Evaluation of the Effect of a Recent Comparative Intradermal Tuberculin Test on the Humoral Diagnosis of Paratuberculosis Using Serum and Milk Samples from Goats.

Paratuberculosis (PTB) and tuberculosis (TB) are two mycobacterial diseases with a severe economic and health impact on domestic ruminants. The ante mortem diagnosis of PTB is hampered, among other factors, by the limited sensitivity of all the available diagnostic techniques. Since TB-infected goats subjected to the comparative intradermal tuberculin test (CITT) may experience a booster effect on their antibody titer and a potential enhancement to the sensitivity of humoral techniques for tuberculosis, in the present study we aimed to evaluate this diagnostic strategy on the humoral diagnosis of PTB in serum and milk samples collected from a caprine herd that was TB free and PTB infected. The results from 120 goats indicated a significant increase (p < 0.001) in the quantitative response detected using an ELISA technique, conducted using serum and milk samples taken 15 and 30 days after performing a CITT (day 0 of the study); although, it did not translate into a significant increase in the number of reactors during any of the testing events (0, 3,15, 30 and 60 days post-CITT). Additionally, the number of ELISA-positive animals was higher for the serum versus the milk samples at both 15 and 30 days post-CITT. The increase in the quantitative ELISA result suggested a diagnostic strategy that maximizes ELISA sensitivity, mainly using serum samples, in PTB-infected herds; although, it may depend on individual differences and the interpretation criteria.

Prevalence and risk factors of bovine tuberculosis in cattle in selected districts of Fafan pastoral settings, Eastern Ethiopia.

Cross-sectional study was conducted from October 2021 to August 2022 to investigate the prevalence and associated risk factors of bovine tuberculosis in cattle in selected districts of the pastoral settings of Fafan zone, Somali region, eastern Ethiopia. A comparative intradermal tuberculin test was performed using purified protein derivatives. Animal-related characteristics, and the owner's knowledge on the importance of BTB were collected using a structured questionnaire. The prevalence was 11.24 % (95 % CI, 8.61-14.35) and 43.3 % (95 % CI, 33.27-53.75) at the individual and herd levels, respectively. There were statistically significant differences in the proportions of positive reactor animals according to body condition score (P = 0.000), age (P = 0.048), seasonal migration (P = 0.038), parity number (P = 0.005), and reproductive status (P = 0.037). Animals with poor body condition scores had a significantly higher likelihood of testing positive, with their odds being 11.4 times greater (COR = 11.408, CI = 3.43-37.94, P < 0.001). In multivariate logistic regression, poor body condition score remained significantly associated with the odds of a positive reaction to tuberculosis (AOR = 0.137, CI = 0.053-0.356, P < 0.001). Similarly, the analysis showed that seasonal migration (AOR = 2.882, CI = 1.155-7.191, P = 0.023) and parity number (AOR = 11.64, CI = 1.818-74.464, P = 0.010) were significant predictors of bovine tuberculosis infection in cattle. According to the questionnaire, 14.2 % (17 of 120) and 13.3 % (16 of 120) of the respondents were knowledgeable about bovine tuberculosis and its transmission from animals to humans, and vice versa, respectively. The general judgment of herders' understanding of bovine tuberculosis transmission methods to humans was very low. The study findings showed a high prevalence of bovine tuberculosis in the study area, emphasizing the need for an effective control and prevention strategy.

Effect of a recent intradermal test on the specificity of P22 ELISA for the diagnosis of caprine tuberculosis.

Caprine tuberculosis (TB) is a zoonotic disease caused by members of the Mycobacterium tuberculosis complex. TB eradication programs in goats are based on the single and comparative intradermal tuberculin tests (SITT and CITT, respectively). Antibody-based diagnostic techniques have emerged as potential diagnostic tools for TB. P22 ELISA has been previously evaluated using samples collected after the intradermal tuberculin tests to maximize the sensitivity, a phenomenon known as booster effect. However, there is no information available on whether the use of this diagnostic strategy could lead to a decrease of its specificity (Sp). The aim of the present study was to elucidate the interference effect of a recent CITT on the Sp of the P22 ELISA in serum and milk samples collected at different times after the CITT from a TB-free herd (n = 113). The number of reactors to P22 ELISA was significantly higher (p < 0.01) on serum samples collected 15 days post-CITT compared to day 0, showing a decrease in Sp from 99.1% (95% CI; 95.2-99.8%) to 88.5% (95% CI; 81.3-93.2%). The number of reactors and the quantitative values of P22 ELISA were significantly higher (p < 0.01) in serum samples compared to milk. No significant (p > 0.05) changes in the Sp of the P22 ELISA were observed throughout the different time samplings using milk No significant (p > 0.05) changes were observed on days 30 and 60 post-CITT. In conclusion, the booster effect strategy may significantly decrease the Sp of P22 ELISA in TB-free herds when serum samples are used but not when milk is tested.

Cost-Effectiveness Analysis Comparing QuantiFERON-TB Gold Plus Test and Tuberculin Skin Test for the Diagnosis of Latent Tuberculosis Infection in Immunocompetent Subjects in Colombia.

OBJECTIVES: To determine the cost-effectiveness of the QuantiFERON-TB Gold Plus (QFT-Plus) test versus the tuberculin skin test in diagnosing latent tuberculosis infection in immunocompetent subjects in the context of the Colombian healthcare system. METHODS: A hypothetical cohort of 2000 immunocompetent adults vaccinated with Bacillus Calmette-Guérin at birth who are asymptomatic for tuberculosis disease was simulated and included in a decision tree over a horizon of <1 year. The direct healthcare costs related to tests, antituberculosis treatment, and medical care were considered, and diagnostic performance was used as a measure of effectiveness. The incremental cost-effectiveness ratio (ICER) was estimated, and univariate deterministic and probabilistic sensitivity analyses were carried out using 5000 simulations. The currency was the US dollar for the year 2022, with a cost-effectiveness threshold of $6666 USD (1 gross domestic product per capita for 2022). RESULTS: QFT-Plus was cost-effective with an ICER of $5687 USD for each correctly diagnosed case relative to a threshold of $6666 USD. In the deterministic analysis, QFT-Plus was cost-effective in half of the proposed scenarios. The variable that most affected the ICER was the prevalence of latent tuberculosis and test sensitivities. In the probabilistic analysis, QFT-Plus was cost-effective in 54.74% of the simulated scenarios, and tuberculin skin test was dominant in 13.84%. CONCLUSIONS: The study provides evidence of the cost-effectiveness of QFT-Plus compared with the tuberculin skin test in diagnosing latent tuberculosis infection in immunocompetent adults in the Colombian context.

Assessment of the diagnostic performance of intradermal tuberculin test and post-mortem inspection for the diagnosis of bovine tuberculosis according to WOAH guidelines.

Bovine tuberculosis (bTB) constitutes a global challenge for public and animal health with still some deficiencies regarding its diagnosis. This study aimed to estimate the accuracy of the single intradermal tuberculin test (SIT) and post-mortem inspection for different diagnostic objectives following WOAH guidelines. Tissue samples from 59 microbiological culture/PCR-positive and 58 microbiological culture/PCR-negative cattle were evaluated. The diagnostic sensitivity and specificity, the positive and negative probability indices as well as the positive and negative predictive values (PPV and NPV) of each technique were estimated for different pretest probabilities. The SIT with strict interpretation demonstrated moderate precision in confirming the absence of infection in populations historically free of bTB, with a 12.1% rate of false positives, but also detecting positive animals in the early stage of the eradication programs, with a 13.6% rate of false negatives. The diagnostic performance for ruling out bTB was notably high (NPV > 90%) in animals with a pre-test probability (PTP) below 42%. Post-mortem inspection constituted an interesting alternative tool to confirm suspected and positive cases for SIT, particularly in areas with bTB prevalence exceeding 19%, where implementing SIT and eradication measures may be impractical. In these areas, the likelihood that animals with tuberculosis-like lesions are affected by the disease surpasses 90%. Similarly, in herds with a PTP below 25%, the absence of bTB could be confidently ruled out with over 90% certainty. These findings highlight the effectiveness of SIT and post-mortem inspection as valuable techniques for current eradication programs and controlling bTB in high-prevalence areas where molecular techniques may not be feasible.

Prevalence of positive tuberculin skin test in a Brazilian sample of rheumatoid arthritis and spondylarthritis patients

SUMMARY OBJECTIVE: Patients with rheumatic diseases have an increased risk of infections, especially tuberculosis. In this study, we aimed to recognize the positivity rate of tuberculosis skin test in patients with rheumatoid arthritis and spondyloarthritis and the characteristics of the patients with positive results. METHODS: Retrospective study of tuberculosis skin test results in patients followed from 2004 to 2021 in a single rheumatology unit. Data related to clinical and epidemiological features, along with treatment information referring to the period in which the tuberculosis skin test was performed, were collected from patients' charts. RESULTS: A total of 723 tests were identified (448 tests in 269 rheumatoid arthritis patients and 275 in 174 spondyloarthritis patients). In the rheumatoid arthritis sample, 31/275 (11.5%) individuals had positive tests, and in the spondyloarthritis, 38/174 (21.8%) had positive tests. In the rheumatoid arthritis sample, patients with positive tuberculosis skin tests used a higher dose of methotrexate than those with negative results (median of 25 mg/week versus median of 20 mg/week respectively; p=0.02). In the spondyloarthritis sample, tuberculosis skin test positivity was associated with alcohol ingestion (13.1% versus 2.9% in users and non-users respectively; p=0.02) and sulfasalazine use (15.7% of positivity in users versus 5% in non-users; p=0.01). CONCLUSION: The tuberculosis skin test-positive prevalence in rheumatoid arthritis was lower than in the spondyloarthritis sample. Patients with rheumatoid arthritis using a higher dosage of methotrexate or with spondyloarthritis using sulfasalazine had more frequency of tuberculosis skin test positivity and should be carefully followed by the attending physician in order to avoid the appearance of full-blown tuberculosis.

Effect of a Latent Tuberculosis Infection Programme for Healthcare Workers in a Country with an Intermediate Tuberculosis Burden.

BACKGROUND: Management of latent tuberculosis infection (LTBI) among healthcare workers (HCWs) is crucial for the prevention of nosocomial tuberculosis (TB) transmission. We aimed to determine the effect of an LTBI programme for HCWs in a tertiary care hospital in a country with an intermediate TB burden. METHODS: In 2013, baseline LTBI screening was implemented for newly hired doctors and nurses, along with annual screening of HCWs in high-risk departments. HCWs with LTBI were also provided with treatment. Since 2017, all HCWs without an LTBI test result have been tested for LTBI. We assessed the annual incidence of active TB among HCWs between 2013 and 2020. Additionally, we evaluated the incidence of active TB among HCWs employed at the hospital in 2020, with a specific focus on those who had undergone LTBI tests between 2013 and 2018, considering their LTBI test results and treatment status. MEASUREMENT AND MAIN RESULTS: The incidence of active TB among HCWs significantly decreased between 2013 and 2020. The average risk reduction for pulmonary TB was 10.2% per year (95% CI, 1.0-19.0; p = 0.034). Among HCWs employed at the hospital in 2020, 4,354 individuals underwent LTBI tests between 2013 and 2018. Out of them, 927 (21.3%) tested positive. Nine (1.5%) out of 588 without LTBI treatment developed active TB. Among the 1,285 HCWs who underwent follow-up testing, 62 (4.8%) converted, and one (4.3%) out of the 23 without treatment developed active TB. None of those who received treatment were diagnosed with active TB. CONCLUSION: The LTBI programme significantly reduced the incidence of active TB in HCWs. LTBI screening and treatment should be implemented, particularly in countries with a high or intermediate TB burden.

Estudio descriptivo sobre el uso de ensayo de liberación de interferón gamma en población reclusa con prueba de tuberculina positiva en el Centro Penitenciario de Burgos / Interferon-gamma release assay for the diagnosis of latent tuberculosis infection in the prison population with a positive tuberculin test: a descriptive study in a prison (Burgos, Spain)

Objetivos: En prisiones, existe una alta prevalencia de reclusos que tienen una prueba de tuberculina (PT) positiva mayor de 10 mm y, en ocasiones, se realizan tratamientos para infección tuberculosa latente (ITL) innecesarios. El programa de prevención y control de la tuberculosis (TB) en el medio penitenciario no ha generalizado el uso de uso de QuantiFERON®-TB (QFT) en las cárceles. Nos propusimos describir la implementación y la utilidad del QFT en una población de internos con PT positiva y, de forma secundaria, detectar falsos positivos y evitar tratamientos innecesarios. Secundariamente se han analizado las distintas variables sociodemográficas de la población reclusa. Material y método: Entre diciembre de 2020 y diciembre de 2021, de una población promedio de 300 internos de la cárcel de Burgos, se analizaron todas las pruebas de PT positivas. A todos estos casos positivos, se les midió el valor del QFT. Se analizaron diferentes variables sociodemográficas, y finalmente se evaluó la cantidad de internos con PT positiva, pero con resultado de QFT negativo. Resultados: Un total de 41 internos fueron incluidos en el estudio, con una edad media de 44 años. La proporción de internos nacidos en España fue del 56%, el resto habían nacido en otros países. El 48,8% de todas las PT positivas, fueron QFT negativo. De los 21 internos con QFT+, 12 (57%) estaban vacunados con bacilo de Calmette y Guérin (BCG). Discusión: Se ha observado que el QFT es un método seguro para el diagnóstico de la ITL en prisiones, y que su utilización contribuiría a una selección más específica de los internos que realmente necesitan un tratamiento para ITL. (AU)

Objectives: A high prevalence of prison inmates have a positive tuberculin skin test (TST) and sometimes unnecessary treatment for latent tuberculosis infection (LTBI) is prescribed. The prison tuberculosis prevention and control program has not generalized the use of QuantiFERON (QFT) in prisons. We set out to describe the implementation and usefulness o QFT in a population of inmates with positive TST, and to detect false positives and avoid unnecessary treatments. We also analysed the sociodemographic variables of the inmate population. Material and methods: All the positive TST tests between December 2020 and December 2021 from an average population of 300 inmates in Burgos prison were analysed. The QFT value was measured in all the positive cases. Sociodemographic variables were analysed and finally the number of inmates with positive TST, but with a negative QFT result and therefore not requiring LTBI treatment, was evaluated. Results: A total of 41 inmates were included in the study, with a mean age of 44 years. The proportion between Spanish inmates and foreigners was similar. Of all the positive TST, 48.8% were QFT negative. Discussion: It was observed that QFT is a safe method for the diagnosis of LTBI in prisons and that its use would contribute to a more specific selection of inmates who actually need chemoprophylactic treatment for LTBI. (AU)

Gamma-interferon assay for the ancillary diagnosis of bovine tuberculosis in dairy cattle in urban and adjacent areas of Dhaka city, Bangladesh.

Background and Aim: Bovine tuberculosis (bTB) is an infectious disease of cattle, mainly caused by Mycobacterium bovis. This study aimed to evaluate the efficacy of the interferon-gamma (IFN-γ) assay and single-intradermal comparative tuberculin test (SICTT) in detecting bTB. Materials and Methods: In an earlier study, 150 positive, 83 inconclusive, and 480 negative animals from 24 cattle herds were screened using SICTT. From these groups, 125 positive, 17 inconclusive, and six negative animals were subsequently verified using the IFN-γ assay. Single-intradermal comparative tuberculin test outcomes were interpreted according to standard guidelines, whereas blood samples were collected and stimulated with purified protein derivatives. Sandwich enzyme-linked immunosorbent assay was used to measure secreted IFN-γ. Concordant and Bayesian latent class analyses were performed to evaluate test performance. Results: Results from the IFN-γ assay revealed that 83.2%, 64.7%, and 16.67% of the animals were positive in the SICTT-positive, inconclusive, and negative animal categories, respectively. Sensitivity (SE) and specificity (SP) of SICTT were 83.9% (95% confidence interval [CI]: 77.4-90.1) and 95.7% (95% CI: 86.9-99.7), respectively. Sensitivity and SP for the IFN-γ assay were 78.9% (95% CI: 71.9-85.4) and 83.9% (65.9-95.9), respectively. The use of both tests in parallel increases the SE of bTB detection (~94%), compared with SICTT alone. Conclusion: Use of the IFN-γ assay with SICTT in parallel, predominantly on cattle demonstrating an inconclusive SICTT outcome, boosts bTB detection rate in low resource settings.

Incidence, Diagnosis and Treatment of Otorhinolaryngological, Head and Neck Tuberculosis: A Prospective Clinical Study.

Introduction Tuberculosis is a disease of diversified presentation. It affects almost all organs in the body, and otorhinolaryngological, head and neck involvement is not an exception. Objective To increase awareness about the different clinical presentations of otorhinolaryngological, head and neck tuberculosis, the techniques employed to diagnose it, and to assess the response to the treatment. Methods We conducted a prospective study of 114 patients who presented primarily with otorhinolaryngological, head and neck tuberculosis. Routine blood investigations, chest radiographs, the tuberculin test, and sputum examination for the presence of acid-fast bacilli were performed in all cases. Site-specific investigations were performed in relevant cases only. The patients were treated according to the antitubercular treatment (ATT) regimen recommended by the Indian Ministry of Health and Family Welfare's National Tuberculosis Elimination Program (NTEP), and they were followed up clinically two and six months after starting the ATT. Results Tubercular cervical lymphadenopathy was the most common clinical presentation (85.96%), followed by deep neck abscess (5.27%). Fine-needle aspiration cytology proved to be a reliable tool for the diagnosis of tubercular lymphadenopathy. Improvement at the end of 2 and 6 months of the ATT was observed in 90.35% and 96.50% of the cases respectively. Conclusion The diagnosis of otorhinolaryngological, head and neck tuberculosis requires a high index of clinical suspicion, and the ATT proved to be very effective in reducing the severity of the disease.

Enhancing bovine tuberculosis screening at Dhaka city in Bangladesh: Integrating gamma interferon blood test as ancillary testing with tuberculin skin test.

Tuberculin skin test (TST) is the standard method for screening of bovine tuberculosis (bTB). However, gamma interferon blood test has been introduced in the bTB control program as an ancillary testing with TST in many countries of the world. The objective of this study was to recommend this screening test as an ancillary testing with TST for field application in Bangladesh. In this study 577 cattle of different age, sex and breeds from twenty nine (29) cattle herds were examined to determine skin response against bTB through single intradermal comparative tuberculin test (SICTT) that comprised of positive (n = 81), inconclusive (n = 44) and negative (n = 452) animals. Of which 74 animals that included positive (n = 63), inconclusive (n = 8) and negative (n = 3) animals were taken under this study. Blood samples were collected in heparinized tube and stimulated overnight with bovine and avian purified protein derivatives (PPDs) for the secretion of gamma interferon, and measured via sandwich ELISA. Cohen's kappa statistics was performed for the evaluation of agreement between the two tests. The agreement obtained between two tests was fair (Kappa agreement, K = 24.0%, 95% CI = 16.9-30.5%, P = 0.037). Of positive (n = 63), inconclusive (n = 8) and negative (n = 3) status of animals at SICTT, 82.54% (n = 52), 62.50% (n = 5), and 33.33% (n = 1) were found to be bTB positive respectively through this ancillary test. This test notably corroborates to TST result. A considerable number of inconclusive TB status animals were found to be positive through this gamma interferon assay. Therefore, this test could be used as an ancillary test with TST to maximize the proportion of bTB estimation in the infected cattle herd for early detection of zoonotic tuberculosis in Bangladesh before transmission at the animal-human interface.

Contact Investigations With a Single Tuberculin Skin Test on Infants Exposed to Tuberculosis in a Postpartum Care Center During the Neonatal Period.

BACKGROUND: Tuberculosis (TB) exposure in congregate settings related to neonates is a serious medical and social issue. TB exposure happens during the neonatal period, but contact investigations for exposed infants are usually conducted after the neonatal period. Generally, recommendations for screening and managing close contact are different for neonates and children. Thus, there are challenges in contact investigations. We aimed to report contact investigations with a single tuberculin skin test (TST) on infants exposed to infectious TB in a postpartum care center. METHODS: The index case was a healthcare worker with active pulmonary TB: sputum acid-fast bacilli smear negative, culture positive, and no cavitary lesion. All exposed infants underwent medical examinations and chest X-ray. After TB disease was ruled out, contacts received window period prophylaxis with isoniazid (INH) until three months after the last exposure. TST was performed only once after completing the prophylaxis. RESULTS: A total of 288 infants were selected as high-priority contacts. At the initial contact investigation, the age of infants ranged from 8 to 114 days. None of these exposed infants had TB disease. The prevalence of latent TB infection (LTBI) was 25.3% (73/288; 95% confidence interval [CI], 20.7-30.7). There were no serious adverse events related to the window period prophylaxis or LTBI treatment with INH. During the 1-year follow-up period, no infants progressed to overt TB disease. The size of TST induration in infants vaccinated with percutaneous Bacillus Calmette-Guérin (BCG) vaccine was significantly larger than that of infants vaccinated with intradermal BCG vaccine (median, 8 mm vs. 5 mm; P = 0.002). In multiple logistic regression analysis, independent factors associated with TST positivity (≥ 10 mm induration) were male (adjusted odds ratio [aOR], 2.98; 95% CI, 1.6-5.64), percutaneous BCG vaccination (aOR, 3.30; 95% CI, 1.75-6.48), TST reading between 60 and 72 hours after injecting purified protein derivative (aOR, 2.87; 95% CI, 1.53-5.49), and INH prophylaxis more than four weeks (aOR, 0.49; 95% CI, 0.25-0.94). CONCLUSION: A single TST at three months after the last TB exposure with INH prophylaxis could be used as a main protocol in contact investigations for infants exposed to infectious TB during the neonatal period in congregate settings in Korea.

Latent Tuberculosis Infection in Users of Drug Dependence Care and Follow-up Centers in Barcelona in 2017-2021: A Cross-sectional Descriptive Study.

Introduction: People who consume drugs have a higher risk of latent tuberculosis infection (LTBI). Our objective was to study the characteristics of people who use drugs and who attended the Centers for Drug Dependence Care and Follow-up of Barcelona during 2017-2021 and presented LTBI or did not perform the reading of the tuberculin skin test (TST) after the test had been done. Methods: A cross-sectional, descriptive study in Centers for Drug Dependence Care and Follow-up of Barcelona was performed during 2017-2021. The sociodemographic and epidemiological profile of people who use drugs that underwent a TST was analyzed and were examined the factors associated with LTBI. Additionally, the same sociodemographic and epidemiological analyses were made in PWUD that did not perform the reading of the TST after the test had been done. Adjusted odds ratios (ORa) and 95% confidence intervals (95% CI) were calculated. Results: Nine hundred forty-eight persons were profiled. The prevalence of LTBI was 22.9%, and the following factors were associated with it: be older than 41 years; be users of CAS Baluard, or CAS Horta-Guinardó; coming from a WHO region of high TB incidence; be homeless; and low territorial socioeconomic index. The following factors were associated with not performing the reading of the TST after the test had been done: be users from the CAS Baluard, Barceloneta, Nou Barris and Robadors; be homeless and low TSI. Conclusions: This study improves TB control and highlights the need for this LTBI control program in CASs.

Introducción: Las personas que consumen drogas tienen un mayor riesgo de infección tuberculosa latente (ITL). Nuestro objetivo fue medir las características de las personas que cosumen drogas y que acudieron a los centros de atención y seguimiento (CAS) a las drogodependencias de Barcelona entre 2017-2021 y que presentaron ITL, así como conocer el perfil de las que no acudieron a la lectura de la prueba de la tuberculina (PT). Métodos: Se realizó un estudio descriptivo transversal en los centros de atención y seguimiento a las drogodependencias de Barcelona durante el periodo 2017-2021. Se analizó el perfil sociodemográfico y epidemiológico de las personas que consumen drogas que se sometieron a una PT y se examinaron los factores asociados a la ITL. Además, los mismos análisis sociodemográficos y epidemiológicos se realizaron en las personas que consumen drogas que no realizaron la lectura de la PT después de realizarla. Se calcularon las odds ratio ajustadas (ORa) y los intervalos de confianza de 95% (IC 95%). Resultados: Se estudiaron 948 personas. La prevalencia de ITL fue de 22,9%, y los factores asociados fueron: ser mayor de 41 años, ser usuarios del CAS Baluard, o del CAS Horta-Guinardó, provenir de una región de la Organización Mundial de la Salud de alta incidencia de TB, ser una persona sin hogar y bajo índice socioeconómico territorial (IST). Los siguientes factores se asociaron con no acudir a la lectura de PT después de la realización de la prueba: ser personas usuarias del CAS Baluard, Barceloneta, Nou Barris y Robadors; personas sin hogar y bajo IST. Conclusiones: Este estudio mejora el control de la TB y destaca la necesidad de este programa de control de ITL en los CAS.

Frecuencia de infección tuberculosa latente en estudiantes de Medicina en una universidad privada de Paraguay

Introducción: la infección tuberculosa latente es un estado de respuesta inmune tipo hipersensibilidad celular retardada del organismo a la estimulación por antígenos de Mycobacterium tuberculosis sin evidencia clínica y radiológica de tuberculosis. Puede ser diagnosticada mediante la prueba de tuberculina o derivado proteico purificado de tuberculina. Objetivos: determinar la frecuencia de infección tuberculosa latente en estudiantes de Medicina y las variables asociadas a una reacción positiva en la prueba de tuberculina. Metodología: se realizó un estudio descriptivo de corte transversal, en el cual se procedió a realizar la prueba de tuberculina por el método de Mantoux utilizando 0,1 ml de derivado proteico purificado de tuberculina Tubersol, en estudiantes de la carrera de Medicina de una universidad. Resultados: participaron 290 estudiantes. La frecuencia de infección tuberculosa latente fue 19,3%. Al relacionar las variables demográficas con la reacción positiva en la prueba de tuberculina, los hombres presentaron 1,895 veces mayor probabilidad de dar positivo a la prueba de tuberculina que las mujeres. Conclusiones: la frecuencia de infección tuberculosa latente en estudiantes de la carrera de Medicina fue 19,3% y la variable que presentó asociación estadística a la prueba de tuberculina positiva fue el sexo masculino.

Introduction: Latent tuberculosis infection is a state of delayed cellular hypersensitivity immune response of the organism to stimulation by Mycobacterium tuberculosis antigens without clinical and radiological evidence of tuberculosis. It can be diagnosed by tuberculin test or tuberculin purified protein derivative. Objectives: To determine the frequency of latent tuberculosis infection in medical students and the variables associated with a positive reaction in the tuberculin test. Methodology: A descriptive cross-sectional study was carried out, in which the tuberculin test was made by the Mantoux method using 0.1 ml of purified protein derivative of Tubersol tuberculin in students of the medicine career of a university. Results: Two hundred ninety students participated. The frequency of latent tuberculosis infection was 19.3%. When relating the demographic variables to the positive reaction in the tuberculin test, men were 1,895 times more likely to test positive for the tuberculin test than women. Conclusions: The frequency of latent tuberculosis infection in medical students was 19.3% and the variable that presented a statistical association with the positive tuberculin test was male sex.

Mycobacterium tuberculosis complex detection in rural goat herds in South Africa using Bayesian latent class analysis.

Animal tuberculosis affects a wide range of domestic and wild animal species, including goats (Capra hircus). In South Africa, Mycobacterium tuberculosis complex (MTBC) testing and surveillance in domestic goats is not widely applied, potentially leading to under recognition of goats as a potential source of M. bovis spread to cattle as well as humans and wildlife. The aim of this study was to estimate diagnostic test performance for four assays and determine whether M. bovis infection was present in goats sharing communal pastures with M. bovis positive cattle in the Umkhanyakude district of Northern Zululand, KwaZulu Natal. In 2019, 137 M. bovis-exposed goats were screened for MTBC infection with four diagnostic tests: the in vivo single intradermal comparative cervical tuberculin test (SICCT), in vitro QuantiFERON®-TB Gold (QFT) bovine interferon-gamma release assay (IGRA), QFT bovine interferon gamma induced protein 10 (IP-10) release assay (IPRA), and nasal swabs tested with the Cepheid GeneXpert® MTB/RIF Ultra (GXU) assay for detection of MTBC DNA. A Bayesian latent class analysis was used to estimate MTBC prevalence and diagnostic test sensitivity and specificity. Among the 137 M. bovis-exposed goats, positive test results were identified in 15/136 (11.0%) goats by the SICCT; 4/128 (3.1%) goats by the IPRA; 2/128 (1.6%) goats by the IGRA; and 26/134 (19.4%) nasal swabs by the GXU. True prevalence was estimated by our model to be 1.1%, suggesting that goats in these communal herds are infected with MTBC at a low level. Estimated posterior means across the four evaluated assays ranged from 62.7% to 80.9% for diagnostic sensitivity and from 82.9% to 97.9% for diagnostic specificity, albeit estimates of the former (diagnostic sensitivity) were dependent on model assumptions. The application of a Bayesian latent class analysis and multiple ante-mortem test results may improve detection of MTBC, especially when prevalence is low. Our results provide a foundation for further investigation to confirm infection in communal goat herds and identify previously unrecognized sources of intra- and inter-species transmission of MTBC.

Latent tuberculosis infection prevalence in second generation immigrants from high to low TB burden countries.

BACKGROUND: Latent tuberculosis infection (LTBI) diagnosis in a country with a low tuberculosis burden is complicated. Since the prevalence of LTBI in second generation immigrants has not been well recognized, we conducted a cross-sectional study which aimed to explore the differences in LTBI prevalence between offspring of immigrants from high tuberculosis (TB) burden countries and those whose parents were born in countries with a low TB burden. METHODS: Between May 2014 and April 2018 young native Israelis who were required to perform pre-occupational tuberculin skin tests (TST) (medical and paramedical personnel or teaching assistants of immigrants from high TB burden countries) and who had a TST result of 10mm and above were tested for QuantiFERON-TB In Tube (QFT-GIT). Statistical comparisons were made between second generation immigrants and those with both parents from a low TB burden country. RESULTS: Of 102 patients, 71 were born to parents both of whom were from low-risk countries, 14 to one parent from a high-risk country and 17 to parents both of whom were from a high-risk country. The odds ratio for LTBI was 4.5 (95% CI, 1.2...17.2; p=0.03) if both parents were born in a high-risk country compared to both parents being from a low-risk country and 4.01 (95% CI, 1.12...14.3; p=0.03) higher compared to persons for whom at least one parent was born in a low-risk country. CONCLUSION: The risk for latent TB is significantly higher in second generation immigrants if both parents were born in a high-risk country. IGRA should be considered before treatment to patients with a positive TST if at least one parent was born in a low-risk country in order to confirm LTBI.

Tuberculin skin test versus QuantiFERON-TB gold in-tube for latent tuberculosis screening in people living with HIV in a resource-limited setting.

OBJECTIVE: To compare QuantiFERON-TB Gold-in-Tube (QFT) and tuberculin skin test (TST) in the diagnosis of latent tuberculosis infection (LTBI) among people living with HIV (PLWHIV). METHODS: A cross-sectional study was carried out between 2017-2018. Tuberculin skin test and QFT were performed and their concordance was measured. The gold standard for LTBI was defined as positivity to any of the tests. A logistic regression model was carried out to predict the QFT result in patients with a negative TST. RESULTS: A total of 510 PLWHIV were included, with 409 (80.2%) being male. The mean age of the patients was 41.3 ± 11.8 years. The median time since HIV diagnosis was 5 years (IQR 2-10), with a median CD4+ count of 541 (IQR 340-757) cells/mm3. Overall, 20 patients had an isolated TST+, 22 an isolated QFT+ and 15 had both positive. Concordance between tests showed a kappa coefficient of .37. Overcrowding was the only predictor for a positive QFT after a negative TST (p = .003). CONCLUSION: There was fair agreement between tests in PLWHIV. In conditions of limited access to QTF, a TST-based strategy could be considered, with sequential use of QTF in high-risk patients with a negative result, especially those who live in overcrowded conditions.

Incidence, Diagnosis and Treatment of Otorhinolaryngologicl, Head and Neck Tuberculosis: A Prospective Clinical Study

Abstract Introduction Tuberculosis is a disease of diversified presentation. It affects almost all organs in the body, and otorhinolaryngological, head and neck involvement is not an exception. Objective To increase awareness about the different clinical presentations of otorhinolaryngological, head and neck tuberculosis, the techniques employed to diagnose it, and to assess the response to the treatment. Methods We conducted a prospective study of 114 patients who presented primarily with otorhinolaryngological, head and neck tuberculosis. Routine blood investigations, chest radiographs, the tuberculin test, and sputum examination for the presence of acid-fast bacilli were performed in all cases. Site-specific investigations were performed in relevant cases only. The patients were treated according to the antitubercular treatment (ATT) regimen recommended by the Indian Ministry of Health and Family Welfare's National Tuberculosis Elimination Program (NTEP), and they were followed up clinically two and six months after starting the ATT. Results Tubercular cervical lymphadenopathy was the most common clinical presentation (85.96%), followed by deep neck abscess (5.27%). Fine-needle aspiration cytology proved to be a reliable tool for the diagnosis of tubercular lymphadenopathy. Improvement at the end of 2 and 6 months of the ATT was observed in 90.35% and 96.50% of the cases respectively. Conclusion The diagnosis of otorhinolaryngological, head and neck tuberculosis requires a high index of clinical suspicion, and the ATT proved to be very effective in reducing the severity of the disease.

Prevalence of Latent Tuberculosis Infection and its Associated Factors Among Diabetic Patients Availing Primary Health Care in Terengganu State, Malaysia.

Objectives: Diabetes mellitus (DM) patients are considered to be at high risk for contracting latent tuberculosis infection (LTBI). This study aimed to determine the prevalence of LTBI and its associated factors among diabetic patients attending primary care clinics in Terengganu state, Malaysia. Methods: This cross-sectional study was conducted among diabetic patients attending 11 health clinics in the Terengganu region from June 2017 to November 2018. The selected participants were administered a tuberculin skin test (TST). Simple and multivariate logistic regressions were applied to evaluate the significant associated factors of LTBI. Results: The total number of participants were 703 DM patients. The factors found associated with LTBI were poor diabetic control status (odds ratio (OR) = 8.53; p=0.008), being a healthcare worker (OR = 7.91; p=0.001), history of contact with TB patients (OR = 5.69; p < 0.001), bronchial asthma (OR = 5.28; p=0.019), coronary heart disease (OR = 3.45; p=0.026), and nephropathy (OR = 0.34; p=0.040). The presence of LTBI was found in 34 (4.8%) participants. Conclusions: At 4.8%, the prevalence of LTBI among DM patients in Terengganu is relatively low. Diabetics with poorly controlled blood glucose levels, nephropathy, bronchial asthma, coronary heart disease, history of TB patient contact, or working in the healthcare profession should be periodically tested for LTBI.

[Modality proposal of tuberculosis infection screening in high school contacts]. / Propuesta de modalidad de catastro de infección tuberculosa en contactos escolares de colegios secundarios.

The systematic registry of contacts with the objective of identifying and treating those with tuberculosis infection is one of the pillars established by the WHO in the end Tuberculosis Strategy. The risk of tuberculosis infection in school contacts, although lower than in households, is significant. However, compliance with preventive treatment is low and several points are open to discussion, such as the cutoff of the tuberculin test to be used, the usefulness of starting a chemoprophylactic treatment in the absence of confirmed infection or carrying out studies in contacts of non-bacilliferous index cases. This paper addresses these issues and proposes, with updated evidence, a screening modality for contacts in higher education institutions. This screening proposes to identify those infected using the cut-off point of 5 mm in the tuberculin test, offering preventive treatment and active follow-up only to those with a positive test.

El catastro sistemático de contactos con el objetivo de identificar y tratar a aquellos con infección tuberculosa es uno de los pilares establecidos por la OMS en su Estrategia de Fin a la Tuberculosis. El riesgo de infección tuberculosa en contactos escolares, aunque menor que en los domiciliarios, es significativo. Sin embargo, es bajo el cumplimiento del tratamiento preventivo y varios puntos se prestan a discusión, como ser el corte de la prueba tuberculínica a utilizar, el beneficio de iniciar un tratamiento quimioprofiláctico en ausencia de infección demostrada o de realizar estudios en contactos de casos índice no bacilíferos. Este escrito aborda dichos temas y propone, con evidencia actualizada, una modalidad de estudio para contactos en instituciones de enseñanza secundaria. Dicho catastro propone identificar a los infectados utilizando el punto de corte de 5 mm en la prueba de tuberculina, ofreciendo tratamiento preventivo y seguimiento activo solamente a aquellos con una prueba positiva.