A rapid diagnostic test for human Visceral Leishmaniasis using novel Leishmania antigens in a Laser Direct-Write Lateral Flow Device.

ABSTRACT Visceral Leishmaniasis (VL) causes high morbidity and mortality in low-to-middle-income countries worldwide. In this study, we used Laser Direct-Write (LDW) technology to develop a new Lateral Flow Device (LFD) with double-channel geometry on a low-cost paper platform as a rapid and accurate serodiagnostic assay for human VL. This Duplex VL-LFD was based on a laser-patterned microfluidic device using two recombinant Leishmania proteins, ß-tubulin and LiHyp1, as novel diagnostic antigens. The VL-LFD assay was tested with blood/serum samples from patients diagnosed with VL, Tegumentary Leishmaniasis, Leishmaniasis of unknown identity, other parasitic diseases with similar clinical symptoms, i.e. Leprosy Disease and Chagas Disease, and blood from healthy donors, and compared in parallel with commercial rK39 IT-LEISH® Kit. Clinical diagnosis and real-time Polymerase Chain Reaction assay were used as reference standards. VL-LFD Sensitivity (S ± 95% Confidence Intervals (CI)) of 90.9 (78.9-100) and Specificity (Sp ± 95% CI) of 98.7 (96.1-100) outperformed the IT-LEISH® Kit [S = 77.3 (59.8-94.8), Sp = 94.7 (89.6-99.8)]. This is the first study reporting successful development of an LFD assay using the LDW technology and the VL-LFD warrants comparative testing in larger patient cohorts and in areas with endemic VL in order to improve diagnosis and disease management.

Host immune responses induced by specific Mycobacterium leprae antigens in an overnight whole-blood assay correlate with the diagnosis of paucibacillary leprosy patients in China.

BACKGROUND: Leprosy, caused by Mycobacterium leprae, affects over 200,000 people annually worldwide and remains endemic in the ethnically diverse, mountainous and underdeveloped southwestern provinces of China. Delayed diagnosis of leprosy persists in China, thus, additional knowledge to support early diagnosis, especially early diagnosis of paucibacillary (PB) patients, based on the host immune responses induced by specific M. leprae antigens is needed. The current study aimed to investigate leprosy patients and controls in Southwest China by comparing supernatants after stimulation with specific M. leprae antigens in an overnight whole-blood assay (WBA) to determine whether host markers induced by specific M. leprae antigens improve the diagnosis or discrimination of PB patients with leprosy. METHODOLOGY/PRINCIPAL FINDINGS: Leprosy patients [13 multibacillary (MB) patients and 7 PB patients] and nonleprosy controls [21 healthy household contacts (HHCs), 20 endemic controls (ECs) and 19 tuberculosis (TB) patients] were enrolled in this study. The supernatant levels of ten host markers stimulated by specific M. leprae antigens were evaluated by overnight WBA and multiplex Luminex assays. The diagnostic value in PB patients and ECs and the discriminatory value between PB patients and HHCs or TB patients were evaluated by receiver operator characteristics (ROC) analysis. ML2044-stimulated CXCL8/IL-8 achieved the highest sensitivity of 100%, with a specificity of 73.68%, for PB diagnosis. Compared to single markers, a 3-marker combination model that included ML2044-induced CXCL8/IL-8, CCL4/MIP-1 beta, and IL-6 improved the diagnostic specificity to 94.7% for PB patients. ML2044-stimulated IL-4 and CXCL8/IL-8 achieved the highest sensitivity (85.71% and 100%) and the highest specificity (95.24% and 84.21%) for discriminating PB patients from HHCs and TB patients, respectively. CONCLUSIONS: Our findings suggest that the host markers induced by specific M. leprae antigens in an overnight WBA increase diagnostic and discriminatory value in PB patients with leprosy, with a particularly strong association with interleukin 8.

Application of Mycobacterium Leprae-specific cellular and serological tests for the differential diagnosis of leprosy from confounding dermatoses.

Mycobacterium leprae-specific serological and cell-mediated-immunity/CMI test were evaluated for the differential diagnosis of multibacillary/MB, and paucibacillary/PB leprosy from other dermatoses. Whole-blood assay/WBA/IFNγ stimulated with LID-1 antigen and ELISA tests for IgG to LID-1 and IgM to PGL-I were performed. WBA/LID-1/IFNγ production was observed in 72% PB, 11% MB leprosy, 38% dermatoses, 40% healthy endemic controls/EC. The receiver operating curve/ROC for WBA/LID-1 in PB versus other dermatoses showed 72.5% sensitivity, 61.5% specificity and an area-under-the-curve/AUC=0.75; 74% positive predictive value/PPV, 59% negative predictive value/NPV. Anti PGL-I serology was positive in 67% MB, 8% PB leprosy, 6% of other dermatoses; its sensitivity for MB=66%, specificity=93%, AUC=0.89; PPV=91%, NPV=72%. Anti-LID-1 serology was positive in 87% MB, 7% PB leprosy, all other participants were seronegative; 87.5% sensitivity for MB, 100% specificity, AUC=0.97; PPV=100%, NPV=88%. In highly endemic areas anti-LID-1/PGL-I serology and WBA/LID-1-represent useful tools for the differential diagnosis of leprosy from other confounding dermatoses.

Diagnosis of tuberculosis based on the detection of a cocktail of mycobacterial antigen 85B, ESAT-6 and cord factor by immuno-PCR.

Attempts were made to enhance the sensitivity of immuno-PCR assay based on the detection of cocktail of mycobacterial antigen 85B (Rv1886c), ESAT-6 (Rv3875) and cord factor (trehalose 6,6'-dimycolate) in pulmonary and extrapulmonary TB patients. Detection of Ag85B was found to be superior to the detection of cocktail in TB patients.

Production of monoclonal antibodies for detection of Citrus leprosis virus C in enzyme-linked immuno-assays and immunocapture reverse transcription-polymerase chain reaction.

Citrus leprosis virus C (CiLV-C) causes damage in citrus production in the South and Central America. Since closely related types of citrus viruses have recently been described monoclonal antibodies (MAbs) are needed for accurate and sensitive diagnosis of CiLV-C. In this study, MAbs to the expressed coat protein of CiLV-C were produced for serological detection of CiLV-C in crude extracts of infected tissues in double antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISA), dot blot immunosorbent assays (DBIA) and immuonocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) procedures. Monoclonal antibodies were developed in mice to the purified expressed coat protein of CiLV-C. The published standard protocols of DAS-ELISA, DBIA and IC-RT-PCR were followed for the detection of coat protein p29 of CiLV-C in the crude extracts of CiLV-C infected tissues. Two monoclonal antibodies, designated G10 and C11, were identified from four potential candidates for the specific and sensitive detection of coat protein p29 of CiLV-C in the crude citrus extracts of CiLV-C infected tissues in DAS-ELISA, whereas G10 was also selected based on performance for use in the DBIA and IC-RT-PCR diagnostic assays. Sensitivity analysis comparing the three methods for detection of coat protein p29 of CiLV-C determined that IC-RT-PCR was more sensitive than DAS-ELISA and DBIA. The creation of MAbs to CiLV-C allows for the sensitive and accurate detection of the virus from CiLV-C infected citrus leaf tissues. Successful detection of the virus in three diagnostic assays formats provides flexibility to diagnosticians who can use either ELISA or DBIA for screening large numbers of samples, and IC-RT-PCR for rapid, sensitive confirmation testing.

Comparison of two rapid tests for anti-phenolic glycolipid-I serology in Brazil and Nepal

The diagnosis of leprosy continues to be based on clinical symptoms and early diagnosis and treatment are critical to preventing disability and transmission. Sensitive and specific laboratory tests are not available for diagnosing leprosy. Despite the limited applicability of anti-phenolic glycolipid-I (PGL-I) serology for diagnosis, it has been suggested as an additional tool to classify leprosy patients (LPs) for treatment purposes. Two formats of rapid tests to detect anti-PGL-I antibodies [ML immunochromatography assay (ICA) and ML Flow] were compared in different groups, multibacillary patients, paucibacillary patients, household contacts and healthy controls in Brazil and Nepal. High ML Flow intra-test concordance was observed and low to moderate agreement between the results of ML ICA and ML Flow tests on the serum of LPs was observed. LPs were "seroclassified" according to the results of these tests and the seroclassification was compared to other currently used classification systems: the World Health Organization operational classification, the bacilloscopic index and the Ridley-Jopling classification. When analysing the usefulness of these tests in the operational classification of PB and MB leprosy for treatment and follow-up purposes, the ML Flow test was the best point-of-care test for subjects in Nepal and despite the need for sample dilution, the ML ICA test yielded better performance among Brazilian subjects. Our results identified possible ways to improve the performance of both tests.

Comparison of two rapid tests for anti-phenolic glycolipid-I serology in Brazil and Nepal.

The diagnosis of leprosy continues to be based on clinical symptoms and early diagnosis and treatment are critical to preventing disability and transmission. Sensitive and specific laboratory tests are not available for diagnosing leprosy. Despite the limited applicability of anti-phenolic glycolipid-I (PGL-I) serology for diagnosis, it has been suggested as an additional tool to classify leprosy patients (LPs) for treatment purposes. Two formats of rapid tests to detect anti-PGL-I antibodies [ML immunochromatography assay (ICA) and ML Flow] were compared in different groups, multibacillary patients, paucibacillary patients, household contacts and healthy controls in Brazil and Nepal. High ML Flow intra-test concordance was observed and low to moderate agreement between the results of ML ICA and ML Flow tests on the serum of LPs was observed. LPs were "seroclassified" according to the results of these tests and the seroclassification was compared to other currently used classification systems: the World Health Organization operational classification, the bacilloscopic index and the Ridley-Jopling classification. When analysing the usefulness of these tests in the operational classification of PB and MB leprosy for treatment and follow-up purposes, the ML Flow test was the best point-of-care test for subjects in Nepal and despite the need for sample dilution, the ML ICA test yielded better performance among Brazilian subjects. Our results identified possible ways to improve the performance of both tests.

Immunochromatographic IgG/IgM test for rapid diagnosis of active tuberculosis.

For rapid diagnosis and discrimination between active tuberculosis (TB) and other pulmonary diseases, we evaluated the clinical usefulness of detection of serum immunoglobulin IgG and IgM antibodies raised against mycobacterial 38-kDa, 16-kDa, and 6-kDa antigens by a commercial rapid immunochromatographic IgG/IgM test (Standard Diagnostics, South Korea) in 246 serum samples from three groups of patients: (i) 171 patients with active TB (128 with pulmonary TB [pTB] and 43 with extrapulmonary TB [epTB]), (ii) 73 patients with pulmonary non-TB diseases, and (iii) two leprosy patients. The sensitivities of IgG and IgM in patients with active TB (pTB and epTB) were 68.4% and 2.3%, respectively. IgG had the best performance characteristics, with sensitivities of 78.1% and 39.5% in sera from patients with active pTB and epTB, respectively, and a specificity of 100%. The sensitivities of IgM were poor and were similar for pTB and epTB (2.3%). In contrast, specificity was very elevated (100%). The combination of IgG with IgM did not improve its sensitivity. IgG-mediated responses against the mycobacterial 38-kDa, 16-kDa, and 6-kDa antigens might constitute a clinically useful tool for presumptive diagnosis and discrimination of active pTB from other pulmonary diseases. Moreover, based on its simplicity and rapidity of application, it could be a screening tool for active pTB in poorly equipped laboratories.

Use of the ML-Flow test as a tool in classifying and treating leprosy.

BACKGROUND: The treatment of leprosy is defined by the classification of patients as paucibacillary (PB) or multibacillary (MB). The WHO (World Health Organization) classifies patients according to the number of lesions, but Ridley-Jopling (R & J) also uses complementary exams, which are difficult to use outside reference services. In 2003, a test called ML-Flow, an alternative to Elisa serology, was developed to help classify patients as PB or MB and decide about their treatment. OBJECTIVES: To assess the agreement between the ML-Flow test and slit skin smears, already largely used for MB detection, and to observe the efficacy of the ML-Flow test in the field. MATERIAL AND METHODS: A retrospective study evaluating the medical records of 55 patients who had not undergone previous treatment, diagnosed as PB or MB according to R & J and subjected to slit skin smears and the ML- Flow test. RESULTS: In MB patients, slit skin smears were positive in 80% of the cases, the ML-flow was positive in 82.5%. Among PB patients, the ML-Flow was positive in 37.5% and slit skin smears were negative in 100% of the cases. The agreement between skin smear and ML-Flow results was 87.5%, with a kappa value of 0.59, p <0.001. CONCLUSION: No laboratory test is 100% sensitive and specific for the correct classification of all forms of leprosy. The ML-Flow test is faster, easier to use, and less invasive than slit skin smears and therefore may be useful when making therapeutic decisions in areas of difficult access to reference services.

Uso do teste ML-Flow como auxiliar na classificação e tratamento da hanseníase / Use of the ML-Flow test as a tool in classifying and treating leprosy

FUNDAMENTOS: O tratamento da hanseníase é definido pela classificação de pacientes em paucibacilares (PB) e multibacilares (MB). A OMS (Organização Mundial de Saúde) classifica os doentes de acordo com o número de lesões, mas Ridley-Jopling (R&J) utiliza também exames complementares, porém é de difícil utilização fora dos serviços de referência. Em 2003 foi desenvolvido um teste denominado ML-Flow, uma alternativa à sorologia por ELISA para auxiliar na classificação de pacientes em PB e MB e auxiliar na decisão terapêutica. OBJETIVOS: Observar a concordância entre o teste de ML-Flow e baciloscopia de linfa, exame já consagrado para detecção de MB. Analisar a utilidade do teste de ML-Flow em campo. MATERIAL E MÉTODOS: Estudo retrospectivo avaliando prontuário de 55 pacientes virgens de tratamento, diagnosticados como PB ou MB por R&J. Submetidos à baciloscopia e ao teste de ML-Flow. RESULTADOS: Nos MB, a baciloscopia foi positiva em 80 por cento dos casos, o ML-flow foi positivo em 82,5 por cento. Entre os PB, o ML-Flow foi positivo em 37,5 por cento e a baciloscopia do esfregaço foi negativa em 100 por cento dos casos. A concordância entre os resultados da baciloscopia do esfregaço e ML-Flow foi de 87,5 por cento, kappa=0,59, p<0,001. CONCLUSÃO: Nenhum teste laboratorial é 100 por cento sensível e específico para a correta classificação de todas as formas de hanseníase. O ML-Flow é um teste rápido, de fácil manuseio em campo, menos invasivo que a baciloscopia podendo ser útil para auxiliar na decisão terapêutica em locais de difícil acesso a serviços de referência.

BACKGROUND: The treatment of leprosy is defined by the classification of patients as paucibacillary (PB) or multibacillary (MB). The WHO (World Health Organization) classifies patients according to the number of lesions, but Ridley-Jopling (R & J) also uses complementary exams, which are difficult to use outside reference services. In 2003, a test called ML-Flow, an alternative to Elisa serology, was developed to help classify patients as PB or MB and decide about their treatment. OBJECTIVES: To assess the agreement between the ML-Flow test and slit skin smears, already largely used for MB detection, and to observe the efficacy of the ML-Flow test in the field. MATERIAL AND METHODS: A retrospective study evaluating the medical records of 55 patients who had not undergone previous treatment, diagnosed as PB or MB according to R & J and subjected to slit skin smears and the ML- Flow test. RESULTS: In MB patients, slit skin smears were positive in 80 percent of the cases, the ML-flow was positive in 82.5 percent. Among PB patients, the ML-Flow was positive in 37.5 percent and slit skin smears were negative in 100 percent of the cases. The agreement between skin smear and ML-Flow results was 87.5 percent, with a kappa value of 0.59, p <0.001. CONCLUSION: No laboratory test is 100 percent sensitive and specific for the correct classification of all forms of leprosy. The ML-Flow test is faster, easier to use, and less invasive than slit skin smears and therefore may be useful when making therapeutic decisions in areas of difficult access to reference services.

Insight toward early diagnosis of leprosy through analysis of the developing antibody responses of Mycobacterium leprae-infected armadillos.

Leprosy is a debilitating chronic disease caused by infection with Mycobacterium leprae. A World Health Organization-directed control strategy based upon the identification and treatment of patients has resulted in a marked reduction in the number of registered worldwide leprosy cases over the last 20 years. Despite these efforts, the number of new leprosy cases detected each year now remains relatively stable, and M. leprae infection continues to pose a health problem. It is suggested that earlier diagnosis is required to strengthen control programs. In this study, we have examined the development of antigen-specific immunoglobulin responses within armadillos experimentally infected with M. leprae to identify those responses that develop most rapidly and robustly following infection. Antibody responses to the M. leprae-specific phenolic glycolipid I and several protein antigens previously demonstrated to have diagnostic potential were assessed. Our results identify several antigens that can provide early diagnosis of M. leprae infection but also indicate considerable variability in the development of antigen-specific antibodies. Our data suggest that a combination of antigens is likely required to provide accurate and early leprosy diagnosis.

Rational design and evaluation of a multiepitope chimeric fusion protein with the potential for leprosy diagnosis.

Despite the reduction in the number of leprosy cases registered worldwide as a result of the widespread use of multidrug therapy, the number of new cases detected each year remains stable in many countries. This indicates that Mycobacterium leprae, the causative agent of leprosy, is still being transmitted and that, without an earlier diagnosis, transmission will continue and infection will remain a health problem. The current means of diagnosis of leprosy is based on the appearance of clinical symptoms, which in many cases occur after significant and irreversible nerve damage has occurred. Our recent work identified several recombinant antigens that are specifically recognized by leprosy patients. The goal of the present study was to produce and validate the reactivity of a chimeric fusion protein that possesses the antibody binding properties of several of these proteins. The availability of such a chimeric fusion protein will simplify future test development and reduce production costs. We first identified the antibody binding regions within our top five antigen candidates by performing enzyme-linked immunosorbent assays with overlapping peptides representing the amino acid sequences of each protein. Having identified these regions, we generated a fusion construct of these components (protein advances diagnostic of leprosy [PADL]) and demonstrated that the PADL protein retains the antibody reactivity of the component antigens. PADL was able to complement a protein that we previously produced (the leprosy IDRI [Infectious Disease Research Institute] diagnostic 1 [LID-1] protein) to permit the improved diagnosis of multibacillary leprosy and that had a good ability to discriminate patients with multibacillary leprosy from control individuals. A serological diagnostic test consisting of these antigens could be applied within leprosy control programs to reduce transmission and to limit the appearance of leprosy-associated disabilities and stigmatizing deformities by directing treatment.

Evaluation of ID-PaGIA syphilis antibody test.

BACKGROUND: Laboratory diagnosis of syphilis is usually accomplished by serology. There are currently a large number of different commercial treponemal tests available that vary in format, sensitivity and specificity. AIM: To evaluate the ID-PaGIA Syphilis Antibody Test as an alternative to other specific treponemal tests for primary screening or confirmation of diagnosis. METHODS: Serum samples from healthy adults (n = 100) were used for detection of specificity of ID-PaGIA. To evaluate sensitivity of ID-PaGIA serum samples (n = 101) from patients with confirmed or suspected syphilis were tested for syphilis antibodies with FTA-Abs IgM, ID-PaGIA, ELISA IgM and TPHA tests. RESULTS: No false-positive results were found with ID-PaGIA. Sensitivity of various treponemal tests was the following: FTA-Abs IgM: 95.5%, ID-PaGIA and ELISA IgM: 94%, and TPHA 75%. The positive and negative predictive values of ID-PaGIA were 100 and 89.5%, respectively. CONCLUSIONS: Compared with other treponemal tests ID-PaGIA has excellent sensitivity and specificity.

The additional benefit of the ML Flow test to classify leprosy patients.

The use of the skin lesion counting classification leads to both under and over diagnosis of leprosy in many instances. Thus, there is a need to complement this classification with another simple and robust test for use in the field. Data of 202 untreated leprosy patients diagnosed at FIOCRUZ, Rio de Janeiro, Brazil, was analyzed. There were 90 patients classified as PB and 112 classified as MB according to the reference standard. The BI was positive in 111 (55%) patients and the ML Flow test in 116 (57.4%) patients. The ML Flow test was positive in 95 (86%) of the patients with a positive BI. The lesion counting classification was confirmed by both BI and ML Flow tests in 65% of the 92 patients with 5 or fewer lesions, and in 76% of the 110 patients with 6 or more lesions. The combination of skin lesion counting and the ML Flow test results yielded a sensitivity of 85% and a specificity of 87% for MB classification, and correctly classified 86% of the patients when compared to the standard reference. A considerable proportion of the patients (43.5%) with discordant test results in relation to standard classification was in reaction. The use of any classification system has limitations, especially those that oversimplify a complex disease such as leprosy. In the absence of an experienced dermatologist and slit skin smear, the ML Flow test could be used to improve treatment decisions in field conditions.

Association of the ML Flow serologic test to slit skin smear.

A descriptive, exploratory study was conducted analyzing the association of covariables in the results of the ML Flow serological test and slit skin smear. A total of 60 leprosy cases diagnosed at the state Sanitary Dermatology Referral Center were investigated. Slit skin smear samples were collected from four sites and the results were expressed by the bacillary index. ML Flow was registered in both qualitative and semi-quantitative terms. Cohen's kappa coefficient was used to study the agreement with Landis and Koch's observer criteria for interpretation. For statistical analysis, the logistic regression model and Kruskal-Wallis test were used. ML Flow showed a strong association with slit skin smear results, since a gradual increase in BI was accompanied by a semi-quantitative rise in antibody levels measured by ML Flow, with 100% positivity in cases presenting a positive slit skin smear. Given its strong correlation to slit skin smear, the results of this study provide evidence that the ML Flow test could be a valuable auxiliary tool in the classification and treatment of leprosy patients.

Associação do teste sorológico ML Flow com a baciloscopia / Association of the ML Flow serologic test to slit skin smear

Realizou-se estudo descritivo e exploratório relacionando as covariáveis aos resultados do teste sorológico ML Flow e baciloscopia. Foram estudados 60 casos novos de hanseníase diagnosticados no Centro de Referência em Dermatologia Sanitária. Para a baciloscopia, foi utilizada a coleta de esfregaço dérmico em quatro sítios, sendo o resultado expresso pelo índice bacilocópico. O ML Flow foi registrado de modo qualitativo e semi-quantitativo. Para o estudo da concordância, foi utilizado o índice de Kappa e, para sua interpretação, os critérios de Landis e Koch. Para análise estatística foram realizados a regressão logística e o teste de Kruskal-Wallis. O ML Flow mostrou forte associação com a baciloscopia, observou-se que o aumento gradativo do índice baciloscópico foi acompanhado pelo aumento semi-quantitativo dos níveis de anticorpos medidos pelo ML Flow, tendo sido positivo em 100% dos casos com baciloscopia positiva. Os resultados deste estudo evidenciaram que o ML Flow, por estar fortemente correlacionado à bacilocopia, poderá tornar-se um valioso instrumento auxiliar na classificação e alocação dos pacientes para fins de tratamento.

A descriptive, exploratory study was conducted analyzing the association of covariables in the results of the ML Flow serological test and slit skin smear. A total of 60 leprosy cases diagnosed at the state Sanitary Dermatology Referral Center were investigated. Slit skin smear samples were collected from four sites and the results were expressed by the bacillary index. ML Flow was registered in both qualitative and semi-quantitative terms. Cohen's kappa coefficient was used to study the agreement with Landis and Koch's observer criteria for interpretation. For statistical analysis, the logistic regression model and Kruskal-Wallis test were used. ML Flow showed a strong association with slit skin smear results, since a gradual increase in BI was accompanied by a semi-quantitative rise in antibody levels measured by ML Flow, with 100% positivity in cases presenting a positive slit skin smear. Given its strong correlation to slit skin smear, the results of this study provide evidence that the ML Flow test could be a valuable auxiliary tool in the classification and treatment of leprosy patients.

Detection of Mycobacterium leprae infection in wild nine-banded armadillos (Dasypus novemcinctus) using the rapid ML Flow test.

Mycobaterium leprae infection was investigated in armadillos from the State of Espírito Santo, Brazil. The ML Flow test was performed on 37 nine-banded armadillos and positive results were found in 11 (29.7%). The ML Flow test may be used to identify possible sources of Mycobaterium leprae among wild armadillos.

Detection of Mycobacterium leprae infection in wild nine-banded armadillos (Dasypus novemcinctus) using the rapid ML Flow test

Mycobaterium leprae infection was investigated in armadillos from the State of Espírito Santo, Brazil. The ML Flow test was performed on 37 nine-banded armadillos and positive results were found in 11 (29.7 percent). The ML Flow test may be used to identify possible sources of Mycobaterium leprae among wild armadillos.

Tem sido pesquisado infecção pelo Mycobaterium leprae em tatus provenientes do estado do Espírito Santo-Brasil. O teste rápido ML Flow, foi realizado em 37 tatus selvagens, tendo sido positivo em 11 (29,7 por cento). O teste de ML Flow pode ser utilizado para identificar possíveis fontes de Mycobaterium leprae em tatus selvagens.

Simple and fast lateral flow test for classification of leprosy patients and identification of contacts with high risk of developing leprosy.

The interruption of leprosy transmission is one of the main challenges for leprosy control programs since no consistent evidence exists that transmission has been reduced after the introduction of multidrug therapy. Sources of infection are primarily people with high loads of bacteria with or without clinical signs of leprosy. The availability of a simple test system for the detection of antibodies to phenolic glycolipid-I (PGL-I) of Mycobacterium leprae to identify these individuals may be important in the prevention of transmission. We have developed a lateral flow assay, the ML Flow test, for the detection of antibodies to PGL-I which takes only 10 min to perform. An agreement of 91% was observed between enzyme-linked immunosorbent assay and our test; the agreement beyond chance (kappa value) was 0.77. We evaluated the use of whole blood by comparing 539 blood and serum samples from an area of high endemicity. The observed agreement was 85.9% (kappa = 0.70). Storage of the lateral flow test and the running buffer at 28 degrees C for up to 1 year did not influence the results of the assay. The sensitivity of the ML Flow test in correctly classifying MB patients was 97.4%. The specificity of the ML Flow test, based on the results of the control group, was 90.2%. The ML Flow test is a fast and easy-to-perform method for the detection of immunoglobulin M antibodies to PGL-I of M. leprae. It does not require any special equipment, and the highly stable reagents make the test robust and suitable for use in tropical countries.