Long-term efficacy of BCG vaccination in goat herds with a high prevalence of tuberculosis

Vaccination of goats against tuberculosis (TB) has been promoted as an ancillary tool for controlling the disease in infected livestock herds. A three-year trial to assess the efficacy of BCG vaccine was carried out in five goat herds. At the beginning of the trial (month 0), all animals were tested for TB using thee different diagnostic tests. Animals negative to all tests were vaccinated with BCG and all replacement goat kids were also systematically vaccinated throughout the trial. All animals were tested by Interferon-gamma release assay (IGRA) using vaccine compatible reagents at months 6, 12, 24, and 36. The risk factors for TB infection were also evaluated. At the end of the study, four out of five farms showed variable reductions of the initial prevalence (93.5%, 28.5%, 23.2%, and 14.3% respectively), and an overall incidence reduction of 50% was observed in BCG vaccinated goats, although adult vaccinated goats showed higher incidences than vaccinated goat kids. The unvaccinated positive animals remaining in herds and adult BCG vaccinated goats significantly enhanced the risk of infection in vaccinated animals. A systematic vaccination of goats with BCG, together with the removal of positive unvaccinated animals, may contribute to reducing the TB prevalence in goat herds.info:eu-repo/semantics/publishedVersio

Long-term efficacy of BCG vaccination in goat herds with a high prevalence of tuberculosis

Vaccination of goats against tuberculosis (TB) has been promoted as an ancillary tool for controlling the disease in infected livestock herds. A three-year trial to assess the efficacy of BCG vaccine was carried out in five goat herds. At the beginning of the trial (month 0), all animals were tested for TB using thee different diagnostic tests. Animals negative to all tests were vaccinated with BCG and all replacement goat kids were also systematically vaccinated throughout the trial. All animals were tested by Interferon-gamma release assay (IGRA) using vaccine compatible reagents at months 6, 12, 24, and 36. The risk factors for TB infection were also evaluated. At the end of the study, four out of five farms showed variable reductions of the initial prevalence (93.5%, 28.5%, 23.2%, and 14.3% respectively), and an overall incidence reduction of 50% was observed in BCG vaccinated goats, although adult vaccinated goats showed higher incidences than vaccinated goat kids. The unvaccinated positive animals remaining in herds and adult BCG vaccinated goats significantly enhanced the risk of infection in vaccinated animals. A systematic vaccination of goats with BCG, together with the removal of positive unvaccinated animals, may contribute to reducing the TB prevalence in goat herds

Immunogenicity and protection against mycobacterium caprae challenge in goats vaccinated with BCG and revaccinated after one year

Altres ajuts: INIA/FEDER/RTA2015-00043-C02-01Altres ajuts: INIA-FPI/CPD2016-0109Vaccination has been proposed as a supplementary tool for the control of tuberculosis in livestock. The long-term immunogenicity elicited by bacillus Calmette-Guerin (BCG) and the efficacy of revaccination were investigated in thirty goat kids distributed into three groups: unvaccinated controls, BCG (vaccinated at week 0) and BCG-BCG (vaccinated at weeks 0 and 56). Sixty-four weeks after the first vaccination, all animals were challenged with Mycobacterium caprae and examined post-mortem (pathology and bacterial load) at week 73. Antigen-specific interferon-gamma (IFN-γ) release was measured throughout the experiment. At week 59, peripheral blood mononuclear cells were stained for CD4, CD45RO and IFN-γ to determine the presence of antigen-specific cells secreting IFN-γ. The BCG-BCG group showed reductions in rectal temperatures, M. caprae DNA load in pulmonary lymph nodes (LN), the volume of lesions in pulmonary LN, mineralization in lungs, and higher weight gains compared to unvaccinated controls. IFN-γ responses were undetectable from 32 weeks after primary vaccination until revaccination, when the BCG-BCG group showed detectable IFN-γ production and a greater percentage of antigen-specific CD4+CD45RO+IFNγ+ and CD4−CD45RO+IFNγ+ cells compared to the BCG and control groups, which may be an indicator of the mechanisms of protection. Thus, re-vaccination of goats with BCG appears to prolong protection against infection with M. caprae

Immunogenicity and protection against Mycobacterium caprae challenge in goats vaccinated with BCG and revaccinated after one year

Vaccination has been proposed as a supplementary tool for the control of tuberculosis in livestock. The long-term immunogenicity elicited by bacillus Calmette-Guerin (BCG) and the efficacy of revaccination were investigated in thirty goat kids distributed into three groups: unvaccinated controls, BCG (vaccinated at week 0) and BCG-BCG (vaccinated at weeks 0 and 56). Sixty-four weeks after the first vaccination, all animals were challenged with Mycobacterium caprae and examined post-mortem (pathology and bacterial load) at week 73. Antigen-specific interferon-gamma (IFN-γ) release was measured throughout the experiment. At week 59, peripheral blood mononuclear cells were stained for CD4, CD45RO and IFN-γ to determine the presence of antigen-specific cells secreting IFN-γ. The BCG-BCG group showed reductions in rectal temperatures, M. caprae DNA load in pulmonary lymph nodes (LN), the volume of lesions in pulmonary LN, mineralization in lungs, and higher weight gains compared to unvaccinated controls. IFN-γ responses were undetectable from 32 weeks after primary vaccination until revaccination, when the BCG-BCG group showed detectable IFN-γ production and a greater percentage of antigen-specific CD4+CD45RO+IFNγ+ and CD4-CD45RO+IFNγ+ cells compared to the BCG and control groups, which may be an indicator of the mechanisms of protection. Thus, re-vaccination of goats with BCG appears to prolong protection against infection with M. caprae.info:eu-repo/semantics/publishedVersio

Evaluation of P22 antigenic complex for the immuno-diagnosis of Tuberculosis in BCG vaccinated and unvaccinated goats

Current eradication strategies of tuberculosis (TB) in goats mainly rely on the single intradermal tuberculin test (SIT) and single intradermal cervical comparative tuberculin tests (SICCTs). TB vaccination has been proposed as a cost-effective option in high-prevalence herds or countries where economic compensation for the slaughter of positive animals is not affordable. However, TB vaccination compromises the efficiency of tuberculin-based diagnostic tests. In this study, the performance of a new diagnostic platform, based on the P22 antigenic complex, was assessed for skin test (ST), interferon-gamma release assay (IGRA), and serology under different TB scenarios. The sensitivity (Se) of diagnostic tests was assessed in TB-infected goats from the same farm (herd A, N = 77). The specificity (Sp) was assessed in two TB-negative farms (both vaccinated against paratuberculosis): one TB unvaccinated (herd B, N = 77) and another vaccinated with bacille Calmette-Guérin (BCG) (herd C, N = 68). The single (s) P22-IGRA showed the highest Se among IGRA tests (91%), and the comparative (c) P22-ST showed the highest Sp (100% in herd B and 98% in herd C). Combined interpretation of techniques enabled the best diagnostic performances. Combining the SICCT + sP22-IGRA improved Se (97%) compared to SICCT + tuberculin-based IGRA (95%), with a reduction of Sp (95 and 100%, respectively). Besides, combination of P22-ELISA with cP22-ST or SICCT elicited a similar performance in the non-vaccination context (Se: 94 and 95%; Sp: 95 and 95%, respectively), but Sp was significantly higher for the combination with cP22-ST compared to SICCT in the TB vaccination context (95 and 79%, respectively). The combination of serological tests based on P22 and MPB83 showed higher complementarity and improved 13 percentage points the Se of P22-ELISA alone. These findings suggest that either cell-mediated or antibody-based diagnostic techniques, using the P22 antigen complex, can contribute to improve the immunodiagnostics of TB in goats under different TB control strategies.info:eu-repo/semantics/publishedVersio

A proof‑of‑concept study to investigate the efficacy of heat‑inactivated autovaccines in Mycobacterium caprae experimentally challenged goats

This study aimed to assess the efficacy of a heat-inactivated Mycobacterium caprae (HIMC) vaccine in goats experimentally challenged with the same strain of M. caprae. Twenty-one goats were divided into three groups of seven: vaccinated with heat-inactivated Mycobacterium bovis (HIMB), with HIMC and unvaccinated. At 7 weeks post-vaccination all animals were endobronchially challenged with M. caprae. Blood samples were collected for immunological assays and clinical signs were recorded throughout the experiment. All goats were euthanized at 9 weeks post-challenge. Gross pathological examination, analysis of lung pathology using computed tomography, and bacterial load quantification in pulmonary lymph nodes (LN) by qPCR were carried out. Only HIMC vaccinated goats showed a significant reduction of lung lesions volume and mycobacterial DNA load in LN compared to unvaccinated controls. Both vaccinated groups showed also a significant reduction of the other pathological parameters, an improved clinical outcome and a higher proportion of IFN-γ-producing central memory T cells after vaccination. The results indicated that homologous vaccination of goats with HIMC induced enhanced protection against M. caprae challenge by reducing lung pathology and bacterial load compared to the heterologous vaccine (HIMB). Further large-scale trials are necessary to assess the efficacy of autovaccines under field conditions.info:eu-repo/semantics/publishedVersio

A proof‑of‑concept study to investigate the efficacy of heat‑inactivated autovaccines in Mycobacterium caprae experimentally challenged goats

This study aimed to assess the efficacy of a heat-inactivated Mycobacterium caprae (HIMC) vaccine in goats experimentally challenged with the same strain of M. caprae. Twenty-one goats were divided into three groups of seven: vaccinated with heat-inactivated Mycobacterium bovis (HIMB), with HIMC and unvaccinated. At 7 weeks post-vaccination all animals were endobronchially challenged with M. caprae. Blood samples were collected for immunological assays and clinical signs were recorded throughout the experiment. All goats were euthanized at 9 weeks post-challenge. Gross pathological examination, analysis of lung pathology using computed tomography, and bacterial load quantification in pulmonary lymph nodes (LN) by qPCR were carried out. Only HIMC vaccinated goats showed a significant reduction of lung lesions volume and mycobacterial DNA load in LN compared to unvaccinated controls. Both vaccinated groups showed also a significant reduction of the other pathological parameters, an improved clinical outcome and a higher proportion of IFN-γ-producing central memory T cells after vaccination. The results indicated that homologous vaccination of goats with HIMC induced enhanced protection against M. caprae challenge by reducing lung pathology and bacterial load compared to the heterologous vaccine (HIMB). Further large-scale trials are necessary to assess the efficacy of autovaccines under field conditions.info:eu-repo/semantics/publishedVersio

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Study of vaccines and new strategies for the control of goat tuberculosis

La tuberculosi (TB) és una malaltia infecciosa causada per diferents membres del complex Mycobacterium tuberculosis (MTBC), que pot afectar un ampli ventall d'hostes, inclosos els éssers humans i diferents espècies d'animals domèstics i salvatges. La TB continua sent un problema important de salut animal amb un elevat impacte econòmic a tot el món. En animals domèstics, com ara les cabres, els programes de control de la tuberculosi basats en la prova i el sacrifici dels animals positius no sempre són factibles. Per tant, en les últimes dècades s'ha renovat l'interès en la investigació sobre la vacunació contra la tuberculosi i les proves diagnòstiques associades a la vacuna per al control de la malaltia en els animals. En aquest sentit, la present tesi aporta informació sobre l'eficàcia de diferents estratègies de vacunació contra la TB caprina i les proves diagnòstiques associades a la vacuna en cabres. En el primer estudi es va avaluar l'eficàcia en el camp de la vacunació a llarg termini de cabres amb la vacuna atenuada viva Mycobacterium bovis Bacil Calmette-Guérin (BCG) (soca danesa 1331) en cinc granges caprines amb diferents característiques i maneig. La vacunació sistemàtica de cabrits per a la reposició amb BCG va contribuir a una reducció progressiva de la incidència i de la prevalença de TB en els ramats de cabres. El segon estudi va tractar la durada de les respostes immunes induïdes per la BCG en cabres i l'eficàcia de la vacunació i revacunació amb BCG al cap d'un any. La durada de les respostes immunes induïdes per la vacunació amb BCG va ser inferior a un any i no va conferir una protecció significativa després del desafiament experimental amb M. Caprae, ans el contrari, la revacunació amb BCG després d'un any de la primera vacunació va proporcionar una millor protecció contra la infecció amb M. caprae. En el tercer estudi es va avaluar l'eficàcia d'un candidat vacunal basat en Mycobacterium bovis inactivat per calor (HIMB) en cabres desafiades experimentalment amb M. caprae. La vacunació parenteral amb HIMB va conferir una protecció similar a la vacunació parenteral amb BCG, obrint el camí per a la seva avaluació en condicions de camp. En el quart estudi es va avaluar el complex antigènic P22 (obtingut per immunopurificació de la tuberculina del M. bovis) com a eina per al diagnòstic immunològic (humoral i mediat per cèl·lules) de la TB en cabres. L'estudi es va dur a terme en diferents contextos de vacunació: vacunació amb BCG i contra la paratuberculosi (Mycobacterium avium subesp. paratuberculosis - MAP) i vacuna MAP sola. En animals vacunats amb BCG i MAP, la interpretació combinada del diagnòstic serològic mitjançant P22 i proves cutànies va resultar en una bona estratègia de diagnòstic de la TB en termes d'especificitat i sensibilitat. En tots els estudis de la present tesi, el còctel d'antigen basat en les proteïnes ESAT-6 i CFP-10, aplicat per a l'assaig d'alliberament d'interferó-gamma, es va utilitzar per diferenciar els animals infectats dels vacunats (DIVA). No es va detectar cap reacció d'interferència diagnòstica en els animals vacunats i revacunats amb BCG ,ni en cabres vacunades amb HIMB, fet que confirma la idoneïtat del còctel antigènic ESAT-6 i CFP-10 com a prova diagnòstica DIVA. En síntesi, les troballes de la present tesi encoratgen a l'ús de vacunes contra la TB i de les proves diagnòstiques associades a la vacunació com a estratègia útil per al control de la TB en cabres.La tuberculosis (TB) es una enfermedad infecciosa causada por diferentes miembros del complejo Mycobacterium tuberculosis (MTBC), la cual puede afectar a una amplia variedad de huéspedes, incluidos los seres humanos y diferentes especies de animales domésticos y salvajes. La TB sigue siendo un importante problema de salud animal con un alto impacto económico en todo el mundo. En los animales domésticos, como por ejemplo las cabras, los programas de control de la TB basados en la prueba y el sacrificio de los animales positivos no siempre se pueden llevar a cabo. Por este motivo, durante las últimas décadas se ha renovado el interés por la investigación sobre la vacunación antituberculosa y las pruebas de diagnóstico asociadas a la vacuna para el control de la TB animal. En este sentido, la presente tesis aporta información sobre la eficacia de diferentes estrategias de vacunación contra la tuberculosis en cabras y las pruebas de diagnóstico asociadas a la vacuna en esta especie. El primer estudio evaluó la eficacia en el campo de una vacunación a largo plazo de cabras con la vacuna viva atenuada de Mycobacterium bovis Bacilo Calmette-Guérin (BCG) (cepa danesa 1331) en cinco granjas de cabras con diferentes características y manejo. La vacunación sistemática de cabritos de la reposición con BCG contribuyó a una reducción progresiva de la incidencia y de la prevalencia de la TB en los rebaños de cabras. El segundo estudio abordó la duración de las respuestas inmunes provocadas por la BCG en cabras, así como la eficacia de la vacunación y revacunación con BCG después de un año. La duración de la respuesta inmunitaria inducida por la vacunación con BCG fue inferior a un año y no confirió una protección significativa frente a la infección experimental con M. caprae. Por el contrario, la revacunación con BCG después de un año de la primera vacunación proporcionó una mejor protección contra el desafío con M. caprae. En el tercer estudio se evaluó la eficacia de un candidato vacunal basado en Mycobacterium bovis inactivado por calor (HIMB) en cabras desafiadas experimentalmente con M. caprae. La vacunación parenteral con HIMB mostró una protección similar a la conferida por la vacuna BCG parenteral. Estos hallazgos abren el camino para su evaluación en condiciones de campo. El cuarto estudio evaluó el desempeño del complejo antigénico P22 (obtenido por inmunopurificación de la tuberculina de M. bovis) para el inmunodiagnóstico (serológico y mediado por células) de la TB en cabras. Este estudio se llevó a cabo en diferentes contextos de vacunación: vacuna BCG y vacuna contra la paratuberculosis (Mycobacterium avium subesp. paratubercuclosis - MAP) y vacunación contra MAP sola. En animales vacunados con BCG y MAP, la interpretación combinada del diagnóstico serológico utilizando P22 y pruebas cutáneas fue una estrategia de diagnóstico eficaz en términos de especificidad y sensibilidad. En todos los estudios de la presente tesis se utilizó el cóctel de antígenos basado en las proteínas ESAT-6 y CFP-10, aplicado para el ensayo de liberación de interferón-gamma, para la diferenciación de animales infectados de vacunados (DIVA). No se detectó ninguna reacción de interferencia diagnóstica ni en cabras vacunadas ni revacunadas con BCG, así como tampoco en cabras vacunadas con HIMB, lo que confirma la idoneidad del cóctel antigénico ESAT-6 y CFP-10 como prueba de diagnóstico DIVA. Los hallazgos generales de la presente tesis apoyan el uso de vacunas contra la tuberculosis y de las pruebas de diagnóstico asociadas a la vacunación como una estrategia útil para el control de la TB en cabras.Tuberculosis (TB) is an infectious disease caused by different members of the Mycobacterium tuberculosis complex (MTBC) which can affect a wide range of hosts, including different species of domestic and wild animals and humans. TB is still an important animal health issue with a high economic impact worldwide. In domestic animals, such as goats, TB control programs based on test-and-slaughter of positives are not always feasible. Therefore, the interest in the research on TB vaccination and vaccine-associated diagnostic tests for the disease control in animals has been renewed. In this regard, the present thesis provided insights into the efficacy of different vaccination strategies against caprine TB and vaccine-associated diagnostic tests in goats. The first study evaluated the efficacy in the field of a long-term vaccination of goats with the live-attenuated Bacilli Calmette-Guérin (BCG) vaccine (Danish 1331 strain) in five goat farms with different characteristics and management. The systematic vaccination of replacement goat kids with BCG contributed to a progressive reduction of TB incidence and prevalence in goat herds. The second study addressed the duration of immune responses elicited by BCG in goats and the efficacy of BCG vaccination and revaccination after one year. The lifespan of immune responses evoked by BCG vaccination was lower than one year and did not confer significant protection after M. caprae experimental challenge. On the contrary, BCG revaccination after one year of first vaccination provided better protection against M. caprae challenge. The third study evaluated the efficacy of the Heat-Inactivated Mycobacterium bovis (HIMB) vaccine candidate in experimentally M. caprae infected goats. Parenteral vaccination with HIMB showed similar protection to parenteral BCG vaccination, paving the way for its evaluation under field conditions. The fourth study assessed the performance of the antigen complex P22 (obtained by immunopurification of M. bovis tuberculin) for cell-mediated and serological immunodiagnosis of TB in goats under different vaccination contexts: BCG and Mycobacterium avium subesp. paratuberculosis (MAP) vaccination and MAP vaccination alone. In BCG and MAP vaccinated animals, combined interpretation of serological diagnostic using P22 and skin tests was a performant TB diagnostic strategy in terms of specificity and sensitivity. In all studies of the present thesis, the antigen cocktail based on ESAT-6 and CFP-10 proteins, applied for the Interferon-gamma release assay, was used for Differentiating infected from vaccinated animals (DIVA). Any diagnostic interference reaction was detected neither in BCG nor in BCG revaccinated, nor in HIMB vaccinated goats, confirming the suitability of ESAT-6 and CFP-10 antigen cocktail as a DIVA diagnostic test. Overall findings of the present thesis encourage the use of vaccines against TB and the vaccine-associated diagnostic tests as a useful strategy for control of TB in goats

Field evaluation of the efficacy of Mycobacterium bovis BCG vaccine against tuberculosis in goats

Abstract Background Control of animal tuberculosis (TB) through vaccination has emerged as a long-term strategy to complement test and slaughter control strategy. A pilot trial under field conditions was conducted in a goat herd with high TB prevalence to assess the efficacy of the Mycobacterium bovis BCG vaccine. Results Twenty-three goat kids vaccinated with BCG and other 22 unvaccinated control kids were euthanized at 18 months post-vaccination. Gross pathological and histopathological examination of target tissues was performed for detection of tuberculous lesions and assessment of vaccine efficacy. Mycobacterial culture and DNA detection were used to confirm Mycobacterium caprae infection. Vaccination significantly reduced the number of animals with TB lesions compared to unvaccinated controls (35% and 77%, respectively; P < 0.01). This reduction was even higher if only extra-pulmonary infection was considered (17% and 68%, respectively; P < 0.001). Conclusions This trial demonstrates that BCG vaccination of goats can significantly reduce the TB lesion rates in high disease exposure conditions, indicating that vaccination could contribute to the control of TB in domestic goats