. Results showed that after in vitro stimulation from spleen cell cultures using rLiHyp1 or a Leishmania antigenic extract (SLA), rLiHyp1/S and rLiHyp1/M groups developed a Th1-type immune response, which was characterized by high levels of IFN-γ, IL-2, TNF-α and IL-12 cytokines, nitrite, and IgG2a isotype antibodies when compared to values found in the control (saline, saponin, micelles alone) groups, which showed higher levels of anti-SLA IL-4, IL-10, and IgG1 antibodies before and after challenge. In addition, mice receiving rLiHyp1/S or rLiHyp1/M presented significant reductions in the lesion average diameter and parasite load in the infected tissue and internal organs. Blood samples were collected from healthy subjects and TL patients to obtain PBMC cultures, which were in vitro stimulated with rLiHyp1 or SLA, and results showed higher lymphoproliferation and IFN-γ production after stimulus using rLiHyp1, as compared to values found using SLA. These results suggest that rLiHyp1 plus adjuvant was protective against experimental TL and could also be considered for future studies as a vaccine candidate against human disease. [ABSTRACT FROM AUTHOR]

Leishmaniasis, an infectious disease, manifests itself mostly in two forms, cutaneous leishmaniasis (CL) and, a more severe and potentially deadly form, visceral leishmaniasis (VL). The current control strategy for leishmaniasis relies on chemotherapy drugs such as sodium antimony gluconate (SAG) and meglumine antimoniate (MA). However, all these chemotherapy compounds have poor efficacy, and they are associated with toxicity and other adverse effects, as well as drug resistance. While research in vaccine development for leishmaniasis is continuously progressing, no vaccine is currently available. However, some experimental vaccines such as LEISH-F1+MPL-SE (V) have demonstrated some efficacy when used as drugs for CL patients. In this paper we use a mathematical model to address the following question: To what extent vaccine shots can enhance the efficacy of standard chemotherapy treatment of leishmaniasis? Starting with standard MA treatment of leishmaniasis and combining it with three injections of V , we find, by Day 84, that efficacy increased from 29% to 65–91% depending on the amount of the vaccine. With two or just one injection of V , efficacy is still very high, but there is a definite resurgence of the disease by end-time. [ABSTRACT FROM AUTHOR]

Under perturbing conditions such as infection with Leishmania, a protozoan parasite living within the phagosomes in mammalian macrophages, cellular and organellar structures, and metabolism are dynamically regulated for neutralizing the pressure of parasitism. However, how modulations of the host cell metabolic pathways support Leishmania infection remains unknown. Herein, we report that lipid accumulation heightens the susceptibility of mice to L. donovani infection and promotes resistance to first‐line anti‐leishmanial drugs. Despite being pro‐inflammatory, the in vitro generated uninfected lipid‐laden macrophages (LLMs) or adipose‐tissue macrophages (ATMs) display lower levels of reactive oxygen and nitrogen species. Upon infection, LLMs secrete higher IL‐10 and lower IL‐12p70 cytokines, inhibiting CD4+ T cell activation and Th1 response suggesting a key modulatory role for intramacrophage lipid accumulation in anti‐leishmanial host defence. We, therefore, examined this causal relationship between lipids and immunomodulation using an in vivo high‐fat diet (HFD) mouse model. HFD increased the susceptibility to L. donovani infection accompanied by a defective CD4+ Th1 and CD8+ T cell response. The white adipose tissue of HFD mice displays increased susceptibility to L. donovani infection with the preferential infection of F4/80+CD11b+CD11c+ macrophages with higher levels of neutral lipids reserve. The HFD increased resistance to a first‐line anti‐leishmanial drug associated with a defective adaptive immune response. These data demonstrate that the accumulation of neutral lipids contributes to susceptibility to visceral leishmaniasis hindering host‐protective immune response and reducing the efficacy of antiparasitic drug therapies. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a group of vector-borne, parasitic diseases caused by over 20 species of the protozoan Leishmania spp. The three major disease classifications, cutaneous, visceral, and mucocutaneous, have a range of clinical manifestations from self-healing skin lesions to hepatosplenomegaly and mucosal membrane damage to fatality. As a neglected tropical disease, leishmaniasis represents a major international health challenge, with nearly 350 million people living at risk of infection a year. The current chemotherapeutics used to treat leishmaniasis have harsh side effects, prolonged and costly treatment regimens, as well as emerging drug resistance, and are predominantly used for the treatment of visceral leishmaniasis. There is an undeniable need for the identification and development of novel chemotherapeutics targeting cutaneous leishmaniasis (CL), largely ignored by concerted drug development efforts. CL is mostly non-lethal and the most common presentation of this disease, with nearly 1 million new cases reported annually. Recognizing this unaddressed need, substantial yet fragmented progress in early drug discovery efforts for CL has occurred in the past 15 years and was outlined in this review. However, further work needs to be carried out to advance early discovery candidates towards the clinic. Importantly, there is a paucity of investment in the translation and development of therapies for CL, limiting the emergence of viable solutions to deal with this serious and complex international health problem. [ABSTRACT FROM AUTHOR]

Visceral leishmaniasis is a neglected zoonotic protozoal disease caused by Leishmania infantum and Leishmania donovani that is transmitted by sandflies (Phlebotamine flies). In November 2020, a case of leishmaniasis was diagnosed in a captive tiger through microscopy and L. infantum was confirmed by PCR and sequencing analysis. DNA sequencing of the amplicon revealed close homology with Leishmania sequences available in GenBank. Alignments and phylogenetic analyses of the Leishmania infantum from a tiger in Pakistan indicated 94-100 % identity with Leishmania from animals and 98.8-100% with Leishmania from humans origins suggesting the need for screening of animals before transporting, and of humans before taking care of captive animals, in order to prevent transboundary spread of Leishmania. [ABSTRACT FROM AUTHOR]

Canine visceral leishmaniasis (CVL) is a significant vector-borne Meta zoonotic disease caused by agents of the L. donovani complex. The disease is transmitted by the bite of phlebotomine female sandflies of the genera Phlebotomus and Lutzomyia in the old and new worlds, respectively. This study was conducted to assess the knowledge, attitude, and practices of the residents about CVL based on the One Health concept in two towns of the Oromia Region, Ethiopia. A community-based cross-sectional study was conducted between October 2019 and September 2020, using an interview questionnaire as the study instrument. The study participants were selected through a simple random sampling method. Pearson's Chi-square and logistic regression tests were used to evaluate the association between the study participants' knowledge, attitude, and practices toward CVL and possible risk factors. The study included a total of 400 participants, and the results indicated that 77.25% had good knowledge, 60.5% had a favorable attitude, and 59.25% had good practices toward CVL. The town of Ejaji and dog ownership were significantly associated with good knowledge (p = 0.001), and attitude (p = 0.001) towards CVL, while having a dog (p = 0.001), having a diploma (p = 0.019) or degree and above (0.018), being divorced or widowed (0.012), and being Oromo (p = 0.013) were all significantly associated with good CVL practice. Most participants in both study areas had good knowledge but moderate attitudes and practices toward CVL. Therefore, it is crucial to undertake comprehensive community health education and awareness programs of zoonotic visceral leishmaniasis and its vectors based on the One Health concept through various means. [ABSTRACT FROM AUTHOR]

Visceral leishmaniosis (VL) is one of the neglected tropical diseases despite being responsible for serious clinical symptoms, some of which lead to fatal outcomes. Thus, there is a need to apply accurate, rapid, and specific diagnostic measurements in order to control the disease and reduce the mortality rate. We aimed to develop and validate a multiplex LAMP assay for the diagnosis of VL caused by Leishmania infantum (L. infantum). Moreover, a thorough assessment was conducted to determine the effectiveness of multiplex LAMP in identifying various Leishmania species, such as Leishmania tropica (L. tropica) and Leishmania major (L. major) in comparison to Leishmania infantum (L. infantum). The diagnostic performance of the multiplex LAMP method for VL was compared to each LAMP assay, real-time polymerase chain reaction (RT-qPCR), and nested PCR technique. Two separated primers were set and used in a multiplex LAMP assay which was designed based on the ITS2 (internal transcribed spacer II) and were selected on the basis of conserved and high copy number region. Multiplex LAMP primers were designed using an online tool available at https://www.primerexplorer.jp/e. The alignment was performed using MEGA5, and the primers were further adjusted utilizing GENE Runner software. All molecular methods were tested on the serial dilution of cloned plasmid containing ITS region from standard strains of L. infantum, L. tropica, and L. major. Moreover, multiplex LAMP assay was evaluated and compared based on both standard strains and 55 clinical samples from humans as well as dogs. Various approaches were applied to interpret the multiplex LAMP reaction which deciphered a higher sensitivity when compared to the RT-qPCR for L. infantum (one copy number of plasmid, equal to 0.85 femtograms (fg) of plasmid concentration, and 0.004 parasite DNA per μL) detection while these three standard strains of Leishmania were confirmed to contain 40 DNA copies using RT-qPCR. Additionally, the multiplex LAMP detection limit was approximately equivalent to RT-qPCR for L. major and L. tropica, which included 0.342 picograms (pg) and 342 femtograms (fg) of plasmid concentration, 4 × 103 and 4 × 102 copy number of plasmid, and 17.1 and 1.71 parasite DNA per μL for L. major and L. tropica, respectively. Nested PCR exhibited a lower detection limit for L. infantum of 4 × 106 plasmid copy number compared to multiplex LAMP and RT-qPCR. Multiplex LAMP has the potential for accurate and rapid detection of infectious disease, successful treatment, and finding and monitoring asymptomatic cases, especially in low-income countries. [ABSTRACT FROM AUTHOR]

Nepal, Bangladesh, and India signed a Memorandum of Understanding (MoU) in 2005 to eliminate visceral leishmaniasis (VL) as a public health problem from the Indian subcontinent by 2015. By 2021, the number of reported VL cases in these countries had declined by over 95% compared to 2007. This dramatic success was achieved through an elimination programme that implemented early case detection and effective treatment, vector control, disease surveillance, community participation, and operational research that underpinned these strategies. The experience offered an opportunity to assess the contribution of implementation research (IR) to VL elimination in Nepal. Desk review and a stakeholder workshop was conducted to analyse the relationship between key research outputs, major strategic decisions in the national VL elimination programme, and annual number of reported new cases over time between 2005 and 2023. The results indicated that the key decisions across the strategic elements, throughout the course of the elimination programme (such as on the most appropriate tools for diganostics and treatment, and on best strategies for case finding and vector management), were IR informed. IR itself responded dynamically to changes that resulted from interventions, addressing new questions that emerged from the field. Close collaboration between researchers, programme managers, and implementers in priority setting, design, conduct, and review of studies facilitated uptake of evidence into policy and programmatic activities. VL case numbers in Nepal are now reduced by 90% compared to 2005. Although direct attribution of disease decline to research outputs is difficult to establish, the Nepal experience demonstrates that IR can be a critical enabler for disease elimination. The lessons can potentially inform IR strategies in other countries with diseases targeted for elimination. Author summary: Investigators supported by TDR, WHO, and other partners engaged with national stakeholders (policy makers, implementers, clinicians, public health workers, and others) in the development and validation of strategies for elimination of visceral leishmaniasis (VL) in Nepal in the context of the regional Kala Azar Elimination Programme. Linkage and regular consultations with the national programme guided the research focus and facilitated continued uptake of results into policy and implementation of evidence-based interventions. Knowledge from implementation research led to public health programme decisions that facilitated VL elimination in Nepal. [ABSTRACT FROM AUTHOR]

Background: Parasitological investigation of bone marrow, splenic or lymph node aspirations is the gold standard for the diagnosis of visceral leishmaniasis (VL). However, this invasive test requires skilled clinical and laboratory staff and adequate facilities, and sensitivity varies depending on the tissue used. The direct agglutination test (DAT) is a serological test that does not need specialised staff, with just minimal training required. While previous meta-analysis has shown DAT to have high sensitivity and specificity when using parasitology as the reference test for diagnosis, meta-analysis of DAT compared to other diagnostic techniques, such as PCR and ELISA, that are increasingly used in clinical and research settings, has not been done. Methods: We conducted a systematic review to determine the diagnostic performance of DAT compared to all available tests for the laboratory diagnosis of human VL. We searched electronic databases including Medline, Embase, Global Health, Scopus, WoS Science Citation Index, Wiley Cochrane Central Register of Controlled Trials, Africa-Wide Information, LILACS and WHO Global Index. Three independent reviewers screened reports and extracted data from eligible studies. A meta-analysis estimated the diagnostic sensitivity and specificity of DAT. Results: Of 987 titles screened, 358 were selected for full data extraction and 78 were included in the analysis, reporting on 32,822 participants from 19 countries. Studies included were conducted between 1987–2020. Meta-analysis of studies using serum and DAT compared to any other test showed pooled sensitivity of 95% (95%CrI 90–98%) and pooled specificity of 95% (95%CrI 88–98%). Results were similar for freeze-dried DAT and liquid DAT when analysed separately. Sensitivity was lower for HIV-positive patients (90%, CrI 59–98%) and specificity was lower for symptomatic patients (70%, CrI 43–89%). When comparing different geographical regions, the lowest median sensitivity (89%, CrI 67–97%) was in Western Asia (five studies). Conclusions: This systematic review and meta-analysis demonstrates high estimated pooled sensitivity and specificity of DAT for diagnosis of VL, although sensitivity and specificity were lower for different patient groups and geographical locations. This review highlights the lack of standardisation of DAT methods and preparations, and the lack of data from some important geographical locations. Future well-reported studies could provide better evidence to inform test implementation for different patient populations and use cases. PROSPERO registration: CRD42021240830 [ABSTRACT FROM AUTHOR]

Molecular surveillance of resistance is an increasingly important part of vector borne disease control programmes that utilise insecticides. The visceral leishmaniasis (VL) elimination programme in India uses indoor residual spraying (IRS) with the pyrethroid, alpha-cypermethrin to control Phlebotomus argentipes the vector of Leishmania donovani, the causative agent of VL. Prior long-term use of DDT may have selected for knockdown resistance (kdr) mutants (1014F and S) at the shared DDT and pyrethroid target site, which are common in India and can also cause pyrethroid cross-resistance. We monitored the frequency of these marker mutations over five years from 2017–2021 in sentinel sites in eight districts of north-eastern India covered by IRS. Frequencies varied markedly among the districts, though finer scale variation, among villages within districts, was limited. A pronounced and highly significant increase in resistance-associated genotypes occurred between 2017 and 2018, but with relative stability thereafter, and some reversion toward more susceptible genotypes in 2021. Analyses linked IRS with mutant frequencies suggesting an advantage to more resistant genotypes, especially when pyrethroid was under-sprayed in IRS. However, this advantage did not translate into sustained allele frequency changes over the study period, potentially because of a relatively greater net advantage under field conditions for a wild-type/mutant genotype than projected from laboratory studies and/or high costs of the most resistant genotype. Further work is required to improve calibration of each 1014 genotype with resistance, preferably using operationally relevant measures. The lack of change in resistance mechanism over the span of the study period, coupled with available bioassay data suggesting susceptibility, suggests that resistance has yet to emerge despite intensive IRS. Nevertheless, the advantage of resistance-associated genotypes with IRS and under spraying, suggest that measures to continue monitoring and improvement of spray quality are vital, and consideration of future alternatives to pyrethroids for IRS would be advisable. Author summary: Visceral leishmaniasis (VL) is a deadly parasitic disease with a primary focus in north-eastern India. Control of the sand fly, Phlebotomus argentipes, vector of VL in India, is primarily reliant upon spraying the internal walls of houses and animal shelters with residual pyrethroid insecticide. Spray programmes depend upon well-controlled spraying and effective insecticides to which the targeted insects are susceptible. Changing insecticides is logistically challenging, therefore early detection of insecticide resistance is crucial. As part of a wider programme of entomological surveillance we used molecular resistance assays of knockdown resistance (kdr) mutations to investigate evidence for changing resistance profiles, and possible links with the spraying programme across a system of eight districts in north-eastern India. Mutant frequencies varied substantially in space and time, with a major change across the first two years of the study, but stability for the remainder. Resistance-associated kdr alleles were positively associated with indices of spray coverage and with under spraying, suggesting that this creates vulnerability to development of pyrethroid resistance. However, the most strongly resistance conferring mutant genotype was rarely detected, suggesting overall that notable resistance is not yet emerging, despite wide coverage of the spray programme. This is an encouraging result for the VL elimination programme but with apparent advantage of resistance alleles in sprayed areas it would be wise to seek alternative insecticides for spraying. [ABSTRACT FROM AUTHOR]

Background: Visceral leishmaniasis (VL), a life-threatening neglected tropical disease, is targeted for elimination from Nepal by the year 2026. The national VL elimination program is still confronted with many challenges including the increasingly widespread distribution of the disease over the country, local resurgence and the questionable efficacy of the key vector control activities. In this study, we assessed the status and risk of Leishmania donovani transmission based on entomological indicators including seasonality, natural Leishmania infection rate and feeding behavior of vector sand flies, Phlebotomus argentipes, in three districts that had received disease control interventions in the past several years in the context of the disease elimination effort. Methods: We selected two epidemiologically contrasting settings in each survey district, one village with and one without reported VL cases in recent years. Adult sand flies were collected using CDC light traps and mouth aspirators in each village for 12 consecutive months from July 2017 to June 2018. Leishmania infection was assessed in gravid sand flies targeting the small-subunit ribosomal RNA gene of the parasite (SSU-rRNA) and further sequenced for species identification. A segment (~ 350 bp) of the vertebrate cytochrome b (cytb) gene was amplified from blood-fed P. argentipes from dwellings shared by both humans and cattle and sequenced to identify the preferred host. Results: Vector abundance varied among districts and village types and peaks were observed in June, July and September to November. The estimated Leishmania infection rate in vector sand flies was 2.2% (1.1%–3.7% at 95% credible interval) and 0.6% (0.2%–1.3% at 95% credible interval) in VL and non-VL villages respectively. The common source of blood meal was humans in both VL (52.7%) and non-VL (74.2%) villages followed by cattle. Conclusions: Our findings highlight the risk of ongoing L. donovani transmission not only in villages with VL cases but also in villages not reporting the presence of the disease over the past several years within the districts having disease elimination efforts, emphasize the remaining threats of VL re-emergence and inform the national program for critical evaluation of disease elimination strategies in Nepal. [ABSTRACT FROM AUTHOR]

Leishmania infections are global, occurring in 98 countries and all World Health Organization (WHO) regions with 600 million to 1 billion people at risk of infection. Visceral leishmaniasis is associated with almost 20,000 reported deaths annually, with children under 5 years of age being at the greatest risk of mortality. Amongst WHO-recognised Neglected Tropical Diseases (NTDs), leishmaniasis is one of the most important in terms of mortality and morbidity. With an increasing global burden of disease and a growing threat from climate change, urbanisation and drug resistance, there remains an imperative to develop leishmaniasis vaccines. New tools to understand correlates of protection and to assess vaccine efficacy are being developed to ease the transition into larger scale efficacy trials or provide alternate routes to licensure. Early indications suggest a diverse portfolio of manufacturers exists in endemic countries with an appetite to develop leishmaniasis vaccines. This Vaccine Value Profile (VVP) provides a high-level, comprehensive assessment of the currently available data to inform the potential public health, economic, and societal value of leishmaniasis vaccines. The leishmaniasis VVP was developed by a working group of subject matter experts from academia, public health groups, policy organizations, and non-profit organizations. All contributors have extensive expertise on various elements of the leishmaniasis VVP and have collectively described the state of knowledge and identified the current gaps. The VVP was developed using only existing and publicly available information. [ABSTRACT FROM AUTHOR]

The leishmanin skin test was used for almost a century to detect exposure and immunity to Leishmania, the causative agent of leishmaniasis, a major neglected tropical disease. Due to a lack of antigen used for the intradermal injection, the leishmanin skin test is no longer available. As leishmaniasis control programs are advancing and new vaccines are entering clinical trials, it is essential to re-introduce the leishmanin skin test. Here we establish a Leishmania donovani strain and describe the production, under Good Laboratory Practice conditions, of leishmanin soluble antigen used to induce the leishmanin skin test in animal models of infection and vaccination. Using a mouse model of cutaneous leishmaniasis and a hamster model of visceral leishmaniasis, soluble antigen induces a leishmanin skin test response following infection and vaccination with live attenuated Leishmania major (LmCen-/-). Both the CD4+ and CD8+ T-cells are necessary for the leishmanin skin test response. This study demonstrates the feasibility of large-scale production of leishmanin antigen addressing a major bottleneck for performing the leishmanin skin test in future surveillance and vaccine clinical trials. As leishmaniasis control programs and new vaccines are advancing, it is necessary to re-introduce the leishmanin skin test to monitor transmission and immunity. This study describes the generation and validation of a new leishmanin skin test antigen for future re-introduction into endemic countries. [ABSTRACT FROM AUTHOR]

• Essential genes (Pyridoxal kinase and sterol alpha-14 demethylase) are drug targets. • Discerned the atomistic interactions of small molecules with target proteins through Molecular Docking and MD Simulations. • Non-bonded contacts and MM-PBSA calculations aided in deciphering nitazoxanide and artemisinin dynamic interactions with the target proteins. • This biocomputing study identified plausible drug inhibitors against essential leishmanial genes. Leishmania donovani , an obligatory intracellular flagellate pathogen, is the underlying cause of visceral leishmaniasis (VL), a fatal disease that poses a significant challenge to existing therapeutic approaches and leads to human mortality. In an endeavor to find an antileishmanial drug to combat VL, we aimed to assess the approved drug molecules against the specific drug targets of VL. In this study, a theoretical method was used to select two essential therapeutic targets (pyridoxal kinase [PK] and sterol alpha-14 demethylase [SDM]) which were present in both the data set of essential genes and drug target proteins. The selected PK and SDM proteins in L. donovani play pivotal roles as essential enzymes in the crucial vitamin B6 salvage and sterol biosynthesis pathways, respectively, leading to pathogenicity in humans. In addition to that drugs were gathered from the DrugBank and Drug Central databases and 325 (out of 4867) compounds having anti-parasitic properties were screened by PASS analysis. Consequently, three ligands (referred to as Lig_1, Lig_2, and Lig_3) were chosen based on their elevated Pa values, docking scores, and notable medicinal applications. Moreover, the result obtained from MD simulation suggests Lig_1 [Nitazoxanide (PubChem ID-41684)] does not affect the structural integrity of both targets. Additionally, evaluation of total binding energies by MMPBSA analysis showed stronger binding of Lig_1 with PK and SDM is -100.71 and -175.61 kJ/mol, respectively compared to others. As a whole, the methodology employed in this research involves the simultaneous identification of suitable protein targets and potential inhibitors. Through this investigation, we have demonstrated that compounds derived from a biocomputing approach exhibit interaction mechanisms as inhibitors against drug targets, offering a promising avenue for addressing VL. [ABSTRACT FROM AUTHOR]

A series of rosmarinic acid-β-amino-α-ketoamide hybrids were synthesized and rationally repurposed towards the identification of new antileishmanial hit compounds. Two hybrids, 2g and 2h, showed promising activity (IC50 values of 9.5 and 8.8 μM against Leishmania donovani promastigotes, respectively). Their activities were comparable to erufosine. In addition, cytotoxicity evaluation employing human THP-1 cells revealed that the two hybrids 2g and 2h possess no cytotoxic effects up to 100 µM, while erufosine possessed cytotoxicity with CC50 value of 19.4 µM. In silico docking provided insights into structure–activity relationship emphasizing the importance of the aliphatic chain at the α-carbon of the cinnamoyl carbonyl group establishing favorable binding interactions with LdCALP and LARG in both hybrids 2g and 2h. In light of these findings, hybrids 2g and 2h are suggested as potential safe antileishmanial hit compounds for further development of anti-leishmanial agents. [ABSTRACT FROM AUTHOR]

Objectives To improve visceral leishmaniasis (VL) treatment in Eastern Africa, 14- and 28-day combination regimens of paromomycin plus allometrically dosed miltefosine were evaluated. As the majority of patients affected by VL are children, adequate paediatric exposure to miltefosine and paromomycin is key to ensuring good treatment response. Methods Pharmacokinetic data were collected in a multicentre randomized controlled trial in VL patients from Kenya, Sudan, Ethiopia and Uganda. Patients received paromomycin (20 mg/kg/day for 14 days) plus miltefosine (allometric dose for 14 or 28 days). Population pharmacokinetic models were developed. Adequacy of exposure and target attainment of paromomycin and miltefosine were evaluated in children and adults. Results Data from 265 patients (59% ≤12 years) were available for this pharmacokinetic analysis. Paromomycin exposure was lower in paediatric patients compared with adults [median (IQR) end-of-treatment AUC0–24h 187 (162–203) and 242 (217–328) µg·h/mL, respectively], but were both within the IQR of end-of-treatment exposure in Kenyan and Sudanese adult patients from a previous study. Cumulative miltefosine end-of-treatment exposure in paediatric patients and adults [AUCD0–28 517 (464–552) and 524 (456–567) µg·day/mL, respectively] and target attainment [time above the in vitro susceptibility value EC90 27 (25–28) and 30 (28–32) days, respectively] were comparable to previously observed values in adults. Conclusions Paromomycin and miltefosine exposure in this new combination regimen corresponded to the desirable levels of exposure, supporting the implementation of the shortened 14 day combination regimen. Moreover, the lack of a clear exposure–response and exposure–toxicity relationship indicated adequate exposure within the therapeutic range in the studied population, including paediatric patients. [ABSTRACT FROM AUTHOR]

Feline leishmanial infection is reported worldwide, but the epidemiological role of domestic cats in the leishmaniasis cycle remains unclear, and cats might act as cryptic reservoir hosts in endemic areas with no feline leishmaniosis cases. Considering that, a serological screening for anti-Leishmania spp. antibodies was performed by indirect immunofluorescence antibody test (IFAT) in 389 necropsied cats' serum samples from a new visceral leishmaniasis transmission area with no feline leishmanial infection reported to unveil if the cats are being exposed to the parasite. The overall seroprevalence for Leishmania spp. was 11.05% (43/389). No association was found between sex, neutering status, age group, breed, coat length, feline immunodeficiency virus (FIV) infection, and Leishmania spp. antibody detection. A positive association was found with coat color (cats within the orange spectrum with white [particolor]) (OR = 2.47, CI 95% 1 – 6.13, P = 0.044) and a negative association (OR = 0.38, CI 95% 0.18 – 0.79, P = 0.01) between feline leukemia virus (FeLV) infection and IFAT positivity for Leishmania spp. Therefore, it is concluded that the seroprevalence found was greater than 10%, indicating contact of the protozoan with cats in the region served. [ABSTRACT FROM AUTHOR]

Background: A cohort study for 2 years period analysed the prevalence, incidence and clinical–immunological features of canine Leishmania (L.) chagasi‐infection in 316 mongrel dogs in a visceral leishmaniasis‐endemic area in Pará State, Brazil. Objective/Methods: Diagnosis of infection was performed by the indirect fluorescent antibody test (IFAT‐IgG), the leishmanin skin test (LST) and a parasite search (from the popliteal lymph node aspiration) at the beginning of the study and at 6, 12 and 24 months intervals. Results: IFAT/LST revealed three immune profiles of infection: (I) IFAT(+)/LST(−) (81), (II) IFAT(−)/LST(+) (17) and (III) IFAT(+)/LST(+) (13). Prevalence of profiles I, II and III were 25.6, 5.4 and 4.1%, and an overall prevalence 35.1%. Incidence of profiles I, II and III were 5.4, 0.3 and 0.0%, and an overall incidence 5.7% dogs per month. Incidence at the age ranges <1 year, ≥1 year, <7 years and ≥7 years evidenced a highest rate in the age range <1 year (6.6% dogs per month). Parasitological diagnosis was positive in 19% dogs at the prevalence (85.7% profile I), and in 11% at the incidence (100% profile I). The clinical picture of 179 infected dogs showed 145 (81%) of profile I (82% subclinical); 21 (11.7%) of profile II (100% subclinical); and 13 (7.3%) of profile III (84.6% subclinical). Conversion from subclinical to sick dogs was higher (p < 0.05) in profile I (40.2%) than in profiles II (5.8%) and III (9%). Immunological conversion showed that only 3.2% of profile I dogs (prevalence) converted to LST(+) (two at the end of the first 6 months and 1 after 24 months), while 82.3% of profile II dogs converted to IFAT(+) (11 in the first 6 months, whereas three after 12 months). A 100% death rate was observed in dogs from profile I alone. Conclusion: These results reinforce the need of adopting preventive strategies against CVL as early as in the first semester of the dog's life. [ABSTRACT FROM AUTHOR]

Les leishmanioses sont des maladies tropicales négligées, causées par une quinzaine d'espèces d'un protozoaire flagellé du genre Leishmania et transmises par un moucheron hématophage, le phlébotome. Il existe trois principales formes cliniques : les leishmanioses cutanées, cutanéomuqueuses et viscérales selon la dissémination des parasites dans le système des phagocytes mononucléés. En 2021, les leishmanioses sont endémiques de 99 pays sur tous les continents habités hors Océanie et les dernières estimations font état de 600 000 à 1 million de cas de leishmanioses cutanées et de 50 000 à 90 000 cas de leishmanioses viscérales annuels. En France métropolitaine, les cas autochtones sont beaucoup moins fréquents que ceux d'importation. Le diagnostic de référence est la PCR sur sang pour les leishmanioses viscérales et la PCR sur prélèvement cutané pour les versions cutanées. Cet examen doit être associé à la sérologie dans le cadre des leishmanioses viscérales et cutanéomuqueuses. L'identification de l'espèce en cause est souhaitable dans les formes cutanées ou cutanéomuqueuses pour orienter la prise en charge thérapeutique. La complexité du diagnostic et du traitement peut rendre parfois nécessaire l'aide d'un centre spécialisé. Leishmaniasis is a neglected tropical disease caused by around fifteen species of a flagellate protozoan of the genus Leishmania, transmitted by a haematophagous sandfly. There are three main clinical forms: cutaneous leishmaniasis, mucocutaneous leishmaniasis and visceral leishmaniasis, depending on the dissemination of the parasites in the mononuclear phagocyte system. In 2021, leishmaniasis is endemic in 99 countries on all inhabited continents excluding Oceania, and the latest estimates put the number of cases of cutaneous leishmaniasis at between 600,000 and 1 million, and the number of cases of visceral leishmaniasis at between 50,000 and 90,000 per year. In metropolitan France, native cases are much less frequent than imported cases. The reference diagnosis is PCR on blood for visceral leishmaniasis and PCR on skin samples for cutaneous leishmaniasis. This test must be combined with serology for visceral and mucocutaneous leishmaniasis. Identification of the species involved is recommended for cutaneous or mucocutaneous forms in order to guide therapeutic management. The complexity of diagnosing and treating leishmaniasis may sometimes require the assistance of a specialist centre. [ABSTRACT FROM AUTHOR]

COVID-19 has largely impacted the management of Visceral leishmaniasis (VL), like several other Neglected Tropical Diseases. The impact was particularly evident in Lower and Middle-Income countries where the already inadequate healthcare resources were diverted to managing the COVID-19 pandemic. Bangladesh achieved the elimination target for VL in 2016. To sustain this success, early diagnosis and treatment, effective vector control, and periodic surveillance are paramount. However, the specific control measures for VL in Bangladesh that were hampered during COVID-19 and their extent are unknown. This study aimed at identifying the gaps and challenges in the follow-up of treated VL patients by interviewing both the treated VL cases and their health service providers. We followed VL cases treated between 2019 and 2020 in five VL endemic subdistricts (upazilas) both retrospectively and prospectively to monitor clinical improvement, relapse, or other consequences. Moreover, interviews were conducted with the health service providers to assess the impact of COVID-19 on VL case detection, treatment, reporting, vector control operations, and logistic supply chain management. There was no added delay for VL diagnosis; however, VL treatment initiation and reporting time increased almost two-fold due to COVID-19. Indoor Residual Spraying activity was significantly hampered due to a shortage of insecticides. Out of 44 enrolled and treated VL patients, two relapsed (4.5 %), two developed Para Kala-Azar Dermal Leishmaniasis (4.5 %), and three (6.8 %) Post Kala-Azar Dermal Leishmaniasis (PKDL). The health service providers highlighted patients' unwillingness to visit the hospital, financial constraints, and distance from the hospitals as the main reasons for missed follow-up visits (20.5 %). Building good communication in the community, awareness schemes, and incentive-based approaches were suggested as possible solutions to mitigate these problems. Long-term follow-up is required for the early detection and management of VL relapse and PKDL cases. Effective vector control measures, capacity development, and identification of new VL hotspots are pivotal in the VL endemic regions to sustain the elimination goal. • The impact of the novel coronavirus (COVID-19) outbreak on visceral leishmaniasis (VL) case management and control services. • The importance of long-term follow-up of treated VL. • Factors responsible for missed post-treatment follow-up from the patients' and service providers' perspectives. • Recommendations by health service providers to increase post-treatment follow-up visits. • The findings of this study will help the national kala-azar elimination programme in future pandemic preparedness to sustain the VL elimination achievements. [ABSTRACT FROM AUTHOR]

We aimed to estimate the diagnostic latency of patients with visceral leishmaniasis (VL). A monocentric retrospective observational study was conducted including all confirmed cases of VL diagnosed from January 2005 to March 2022. Epidemiological and clinical characteristics of patients with VL were collected. The diagnostic latency was defined as the number of days between the first contact with a health-care provider for signs and/or symptoms referable to VL and the laboratory diagnosis of leishmaniasis. Twenty-four cases of VL were included in the study, mostly male (75%) and Italians (79.2%), with a median age of 40 years [Inter Quartile Range (IQR 30–48)]. Fourteen (58.3%) VL cases were people living with HIV (PLWH) and 4 (16.6%) subjects were on immunosuppressive therapy. For VL the median diagnostic latency was 54 days (IQR 28–162). The shorter diagnostic latency was observed in PLWH [31 days (IQR 20–47)] followed by immunocompetent patients [160 days (IQR 133–247)] and those on immunosuppressive therapy [329 days (IQR 200–678)]. Twelve patients (50%) reported at least one medical encounter before the diagnosis of VL and 6 patients received a wrong therapy. Diagnostic delay in VL was significant in patients under immune suppressive treatment. [ABSTRACT FROM AUTHOR]

The disease Leishmaniasis is a neglected illness with two major forms clinically including cutaneous leishmaniasis and visceral leishmaniasis. From almost 100 endemic countries, an estimated one million additional records of leishmaniasis each year are documented. In the past decade, the number of confirmed cases of visceral leishmaniasis has decreased dramatically as a consequence of an improved approach to diagnosis and care and more intensive, though usual cycles may play a role in the severity of disease transmission. In the cutaneous form of leishmania disease (CL), the lesion is located in some parts like the face and arms. Whereas a visceral form of leishmania (VL) disease the parasite infects internal organs such as the liver and pancreas. Reports from the World Health Organization (WHO) record leishmaniasis as one of the ignored temperate disorders for which the improvement of novel therapies is required. Significant evidence gaps remain, and new methods are required before leishmaniasis can be definitively managed. Recent advances in our understanding of leishmaniasis and its clinical manifestations, as well as the immunological aspects of leishmaniasis, are the key objectives of this study. [ABSTRACT FROM AUTHOR]

Background: Co-endemicity of neglected tropical diseases (NTDs) necessitates that these diseases should be considered concomitantly to understand the relationship between pathology and to support disease management and control programs. The aims of the study were to assess the prevalence of filarial infection in asymptomatic Leishmania donovani infected individuals and the correlation of Wuchereria bancrofti infection with progression to clinical visceral leishmaniasis (VL) in Bihar, India. Methodology/Principal findings: Within the Muzaffarpur-TMRC Health and Demographic Surveillance System (HDSS) area, a cohort of Leishmania seropositive (n = 476) or seronegative individuals (n = 1130) were sampled annually for three years for filarial infection and followed for progression to clinical VL. To corroborate the results from the cohort study, we also used a retrospective case-control study of 36 VL cases and 71 controls selected from a subset of the HDSS population to investigate the relationship between progression to clinical VL and the prevalence of filarial infection at baseline. Our findings suggest a higher probability of progression to clinical VL in individuals with a history of filarial infection: in both the cohort and case-control studies, progression to clinical VL was higher among filaria infected individuals (RR = 2.57, p = 0.056, and OR = 2.52, p = 0.046 respectively). Conclusion: This study describes that progression to clinical VL disease is associated with serological evidence of prior infection with W. bancrofti. The integration of disease programs for Leishmania and lymphatic filariasis extend beyond the relationship of sequential or co-infection with disease burden. To ensure elimination targets can be reached and sustained, we suggest areas of co-endemicity would benefit from overlapping vector control activities, health system networks and surveillance infrastructure. Author summary: India has committed to eliminate two neglected tropical diseases (NTDs) as a public health problem: visceral leishmaniasis (VL) and lymphatic filariasis (LF), both of which are transmitted by vectors and are caused by the parasites Leishmania donovani and Wuchereria bancrofti, respectively. Notably, the majority of L. donovani infections do not lead to a clinical event of VL and asymptomatic infections significantly outnumber the clinical cases. While mixed infections with Leishmania parasites and those causing lymphatic filariasis have been reported, the influence of the immune response triggered by filarial infection on the clinical manifestations and progression of both disorders is not well understood. The Muzaffarpur-TMRC Health and Demographic Surveillance System (HDSS) in Bihar is a well-established demographic platform in an area with the highest incidence of L. donovani infections in India which is also co-endemic for lymphatic filariasis. We used both cohort and case-control study designs within the HDSS population to assess the prevalence of filarial infection in blood samples and examine the association between filarial infection and the progression to clinical VL. Our findings strongly suggest there is an increased risk of progression to clinical VL in individuals with a history of infection with W. bancrofti: in both the study designs, progression to clinical VL was higher among filaria-infected individuals. These results highlight that the co-endemicity of these NTDs necessitates an integrated approach in diagnosis and disease management to ensure elimination targets can be achieved and sustained. [ABSTRACT FROM AUTHOR]

Background: Visceral leishmaniasis is caused by the parasites Leishmania donovani spices complex that can spread to internal organs and the disease is fatal with a fatality rate of nearly 100% if left untreated. Visceral Leishmania-HIV (HIV1) coinfection disease is a new clinical form of leishmaniasis very serious disease in the endemic part of the world. It also served as the primary cause of death in the lowlands of Ethiopia with the endemic Humara and Metema that are located near the Sudanese border. Methods: A total of 153 visceral leishmaniases with HIV co-infection secondary data was taken from the medical chart of patients from January 2015 to January 2021 and a hospital-based cross-sectional study design was carried out to retrieve relevant information. The data entered by SPSS and analysed using STATA version 14 and R4.2.1 statistical software packages using a non-parametric Model, semi-parametric Cox proportional hazard survival models at 5% significance level. Result: Among the total visceral leishmaniasis with HIV co-infected patients 3.27% were females and 96.73% were males, 19 (12.42%) patients died and 134(87.58%) patients were censored. The Cox proportional hazard model result indicates that severe acute malnutrition, baseline CD4+ cell count ≥100, and underweight significantly contributed to the survival time of a patient. Cox proportional hazard model shows that severe acute malnutrition (HR=4.40027, 95% CI= 2.455061 262.7934, P-value=0.007), baseline CD4+cell count ≥100 (HR=0.2714623, 95% CI= 0.0764089 0.9644395, P-value=0.044), and Underweight (HR=4.678169, 95% CI= 1.970097 11.10872, P-value=0.040) significantly contributed to a shorter survival time. Conclusion: Visceral leishmaniases with HIV co-infected patients show a large number of deaths occurred in the earlier days of treatment this implies that Visceral leishmaniasis accelerates HIV replication and disease progression death. The researcher suggests that people be aware of the burden posed by those risk factors and knowledgeable about the diseases. So, the researcher recommended that to health workers implement primary health care in those patients and careful consideration of a neglected parasitic disease. [ABSTRACT FROM AUTHOR]

Background: Serum or whole blood collection, processing, transport and storage still present significant challenges in low resource settings where mass surveillance is required to sustain disease elimination. Therefore, in this study, we explored the diagnostic efficacy of dried blood spots (DBS) as a minimally invasive and potentially cost-effective alternative sampling technique to whole blood sampling procedures for subsequent detection of Leishmania donovani antibodies or DNA. Methodology and principal findings: Archived serum, DNA samples from whole blood of visceral leishmaniasis (VL) cases and healthy controls, and DBS from corresponding cases and controls, were used. Both molecular and serological assays were optimized to detect L. donovani antibodies or DNA in DBS elute and results were compared against those obtained with whole blood. Serological assays (both rK28 ELISA and rK39 ELISA) of DBS samples showed sensitivity and specificity of 100% and had excellent agreement with results from whole blood samples (kappa value ranged from 0.98–1). Bland-Altman analysis of OD values from rK28-ELISA with DBS elute and patients' serum showed an excellent agreement (ICC = 0.9) whereas a good agreement (ICC = 0.8) was observed in the case of rK39-ELISA. However, qPCR and RPA of DBS samples had a diminished sensitivity of 76% and 68%, respectively, and poor agreement was observed with the whole blood samples. Conclusion: Our results demonstrate that DBS offer excellent diagnostic efficiency for serological assays and represent a viable alternative to whole blood sampling procedures. Author summary: Since the inception of the National Kala-azar Elimination Program (NKEP) in 2005, visceral leishmaniasis (VL) cases have declined significantly in Bangladesh. Bangladesh has achieved the elimination targets set by the WHO and continuous strides have been enforced by the government and non-government organizations in the present maintenance phase. To sustain the outcomes of the NKEP, move towards a zero-transmission goal and subvert the endgame challenges, an effective surveillance strategy is a primary focus. As part of this strategy, we examined whether using dried blood spots (DBS), rather than whole blood samples as currently recommended, could serve as a minimally invasive sampling technique prior to subsequent diagnostic tests. We determined the accuracy of molecular and serological assays using DBS samples compared with whole blood samples. While using DBS, excellent diagnostic accuracy was observed for serological assays (rK28 ELISA and rK39 ELISA), whereas sensitivity and specificity using molecular assays for DNA detection (qPCR and RPA) declined in comparison to whole blood. Given the low cost and field feasibility of DBS, we believe this simple sample collection technique coupled with serology-based detection of L. donovani meets the requirements for mass surveillance towards detecting residual VL transmission. [ABSTRACT FROM AUTHOR]

Background: Follow-up assessment of visceral leishmaniasis (VL) treated cases is important to monitor the long term effectiveness of treatment regimens. The main objective of this study was to identify the gaps and challenges in the follow-up of treated VL cases, to monitor treatment outcome and to assess the impact of COVID-19 on VL elimination services and activities. Methods: Clinicians treating VL patients, district focal persons for VL, and patients treated for VL in seven high endemic districts in Nepal during 2019–2022 were interviewed to collect data on challenges in the follow-up of VL treated patients as per national strategy. Results: Follow up status was poor in two districts with the largest number of reported cases. The majority of cases were children under 10 years of age (44.2%). Among 104 VL treated cases interviewed, 60.6% mentioned that clinicians had called them for follow-up but only 37.5% had complied. Among 112 VL treated cases followed up, 8 (7.14%) had relapse and 2 (1.8%) had PKDL. Among 66 cases who had VL during the COVID-19 lock down period, 32 (48.5%) were diagnosed within 1 week; however, 10 (15.1%) were diagnosed only after 4 weeks or more. During the COVID-19 pandemic, there was no active search for VL because of budget constraints and lack of diagnostic tests, and no insecticide spraying was done. Conclusion: Relapses and PKDL are challenges for VL elimination and a matter of concern. Successful implementation of the national strategy for follow up of treated VL cases requires addressing elements related to patients (awareness, transport, communication) clinicians (compliance) and organization of service delivery (local health worker training and deployment). COVID-19 did not have much impact on VL diagnosis and treatment; however, public health programmes including active case detection and insecticide spraying for vector control were severely reduced. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a widespread group of infectious diseases that significantly impact global health. Despite high prevalence, leishmaniasis often receives inadequate attention in the prioritization of measures targeting tropical diseases. The causative agents of leishmaniasis are protozoan parasites of the Leishmania genus, which give rise to a diverse range of clinical manifestations, including cutaneous and visceral forms. Visceral leishmaniasis (VL), the most severe form, can be life-threatening if left untreated. Parasites can spread systemically within the body, infecting a range of organs, such as the liver, spleen, bone marrow and lymph nodes. Natural reservoirs for these protozoa include rodents, dogs, foxes, jackals, and wolves, with dogs serving as the primary urban reservoir for Leishmania infantum. Dogs exhibit clinical and pathological similarities to human VL and are valuable models for studying disease progression. Both human and canine VL provoke clinical symptoms, such as organ enlargement, fever, weight loss and abnormal gamma globulin levels. Hematologic abnormalities have also been observed, including anemia, leukopenia with lymphocytosis, neutropenia, and thrombocytopenia. Studies in dogs have linked these hematologic changes in peripheral blood to alterations in the bone marrow. Mouse models of VL have also contributed significantly to our understanding of the mechanisms underlying these hematologic and bone marrow abnormalities. This review consolidates information on hematological and immunological changes in the bone marrow of humans, dogs, and mice infected with Leishmania species causing VL. It includes findings on the role of bone marrow as a source of parasite persistence in internal organs and VL development. Highlighting gaps in current knowledge, the review emphasizes the need for future research to enhance our understanding of VL and identify potential targets for novel diagnostic and therapeutic approaches. [ABSTRACT FROM AUTHOR]

Copyright of Arquivos de Ciências da Saúde da UNIPAR is the property of Associacao Paranaense de Ensino e Cultura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Leishmaniasis is a parasitic disease caused by more than 20 Leishmania species. This disease is spread by vectors. Many researchers agree that Leishmania was spread to mammals by sandflies of the genus Phlebotomus and Lutzomyia. Leishmaniasis is still considered one of the most neglected diseases by the World Health Organization (WHO). An estimated 0.7-1 million new cases of leishmaniasis are reported annually from approximately 100 endemic countries. The types of leishmaniasis in humans are the visceral (VL), cutaneous (CL), mucocutaneous (MCL), diffuse cutaneous (DCL), and post kala-azar dermal (PKDL) forms of Leishmaniasis. The aim of this study is to perform phylogenetic analysis of Leishmania origin based on ITS1 gene region using insilico techniques. In this way, it is also aimed to take a snapshot of a meta-analysis of vertical and horizontal spread at the global level. Methods: In this study, Leishmania ITS1 region sequences presented with the GenBank data of the National Center for Biotechnology Information, USA, (NCBI) until 15.05.2019 were taken and analyzed by in-silico techniques. 914 sequences were obtained for the Leishmania ITS1 region in the NCBI database. All sequences were examined and sequences without indel problems were selected from these strains mapped according to the consensus sequence. It was decided to form a phylogenetic tree with the forms that were examined and 65 strains were obtained by removing the sub-branches. Results: The phylogenetic tree obtained in this study showed that Leishmania strains clustered in six branches according to the ITS1 region. Here, a phylogenetic tree is drawn and the molecular epidemiological and demographic data of these six generations and beyond, which are obtained as a result of the genetic relationships between the strains, are summarized. Conclusion: In conclusion, Leishmaniasis is an important public health problem that can be seen in many developing countries. In this study, the strains examined using the in-silico method were isolated from different geographies of the world between 1984 and 2018. The phylogenetic relationships between these strains show not only the vertical spread of the origins over the years, but also the horizontal spread geographically. These species were obtained from different host and tissue types. Thus, the relationships of Leishmania strains in the host-vector-reservoir chain are explained. Therefore, it is clear that there is a need for more meta-analysis studies such as this study on factors and their diffusion. [ABSTRACT FROM AUTHOR]

Post kala-azar dermal leishmaniasis (PKDL) is the only dermal form of leishmaniasis that presents with hypopigmentation comparable with vitiligo, leprosy, and pitryasis versicolor. In the absence of an animal model, the mechanism(s) responsible for melanocyte loss/dysfunction in PKDL is/are poorly defined. Although the destruction of melanocytes is considered multifactorial, immune dysregulation is one of the key contributory players in this and other hypopigmentary dermatoses. Understanding of the complex interplay between immune cells and mediators, leading to the loss/destruction of melanocytes in PKDL, could translate into 'host-directed' chemotherapeutic strategies to prevent the stigma associated with hypopigmentation. Post kala-azar dermal leishmaniasis (PKDL), a heterogeneous dermal sequela of visceral leishmaniasis (VL), is challenging in terms of its etiopathogenesis. Hypopigmentation is a consistent clinical feature in PKDL, but mechanisms contributing to the loss of melanocytes remains poorly defined. Like other hypopigmentary dermatoses – for example, vitiligo, psoriasis, and leprosy – the destruction of melanocytes is likely a multifactorial phenomenon, key players being immune dysregulation and inflammation. This review focuses on immunological mechanisms responsible for the 'murder' of melanocytes, prime suspects at the lesional sites being CD8+ T cells and keratinocytes and their criminal tools being proinflammatory cytokines, for example, IFN-γ, IL-6, and TNF-α. Collectively, these may cause decreased secretion of melanocyte growth factors, loss/attenuation of cell adhesion molecules and inflammasome activation, culminating in melanocyte death. [ABSTRACT FROM AUTHOR]

Cutaneous leishmaniasis is an infectious dermatosis caused by protozoa of the genus Leishmania spp. The World Health Organization reports 700,000-1,000,000 cases per year. Its clinical forms include cutaneous leishmaniasis, mucocutaneous leishmaniasis and visceral leishmaniasis, and the diagnosis is established by histopathology, dermoscopy, Montenegro skin test, and serology. The case of a 38-year-old male with an epidemiological history is presented: recent visit to an endemic area for Leishmaniasis. Skin phototype IV/VI, presenting dermatosis in the malar region characterized by erythematous plaque with regular well-defined borders and a hematocyst on its surface, without outflow of pruritic secretion of months of evolution. By clinical, epidemiological, and histopathological definition, a definitive diagnosis of localized cutaneous leishmaniasis was established, and treatment with meglumine antimoniate was initiated with a once weekly application schedule of 3 mL intralesionally, with intervals of one week between applications, for a period of 8 weeks, with satisfactory evolution after 6 months of treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: This study aimed to compare the true diagnostic potential of the recombinant chimeric protein Q5 in an ELISA assay using a large number of sera from CVL-suspected dogs. Sera from dogs with a CVL positive diagnosis based on the rapid DPP test (n = 406) and negative samples from healthy dogs (n = 46) were used for ELISA tests using the recombinant Q5. Overall, similar levels of lower sensitivity (67–68%) were seen for both the commercial EIE-LVC test and the Q5 ELISA when all assessed sera were considered, but a much greater sensitivity (92%) was seen for those samples from symptomatic dogs only. In contrast, many negative results were observed for the DPP-positive sera from asymptomatic dogs or from those with no clinical information available. The results reveal a higher-than-expected incidence of likely false-positive results for DPP, reinforcing the need for other recombinant proteins, such as the chimeric Q5, to be investigated as possible alternatives to the currently used CVL diagnostic methods. Dogs are considered the major domestic reservoir for human visceral leishmaniasis, a serious disease caused by the Leishmania infantum parasite. Diagnosis of canine visceral leishmaniasis (CVL) is critical for disease control, with several methods currently available. Among the serological tests, the DPP rapid test and the EIE-LVC, more commonly used in Brazil, are associated with variable sensitivity and specificity. Research with novel recombinant proteins such as the ELISA with the recombinant chimeric protein Q5 may therefore improve the CVL diagnosis. This study aimed to evaluate the true diagnostic potential of Q5 in an ELISA assay using a large number of CVL-suspected sera (406) with a previous positive diagnosis based on the rapid DPP test. Sera from the DPP-positive dogs, also assessed with the EIE-LVC test, were compared with sera from healthy dogs (n = 46) and used for ELISA tests using the recombinant Q5. The resulting data as well as the correlation with the clinical signs and the environmental characteristics of the animals were analyzed using Medal and GraphPad Prism 8.0. Overall, similar levels of lower sensitivity (67–68%) were seen for both the commercial EIE-LVC test and the Q5 ELISA when all assessed sera were considered, but a much greater sensitivity (92%) was seen for those samples from symptomatic dogs only. In contrast, many negative results were observed for the DPP-positive sera from asymptomatic dogs or those with no clinical information available. A selection of those sera were tested yet again in new ELISA assays using a second batch of the recombinant Q5, purified under milder denaturing conditions, as well as using another recombinant protein (Lci13). The results reveal a higher-than-expected incidence of likely false-positive results for DPP, reinforcing the need for other recombinant proteins, such as the chimeric Q5, to be investigated as possible alternatives to the currently used CVL diagnostic methods. [ABSTRACT FROM AUTHOR]

Leishmania infantum is the etiological agent of zoonotic visceral leishmaniasis (ZVL). The disease is endemic in Central and South America, Central and South East Asia, and the Mediterranean basin. Dogs are the main reservoir, with an estimated prevalence of approximately 2.5 million dogs in Southern Europe. Current treatments cause side effects, disease recurrence, and drug resistance. Therefore, the development of vaccines against canine leishmaniasis is necessary. We have generated a DNA vaccine based on the non-replicative antibiotic resistance marker-free plasmid vector pPAL that contains the encoding gene for the L. infantum activated protein kinase C receptor analog (LACK). Homologous pPALLACK prime-boost intranasal administration confers efficacious protection in Beagle dogs with a reduction of clinical signs and a statistically significant reduction of the parasite burden in the bone marrow of more than 90% of dogs after experimental infection with highly infective promastigotes. This DNA vaccine elicits a robust cellular immune response skewed towards the Th1 profile. [ABSTRACT FROM AUTHOR]

Introduction: Visceral leishmaniasis (VL) is caused by Leishmania donovani. The purine and pyrimidine pathways are essential for L. donovani. Simultaneously inhibiting multiple targets could be an effective strategy to eliminate the pathogen and treat VL. Objective: We aimed to target the essential enzymes of L. donovani and inhibit them using a multi‐target approach. Materials and methods: A systematic analytical method was followed, in which first reported inhibitors of two essential enzymes (adenine phosphoribosyl‐transferase [APRT] and dihydroorotate dehydrogenase [DHODH]) were collected and then ADMET and PASS analyses were conducted using the Lipinski rule and Veber's rule. Additionally, molecular docking between screened ligands and proteins were performed. The stability of complexes was analyzed using molecular dynamics (MD) simulations and MMPBSA analysis. Results: Initially, 6,220 unique molecules were collected from the PubChem database, and then the Lipinski rule and Veber's rule were used for screening. In total, 203 compounds passed the ADMET test; their antileishmanial properties were tested by PASS analysis. As a result, 15 ligands were identified. Molecular docking simulations between APRT or DHODH and these 15 ligands were performed. Four molecules were found to be plant‐derived compounds. Lig_2 and Lig_3 had good docking scores with both proteins. MD simulations were performed to determine the dynamic behavior and binding patterns of complexes. Both MD simulations and MMPBSA analysis showed Lig_3 is a promising antileishmanial inhibitor of both targets. Conclusion: Promising plant‐derived compounds that might be used to combat VL were obtained through a multi‐target approach. The public health hazard posed by visceral leishmaniasis is significant, and there are currently no effective medications. A multi‐target approach utilizing various screening strategies was used to obtain promising ligands. Together, the screening of molecules, molecular docking, MD simulations, and MMPBSA investigation suggest that Lig_3 (PubChem CID‐44610153) can be considered a lead inhibitor compound of APRT and DHODH of L. donovani. The findings of this study may serve as a reference in the field of medicine and other related research. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central China Normal University is the property of Huazhong Normal University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Leishmaniasis is a serious public and veterinary health concern. Species of the subgenus Larroussius are the suspected and proven vectors of the leishmaniasis visceral form. This study was aimed at investigating the spatiotemporal dynamics of Phlebotomus perniciosus (Diptera: Psychodidae) and characterizing its habitats using satellite images. The entomological sampling was based on a preliminary stratification of the study area, in which the sandflies were collected at 12 selected stations in Fez City using sticky paper traps. The environmental factors studied for each station were land surface temperature (LST), normalized difference vegetation index (NDVI), and soil moisture index (SMI). Correlations between the number of species of sandflies and each of the environmental factors were evaluated using Pearson's correlation. Differences were considered significant at p < 0.05 (95% confidence level). Two species of the subgenus Larroussius, which are vectors of visceral leishmaniasis, Ph. perniciosus (96.54%) and Ph. longicuspis (3.46%), were found in the collected 231 specimens. Statistical analysis of the environmental factors also demonstrated a significant positive correlation between the number of Ph. perniciosus and LST in all environments. However, the correlation between the isolated species and NDVI was not strong and only significant in the urban area (r = 0.79, p = 0.0018), and no significant correlation was found with the SMI. The findings of this study could help health authorities develop appropriate future vector control strategies. [ABSTRACT FROM AUTHOR]

Dogs with visceral leishmaniasis play a key role in the transmission cycle of Leishmania infantum to humans in the urban environment. There is a consensus regarding the importance of developing a vaccine to control this disease. Despite many efforts to develop a protective vaccine against CVL, the ones currently available, Leish-tec® and LetiFend®, have limited effectiveness. This is due, in part, to the complexity of the immune response of the naturally infected dogs against the parasite and the complexity of the parasite transmission cycle. Thus, strategies, such as the development of a transmission-blocking vaccines (TBVs) already being applied to other vector-borne diseases like malaria and dengue, would be an attractive alternative to control leishmaniasis. TBVs induce the production of antibodies in the vertebrate host, which can inhibit parasite development in the vector and/or interfere with aspects of vector biology, leading to an interruption of parasite transmission. To date, there are few TBV studies for CVL and other leishmaniasis forms. However, the few studies that exist show promising results, thus justifying the further development of this approach. [ABSTRACT FROM AUTHOR]