Tuberculose em Idade Pediátrica: Experiência de 12 Anos num Centro Terciário de Referência em Portugal

Introduction: The diagnosis of tuberculosis in children is a challenge namely because extrapulmonary tuberculosis and severe disease are more frequent in this age group. The aim of this study was to evaluate and reflect about severe tuberculosis in pediatric age, in a metropolitan area of Lisbon.Material and Methods: Descriptive study about patients under 18 years of age admitted with tuberculosis disease in a tertiary pediatric hospital, from 2008 to 2019 (12 years).Results: We report 145 patients, average of 12 cases/year, with an increase in the last three years. Median age of 12.9 years, 42.8% born in Portuguese-speaking African countries and 20% had a chronic disease. The diagnosis was pulmonary tuberculosis in 52.4% (n = 76) and extrapulmonary tuberculosis in 47.6%: lymphatic (n = 26), skeletal (n = 15), miliary (n = 8), meningeal (n = 7), peritoneal/ intestinal (n = 6), pleural (n = 4), renal (n = 1), cutaneous (n = 1), thoracic wall (n = 1) and salivary glands (n = 1). The tuberculin test was positive in 78/99 (78.8%) and Interferon Gamma Release Assay in 61/90 (67.8%). In 20.7% (n = 30) acid-fast bacilli were identified in gastric aspirate/sputum and the agent was identified in 59.3% (n = 86). Tuberculosis was resistant in 11% (n = 16). Patients with extrapulmonary tuberculosis were younger (p = 0.006) and had more prolonged therapy (p < 0.001). Therapy-related complications occurred in 11% (n = 16). One patient died (with terminal cancer).Conclusion: This study highlights the need for screening of tuberculosis in children from endemic countries, patients with immunosuppression and chronic disease.

A Short History of the BCG Vaccine

BCG vaccine continues to be controversial, live attenuated BCG is still the only vaccine in use which is able to prevent TB in humans. It is still difficult to determine which strain should be used and further detailed analysis of the genomics and immunogenicity of BCG sub-strains may provide an answer to this important question. The only vaccine available is the BCG (Bacille Calmette-Guerin), that has been used for about 100 years, with remarkable results. The majority of the world followed the lead of Europe and the WHO and introduced routine BCG vaccination according to various schedules. According to the Methodological Guide for the Implementation of the National Program for the Prevention, Surveillance and Control of Tuberculosis, BCG vaccination is indicated for all newborns, at the age of 2-7 days (if there are no contraindications), before discharge from maternity and without preliminary tuberculin test.

Immunodiagnostic Tests in the Assessment of Specific Sensitization to M. tuberculosis in Children under the Current Epidemical Situation

The objective: to study the degree of specific sensitization according to the results of intradermal immunodiagnostic tests in children with different manifestations of tuberculosis infection under the current epidemic situation.Subjects and Methods. The degree of tuberculin sensitization was studied in 299 children from different age groups (0-14 years old) who were registered for dispensary follow-up in 2018-2019.Based on the results of a tuberculosis recombinant allergen test (TRA), the degree of specific sensitization was studied in children with tuberculin tests conversion (n = 102) and infected with Mycobacterium tuberculosis (MTB) for 2 years or more (n = 165) exposed to tuberculous infection in their families and from healthy environment, and 145 patients under 14 years old with local respiratory tuberculosis.Results. Moderate sensitization to tuberculin predominated in children with converted tuberculin test exposed to tuberculous infection in their families and those from healthy environments. According to the results of TRA test, a high degree of sensitization was observed 4.7 times more frequently in children with tuberculin test conversion exposed to tuberculosis in their families. In children from healthy environments, negative responses to TRA test were registered 2.4 times more frequently. In 73% of children infected with MTB, results of annual Mantoux tests didn’t differ much. Hyperergic reactions to TRA test in infected children exposed to tuberculous infection were 10 times more frequent than in those from healthy environments. A direct correlation was found between the high degree of sensitization to active M. tuberculosis and exposure to a tuberculosis case with a positive result of sputum test (χ2 < 0.001, p < 0.05). In the case of converted tuberculin test and infection with M. tuberculosis for 2 years or more, pronounced and hyperergic reactions to TRA test were registered with equal frequency and did not depend on the timing and duration of infection. A high risk factor and predictor of the disease development is high sensitization of the host to active M. tuberculosis which is found in patients with tuberculosis using TRA test six times more frequently versus Mantoux test (OR 5.951, 95% CI 3.548 and 9.981). The demonstrated results are important for the identification of children facing a high risk to develop active tuberculosis and preventive treatment prescription.

Host Serum Proteins as Potential Biomarkers of Bovine Tuberculosis Resistance Phenotype

Eradication of bovine tuberculosis (bTB) continues to be a worldwide challenge. The lack of reliable vaccines dampens the control and eradication programs of Mycobacterium bovis infection and spread. Selection and breeding of cattle resistant to M. bovis infection would greatly enhance the effectiveness of bTB eradication programs. Here, we have evaluated the potential of serum proteins as biomarkers of cattle resistance to bTB in Holstein-Friesian cows, 6–8-year-old, born and raised in similar conditions in herds with bTB prevalence &gt;30%. Serum proteins obtained from uninfected cows (bTB-resistant; R) were compared to those from infected cows (bTB-susceptible; S), defined by a negative or positive bTB diagnosis, respectively. bTB diagnosis included: (i) single intradermal (caudal fold) tuberculin test, (ii) whole blood IFN-gamma test, (iii) gross visible lesions in lymph nodes and lungs by inspection at the abattoir, and (iv) a bacteriological culture for M. bovis. Using 2D-GE and LC-ESI-MS/MS, we found higher expression levels of primary amine oxidase (AO), complement component 5 (C5), and serotransferrin (TF) in R cattle than S cattle. In-house developed and standardized ELISAs for these novel biomarkers showed the best sensitivities of 72, 77, 77%, and specificities of 94, 94, 83%, for AO, C5, and TF, respectively. AUC-ROC (95% CI) values of 0.8935 (0.7906–0.9964), 0.9290 (0.8484–1.010), and 0.8580 (0.7291–0.9869) were obtained at cut-off points of 192.0, 176.5 ng/ml, and 2.1 mg/ml for AO, C5, and TF, respectively. These proteins are involved in inflammatory/immunomodulatory responses to infections and may provide a novel avenue of research to determine the mechanisms of protection against bTB. Overall, our results indicate that these proteins could be novel biomarkers to help identify cattle resistant to bTB, which in turn could be used to strengthen the effectiveness of existing eradication programs against bTB.

Bayesian Estimation of Diagnostic Accuracy of Three Diagnostic Tests for Bovine Tuberculosis in Egyptian Dairy Cattle Using Latent Class Models

The aim of the present study was to calculate the sensitivity (Se) and specificity (Sp) of the single cervical tuberculin test (SCT), rapid lateral flow test (RLFT), and real-time polymerase chain reaction (RT-PCR) for the diagnosis of Mycobacterium bovis (M. bovis) infection in Egyptian dairy cattle herds within a Bayesian framework. The true M. bovis infection within-herd prevalence was assessed as a secondary objective. Data on the test results of SCT, RLFT, and RT-PCR for the detection of M. bovis were available from 245 cows in eleven herds in six major governorates in Egypt. A Bayesian latent class model was built for the estimation of the characteristics of the three tests. Our findings showed that Se of SCT (0.93 (95% Posterior credible interval (PCI): 0.89–0.93)) was higher than that of RT-PCR (0.83 (95% PCI: 0.28–0.93)) but was similar to the Se of RLFT (0.93 (95% PCI: 0.31–0.99)). On the contrary, SCT showed the lowest Sp estimate (0.60 (95% PCI: 0.59–0.65)), whereas Sp estimates of RT-PCR (0.99 (95% PCI: 0.95–1.00)) and RLFT (0.99 (95% PCI: 0.95–1.00)) were comparable. The true prevalence of M. bovis ranged between 0.07 and 0.71. In conclusion, overall, RT-PCR and RLFT registered superior performance to SCT, making them good candidates for routine use in the Egyptian bovine tuberculosis control program.

The natural route of infection of guinea pigs from cows with tuberculosis in a cattle farm

The success of the fight against tuberculosis depends on timely and accurate diagnosis, since the identification and removal of animals suspected of the disease from the herd at the very beginning of the development of the infectious process is the main condition for recreational activities. Prevention of tuberculosis is based on the implementation of measures to prevent the introduction of the pathogen into a safe economy. Control of well-being is achieved by checking the number of cattle by intradermal tuberculin test twice a year (in spring and autumn), young cattle from two months of age and cattle of the feeding group - once a year. Carrying out such studies is quite sufficient, since it is known that the delayed-type hypersensitivity state develops 7-45 days after infection of cattle with M. bovis tuberculosis pathogen. The main disadvantage of allergic studies is the well-known fact that the reaction to the intradermal administration of tuberculin indicates only the sensitization of the animal's body by various types of mycobacteria. Non-tuberculosis mycobacteria do not cause pathological changes characteristic of tuberculosis in cattle and even in guinea pigs that are very sensitive to infection. Therefore, when monitoring the welfare of farms, the results of allergic studies are considered indicative, and the reacting animals are suspected of being infected. Decisive in the diagnosis is pathological or laboratory confirmation of tuberculosis in animals killed for diagnostic purposes. There is little data in the literature on the timing of the development of the infectious process and the identification of pathological changes in cattle characteristic of tuberculosis. Data on the timing of the detection of changes characteristic of tuberculosis in guinea pigs with natural infection from sick cows was not found. Previously conducted studies in an experiment on natural infection of cattle with tuberculosis, the authors found that when healthy cows are introduced into a dysfunctional herd, they become infected with tuberculosis with the formation of characteristic pathological changes approximately 12 months after they are kept together with sick animals. In an experiment on natural infection of guinea pigs, the authors found that guinea pigs in the same room with cows infected with M. bovis become infected and develop tuberculosis. Changes characteristic of tuberculosis in experimental guinea pigs are detected 5 months after they are kept together with sick cows. Based on a review of the literature and the results of the studies conducted, the authors propose to use guinea pigs as a laboratory model for reproducing tuberculosis in order to control the welfare of livestock farms in safe farms or to assess the quality of recreational activities in farms with tuberculosis.

The distribution of tuberculin reaction among children at school entry in Madaba, Jordan

The present study reports the results of a tuberculin test survey of a representative sample of BCG unvaccinated children at school entry age in the Madaba district in Jordan in 1991-92. Preschool household contacts of positive schoolchildren and a 5% random sample of negative schoolchildren were also screened by the same test. Three out of the 746 children screened by the initial school survey were found to be positive giving a prevalence rate of 0.4%. The overall prevalence rate of infection among preschool contacts was found to be 10.1% [28.6% among the contacts of the positive schoolchildren compared to 8.1% among contacts of the negative children]

Effect of the Inoculation Site of Bovine and Avian Purified Protein Derivatives (PPDs) on the Performance of the Intradermal Tuberculin Test in Goats From Tuberculosis-Free and Infected Herds

The single and comparative intradermal tuberculin (SIT and CIT) tests are used for the ante-mortem diagnosis of caprine tuberculosis (TB). The tuberculin injection site has been associated with a different performance of the test in cattle. In contrast to that required in cattle in Europe (cervical injection), it can be carried out in the scapular region in goats. Nevertheless, there are no previous data concerning the effect of the injection site on the performance of the test in goats. The aim of the present study was to evaluate the effect of two different inoculation sites (cervical and scapular) on the performance of the SIT/CIT tests. This was done by intradermally inoculating 309 goats from two infected herds and one TB-free herd with both avian and bovine PPDs in the mid-cervical and scapular regions. None of the animals from the TB-free herd had positive reactions, and the number of reactors was not significantly higher, regardless of the inoculation site, in the high and low prevalence herds. However, significantly higher increases in skin fold thickness were observed on the cervical site when compared to the scapular site after the avian and bovine PPD inoculations in the TB-free herd (p &lt; 0.001) and after the bovine PPD injection in the high prevalence herd (p = 0.003). The presence of clinical signs was also more evident on the cervical site when using avian and bovine PPDs in the high prevalence herd (p &lt; 0.01). In contrast, increases in higher skin fold thickness were observed on the scapular site when compared to the cervical site after the bovine and avian PPD inoculations were employed in the low prevalence herd (p &lt; 0.01). These results suggest that the cervical injection of PPDs may improve the sensitivity of the intradermal tuberculin test in high TB prevalence caprine herds, mainly owing to the increased presence of local clinical signs and a better performance of the CIT test. Moreover, specificity was not affected when using standard interpretations, although further analyses in a great number of herds are required in order to confirm these findings.