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Introduction: Visceral leishmaniasis (VL) is an important tropical and neglected disease and represents a serious global health problem. The initial interaction between the phagocytes and the parasite is crucial to determine the pathogen's capacity to initiate infection and it shapes the subsequent immune response that will develop. While type-1 T-cells induce IL-6, IL-1β, TNF-α, and IL-12 production by monocytes/macrophages to fight the infection, type-2 T-cells are associated with a regulatory phenotype (IL-10 and TGF-β) and successful infection establishment. Recently, our group demonstrated the role of an important Th1/ Th17 T-cell population, the mucosal-associated invariant T (MAIT) cells, in VL. MAIT cells can respond to L. infantum by producing TNF-α and IFN-γ upon MR1- dependent activation. Objective and methods: Here, we describe the impact of the MR1-blockage on L. infantum internalization on the functional profile of circulating neutrophils and monocytes as well as the impact of the MR1-blockage on the soluble mediator signatures of in vitro whole blood cultures. Results: Overall, our data showed that VL patients presents higher percentage of activated neutrophils than asymptomatic and non-infected controls. In addition, MR1 blockade led to lower TNF-α and TGF-β production by non-activated neutrophils from asymptomatic individuals. Moreover, TNF-α and IL-10 production by monocytes was higher in VL patients. In the analysis of soluble mediators produced in vitro, MR1-blockade induced a decrease of IFN-γ and an increase of IL-10, IL-27 and IL-33 in the cell cultures of AS group, a cytokine pattern associated with type 2 deleterious response. Discussion and conclusion: These data corroborate the hypothesis that MR1- restricted responses are associated to a protective role during Leishmania infection. [ABSTRACT FROM AUTHOR]

A series of 61 thiazolidine-2,4-diones bearing a styryl group at position 5 was synthesized in 2–5 steps and their structure was proved by elemental and spectral analyses. The compounds obtained were evaluated in vitro against the promastigote stage of the kinetoplastid parasite Leishmania infantum and the human HepG2 cell line, to determine selectivity indices and to compare their activities with those of antileishmanial reference drugs. The study of structure–activity relationships indicated the potential of some derivatives bearing a nitro group on the phenyl ring, especially when located at the meta position. Thus, among the tested series, compound 14c appeared as a hit compound with good antileishmanial activity (EC50 = 7 µM) and low cytotoxicity against both the hepatic HepG2 and macrophage THP-1 human cell lines (CC50 = 101 and 121 µM, respectively), leading to good selectivity indices (respectively, 14 and 17), in comparison with the reference antileishmanial drug compound miltefosine (EC50 = 3.3 µM, CC50 = 85 and 30 µM, SI = 26 and 9). Regarding its mechanism of action, among several possibilities, it was demonstrated that compound 14c is a prodrug bioactivated, predominantly by L. donovani nitroreductase 1, likely leading to the formation of cytotoxic metabolites that form covalent adducts in the parasite. Finally, compound 14c is lipophilic (measured CHI LogD7.7 = 2.85) but remains soluble in water (measured PBS solubility at pH7.4 = 16 µM), highlighting the antileishmanial potential of the nitrostyrylthiazolidine-2,4-dione scaffold. [ABSTRACT FROM AUTHOR]

Visceral Leishmaniasis is considered one of the endemic parasitic diseases transferred via sand fly Phlebotomus alexandri bite that can be transferred Leishmania infantum. This study aimed to detect visceral leishmaniasis in peripheral blood for patients using IFA test and kDNA polymerase chain reaction. Eighty samples were collected in the period (September 2022 -December 2023) from patients (1-10 years of age) suspected of VL and admitted to hospitals at several governorates in Iraq. IFAT showed positive results for 65 out of 80 samples with visceral leishmaniasis by L.infantum (81%). While kDNA results showed 60 out of 80 samples with visceral leishmaniasis by L.infantum (75% )., the sensitivity and specificity of IFA were 92% and 100% comparison with PCR. Concerning the results sequencing of PCR products, there was one isolate of L.infantum that differed from the global isolates in the NCBI It was found variation sequences in position substitution including deletion, transition, and transversion in the local isolate registered with accession number OR886069.1 . Moreover, it was observed in the phylogenetic tree analysis, there were the highest and lowest similarity distances of the Iraqi isolate with other isolates that including the French isolate, and the Iranian isolate. [ABSTRACT FROM AUTHOR]

A series of 61 thiazolidine-2,4-diones bearing a styryl group at position 5 was synthesized in 2–5 steps and their structure was proved by elemental and spectral analyses. The compounds obtained were evaluated in vitro against the promastigote stage of the kinetoplastid parasite Leishmania infantum and the human HepG2 cell line, to determine selectivity indices and to compare their activities with those of antileishmanial reference drugs. The study of structure–activity relationships indicated the potential of some derivatives bearing a nitro group on the phenyl ring, especially when located at the meta position. Thus, among the tested series, compound 14c appeared as a hit compound with good antileishmanial activity (EC50 = 7 µM) and low cytotoxicity against both the hepatic HepG2 and macrophage THP-1 human cell lines (CC50 = 101 and 121 µM, respectively), leading to good selectivity indices (respectively, 14 and 17), in comparison with the reference antileishmanial drug compound miltefosine (EC50 = 3.3 µM, CC50 = 85 and 30 µM, SI = 26 and 9). Regarding its mechanism of action, among several possibilities, it was demonstrated that compound 14c is a prodrug bioactivated, predominantly by L. donovani nitroreductase 1, likely leading to the formation of cytotoxic metabolites that form covalent adducts in the parasite. Finally, compound 14c is lipophilic (measured CHI LogD7.7 = 2.85) but remains soluble in water (measured PBS solubility at pH7.4 = 16 µM), highlighting the antileishmanial potential of the nitrostyrylthiazolidine-2,4-dione scaffold.

Visceral leishmaniasis is an important global health problem with an estimated of 50,000 to 90,000 new cases per year. VL is the most serious form of leishmaniasis as it can be fatal in 95% of the cases if it remains untreated. VL is a particularly acute problem in Brazil which contributed with 97% of all cases reported in 2020 in the Americas. In this country, VL affects mainly the poorest people in both urban and rural areas and continues to have a high mortality rate estimated around 8.15%. Here, we performed a temporal parasite population study using whole genome sequence data from a set of 34 canine isolates sampled in 2008, 2012 and 2015 from a re-emergent focus in Southeastern Brazil. Our study found the presence of two distinct sexual subpopulations that corresponded to two isolation periods. These subpopulations diverged hundreds of years ago with no apparent gene flow between them suggesting a process of rapid replacement during a two-year period. Sequence comparisons and analysis of nucleotide diversity also showed evidence of balancing selection acting on transport-related genes and antigenic families. To our knowledge this is the first population genomic study showing a turn-over of parasite populations in an endemic region for leishmaniasis. The complexity and rapid adaptability of these parasites pose new challenges to control activities and demand more integrated approaches to understand this disease in New World foci. [ABSTRACT FROM AUTHOR]

BACKGROUND Visceral leishmaniasis (VL) is a tropical neglected disease with high associated rates of mortality. Several studies have highlighted the importance of the intestinal tract (IT) and gut microbiota (GM) in the host immunological defense. Data in the literature on parasite life cycle and host immune defense against VL are scarce regarding the effects of infection on the IT and GM. OBJECTIVES This study aimed to investigate changes observed in the colon of Leishmania infantum-infected hamsters, including alterations in the enteric nervous system (ENS) and GM (specifically, levels of bifidobacteria and lactobacilli). METHODS Male hamsters were inoculated with L. infantum and euthanised at four or eight months post-infection. Intestines were processed for histological analysis and GM analysis. Quantitative polymerase chain reaction (qPCR) was performed to quantify each group of bacteria: Bifidobacterium spp. (Bf) and Lactobacillus spp (LacB). FINDINGS Infected hamsters showed histoarchitectural loss in the colon wall, with increased thickness in the submucosa and the mucosa layer, as well as greater numbers of intraepithelial lymphocytes. Forms suggestive of amastigotes were seen inside mononuclear cells. L. infantum infection induced changes in ENS, as evidenced by increases in the area of colonic enteric ganglia. Despite the absence of changes in the levels of Bf and LacB during the course of infection, the relative abundance of these bacteria was associated with parasite load and histological alterations. MAIN CONCLUSIONS Our results indicate that L. infantum infection leads to important changes in the colon and suggest that bacteria in the GM play a protective role.

Leishmaniasis is a much-neglected tropical disease, especially in developing countries. Visceral Leishmaniasis (VL) is the most severe form of this infection caused by Leishmania infantum specie. It affects the splenic and hepatic systems and, when left untreated, it is fatal in 95% of cases. There is no human vaccine available and the recommended treatment not only presents adverse effects but it enables the development of resistant strains if interrupted. Hence, the urgent search for new leishmanicidal compounds. In the present work, we evaluated the in vitro leishmanicidal action of new thiosemicarbazone and thiazolidine compounds against the evolutionary forms of L. infantum, as well as their hemolytic activity, ultrastructural alterations, cytotoxicity, and nitric oxide levels on peritoneal macrophages. The inhibitory concentration 50% (IC50) against promastigote forms varied from 8.62 to 34.36 µM. In the evaluation of cytotoxicity, values of CC50 in peritoneal macrophages varied from 31.80 to 196.38 µM. Data showed that compounds JW-16.2 and GT-14 were the most promising in the series as they displayed the highest CC50 (184.58 and 196.38 μM), SI (19 and 15), low hemolytic activity, induced NO production in uninfected and infected macrophages and reduced survival of amastigotes (24.39 and 16.51 μM). Ultrastructural alterations, such as shrinkage of the cell body, shortening of the flagellum, and vacuolization of the cytoplasm, were identified. Promastigote forms treated with compounds GT-14 showed depolarization of mitochondria. Therefore, both compounds are promising due to low cytotoxicity to mammalian cells and leishmanicidal action. [ABSTRACT FROM AUTHOR]

Leishmaniasis is still a serious neglected tropical disease that may cause death in infected individuals. At present, the clinical diagnosis and treatment monitoring still rely on parasitological culture and microscopy that needs experienced technicians. The low sensitivity and inconvenience of microscopic examination could cause misdiagnosis and relapse of leishmaniasis. There is an urgent need for developing a sensitive and easily operated diagnostic method for the diagnosis and disease management of leishmaniasis. Thus, a quantitative real-time PCR (qPCR) based on the conversed regions of kinetoplast minicircle DNA (mkDNA) of Leishmania spp. was developed to detect different species of Leishmania. The designed mkDNA-based qPCR was able to detect as low as one copy of Leishmania mkDNA or DNA from single parasite. It also detected Pan- Leishmania protozoa including Leishmania donovani, Leishmania infantum and Leishmania major without cross-reaction with other pathogen DNAs available in our lab. This method was clinically applied to quantitatively detect skin lesion samples from 20 cutaneous leishmaniasis (CL) and bone marrow and/or PBMC samples from 30 current and cured visceral leishmaniasis (VL) patients, and blood samples from 11 patients with other infections and 5 normal donors as well. Total 20 skin lesion samples from current CL patients and 20 bone marrow and/or PBMC samples from current VL patients were all detected as positive with qPCR without cross-reaction with samples from patients with malaria, brucellosis and dengue or normal donors. Two VL patients with parasite converted to microscopically negative after treatment were detected positive with qPCR. The patients with bigger skin lesion in CL and higher level of immunoglobulin or splenomegaly in VL, had the higher parasite load detected by qPCR. The parasite load was significantly reduced after treatment. In conclusion, the mkDNA-based qPCR assay that we developed in this study can be used not only for diagnosis of both cutaneous and visceral leishmaniasis with high sensitivity and specificity, but also for evaluating the severity and treatment efficacy of this disease, presenting a rapid and accurate tool for clinical surveillance, treatment monitoring and the end point determination of leishmaniasis. [ABSTRACT FROM AUTHOR]

Objective: There exist various diagnostic tests to detect visceral leishmaniasis, but the most efficient ones have not been demonstrated yet. Herein, we evaluated the accuracy of these diagnostic tests in Iran. Methodology: English and Persian database searching was done from 1993 to 2016. According to heterogeneity of the studies, estimations of the study were pooled by random-effects model. Totally, twenty investigations were eligible for current review with 2115 patients as pooled sample size. Results: The overall pooled estimate of sensitivity and specificity for all diagnostic tests were 0.92 ([95% CI = 0.90-0.95]) and 0.92 ([95% CI = 0.89-0.94]), respectively. Also, the separate sensitivity and specificity of each test were as follow: PCR: 1.00 ([95% CI = 0.99-1.01]) and 0.37 ([95% CI = 0.25-0.49]); DAT: 0.93 ([95% CI = 0.89-0.96]) and 0.92 ([95% CI = 0.89-0.94]); ELISA: 0.78 ([95% CI = 0.47-1.09]) and 1.00 ([95% CI = 0.99-1.01]) as well as IFA: 0.50 ([95% CI = 0.29-0.72]) and 0.96 ([95% CI = 0.95-0.97]). Conclusions: The specificity and sensitivity of PCR and DAT as molecular and serological tests, respectively, are remarkable to detect visceral leishmaniasis; hence, it is highly recommended to simultaneously employ these diagnostic tests for this widespread infection. [ABSTRACT FROM AUTHOR]

N -oxide derivatives compounds such as furoxan and benzofuroxan are promising scaffolds for designing of new antileishmanial drugs. A series of furoxan (1,2,5-oxadiazole 2- N -oxide) (compounds 4a-b , and 14a-f ) and benzofuroxan (benzo[c][1,2,5]oxadiazole1- N -oxide) (compounds 8a-c ) derivatives were evaluated against in vitro cultured L. infantum promastigotes and amastigotes. The compounds exhibited activity against promastigote and intracellular amastigote forms with EC 50 values ranging from 2.9 to 71.2 μM and 2.1 to 18.2 μM, respectively. The most promising compound, 14e , showed good antileishmanial activity (EC 50 = 3.1 μM) against intracellular amastigote forms of L. infantum with a selectivity index, based on murine macrophages (SI = 66.4), almost 3-times superior to that presented by the standard drug amphotericin B (AmpB). The efficacy of 14e to eliminate the parasites in vivo was also demonstrated. Treatment of L. infantum -infected hamsters with compound 14e at 3.0 mg/Kg/day led to a meaningful reduction of parasite load in spleen (49.9%) and liver (54.2%), respectively; these data were corroborated by histopathological analysis, which also revealed reduction in the number of inflammatory cells in the liver of the treated animals. Moreover, histological analysis of the spleen and kidney of treated animals did not reveal alterations suggestive of toxic effects. The parasite load reduction might be related to NO production, since this molecule is a NO-donor. We observed neither side effects nor elevation of hepatic/renal biomarker levels in the plasma. The data herein presented suggest that the compound should be considered in the development of new drugs for treatment of visceral leishmaniasis. [ABSTRACT FROM AUTHOR]

Background: The aim of present study was to evaluate the protective efficacy of live recombinant L. tarentolae expressing KMP11-NTGP96-GFP fusion as candidates for live engineered recombinant vaccine against visceral leishmaniasis in BALB/c mice. Methods: KMP-11 and NT-GP96 genes cloned into the pJET1.2/blunt cloning vector and then into pEGFP-N1 expression vector. The KMP-11, NT-GP96 and GFP fused in pEGFP-N1 and subcloned into Leishmanian pLEXSY-neo vector. Finally this construct was transferred to L. tarentolae by electroporation. Tranfection was confirmed by SDS-PAGE, WESTERN blot, flowcytometry and RT-PCR. Protective efficacy of this construct was evaluated as a vaccine candidate against visceral leishmaniasis. Parasite burden, humoral and cellular immune responses were assessed before and at 4 weeks after challenge. Results: KMP- NT-Gp96-GFP Fusion was cloned successfully into pLEXSY -neo vector and this construct successfully transferred to L. tarentolae. Finding indicated that immunization with L. tarentolae tarentolae-KMP11-NTGP96-GFP provides significant protection against visceral leishmaniasis and was able to induce an increased expression of IFN-γ and IgG2a. Following challenge, a reduced parasite load in the spleen of the KMP11-NTGP96-GFP immunized group was detected. Conclusion: The present study is the first to use a combination of a Leishmania antigen with an immunologic antigen in live recombinant L. tarentolae and results suggest that L. tarentolae-KMP11-NTGP96-GFP could be considered as a potential tool in vaccination against visceral leishmaniasis and this vaccination strategy could provide a potent rout for future vaccine development.

Leishmaniases are parasitic diseases frequent in the Mediterranean Basin. Visceral leishmaniasis (VL) is a notifiable parasitic disease that increased in incidence in Morocco over the past few years and has recently emerged in several new foci, causing a public health problem in Morocco. The aim of this study is to describe the spatio-temporal distribution of VL in Morocco between 1990 and 2014 period in order to highlight important features and trends of VL and its epidemiology and to assess whether the activity of the unit reflects the situation of the disease at the national level and whether it could constitute an indicator of public health relevance. Two thousand four hundred and twenty one cases were reported in Morocco between 1990 and 2014 with an average annual reported incidence rate of 0.4 cases per 100.000 inhabitants. Before 1996 the average annual incidence of VL was 50 cases on average. After this date the number of cases increased and then remained stable with around 100–150 cases per year. Children whose age varies between 1 and 4 years old are the most affected with 1327 (74%) of total cases; nevertheless the adult starts to be affected by the disease. In 2000, 65% of positive cases of VL are concentrated at both northern regions: Taza-Al Hoceima- Taounate with 45% of cases, Tanger- Tetouan mainly represented by Chefchaoun with 20% of cases. The Fez-Boulemane region located in the center recorded 12% of cases. Throughout the years the map VL distribution has been progressively changed and spatial spread of the disease to the center is noted in 2007. 2014 has been marked by an even greater extension of the disease to the center and south of Morocco. Nationally in 2014, 34 of 75 provinces and prefectures are affected compared to 2000, when 22 out of 82 provinces and prefectures were affected. Leishmania infantum was identified the causative agent based on species- specific PCR-Lei70 assay. VL remains a sporadically endemic parasitic disease in Morocco with a progressive extension of its range of distribution. Such a situation would relate to the geographical succession of Phlebotomine sand fly vectors, the difficulty of actions against the canine population reservoirs of L. infantum and unfavorable socio-economic factors. [ABSTRACT FROM AUTHOR]

Herein, we evaluated the treatment strategy employing a therapeutic heterologous vaccine composed of antigens of Leishmania braziliensis associated with MPL adjuvant (LBMPL vaccine) for visceral leishmaniasis (VL) in symptomatic dogs naturally infected by Leishmania infantum. Sixteen dogs received immunotherapy with MPL adjuvant (n = 6) or with a vaccine composed of antigens of L. braziliensis associated with MPL (LBMPL vaccine therapy, n = 10). Dogs were submitted to an immunotherapeutic scheme consisting of 3 series composed of 10 subcutaneous doses with 10-day interval between each series. The animals were evaluated before (T0) and 90 days after treatment (T90) for their biochemical/hematological, immunological, clinical, and parasitological variables. Our major results showed that the vaccine therapy with LBMPL was able to restore and normalize main biochemical (urea, AST, ALP, and bilirubin) and hematological (erythrocytes, hemoglobin, hematocrit, and platelets) parameters. In addition, in an ex vivo analysis using flow cytometry, dogs treated with LBMPL vaccine showed increased CD3+ T lymphocytes and their subpopulations (TCD4+ and TCD8+), reduction of CD21+ B lymphocytes, increased NK cells (CD5-CD16+) and CD14+ monocytes. Under in vitro conditions, the animals developed a strong antigen-specific lymphoproliferation mainly by TCD4+ and TCD8+ cells; increasing in both TCD4+IFN-γ+ and TCD8+IFN-γ+ as well as reduction of TCD4+IL-4+ and TCD8+IL-4+ lymphocytes with an increased production of TNF-α and reduced levels of IL-10. Concerning the clinical signs of canine visceral leishmaniasis, the animals showed an important reduction in the number and intensity of the disease signs; increase body weight as well as reduction of splenomegaly. In addition, the LBMPL immunotherapy also promoted a reduction in parasite burden assessed by real-time PCR. In the bone marrow, we observed seven times less parasites in LBMPL animals compared with MPL group. The skin tissue showed a reduction in parasite burden in LBMPL dogs 127.5 times higher than MPL. As expected, with skin parasite reduction promoted by immunotherapy, we observed a blocking transmission to sand flies in LBMPL dogs with only three positive dogs after xenodiagnosis. The results obtained in this study highlighted the strong potential for the use of this heterologous vaccine therapy as an important strategy for VL treatment. [ABSTRACT FROM AUTHOR]

• Better performance was obtained compared to more commonly used antigens. • Dyn-1 showed excellent ability to identify asymptomatic dogs (100% sensitivity). • Overall, the ability of rDyn-1 to identify dogs with CanL was 97% (sensitivity). • rDyn-1-based ELISA assays could be advantageous over classic diagnostic tests. Visceral leishmaniasis (VL) is a fatal manifestation of an infection caused by intracellular protozoa of the Leishmania genus. In New World countries, VL is classified as a zoonotic disease with domestic dogs acting as its main reservoir. Asymptomatic dogs are as competent to transmit Leishmania to the vectors as symptomatic dogs, however current diagnostic tests are limited and present low sensitivity for this important group. The development of accurate tests is fundamental to the early diagnosis, treatment, and control of canine leishmaniasis. In this study, we investigated the use of a recombinant protein (dynamin-1-like protein, Dyn-1) from L. infantum, as a potential target antigen for leishmaniasis serodiagnosis in both symptomatic and asymptomatic dogs. The antigenic performance of the protein was evaluated by means of ELISA assays using sera from symptomatic (n = 25), asymptomatic (n = 34) and non-infected dogs (n = 36) using ELISA. In addition, sera from dogs experimentally infected with Trypanosoma cruzi (n = 49) and naturally infected with Babesia sp. (n = 8) were tested to evaluate possible cross-reactivity. A crude soluble antigen (CSA) of Leishmania was used as an antigen control and K39 and K26 were used as reference antigens because they are already widely used in commercial tests. rDyn-1-based assay showed the highest sensitivity (97%) compared to the antigens K39 (88%), K26 (86%) and crude extract (95%). The highest specificity among the tests was also obtained with the protein rDyn-1 (94%), compared with the other antigens K39 (81%), K26 (87%), and crude extract (77%). This study showed that the rDyn-1 ELISA assay was able to identify 100% of asymptomatic dogs, establishing its potential as a target for the diagnosis of canine leishmaniasis. [ABSTRACT FROM AUTHOR]

The leishmaniasis are a group of vector-borne diseases caused by a protozoan parasite from the genus Leishmania. In this study, a series of thiazolopyrimidine derivatives were designed and synthesized as novel antileishmanial agents with Lm PTR1 inhibitory activity. The final compounds were evaluated for their in vitro antipromastigote activity, Lm PTR1 and h DHFR enzyme inhibitory activities, and cytotoxicity on RAW264.7 and L929 cell lines. Based on the bioactivity results, three compounds, namely L24f , L24h and L25c , were selected for evaluation of their in vivo efficacy on CL and VL models in BALB/c mice. Among them, two promising compounds, L24h and L25c, showed in vitr o antipromastigote activity against L. tropica with the IC 50 values of 0.04 μg/ml and 6.68 μg/ml; against L. infantum with the IC 50 values of 0.042 μg/ml and 6.77 μg/ml, respectively. Moreover, the title compounds were found to have low in vitro cytotoxicity on L929 and RAW264.7 cell lines with the IC 50 14.08 μg/ml and 21.03 μg/ml, and IC 50 15.02 μg/ml and 8.75 μg/ml, respectively. Lm PTR1 enzyme inhibitory activity of these compounds was determined as 257.40 μg/ml and 59.12 μg/ml and their selectivity index (SI) over h DHFR was reported as 42.62 and 7.02, respectively. In vivo studies presented that L24h and L25c have a significant antileishmanial activity against footpad lesion development of CL and at weight measurement of VL group in comparison to the reference compound, Glucantime®. Also, docking studies were carried out with selected compounds and other potential Leishmania targets to detect the putative targets of the title compounds. Taken together, all these findings provide an important novel lead structure for the antileishmanial drug development. [Display omitted] • A series of thiazolopyrimidine derivatives were synthesized as novel antileishmanials. • L24f , L24h and L25c showed in vitro antipromastigote activity and low cytotoxicity. • L24f , L24h and L25c showed moderate Lm PTR1 inhibition and h DHFR selectivity. • L24h and L25c have shown in vivo activity on CL and VL models of BALB/c mice. [ABSTRACT FROM AUTHOR]

Introduction:Visceral leishmaniasis (Kala-azar) is a major parasitic disorder caused by species of Leishmania genus, namely L. donovani and L. infantum. Epidemiologic evidence indicates that visceral leishmaniasis is common in certain regions of Jahrom town in the province of Fars, Iran. The present study was conducted with the aim of identifying the causative agent of visceral leishmaniasis in this town. Material and Methods:This is an experimental study on 16 patients admitted with Kala-azar in Shahid Motahari Hospital, Jahrom, from 1997 to 2004. Bone marrow samples were obtained from patients. DNA was extracted from microscopic slides and specific polymerase chain reaction (PCR) was used to identify the parasite species. For this purpose, a segment of minicircle kinetoplast DNA of the parasite was amplified using LINR4 and LIN17 primers. The products were evaluated by electrophoresis in 1.5% agarose gel.Results:All patients were serologically positive on indirect immunofluorescent assay. On direct examination of bone marrow smears, parasitic amastigotes (Leishman bodies) were observed in large numbers. All specimens produced a 720 base-pair band on PCR. Comparing these bands to the standard species bands identified L. infantum in all our patients.Conclusion:The findings of the present study indicate that using one-step polymerase chain reaction and LINR4 and LIN17 primers is a simple and rapid method for identification of species. Also, the causative agent for visceral leishmaniasis is L. infantum in all our patients.

Introduction: Visceral leishmaniasis (VL) or Kala-azar is an important parasitic diseases caused by protozoan parasites of the genus Leishmania including L. donovani, L. infantum. Epidemiological evidences show that VL is frequently common in some areas of Jahrom district in Fars Province. This study aimed to characterize the causative agent of VL in this region. Materials and Methods: Bone marrow sample was obtained from 16 VL patients from Pediatric hospital in Jahrom town. DNA was extracted from the microscopic slides and checked by specific PCR to find out the species of the parasite. To do it, a segment of minicirclekinetoplast DNA was amplified, using LINR4 and LIN17 primers. Products of PCR were evaluated by electrophoresis, using 1.5% agarose. Results: Anti-leishmania antibody was detected in all patients by IFAT. Examination of bone marrow smears demonstrated numerous amastigotes of Leishmania (Leishman bodies) in the samples. All the samples produced a 720 bp band in PCR assay. The isolates were compared with reference strains and revealed that all the isolates are L. infantum. Conclusion: Our findings showed that species characterization with one-step PCR by LIN17 and LINR4 is simple and fast it was also confirmed that the causative agent of VL in Jahrom is L. infantum.

Background: The aim of present study was to evaluate the protective efficacy of live recombinant L. tarentolae expressing KMP11-NTGP96-GFP fusion as candidates for live engineered recombinant vaccine against visceral leishmaniasis in BALB/c mice. Methods: KMP-11 and NT-GP96 genes cloned into the pJET1.2/blunt cloning vector and then into pEGFP-N1 expression vector. The KMP-11, NT-GP96 and GFP fused in pEGFP-N1 and subcloned into Leishmanian pLEXSY-neo vector. Finally this construct was transferred to L. tarentolae by electroporation. Tranfection was confirmed by SDS-PAGE, WESTERN blot, flowcytometry and RT-PCR. Protective efficacy of this construct was evaluated as a vaccine candidate against visceral leishmaniasis. Parasite burden, humoral and cellular immune responses were assessed before and at 4 weeks after challenge. Results: KMP- NT-Gp96-GFP Fusion was cloned successfully into pLEXSY -neo vector and this construct successfully transferred to L. tarentolae. Finding indicated that immunization with L. tarentolae tarentolae-KMP11-NTGP96-GFP provides significant protection against visceral leishmaniasis and was able to induce an increased expression of IFN- and IgG2a. Following challenge, a reduced parasite load in the spleen of the KMP11-NTGP96-GFP immunized group was detected. Conclusion: The present study is the first to use a combination of a Leishmania antigen with an immunologic antigen in live recombinant L. tarentolae and results suggest that L. tarentolae-KMP11-NTGP96-GFP could be considered as a potential tool in vaccination against visceral leishmaniasis and this vaccination strategy could provide a potent rout for future vaccine development. [ABSTRACT FROM AUTHOR]

Abstract: Over a period of ten years, a series of 694 Leishmania strains from Tunisian leishmaniasis foci were isolated and identified by isoenzymatic analysis. Strains were obtained from human cutaneous and visceral leishmaniasis in immunocompetent subjects, visceral leishmaniasis in imunocompromised individuals and from dogs with visceral leishmaniasis. Two classically dermotropic species, Leishmania (L.) major and Leishmania killicki were found. L. major with the single zymodeme MON-25 was the most isolated in cutaneous leishmaniasis foci of the Centre and South of Tunisia with a recent northern extension. L. killicki zymodeme MON-8 was sporadically found both in its classical microfocus of Tataouine in southeastern Tunisia as well as in some new foci in Southwestern, Central and Northern Tunisia. Leishmania infantum with its three zymodemes MON-1, MON-24 and MON-80 was isolated from both visceral and cutaneous human cases. The majority of L. infantum strains were found in the Northern part of the country; however, some strains were reported for the first time in the Southern part. L. infantum MON-1 was the only zymodeme isolated from canine leishmaniasis. [Copyright &y& Elsevier]

The background of this article is as follows: Few data are available about the persistence of serum-specific IgG antibodies to L. infantum after acute VL. The objective of this article is to evaluate the persistence of antibodies against L. infantum in patients healed from acute VL, and the kinetic of the same antibodies observed in 2 cases of VL relapse and 2 cases of resistance to therapy. The methods which we used to obtain our objective are the following: 55 apparently immunocompetent, HIV-negative patients were examined for antibodies to L. infantum by IFAT over 14 years period, and we got the following results: Serum-specific IgG antibodies titers decrease slowly, but constantly. In the patients with a diagnosis of VL relapse, the kinetic of antibodies was characterized by an initial reduction, and a subsequent antibody levels rapidly increase, while in the patients with a clinical and parasitological diagnosis of VL not responding to specific therapy, we demonstrated persistent high level of antibodies to L. infantum. Finally, we conclude that specific antibodies to L. infantum might persist for many years, and decrease slowly, but steadily. The persistence of these specific antibodies is not related to poor therapeutic response or prognosis, but an acute increase in their levels might be a sentinel of a VL relapse, while persistence of high antibody levels could suggest a resistance to therapy. [ABSTRACT FROM AUTHOR]

Introduction: Visceral leishmaniasis (VL) or Kala-azar is an important parasitic diseases caused by protozoan parasites of the genus Leishmania including L. donovani, L. infantum. Epidemiological evidences show that VL is frequently common in some areas of Jahrom district in Fars Province. This study aimed to characterize the causative agent of VL in this region. Materials and Methods: Bone marrow sample was obtained from 16 VL patients from Pediatric hospital in Jahrom town. DNA was extracted from the microscopic slides and checked by specific PCR to find out the species of the parasite. To do it, a segment of minicirclekinetoplast DNA was amplified, using LINR4 and LIN17 primers. Products of PCR were evaluated by electrophoresis, using 1.5% agarose. Results: Anti-leishmania antibody was detected in all patients by IFAT. Examination of bone marrow smears demonstrated numerous amastigotes ofLeishmania (Leishman bodies) in the samples. All the samples produced a 720 bp band in PCR assay. The isolates were compared with reference strains and revealed that all the isolates are L. infantum. Conclusion: Our findings showed that species characterization with one-step PCR by L1N17 and L1NR4 is simple and fast; it was also confirmed that the causative agent of VL in Jahrom is L. infantum. [ABSTRACT FROM AUTHOR]

Abstract: We have performed a combination of microcapillary cultivation method and restriction fragment length polymorphism (RFLP) analysis of amplified products by 1 single PCR of miniexon region of Leishmania for molecular diagnosis and genotyping of different Leishmania species isolated from cutaneous leishmaniasis (CL) and visceral leishmaniasis. We have analyzed 10 microcapillary cultivated isolates from cutaneous cases and 5 microcapillary cultivated isolates from visceral cases (totally 15) by polymerase chain reaction–RFLP (PCR-RFLP). Of 10 isolates, 3 (30%) were genotyped as Leishmania infantum and 7 (70%) of 10 isolates were genotyped as Leishmania tropica from the microcapillary cultivated isolates of cutaneous cases. On the other hand, all 5 isolates (100%) were genotyped as L. infantum from microcapillary cultivated visceral cases. Our most interesting finding is the presence of 3 L. infantum isolates in CL cases without kala-azar history. Therefore, we suggest that further investigations must be done about this subject. On the other hand, we suggest the combination of microcapillary culture method and PCR-RFLP of miniexon region of leishmaniae can be used in routine laboratory experimentation because of their simple, cheap, and rapid benefits (within a week), whereas other different approaches offer a multitude of valid taxonomic characters for species identification. [Copyright &y& Elsevier]

It is estimated that there are 400000 new cases of visceral leishmaniasis each year, with about 30,000 deaths. Therefore, detection of this pathogen and its species is highly vital for overall health of the community. In the present research, a DNA-based biosensor, namely genosensor, was introduced for detection of genomic DNA of Leishmania infantum. The genosensor was fabricated based on the transduction of cadmium sulfide nanosheets and recognition of a particular single stranded DNA sequence, and worked in label-, marker-, tag- and PCR-free manners. Impedimetric measurements were performed in a wide range of frequency (recording Nyquist diagrams) without applying external force (working at open circuit potential) upon hybridization of DNA targets with the cadmium sulfide nanosheets surface-immobilized probe. The genosensor detected the complementary DNA strand in a concentration range of 1.0 × 10−14 to 1.0 × 10−6 mol L−1 and a detection limit (DL) of 0.81 fmol L−1 (6.5 fg mL−1), and genomic DNA of Leishmania infantum in a concentration range of 5–50 ng μL−1 and a DL of 1.2 ng μL−1. The genosensor had a very good selectivity, fabrication reproducibility and stability, and was applicable for practical applications. Image 1 • A specific DNA sequence was selected from gene sequence of Leishmania infantum. • The DNA sequence was immobilized on cadmium sulfide nanosheets to fabricate a genosensor. • The genosensor detected targets with a nice selectivity. • Leishmania infantum genomic DNA was quantified by the genosensor in clinical samples. [ABSTRACT FROM AUTHOR]