Diagnosis of human brucellosis: Systematic review and meta-analysis.

BACKGROUND: Brucellosis, a widely spread zoonotic disease, poses significant diagnostic challenges due to its non-specific symptoms and underreporting. Timely and accurate diagnosis is crucial for effective patient management and public health control. However, a comprehensive comparative review of available diagnostic tests is lacking. METHODOLOGY/PRINCIPAL FINDINGS: This systematic review addressed the following question: 'What is the accuracy of the available tests to confirm human brucellosis?' Two independent reviewers examined articles published up to January 2023. The review included original studies reporting symptomatic patients with brucellosis suspicion, through any index test, with sensitivity and/or specificity as outcomes. As exclusion criteria were considered: sample size smaller than 10 patients, studies focusing on complicated brucellosis, and those lacking essential information about index or comparator tests. Sensitivity and specificity were assessed, with consideration for the index test, and 'culture' and 'culture and standard tube agglutination test (SAT)' were used as reference standards. Bias assessment and certainty of evidence were carried out using the QUADAS-2 and GRADE tools, respectively. A total of 38 studies reporting diagnostic test performance for human brucellosis were included. However, the evidence available is limited, and significant variability was observed among studies. Regarding the reference test, culture and/or SAT are deemed more appropriate than culture alone. Rose Bengal, IgG/IgM ELISA, and PCR exhibited equally high performances, indicating superior overall diagnostic accuracy, with very low certainty of the evidence. CONCLUSIONS/SIGNIFICANCE: This systematic review underscores the potential of the Rose Bengal test, IgG/IgM ELISA, and PCR as promising diagnostic tools for brucellosis. However, the successful implementation and recommendations for their use should consider the local context and available resources. The findings highlight the pressing need for standardization, improved reporting, and ongoing advancements in test development to enhance the accuracy and accessibility of brucellosis diagnosis.

Quality of life of patients with cutaneous leishmaniasis: A comparative analysis of the EQ-5D-3L and CLIQ questionnaires.

PURPOSE: To evaluate the performance of the Cutaneous Leishmaniasis Impact Questionnaire (CLIQ) using the EuroQol-5 Dimension (EQ-5D-3L) as a reference standard (criterion validation); to evaluate the responsiveness of the instruments and estimate a cut-off point for the CLIQ to be able to discriminate between high and low impacts of cutaneous leishmaniasis on patients. METHODS: Between 2020 and 2022, a longitudinal validation study was conducted at a reference centre for leishmaniasis in Brazil. The EQ-5D-3L and CLIQ questionnaires were administered before, during and after treatment for cutaneous leishmaniasis. The correlation between the instruments was assessed using Spearman's correlation coefficient, responsiveness was assessed using the Wilcoxon test, and CLIQ cut-off points were proposed based on results of the EQ-5Q-3L, dichotomized between patients reporting no problems' and 'some or extreme problems'. RESULTS: There were satisfactory correlation coefficients between the two instruments before (-0.596) and during treatment (-0.551) and a low correlation between the instruments after the end of treatment (-0.389). In general, the responsiveness of the instruments was satisfactory. The CLIC scores that maximized sensitivity and specificity for recognizing impaired health status before and during treatment were 7 points and 17 points, respectively. However, at the end of treatment, based on the results for the EQ-5D-3L, the CLIC was not able to discriminate between individuals with high and low impacts of the disease. CONCLUSION: The CLIQ corresponds well with the EQ-5D-3L when applied before and during treatment but does not seem to be appropriate for follow-up evaluations after the end of treatment.

Cost-effectiveness of serological tests for human visceral leishmaniasis in the Brazilian scenario.

Human visceral leishmaniasis (VL) is a severe and potentially fatal parasitic disease if not correctly diagnosed and treated. Brazil is one of the three countries most endemic for VL and, like most countries affected by this disease, has a large budget constraint for the incorporation of new health technologies. Although different diagnostic tests for VL are currently available in the country, economic studies evaluating diagnostic kits are scarce. The objective of this study was to conduct a cost-effectiveness analysis of the nine available diagnostic tests for human VL in HIV-infected and uninfected patients in Brazil. The perspective of analysis was the Brazilian public health system, and the outcome of interest was "cases diagnosed correctly". The costs of the tests were estimated using the microcosting technique, and comparisons were performed with decision trees. Sensitivity analyses were explored applying variations in cost and effectiveness values. For VL diagnosis among HIV-uninfected patients, using blood samples for the rapid tests (RDTs), the noncommercial direct agglutination test (DAT-LPC) and IT-LEISH were cost-effective tests compared with the baseline OnSite test, but they presented different incremental cost-effectiveness ratios (ICER) of US$7.04 and US$ 205.40, respectively. Among HIV-infected patients, DAT-LPC was the most cost-effective diagnostic test. Comparisons among the tests with the same methodology, based on the low ICER values, revealed that IT-LEISH was the most cost-effective test among the RDTs and the Ridascreen Leishmania Ab among the ELISA tests. These results confirm that cost-effectiveness analyses can provide useful information to support the incorporation of new health technologies within a known scenario and willingness to pay threshold. It was observed that tests based on the same methodologies presented different cost-effectiveness ratios for the same group of patients and that different tests should be recommended for different patient groups. DAT-LPC was an important cost-effective strategy for all patients, requiring minimum laboratorial infrastructure, and IT-LEISH was the cost-effective test for VL screening in HIV-uninfected patients. IT-LEISH and DAT-LPC have complementary profiles and should both be provided by the Brazilian health system.

Intralesional infiltration versus parenteral use of meglumine antimoniate for treatment of cutaneous leishmaniasis: A cost-effectiveness analysis.

Cutaneous leishmaniasis (LC) is a complex and variable disease in terms of epidemiology, aetiology, pathology and clinical characteristics. The mainstay of treatment is still pentavalent antimony (Sbv) compounds administered systemically, despite their recognized toxicity. The advantages of antimony intralesional (IL) infiltration are the use of lower doses of Sbv and, therefore, less toxic effects. The objective of this study was to estimate the cost-effectiveness ratio of intralesional meglumine antimoniate therapy (IL-MA) compared with endovenous meglumine antimoniate therapy (EV-MA) for the treatment of CL in the context of the Brazilian National Health System (SUS). An analytical decision model (decision tree) was developed using TreeAge Pro 2018 software. Data from the open-label, uncontrolled phase II clinical trial evaluating IL-MA were used as a reference for posology, efficacy, and adverse event rates (AE). The same premises for the intravenous approach (EV-MA) were extracted from systematic literature reviews. Macro and micro calculations of spending were included in the analysis. The IL-MA and EV-MA strategies had a total cost per patient cured of US$330.81 and US$494.16, respectively. The intralesional approach was dominant, meaning it was more economic and effective than was endovenous therapy. The incremental cost-effectiveness ratio showed that IL-MA could result in savings of US$864.37 for each additional patient cured, confirming that the IL-MA strategy is cost effective in the context of the Brazilian public health scenario.

Performance of serological tests available in Brazil for the diagnosis of human visceral leishmaniasis.

BACKGROUND: Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is potentially fatal if not diagnosed and treated. Accurate and timely diagnosis is considered one of the pillars needed for the reduction in disease-related lethality. Brazil is currently one of the three eco-epidemiological hotspots for this disease. Several serological tests are commercially available in this country for VL diagnosis, although information on the performance of these tests is fragmented and insufficient. The aim of this study was to directly compare the performance of six commercial kits: three enzyme-linked immunosorbent assays (ELISAs), two immunofluorescence antibody tests (IFATs), one immunochromatographic test (ICT), besides one ICT, currently not commercially available in Brazil and one in-house direct agglutination test (DAT-LPC), not yet marketed. METHODOLOGY/PRINCIPAL FINDINGS: A panel of 236 stored samples from patients with clinically suspected VL, including 77 HIV-infected patients, was tested. IT-LEISH and DAT-LPC showed the highest accuracy rate among the non-HIV-infected patients, 96.2% [CI95%: 92.8-99.7%] and 95.6% [CI95%: 91.9-99.3%], respectively. For the ELISA tests evaluated, the maximum accuracy was 91.2%, and in the inter HIV-status group analysis, no significant differences were observed. For both IFATs evaluated, the maximum accuracy was 84.3%, and a lower accuracy rate was observed among the HIV-infected patients (p = 0.039) than among the non-HIV-infected patients. The DAT-LPC was the most accurate test in the HIV-infected patients (p≤0.115). In general, no significant difference in accuracy was observed among the VL-suspected patients stratified by age. CONCLUSIONS/SIGNIFICANCE: In summary, the differences in the performance of the tests available for VL in Brazil confirm the need for local studies before defining the diagnostic strategy.

Immune Activation and Bacterial Translocation: A Link between Impaired Immune Recovery and Frequent Visceral Leishmaniasis Relapses in HIV-Infected Patients.

The maintenance of chronic immune activation due to leishmaniasis or even due to microbial translocation is associated with immunosenescence and may contribute to frequent relapses. Our aim was to investigate whether patients with HIV-associated visceral leishmaniasis (VL/HIV) who experience a single episode of VL have different immunological behaviors in comparison to those who experience frequent relapses. VL/HIV patients were allocated to non-relapsing (NR, n = 6) and relapsing (R, n = 11) groups and were followed from the active phase of VL up to 12 months post-treatment (mpt). The patients were receiving highly active antiretroviral therapy (HAART) and secondary prophylaxis after VL therapy. During active VL, the two groups were similar in all immunological parameters, including the parasite load. At 6 and 12 mpt, the NR group showed a significant gain of CD4+ T cells, a reduction of lymphocyte activation, and lower soluble CD14 and anti-Leishmania IgG3 levels compared to the R group. The viral load remained low, without correlation with the activation. The two groups showed elevated but similar percentages of senescent T cells. These findings suggest a decreased ability of the R group to downmodulate immune activation compared to the NR group. Such functional impairment of the effector response may be a useful indicator for predicting clinical prognosis and recommending starting or stopping secondary prophylaxis.

Cost-effectiveness analysis of diagnostic tests for human visceral leishmaniasis in Brazil.

BACKGROUND: The objective of study was to estimate the incremental cost-effectiveness ratio (ICER) of diagnostic options for visceral leishmaniasis (VL) in Brazil. METHODS: Six diagnostic tests were considered: IT LEISH, Kalazar Detect, DAT-LPC (DAT made in the Laboratório de Pesquisas Clínicas), IFAT, PCR and direct examination of bone marrow aspirate performed in either an ambulatory or a hospital setting. A database was built using the cost and effectiveness. The perspective of this study was the Brazilian public healthcare system and the results were expressed in costs per correctly diagnosed cases. RESULTS: In a favorable hypothetical scenario, DAT-LPC presented the lowest cost (US$4.92) and highest effectiveness (99%). Paired analyses showed that IT LEISH was dominant compared to IFAT, microscopy and Kalazar Detect and that Kalazar Detect was dominant over IFAT and microscopy. PCR was dominant over the bone marrow aspirate in the hospital and showed an ICER of 57.76 compared with aspirate in an ambulatory setting. CONCLUSIONS: These results highlight the need for the revision of algorithm for VL diagnostic in Brazil. Replacements of IFAT with DAT-LPC, Kalazar Detect with IT LEISH and bone marrow aspirate performed in a hospital setting with PCR are cost-effective public health measures.

Use of the Kala-Azar Detect® and IT-LEISH® rapid tests for the diagnosis of visceral leishmaniasis in Brazil.

The performances of two rapid tests and a standard serological test for the diagnosis of visceral leishmaniasis (VL) were compared using sera from 193 patients with VL and 85 controls. The Kala-Azar Detect(®), IT-LEISH(®) and IFI-LH(®) assays showed sensitivities of 88.1%, 93.3% and 88.6%, respectively, and specificities of 90.6%, 96.5% and 80%, respectively. The sensitivity values were similar for both rapid tests, but the specificity and positive predictive values of IT-LEISH(®) were higher than the corresponding values for IFI-LH(®). Both rapid tests showed satisfactory performances and can be used in primary health care settings; however, IT-LEISH(®) permits the use of whole blood, making this assay more suitable for bedside diagnosis.

Use of the Kala-Azar Detect® and IT-LEISH® rapid tests for the diagnosis of visceral leishmaniasis in Brazil

The performances of two rapid tests and a standard serological test for the diagnosis of visceral leishmaniasis (VL) were compared using sera from 193 patients with VL and 85 controls. The Kala-Azar Detect®, IT-LEISH® and IFI-LH® assays showed sensitivities of 88.1%, 93.3% and 88.6%, respectively, and specificities of 90.6%, 96.5% and 80%, respectively. The sensitivity values were similar for both rapid tests, but the specificity and positive predictive values of IT-LEISH® were higher than the corresponding values for IFI-LH®. Both rapid tests showed satisfactory performances and can be used in primary health care settings; however, IT-LEISH® permits the use of whole blood, making this assay more suitable for bedside diagnosis.

Latent class analysis of diagnostic tests for visceral leishmaniasis in Brazil.

OBJECTIVE: To estimate the sensitivities and specificities of different diagnostic tests for visceral leishmaniasis (VL) using latent class analysis (LCA). METHODS: This study was performed using data from a prospective study conducted in four Brazilian states from May 2004 to May 2007. Five diagnostic tests for VL were evaluated in 285 VL cases and 119 non-cases: microscopy, indirect fluorescence antibody test (IFAT), enzyme-linked immunosorbent assay using recombinant K39 antigen (rK39-ELISA), direct agglutination test (DAT) and the rK39 rapid test. RESULTS: Microscopy showed sensitivity of 77.0% (CI: 71.5-81.5) and specificity of 99.0% (CI: 94.0-99.7). The IFAT and the DAT showed similar sensitivities, 88.3% (CI: 84.0-92.0) and 88.5% (CI: 84.1-92.0), respectively, but the DAT had a higher specificity (95.4%, CI: 89.2-98.1) than did the IFAT (83.0%, CI: 75.0-88.2). The rK39-ELISA and the rK39 rapid test showed sensitivities of 99.0% (CI: 96.3-99.6) and 94.0% (CI: 90.1-96.3), and specificities of 82.5% (CI: 75.0-88.3) and 100% (CI: 97.0-100.0%), respectively. CONCLUSIONS: Considering the lack of an adequate reference standard, LCA proved to be a useful tool in validating diagnostic methods for VL. The DAT and the rK39 rapid test showed better performance. Thus, clinically suspected cases of VL in a Brazilian endemic area could be treated based on the positivity of one of these tests.

Predictive models for the diagnostic of human visceral leishmaniasis in Brazil.

BACKGROUND AND OBJECTIVES: In Brazil, as in many other affected countries, a large proportion of visceral leishmaniasis (VL) occurs in remote locations and treatment is often performed on basis of clinical suspicion. This study aimed at developing predictive models to help with the clinical management of VL in patients with suggestive clinical of disease. METHODS: Cases of VL (n = 213) had the diagnosis confirmed by parasitological method, non-cases (n = 119) presented suggestive clinical presentation of VL but a negative parasitological diagnosis and a firm diagnosis of another disease. The original data set was divided into two samples for generation and validation of the prediction models. Prediction models based on clinical signs and symptoms, results of laboratory exams and results of five different serological tests, were developed by means of logistic regression and classification and regression trees (CART). From these models, clinical-laboratory and diagnostic prediction scores were generated. The area under the receiver operator characteristic curve, sensitivity, specificity, and positive predictive value were used to evaluate the models' performance. RESULTS: Based on the variables splenomegaly, presence of cough and leukopenia and on the results of five serological tests it was possible to generate six predictive models using logistic regression, showing sensitivity ranging from 90.1 to 99.0% and specificity ranging from 53.0 to 97.2%. Based on the variables splenomegaly, leukopenia, cough, age and weight loss and on the results of five serological tests six predictive models were generated using CART with sensitivity ranging from 90.1 to 97.2% and specificity ranging from 68.4 to 97.4%. The models composed of clinical-laboratory variables and the rk39 rapid test showed the best performance. CONCLUSION: The predictive models showed to be a potential useful tool to assist healthcare systems and control programs in their strategical choices, contributing to more efficient and more rational allocation of healthcare resources.

Avaliação de diferentes abordagens para o diagnóstico da leishmaniose visceral humana

A leishmaniose visceral (LV) é uma doença parasitária grave que afeta anualmente 500.000pessoas em 65 países. No Brasil, mais de 15.000 casos de LV foram registrados entre os anosde 2007 e 2010, com 880 mortes. Esta elevada taxa de letalidade está, em parte, relacionada àineficiência dos serviços de saúde em diagnosticar e tratar precocemente os pacientes. Odiagnóstico da LV exige suspeição clínica e confirmação laboratorial eficientes. Assim, umareestruturação do algoritmo e do arsenal de métodos diagnósticos disponíveis nos serviços desaúde pode ajudar a melhorar este cenário, aumentando o acesso e a disponibilização de testesnos municípios. O objetivo deste estudo foi avaliar o desempenho de diferentes abordagenspara o diagnóstico da LV humana no Brasil, através da avaliação do desempenho do teste deaglutinação direta (DAT) e do teste rápido IT-LEISH; do desenvolvimento e validação demodelos preditivos clínico-laboratoriais e da avaliação de métodos diagnósticos pela análisede classes latentes (ACL)

O grupo de estudo compreendeu 404 pacientes, residentes no Piauí,Maranhão, Bahia e Minas Gerais, com suspeita de LV, submetidos ao exame do aspirado demedula óssea e à coleta de sangue para a realização dos testes sorológicos. Para a avaliação dodesempenho do DAT e do IT-LEISH® foi utilizada a análise de validação clássica (AVC)utilizando como padrão de referência o exame do aspirado de medula óssea. Para odesenvolvimento e a validação dos modelos preditivos foram utilizados dadosepidemiológicos, clínicos e laboratoriais dos pacientes avaliados. Os modelos preditivosutilizando regressão logística múltipla (RLM) foram desenvolvidos no software STATA® eaqueles utilizando árvore de classificação e regressão (CART) foram desenvolvidos nosoftware SPLUS®. Para a avaliação da aplicabilidade da ACL foram utilizados dados doestudo de validação do IT-LEISH® e do DAT e a análise foi realizada no software R. O DATe o IT-LEISH apresentaram, pela AVC, sensibilidades e especificidades de 90 e 93%; 93 e97%, respectivamente. O modelo preditivo composto pelas variáveis clínicas e laboratoriaisassociadas ao teste rápido foi o que apresentou melhor desempenho, tanto pela RLM, quantopor CART (sensibilidade de 90,1% e especificidade de 97,2-97,4%). A ACL mostrou-se útilna validação de testes diagnósticos para LV no Brasil, estimando para o DAT e o IT-LEISHsensibilidades de 88,5 e 94% e especificidades de 95,4 e 100%, respectivamente. Diante doelevado desempenho apresentado, o DAT e o teste rápido IT-LEISH estão indicados para odiagnóstico da LV humana no Brasil. Os modelos preditivos desenvolvidos são úteis epoderiam ser utilizados em centros de referência para a doença no país. A ACL está indicadapara validação de testes diagnósticos no país e quando possível deve ser utilizada

Avaliação de diferentes abordagens para o diagnóstico da leishmaniose visceral humana / Evaluation of different approaches to the diagnosis of human visceral leishmaniasis

A leishmaniose visceral (LV) é uma doença parasitária grave que afeta anualmente 500.000pessoas em 65 países. No Brasil, mais de 15.000 casos de LV foram registrados entre os anosde 2007 e 2010, com 880 mortes. Esta elevada taxa de letalidade está, em parte, relacionada àineficiência dos serviços de saúde em diagnosticar e tratar precocemente os pacientes. Odiagnóstico da LV exige suspeição clínica e confirmação laboratorial eficientes. Assim, umareestruturação do algoritmo e do arsenal de métodos diagnósticos disponíveis nos serviços desaúde pode ajudar a melhorar este cenário, aumentando o acesso e a disponibilização de testesnos municípios. O objetivo deste estudo foi avaliar o desempenho de diferentes abordagenspara o diagnóstico da LV humana no Brasil, através da avaliação do desempenho do teste deaglutinação direta (DAT) e do teste rápido IT-LEISH; do desenvolvimento e validação demodelos preditivos clínico-laboratoriais e da avaliação de métodos diagnósticos pela análisede classes latentes (ACL). O grupo de estudo compreendeu 404 pacientes, residentes no Piauí,Maranhão, Bahia e Minas Gerais, com suspeita de LV, submetidos ao exame do aspirado demedula óssea e à coleta de sangue para a realização dos testes sorológicos. Para a avaliação dodesempenho do DAT e do IT-LEISH® foi utilizada a análise de validação clássica (AVC)utilizando como padrão de referência o exame do aspirado de medula óssea. Para odesenvolvimento e a validação dos modelos preditivos foram utilizados dadosepidemiológicos, clínicos e laboratoriais dos pacientes avaliados. Os modelos preditivosutilizando regressão logística múltipla (RLM) foram desenvolvidos no software STATA® eaqueles utilizando árvore de classificação e regressão (CART) foram desenvolvidos nosoftware SPLUS®. Para a avaliação da aplicabilidade da ACL foram utilizados dados doestudo de validação do IT-LEISH® e do DAT e a análise foi realizada no software R. O DATe o IT-LEISH apresentaram, pela AVC, sensibilidades e especificidades de 90 e 93%; 93 e97%, respectivamente. O modelo preditivo composto pelas variáveis clínicas e laboratoriaisassociadas ao teste rápido foi o que apresentou melhor desempenho, tanto pela RLM, quantopor CART (sensibilidade de 90,1% e especificidade de 97,2-97,4%). A ACL mostrou-se útilna validação de testes diagnósticos para LV no Brasil, estimando para o DAT e o IT-LEISHsensibilidades de 88,5 e 94% e especificidades de 95,4 e 100%, respectivamente. Diante doelevado desempenho apresentado, o DAT e o teste rápido IT-LEISH estão indicados para odiagnóstico da LV humana no Brasil. Os modelos preditivos desenvolvidos são úteis epoderiam ser utilizados em centros de referência para a doença no país. A ACL está indicadapara validação de testes diagnósticos no país e quando possível deve ser utilizada.