Indian Visceral Leishmaniasis Research Articles

Molecular, structural, and functional characterization of delta subunit of T-complex protein-1 from Leishmania donovani.

Chaperonins/Heat shock protein 60 are ubiquitous multimeric protein complexes that assist in the folding of partially and/or misfolded proteins using metabolic energy into their native stage. The eukaryotic group II chaperonin, also referred as T-complex protein-1 ring complex (TRiC)/T-complex protein-1 (TCP1)/chaperonin containing T-complex protein (CCT), contains 8-9 paralogous subunits, arranged in each of the two rings of hetero-oligomeric complex. In Leishmania, till date, only one subunit, LdTCP1γ, has been well studied. Here, we report the molecular, structural, and functional characterization of TCP1δ subunit of Leishmania donovani (LdTCP1δ), the causative agent of Indian kala-azar. LdTCP1δ gene exhibited only 27.9% identity with LdTCP1γ and clustered in a separate branch in the phylogenic tree of LdTCP1 subunits. The purified recombinant protein formed a high molecular weight complex (0.75 MDa), arranged into 16-mer assembly, and performed in vitro chaperonin activity as assayed by ATP-dependent luciferase folding. LdTCP1δ exhibits 1.8-fold upregulated expression in metabolically active, rapidly dividing log phase promastigotes. Over-expression of LdTCP1δ in promastigotes results in increased infectivity and rate of multiplication of intracellular amastigotes. The study thus establishes the existence of an individual functionally active homo-oligomeric complex of LdTCP1δ chaperonin with its role in parasite infectivity and multiplication.

A Systematic Assessment of Leishmania donovani Infection in Domestic and Wild Animal Reservoir Hosts of Zoonotic Visceral Leishmaniasis in India

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

Effect of indoor residual spraying on sandfly abundance and incidence of visceral leishmaniasis in India, 2016–22: an interrupted time-series analysis and modelling study

Efforts to eliminate visceral leishmaniasis in India mainly consist of early detection and treatment of cases and indoor residual spraying with insecticides to kill the phlebotomine sandfly Phlebotomus argentipes that transmits the causative Leishmania protozoa. In this modelling study, we aimed to estimate the effect of indoor residual spraying (IRS) on vector abundance and transmission of visceral leishmaniasis in India. In this time-series analysis and modelling study, we assessed the effect of IRS on vector abundance by using indoor vector-abundance data (from 2016 to 2022) and IRS quality-assurance data (from 2017-20) from 50 villages in eight endemic blocks in India where IRS was implemented programmatically. To assess a potential dose-response relation between insecticide concentrations and changes in sandfly abundance, we examined the correlation between site-level insecticide concentrations and the site-level data for monthly sandfly abundances. We used mathematical modelling to link vector data to visceral leishmaniasis case numbers from the national Kala-Azar Management Information System registry (2013-21), and to predict the effect of IRS on numbers of averted cases and deaths. IRS was estimated to reduce indoor sandfly abundance by 27% (95% CI 20-34). Concentrations of insecticides on walls were significantly-but weakly-associated with the degree of reduction in vector abundance, with a reduction of -0·0023 (95% CI -0·0040 to -0·0007) sandflies per mg/m2 insecticide (p=0·0057). Reported case numbers of visceral leishmaniasis were well explained by trends in vector abundance. Village-wide IRS in response to a newly detected case of visceral leishmaniasis was predicted to reduce disease incidence by 6-40% depending on the presumed reduction in vector abundance modelled. Indoor residual spraying has substantially reduced sandfly abundance in India, which has contributed to reductions in visceral leishmaniasis and related deaths. To prevent the re-emergence of visceral leishmaniasis as a public health problem, surveillance of transmission and sandfly abundance is warranted. Bill & Melinda Gates Foundation. For the Hindi translation of the abstract see Supplementary Materials section.

Correction for Ghoshal et al., "9-O-Acetylated Sialoglycoproteins Are Important Immunomodulators in Indian Visceral Leishmaniasis".

Correction for Ghoshal et al., "9-O-Acetylated Sialoglycoproteins Are Important Immunomodulators in Indian Visceral Leishmaniasis".

Visceral Leishmaniasis-Human Immunodeficiency Virus-Coinfected Patients Are Highly Infectious to Sandflies in an Endemic Area in India.

In an area endemic with Indian visceral leishmaniasis (VL), we performed direct xenodiagnosis to evaluate the transmission of Leishmania donovani from patients with VL-human immunodeficiency virus (HIV) coinfection to the vector sandflies, Phlebotomus argentipes. Fourteen patients with confirmed VL-HIV coinfection, with a median parasitemia of 42 205 parasite genome/mL of blood, were exposed to 732 laboratory-reared pathogen-free female P argentipes sandflies on their lower arms and legs. Microscopy revealed that 16.66% (122/732) of blood-fed flies were xenodiagnosis positive. Notably, 93% (13/14) of the VL-HIV group infected the flies, as confirmed by quantitative polymerase chain reaction and/or microscopy, and were 3 times more infectious than those who had VL without HIV.

Post kala-azar dermal leishmaniasis in the Indian sub-continent: challenges and strategies for elimination.

Visceral leishmaniasis (VL) is a severe and often fatal form of leishmaniasis caused by Leishmania donovani in the Indian sub-continent. Post Kala-azar Dermal Leishmaniasis (PKDL) is a late cutaneous manifestation of VL, typically occurring after apparent cure of VL, but sometimes even without a prior history of VL in India. PKDL serves as a significant yet neglected reservoir of infection and plays a crucial role in the transmission of the disease, posing a serious threat to the VL elimination program in the Indian sub-continent. Therefore, the eradication of PKDL should be a priority within the current VL elimination program aimed at achieving a goal of less than 1 case per 10,000 in the population at the district or sub-district levels of VL endemic areas. To accomplish this, a comprehensive understanding of the pathogenesis of PKDL is essential, as well as developing strategies for disease management. This review provides an overview of the current status of diagnosis and treatment options for PKDL, highlighting our current knowledge of the immune responses underlying disease development and progression. Additionally, the review discusses the impact of PKDL on elimination programs and propose strategies to overcome this challenge and achieve the goal of elimination. By addressing the diagnostic and therapeutic gaps, optimizing surveillance and control measures, and implementing effective intervention strategies, it is possible to mitigate the burden of PKDL and facilitate the successful elimination of VL in the Indian sub-continent.

First evidence of experimental genetic hybridization between cutaneous and visceral strains of Leishmania donovani within its natural vector Phlebotomus argentipes

Leishmaniasis is a neglected tropical disease caused by protozoan parasites of genus Leishmania, and transmitted by different species of Phlebotomine sand flies. More than 20 species of Leishmania are known to cause disease in humans and other animals. Leishmania donovani species complex is known to have a vast diversity of clinical manifestations in humans, but underlying mechanisms for such diversity are yet unknown. Long believed to be strictly asexual, Leishmania have been shown to undergo a cryptic sexual cycle inside its sandfly vector. Natural populations of hybrid parasites have been associated with the rise of atypical clinical outcomes in the Indian subcontinent (ISC). However, formal demonstration of genetic crossing in the major endemic sandfly species in the ISC remain unexplored. Here, we investigated the ability of two distinct variants of L. donovani associated with strikingly different forms of the disease to undergo genetic exchange inside its natural vector, Phlebotomus argentipes. Clinical isolates of L. donovani either from a Sri Lankan cutaneous leishmaniasis (CL) patient or an Indian visceral leishmaniasis (VL) patient were genetically engineered to express different fluorescent proteins and drug-resistance markers and subsequently used as parental strains in experimental sandfly co-infection. After 8 days of infection, sand flies were dissected and midgut promastigotes were transferred into double drug-selective media. Two double drug-resistant, dual fluorescent hybrid cell lines were recovered, which after cloning and whole genome sequencing, were shown to be full genomic hybrids. This study provides the first evidence of L. donovani hybridization within its natural vector Ph. argentipes.

Review on Leishmaniasis

Leishmaniasis disease is caused by parasites and its spread by the bite of different types of sand flies. The genus Leishmania is named after the death Sir William Leishman, who discovered the flagellate protozoa which is the causative agent of Kala-azar, the Indian visceral leishmaniasis (VL). On clinical symptoms they have three species: Cutaneous leishmaniasis, visceral leishmaniasis and mucocutaneous leishmaniasis. This infection diagnosis is based on the severity of the condition. In comparison to two other types of leishmaniasis, cutaneous leishmaniasis is not more dangerous. The treatment's effectiveness varies depending on the type of resistance pattern and the infecting species. The lack of a vaccination for human leishmaniasis may be due to a lack of funding in this neglected parasitic disease.

Revealing a Novel Antigen Repressor of Differentiation Kinase 2 for Diagnosis of Human Visceral Leishmaniasis in India.

Visceral leishmaniasis (VL) is one of the major global health concerns due to its association with morbidity and mortality. All available diagnostic tools have been, until now, unable to provide a very specific and cost-effective mode of detection for VL globally. Therefore, the design of robust, specific, and commercially translatable diagnostic tests is urgently required. Currently, we are attempting to identify and explore the diagnostic potential of a novel parasite antigen. Repressor of differentiation kinase 2 (RDK2), a serine/threonine kinase, has a versatile role in parasite life cycle progression. However, its role as a diagnostic candidate for VL has not been investigated. Herein, we cloned and over-expressed LdRDK2 and studied the recombinant RDK2 for the diagnosis of human VL using serum and urine samples. In silico analysis predicted that RDK2 is conserved among Leishmania species with the least conservation in humans. RDK2 developed immune-reactive bands with antibodies present in VL patients’ sera, and it demonstrated no cross-reactivity with sera from healthy controls and other diseases. Additionally, RDK2 antigen demonstrated a significant reactivity with IgG antibodies of VL patients’ sera, with 78% sensitivity and 86.67% specificity as compared to healthy controls and other diseases. Furthermore, we evaluated its utility for non-invasive diagnosis of VL using patients’ urine samples and found 93.8% sensitivity and 85.7% specificity. RDK2 was found to have better sensitivity and treatment response in patients’ urine compared to serum samples, indicating its role as a promising point of care (POC) antigen. In a nutshell, we explored the role of RDK2 as a potential diagnostic marker for VL in both invasive and non-invasive modes as well as its utility as a promising POC antigen for treatment response cases.

Development and Clinical Evaluation of Serum and Urine-Based Lateral Flow Tests for Diagnosis of Human Visceral Leishmaniasis.

Visceral leishmaniasis (VL), a fatal parasitic infection, is categorized as being neglected among tropical diseases. The use of conventional tissue aspiration for diagnosis is not possible in every setting. The immunochromatography-based lateral flow assay (LFA) has attracted attention for a long time due to its ability to give results within a few minutes, mainly in resource-poor settings. In the present study, we optimized and developed the LFA to detect anti-Leishmania antibodies for VL diagnosis. The performance of the developed test was evaluated with serum and urine samples of Indian VL patients and Brazilian sera. The new test exploits well-studied and highly-sensitive purified antigens, LAg isolated from Leishmania donovani promastigotes and protein G conjugated colloidal-gold as a signal reporter. The intensity of the bands depicting the antigen–antibody complex was optimized under different experimental conditions and quantitatively analyzed by the ImageJ software. For the diagnosis of human VL in India, LFA was found to be 96.49% sensitive and 95% specific with serum, and 95.12% sensitive and 96.36% specific with urine samples, respectively. The sensitivity and specificity of LFA were 88.57% and 94.73%, respectively, for the diagnosis of Brazilian VL using patients’ sera infected with Leishmania infantum. LFA is rapid and simple to apply, suitable for field usage where results can be interpreted visually and particularly sensitive and specific in the diagnosis of human VL. Serum and urine LFA may improve diagnostic outcomes and could be an alternative for VL diagnosis in settings where tissue aspiration is difficult to perform.

Geographical Variability in Paromomycin Pharmacokinetics Does Not Explain Efficacy Differences between Eastern African and Indian Visceral Leishmaniasis Patients.

IntroductionIntramuscular paromomycin monotherapy to treat visceral leishmaniasis (VL) has been shown to be effective for Indian patients, while a similar regimen resulted in lower efficacy in Eastern Africa, which could be related to differences in paromomycin pharmacokinetics.MethodsPharmacokinetic data were available from two randomized controlled trials in VL patients from Eastern Africa and India. African patients received intramuscular paromomycin monotherapy (20 mg/kg for 21 days) or combination therapy (15 mg/kg for 17 days) with sodium stibogluconate. Indian patients received paromomycin monotherapy (15 mg/kg for 21 days). A population pharmacokinetic model was developed for paromomycin in Eastern African and Indian VL patients.ResultsSeventy-four African patients (388 observations) and 528 Indian patients (1321 observations) were included in this pharmacokinetic analysis. A one-compartment model with first-order kinetics of absorption and elimination best described paromomycin in plasma. Bioavailability (relative standard error) was 1.17 (5.18%) times higher in Kenyan and Sudanese patients, and 2.46 (24.5%) times higher in Ethiopian patients, compared with Indian patients. Ethiopian patients had an approximately fourfold slower absorption rate constant of 0.446 h–1 (18.2%). Area under the plasma concentration-time curve for 24 h at steady-state (AUCτ,SS) for 15 mg/kg/day (median [interquartile range]) was higher in Kenya and Sudan (172.7 µg·h/mL [145.9–214.3]) and Ethiopia (230.1 µg·h/mL [146.3–591.2]) compared with India (97.26 µg·h/mL [80.83–123.4]).ConclusionThe developed model provides detailed insight into the pharmacokinetic differences among Eastern African countries and India, however the resulting differences in paromomycin exposure do not seem to explain the geographical differences in paromomycin efficacy in the treatment of VL patients.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40262-021-01036-8.

A Novel Antigen, Otubain Cysteine Peptidase of Leishmania donovani, for the Serodiagnosis of Visceral Leishmaniasis and for Monitoring Treatment Response.

Tests for visceral leishmaniasis (VL) are not uniformly effective for all endemic regions. In a serological assay, a novel antigen, otubain cysteine peptidase, compared with rK39, showed comparable sensitivity with Indian VL serum samples and prominently increased sensitivity with Brazilian samples, as well as improved monitoring of the treatment response.

TLR4 and TLR9 polymorphism: Probable role in susceptibility among the population of Bihar for Indian visceral leishmaniasis.

Genetic variations in the host TLRs genes play an important role in susceptibility and/or resistance to visceral leishmaniasis by altering the host-pathogen interaction. In this study, we investigated the association between polymorphisms of TLR4 (Asp299Gly, Thr399Ile) and TLR-9 (T-1237C), with susceptibility to visceral leishmaniasis. A bi-directional PCR amplification of specific alleles technique was used to characterize the distribution of TLR4 (Asp299Gly and Thr399Ile) and TLR9 (T-1237C) polymorphisms. A total of 60 samples were randomly selected from confirmed visceral leishmaniasis patients and 24 endemic healthy volunteers. The samples were genotyped and allele frequencies were determined. We observed that TLR4 Asp299Gly and Thr399Ile genotypes were more frequent in visceral leishmaniasis patients (10% and 15% respectively) compared to controls (4.2% and 8.3% respectively). However, the differences were not significant in TLR4 Asp299Gly and Thr399Ile alleles and genotypes. In the case of TLR9, we observed the frequency of T1237C genotype was higher in visceral leishmaniasis patients (43.3%) than in healthy controls (33.3%). Statistically significant differences were observed in TLR9 T1237C alleles and genotypes. We concluded that TLR9 T1237C, but not TLR4, gene polymorphisms can be regarded as contributors to visceral leishmaniasis susceptibility among the Indian population of Bihar state.

Insecticide susceptibility of Phlebotomus argentipes sandflies, vectors of visceral leishmaniasis in India.

Indoor residual spraying (IRS) with insecticides is the main vector control intervention for the elimination of visceral leishmaniasis in India. After a change in IRS policy in 2015 due to widespread resistance of Phlebotomus argentipes to DDT, IRS with DDT was replaced with alpha-cypermethrin IRS in 2016. The objective of the present study was to evaluate the susceptibility of P.argentipes to DDT and its alternatives, namely malathion and pirimiphos-methyl (organophosphates); alpha-cypermethrin, deltamethrin, lambda-cyhalothrin and permethrin (pyrethroids), and bendiocarb and propoxur (carbamates), in support of visceral leishmaniasis elimination in India. Phlebotomus argentipes sandflies were collected from the visceral-leishmaniasis endemic states of Bihar, Jharkhand and West Bengal. In the WHO tube tests, the phenotypic susceptibility of F1, 2-day old, non-blood fed females were determined against filter papers impregnated with DDT 4%, malathion 5%, pirimiphos-methyl 0.25%, alpha-cypermethrin 0.05%, deltamethrin 0.05%, lambda-cyhalothrin 0.05%, permethrin 0.75%, bendiocarb 0.1% and propoxur 0.1%, which were sourced from Universiti Sains Malaysia. The knockdown of sandflies after 1-h exposure and mortality at 24h after the 1-h exposure period were scored. Mean mortality of P.argentipes 24h after exposure in tube tests was 22.6% for DDT and ≥ 98% for other insecticide-impregnated papers tested. Phlebotomus argentipes continues to be highly resistant to DDT with no reversal of resistance after DDT's withdrawal from IRS. P.argentipes was fully susceptible to pyrethroid, organophosphate and carbamate insecticides tested. Regular monitoring is warranted for insecticide resistance management in sandfly vectors.

Modelling the impact of COVID-19-related programme interruptions on visceral leishmaniasis in India.

BackgroundIn March 2020, India declared a nationwide lockdown to control the spread of coronavirus disease 2019. As a result, control efforts against visceral leishmaniasis (VL) were interrupted.MethodsUsing an established age-structured deterministic VL transmission model, we predicted the impact of a 6- to 24-month programme interruption on the timeline towards achieving the VL elimination target as well as on the increase of VL cases. We also explored the potential impact of a mitigation strategy after the interruption.ResultsDelays towards the elimination target are estimated to range between 0 and 9 y. Highly endemic settings where control efforts have been ongoing for 5–8 y are most affected by an interruption, for which we identified a mitigation strategy to be most relevant. However, more importantly, all settings can expect an increase in the number of VL cases. This increase is substantial even for settings with a limited expected delay in achieving the elimination target.ConclusionsBesides implementing mitigation strategies, it is of great importance to try and keep the duration of the interruption as short as possible to prevent new individuals from becoming infected with VL and continue the efforts towards VL elimination as a public health problem in India.

Differential Regulation of miRNA Profiles of Human Cells Experimentally Infected by Leishmania donovani Isolated From Indian Visceral Leishmaniasis and Post-Kala-Azar Dermal Leishmaniasis.

MicroRNAs are small ribonucleic acid that act as an important regulator of gene expression at the molecular level. However, there is no comparative data on the regulation of microRNAs (miRNAs) in visceral leishmaniasis (VL) and post-kala-azar dermal leishmaniasis (PKDL). In this current study, we compared the expression miRNA profile in host cells (GTHP), with VL strain (GVL) and PKDL strain-infected host cell (GPKDL). Normalized read count comparison between different conditions revealed that the miRNAs are indeed differentially expressed. In GPKDL with respect to GVL and GTHP, a total of 798 and 879 miRNAs were identified, out of which 349 and 518 are known miRNAs, respectively. Comparative analysis of changes in miRNA expression suggested that the involvement of differentially expressed miRNAs in various biological processes like PI3K pathway activation, cell cycle regulation, immunomodulation, apoptosis inhibition, different cytokine production, T-cell phenotypic transitions calcium regulation, and so on. A pathway enrichment study using in silico predicted gene targets of differentially expressed miRNAs showed evidence of potentially universal immune signaling pathway effects. Whereas cytokine–cytokine receptor interaction, phagocytosis, and transforming growth factor beta (TGF-β) signaling pathways were more highly enriched using targets of miRNAs upregulated in GPKDL. These findings could contribute to a better understanding of PKDL pathogenesis. Furthermore, the identified miRNAs could also be used as biomarkers in diagnosis, prognosis, and therapeutics of PKDL infection control.

Role of IL-17 gene polymorphism in Indian kala-azar.

Visceral leishmaniasis or kala-azar is a fatal protozoan disease caused by an obligate intracellular parasite, Leishmania donovani. Susceptibility, establishment of infection and severity of this disease depend upon many factors, but it is the host immune system that plays decisive role in disease progression. Keeping this view into consideration, we investigated the probable relationship between polymorphisms rs2275913 and rs8193036 in IL-17 gene, and its association as a risk factor for kala-azar in an endemic population of Assam, India. A total of 209 subjects, 76 kala-azar cases (male: 46, female: 30, mean age ± SD: 34.60 ± 12.61) and 133 controls (male: 66, female: 67, mean age ± SD: 33.35 ± 14.48) were included in this study. We analysed the polymorphisms, rs2275913 and rs8193036 by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. The data were analysed using logistic regression analysis and SPSS software. The results revealed that the mutant rs8193036 TT genotype conferred 4.7-fold higher risk for kala-azar (p = 0.00991, OR = 4.72, 95% CI = 1.330-16.911). A significant difference was found between the allele frequencies of rs8193036 (p = 0.029, OR = 1.64, 95% CI = 1.04-2.57) when comparisons were done using the genetic models of association. When stratification analysis was done on the basis of active and past cases we found that during active infection rs2275913 A allele was significantly associated with increased risk of kala-azar (p = 0.016, OR = 3.95, 95% CI = 1.21-12.87). The findings revealed that IL-17 genetic variant, rs8193036 is an independent risk factor for kala-azar infection and may contribute in pathogenesis of the disease. Further, rs2275913 polymorphism of IL-17 gene is associated with kala-azar during active infection.

Effectiveness of Single-Dose Liposomal Amphotericin B in Visceral Leishmaniasis in Bihar.

Liposomal amphotericin B (LAmB) is recommended for treatment of Indian visceral leishmaniasis (VL), with a cure rate of more than 95% in the Indian subcontinent. A prospective observational study of 1,143 subjects was performed with a longer follow-up than prior studies (12 months) to evaluate the long-term effectiveness and safety of LAmB for the treatment of VL. Patients received a single dose of 10 mg/kg LAmB and were evaluated for initial cure at day 30 and final cure at 6 and 12 months to see the response to the therapy. Furthermore, predictors of relapse were also calculated. At day 30, the initial cure rate was 100%; however, at 6 months and 12 months, cure rates were 97.0% and 94.2% by per-protocol analysis and 96.9% and 93.9% by intension-to-treat analysis, respectively. Fever was the most common adverse event (AE). There were no deaths and serious AEs. Male gender, weight less than 30 kg, and spleen size more than 4 cm at the start of the treatment were significant risk factors of relapse. Liposomal amphotericin B was found to be very effective and safe in the treatment of VL. A longer follow-up period of 12 months is recommended to pick up late relapses.

A multicentric evaluation of dipstick test for serodiagnosis of visceral leishmaniasis in India, Nepal, Sri Lanka, Brazil, Ethiopia and Spain

Visceral leishmaniasis (VL) is one of the leading infectious diseases affecting developing countries. Colloidal gold-based diagnostic tests are rapid tools to detect blood/serum antibodies for VL diagnosis. Lack of uniformity in the performance of these tests in different endemic regions is a hurdle in early disease diagnosis. This study is designed to validate a serum-based dipstick test in eight centres of six countries, India, Nepal, Sri Lanka, Brazil, Ethiopia and Spain with archived and fresh sera from 1003 subjects. The dipstick detects antibodies against Leishmania donovani membrane antigens (LAg). The overall sensitivity and specificity of the test with 95% confidence intervals were found to be 97.10% and 93.44%, respectively. The test showed good sensitivity and specificity in the Indian subcontinent (>95%). In Brazil, Ethiopia, and Spain the sensitivity and specificity of the dipstick test (83.78–100% and 79.06–100%) were better as compared to the earlier reports of the performance of rK39 rapid test in these regions. Interestingly, less cross-reactivity was found with the cutaneous form of the disease in Spain, Brazil, and Sri Lanka demonstrating 91.58% specificity. This dipstick test can therefore be a useful tool for diagnosing VL from other symptomatically similar diseases and against cutaneous form of leishmaniasis.

Variations in macrophage migration inhibitory factor gene are not associated with visceral leishmaniasis in India

BackgroundThe host genetic factors play important role in determining the outcome of visceral leishmaniasis (VL). Macrophage migration inhibitory factor (MIF) is an important host cytokine, which is a key regulator of innate immune system. Genetic variants in MIF gene have been found to be associated with several inflammatory and infectious diseases. Role of MIF is well documented in leishmaniasis diseases, including Indian visceral leishmaniasis, where elevated level of serum MIF has been associated with VL phenotypes. However, there was no genetic study to correlate MIF variants in VL, therefore, we aimed to study the possible association of three reported MIF gene variants −794 CATT, −173G > C and non-coding RNA gene LOC284889 in Indian VL phenotype. MethodsStudy subjects comprised of 214 VL patients along with ethnically and demographically matched 220 controls from VL endemic regions of Bihar state in India. ResultsWe found no significant difference between cases and controls in allelic, genotypic and haplotype frequency of the markers analysed [-794 CATT repeats (χ2=0.86; p=0.35; OR=0.85; 95% CI=0.61–1.19); −173 G>C polymorphism (χ2=1.11; p=0.29; OR=0.83; 95% CI=0.59–1.16); and LOC284889 (χ2=0.78; p=0.37; OR=0.86; 95% CI=0.61–1.20)]. ConclusionSince we did not find any significant differences between case and control groups, we conclude that sequencing of complete MIF gene and extensive study on innate and adaptive immunity genes may help in identifying genetic variations that are associated with VL susceptibility/resistance among Indians.