Research regarding anti-PGL-I antibodies by ELISA in wild armadillos from Brazil

Armadillos have been involved in leprosy transmission and are considered a source of Mycobacterium leprae in numerous reports. Clinicians from certain areas of the USA consider contact with armadillos a risk factor for leprosy. However, there is a challenge associated with the role of wild armadillos perpetuating human leprosy in the American Continent. The presence of anti-PGL-I antibodies was investigated in wild nine-banded armadillos from leprosy-endemic areas in State of Espirito Santo, Brazil, by ELISA performed on serum samples from 47 armadillos. Positive ELISA was obtained from 5 (10.6%) armadillos. Infected armadillos may play some role in leprosy transmission, disseminating bacilli in the environment, perhaps making it more difficult to interrupt transmission and reduce the number of new leprosy cases. ELISA is an efficient tool for seroepidemiological investigations of Mycobacterium leprae in armadillos.Tatus têm sido envolvidos na transmissão da hanseníase e considerados como fonte de Mycobacterium leprae em muitas publicações. Médicos de partes dos EUA consideram o contato com tatus um fator de risco para hanseníase. Entretanto, há um desafio associado ao papel do tatu na perpetuação da hanseníase no Continente Americano. Foi pesquisada a presença de anticorpos anti-PGL-I em tatus selvagens de áreas endêmicas em hanseníase do Estado do Espírito Santo, Brasil, através de ELISA realizado em amostras de soro de 47 animais. Elisa positivo foi encontrado em 5 (10.6%) tatus. Tatus infectados podem ter algum papel na transmissão da hanseníase disseminando bacilos no meio ambiente, talvez tornando mais difícil a interrupção da cadeia de transmissão e redução do número de casos novos de hanseníase. A técnica de ELISA é um eficiente método para investigação soroepidemiológica da presença do Mycobacterium leprae em tatus.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal do Espírito Santo Departmento de Medicina SocialLondon School of Hygiene & Tropical Medicine Departmento de Infectologia e Doenças TropicaisEscola de Medicina da Santa Casa de Misericórdia Departmento de PatologiaRoyal Tropical InstituteUniversidade Federal de Goiás Instituto de Patologia Tropical e Saúde PúblicaUniversidade Federal de São Paulo (UNIFESP) Departmento de Biologia CelularInstituto Lauro de Souza LimaUniversidade Federal de São Paulo (UNIFESP) Departmento de DermatologiaUNIFESP, Departmento de Biologia CelularUNIFESP, Departmento de DermatologiaSciEL

Prevalence and Diagnosis of Latent Tuberculosis Infection in Young Children in the Absence of a Gold Standard

Introduction For adequate disease control the World Health Organization has proposed the diagnosis and treatment of latent tuberculous infection (LTBI) in groups of risk of developing the disease such as children. There is no gold standard (GS) test for the diagnosis of LTBI. The objective of this study was to estimate the prevalence of LTBI in young children in contact with a household case of tuberculosis (TB-HCC) and determine the accuracy and precision of the Tuberculin Skin Test (TST) and QuantiFERON-TB Gold in-tube (QFT) used in the absence of a GS. Methods We conducted a cross-sectional study in children up to 6 years of age in Manaus/Brazil during the years 2009-2010. All the children had been vaccinated with the BCG and were classified into two groups according to the presence of a TB-HCC or no known contact with tuberculosis (TB). The variables studied were: the TST and QFT results and the intensity and length of exposure to the index tuberculosis case. We used the latent class model to determine the prevalence of LTBI and the accuracy of the tests. Results Fifty percent of the children with TB-HCC had LTBI, with the prevalence depending on the intensity and length of exposure to the index case. The sensitivity and specificity of TST were 73% [95% confidence interval (CI): 53-91] and 97% (95%CI: 89-100), respectively, versus 53% (95%CI: 41-66) and 81% (95%CI:71-90) for QFT. The positive predictive value of TST in children with TB-HCC was 91% (95%CI: 61-99), being 74% for QFT (95%CI: 47-95). Conclusions This is one of the first studies to estimate the prevalence of LTBI in children and the parameters of the main diagnostic tests using a latent class model. Our results suggest that children in contact with an index case have a high risk of infection. The accuracy and the predictive value of the two tests did not significantly differ. Combined use of the two tests showed scarce improvement in the diagnosis of LTBI

A clinical trial for uniform multidrug therapy for leprosy patients in Brazil : rationale and design

Leprosy will continue to be a public health problem for several decades. The World Health Organization (WHO) recommends that, for treatment purposes, leprosy cases be classified as either paucibacillary or multibacillary (MB). A uniform leprosy treatment regimen would simplify treatment and halve the treatment duration for MB patients. The clinical trial for uniform multidrug therapy (U-MDT) for leprosy patients (LPs) in Brazil is a randomised, open-label clinical trial to evaluate if the effectiveness of U-MDT for leprosy equals the regular regimen, to determine the acceptability of the U-MDT regimen and to identify the prognostic factors. This paper details the clinical trial methodology and patient enrolment data. The study enrolled 858 patients at two centres and 78.4% of participants were classified as MB according to the WHO criteria. The main difficulty in evaluating a new leprosy treatment regimen is that no reliable data are available for the current treatment regimen. Relapse, reaction and impaired nerve function rates have never been systematically determined, although reaction and impaired nerve function are the two major causes of nerve damage that lead to impairments and disabilities in LPs. Our study was designed to overcome the need for reliable data about the current treatment and to compare its efficacy with that of a uniform regimen

Soropositividade ao PGL-I em um centro de reintegração para pessoas atingidas pela hanseníase e diferentes Regiões do Município de Anápolis-Goiás / Seropositivity to PGL-I in a reintegration center for people affected by leprosy and different regions in the Municipality of Anápolis-Goiás

Objetivo: Realizar avaliação sorológica comparativa ao antígeno Glicolipídeo Fenólico-I (PGL-I), utilizando o teste ML Flow, entre moradores de uma instituição coordenada pelo movimento de reintegração das pessoas atingidas pela hanseníase àquela encontrada entre áreas adjacentes e geograficamente distantes do município de Anápolis, no estado de Goiás, com o intuito de colaborar na descrição soroepidemiológica da hanseníase. Métodos: Trata-se de uma pesquisa exploratória, observacional e transversal, em forma de levantamento de prevalência, não controlada e não randomizada. Envolveu aplicação do teste imunocromatográfico ML Flow para detecção de anticorpos anti-PGL-I, desenvolvido pelo Instituto de Patologia Tropical e Saúde Pública da Universidade Federal de Goiás, além de questionário semiestruturado direcionado aos determinantes sociais da doença. Os dados foram coletados em 2018 por amostra obtida por conveniência. Resultados: Participaram 79 pessoas, sendo 19 internos da instituição (Grupo 1), 20 moradores circunvizinhos (Grupo 2) e 40 habitantes de áreas distantes do município (Grupo 3), sendo detectadas imunoglobulinas IgM direcionadas ao antígeno em 10,5%, 10% e 2,5%, respectivamente. Nota-se maior soropositividade na instituição e áreas próximas, em contraste com as regiões distantes da cidade. No entanto, os dados obtidos sugerem soroprevalência similar a regiões endêmicas e justifica-se pela configuração histórica do bairro. Além disso, os atuais casos notificados no município estão difusamente distribuídos pelos limites da cidade, sem restrição geográfica excepcional. Conclusão: Esclarecimento sorológico e a informação sobre a patologia favorecem a eliminação da marginalização e estigmas impostos sobre indivíduos que possuíram a doença outrora ou que estão sob condições de vulnerabilidade social abrigados pela instituição

Mycobacterium tuberculosis Infection in Young Children: Analyzing the Performance of the Diagnostic Tests

This study evaluated the performance of the Tuberculin Skin Test (TST) and Quantiferon-TB Gold in-Tube (QFT) and the possible association of factors which may modify their results in young children (0-6 years) with recent contact with an index tuberculosis case. Materials and Methods: A cross-sectional study including 135 children was conducted in Manaus, Amazonas-Brazil. The TST and QFT were performed and the tests results were analyzed in relation to the personal characteristics of the children studied and their relationship with the index case. Results: The rates of positivity were 34.8% (TST) and 26.7% (QFT), with 14.1% of indeterminations by the QFT. Concordance between tests was fair (Kappa = 0.35 P<0.001). Both the TST and QFT were associated with the intensity of exposure (Linear OR = 1.286, P = 0.005; Linear OR = 1.161, P = 0.035 respectively) with only the TST being associated with the time of exposure (Linear OR = 1.149, P = 0.009). The presence of intestinal helminths in the TST+ group was associated with negative QFT results (OR = 0.064, P = 0.049). In the TST- group lower levels of ferritin were associated with QFT+ results (Linear OR = 0.956, P = 0.036). Conclusions: Concordance between the TST and QFT was lower than expected. The factors associated with the discordant results were intestinal helminths, ferritin levels and exposure time to the index tuberculosis case. In TST+ group, helminths were associated with negative QFT results suggesting impaired cell-mediated immunity. The TST-&QFT+ group had a shorter exposure time and lower ferritin levels, suggesting that QFT is faster and ferritin may be a potential biomarker of early stages of tuberculosis infection

Impact of PGL-I Seropositivity on the Protective Effect of BCG Vaccination among Leprosy Contacts: A Cohort Study

Although leprosy has become a neglected disease, it is an important cause of disability, and 250,000 new cases are still diagnosed worldwide every year. The current study was carried out in Brazil, where almost 40,000 new cases of leprosy are diagnosed every year. The study targeted contacts of leprosy patients, who are at the highest risk of contracting the disease. We studied 2,135 contacts who were diagnosed at the Leprosy Outpatient Clinic at the Oswaldo Cruz Foundation in Rio de Janeiro, RJ, Brazil, between 1987 and 2007. The presence of antibodies against a specific Mycobacterium leprae antigen (PGL-I) at the first examination and BCG vaccination status were evaluated. PGL-I-positive contacts had a higher risk of developing leprosy than PGL-I-negative contacts. Among the former, vaccinated contacts were at higher risk than unvaccinated contacts. Our results indicate that contact examination combined with PGL-I testing and BCG vaccination appears to justify the targeting of PGL-I-positive individuals for enhanced surveillance. Furthermore, it is highly recommended that PGL-I-positive contacts and contacts with a high familial bacterial index (i.e., the sum of results from index and co-prevalent cases), regardless of serological response, should be monitored. This group could be considered as a target for chemoprophylaxis