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Leishmaniasis diagnosis: an update on the use of parasitological, immunological and molecular methods.

ABSTRACT: Diagnosis of leishmaniasis has always been a major challenge as its clinical features resemble some other commonly occurring diseases such as tuberculosis, typhoid, and malaria. Reliable laboratory methods become important for differential diagnosis. Demonstration of the parasites in stained preparations of bone marrow and splenic aspirates being risky and invasive is still the gold standard for diagnosis. Serological tests utilizing rapid immunochromatographic formats or rK39 in enzyme linked immune sorbent assay, immunoblotting, direct agglutination test have complications related to high proportions of positive asymptomatic individuals and the inability to diagnose a relapse. Among the molecular techniques, polymerase chain reaction is the most commonly used technique that is successfully implied for diagnosis. This review provides updated information on the recent developments in the field of diagnosis in leishmaniasis, various methods utilized with their advantages and limitations.

SUBMITTER: Thakur S

PROVIDER: S-EPMC7223249 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

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Leishmaniasis diagnosis: an update on the use of parasitological, immunological and molecular methods.

Thakur Shivani S Joshi Jyoti J Kaur Sukhbir S

Journal of parasitic diseases : official organ of the Indian Society for Parasitology 20200316 2

Diagnosis of leishmaniasis has always been a major challenge as its clinical features resemble some other commonly occurring diseases such as tuberculosis, typhoid, and malaria. Reliable laboratory methods become important for differential diagnosis. Demonstration of the parasites in stained preparations of bone marrow and splenic aspirates being risky and invasive is still the gold standard for diagnosis. Serological tests utilizing rapid immunochromatographic formats or rK39 in enzyme linked i ...[more]

PMID: 32419743

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Project description:To estimate the cost-effectiveness of available diagnosis alternatives for Mucosal Leishmaniasis (ML) in Colombian suspected patients. A simulation model of the disease's natural history was built with a decision tree and Markov models. The model´s parameters were identified by systematic review and validated by expert consensus. A bottom-up cost analysis to estimate the costs of diagnostic strategies and treatment per case was performed by reviewing 48 clinical records of patients diagnosed with ML. The diagnostic strategies compared were as follows: 1) no diagnosis; 2) parasite culture, biopsy, indirect immunofluorescence assay (IFA), and Montenegro skin test (MST) combined ; 3) parasite culture, biopsy, and IFA combined; 4) PCR-miniexon; and 5) PCR-kDNA. Three scenarios were modeled in patients with ML clinical suspicion, according to ML prevalence scenarios: high, medium and low. Adjusted sensitivity and specificity parameters of a combination of diagnostic tests were estimated with a discrete event simulation (DES) model. For each alternative, the costs and health outcomes were estimated. The time horizon was life expectancy, considering the average age at diagnosis of 31 years. Incremental cost-effectiveness ratios (ICERs) were calculated per Disability Life Year (DALY) avoided, and deterministic and probabilistic sensitivity analyses were performed. A threshold of willingness to pay (WTP) of three-time gross domestic product per capita (GDPpc) (US$ 15,795) and a discount rate of 3% was considered. The analysis perspective was the third payer (Health System). All costs were reported in American dollars as of 2015. PCR- kDNA was the cost-effective alternative in clinical suspicion levels: low, medium and high with ICERs of US$ 7,909.39, US$ 5,559.33 and US$ 4,458.92 per DALY avoided, respectively. ML diagnostic tests based on PCR are cost-effective strategies, regardless of the level of clinical suspicion. PCR-kDNA was the most cost-effective strategy in the competitive scenario with the parameters included in the present model.

Project description:In past years, many researchers have sought canine visceral leishmaniasis (CVL) prevention through the characterization of Leishmania antigens as vaccine candidates. Despite these efforts, there is still no efficient vaccine for CVL control.In the present study, we performed a pre-clinical vaccine trial using BALB/c mice to compare the effects of the multicomponent LBSap vaccine with those of Leish-Tec® and Leishmune®. Blood was collected to determine the frequency of peripheral blood cells and to evaluate hematologic and immunophenotypic parameters. Liver and spleen samples were collected for parasitological quantification, and spleen samples were used to access the cytokine profile.When measuring total IgG and IgG1 anti-Leishmania levels after the third vaccination and L. infantum challenge, it was evident that all vaccines were able to induce humoral immune response. Regarding the innate immune response, increased levels of NK CD3(-)CD49(+) cells were the hallmark of all vaccinated groups, whereas only the Leish-Tec® group displayed a high frequency of CD14(+) monocytes after L. infantum challenge. Moreover, CD3(+)CD4(+) T cells were the main circulating lymphocytes induced after L. infantum challenge with all evaluated vaccines. Importantly, after L. infantum challenge, splenocytes from the Leishmune® vaccine produced high levels of IL-2, whereas a prominent type 1 immune response was the hallmark of the LBSap vaccine, which presented high levels of IL-2, IL-6, TNF-?, and IFN-?. The efficacy analysis using real-time polymerase chain reaction demonstrated a reduction in the parasitism in the spleen (Leishmune®: 64 %; LBSap: 42 %; and Leish-Tec®: 36 %) and liver (Leishmune®: 71 %; LBSap: 62 %; and Leish-Tec®: 48 %).The dataset led to the conclusion that the LBSap vaccination was able to induce immune and efficacy profiles comparable with those of commercial vaccines, thus demonstrating its potential as a promising vaccine candidate for visceral leishmaniasis control.

Project description:IntroductionCurrently only limited data exist regarding the availability and clinical use of molecular and immunological tests for tuberculosis (TB) in the European setting.MethodsWeb-based survey of Paediatric-Tuberculosis-Network-European-Trialsgroup (ptbnet) and Tuberculosis-Network-European-Trialsgroup (TBnet) members conducted June to December 2013. Both networks comprise clinicians, microbiologists, epidemiologists and researchers predominately based in Europe.Results191 healthcare professionals from 31 European countries participated. Overall, 26.8% of respondents did not have access to the Xpert MTB/RIF assay; only 44.6% had access to the assay in-house. However, a substantial proportion had access to other commercial and/or non-commercial PCR-based assays for TB (68.8% and 31.8%, respectively). Only 6.4% did not have access to any PCR-based assays for TB. A large proportion of participants with access to the Xpert MTB/RIF assay had used it for the analysis of non-respiratory samples [pleural fluid: 36.5%, gastric aspirates: 34.7%, cerebrospinal fluid: 34.7%, stool samples: 4.3%, blood/serum: 2.6%, 'other samples' (which included biopsy/tissue samples, lymph node aspirates, joint aspirates and urine samples): 16.5%]. Regarding interferon-gamma release assays, a greater proportion of respondents had access to the QuantiFERON-TB Gold assay (84.7%) than to the T-SPOT.TB assay (52.2%).ConclusionsBoth immunological and molecular TB tests are widely available across Europe. The QuantiFERON-TB Gold assay is more widely used than the T-SPOT.TB assay, which may reflect the difficulties of integrating an ELISPOT assay into the routine laboratory setting. Although Xpert MTB/RIF assays are optimised and solely licensed for the analysis of sputum samples, in clinical practice they are commonly used for non-respiratory samples. Further research is needed to establish how current molecular TB tests impact on patient care and outcome in the routine clinical setting.

Project description:ObjectivesRecently, improvements have been made to diagnostics for gambiense sleeping sickness control but their performance remains poorly documented and may depend on specimen processing prior to examination. In a prospective study in the Democratic Republic of the Congo, we compared the diagnostic performance of several parasite detection techniques, immune trypanolysis and of m18S PCR on whole blood stored in a stabilisation buffer or dried on filter paper.MethodsIndividuals with CATT whole blood (WB) titer ?1?4 or with clinical signs indicative for sleeping sickness were examined for presence of trypanosomes in lymph node aspirate (LNA) and/or in blood. Blood was examined with Capillary Centrifugation Technique (CTC), mini-Anion Exchange Centrifugation Technique (mAECT) and mAECT on buffy coat (BC). PCR was performed on whole blood (i) stored in guanidine hydrochloride EDTA (GE) stabilisation buffer and (ii) dried on filter paper, and repeatability and reproducibility were assessed. Immune trypanolysis (TL) was performed on plasma.ResultsA total of 237 persons were included. Among 143 parasitologically confirmed cases, 85.3% had a CATT-WB titre of ?1/8, 39.2% were positive in LNA, 47.5% in CTC, 80.4% in mAECT-WB, 90.9% in mAECT-BC, 95.1% in TL and up to 89.5% in PCR on GE-stabilised blood. PCR on GE-stabilised blood showed highest repeatability (87.8%) and inter-laboratory reproducibility (86.9%). Of the 94 non-confirmed suspects, respectively 39.4% and 23.4% were TL or PCR positive. Suboptimal specificity of PCR and TL was also suggested by latent class analysis.ConclusionThe combination of LNA examination with mAECT-BC offered excellent diagnostic sensitivity. For PCR, storage of blood in stabilisation buffer is to be preferred over filter paper. TL as well as PCR are useful for remote diagnosis but are not more sensitive than mAECT-BC. For TL and PCR, the specificity, and thus usefulness for management of non-confirmed suspects remain to be determined.

Dataset Information

Leishmaniasis diagnosis: an update on the use of parasitological, immunological and molecular methods.

Publications

Leishmaniasis diagnosis: an update on the use of parasitological, immunological and molecular methods.

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