Brucella abortus vaccines play a central role in bovine brucellosis control/eradication programs and have been successfully used worldwide for decades. Strain 19 and RB51 are the approved B. abortus vaccines strains most commonly used to protect cattle against infection and abortion. However, due to some drawbacks shown by these vaccines much effort has been undertaken for the development of new vaccines, safer and more effective, that could also be used in other susceptible species of animals. In this paper, we present a review of the main aspects of the vaccines that have been used in the brucellosis control over the years and the current research advances in the development of new B. abortus vaccines.

A cross sectional study was performed to assess the epidemiological status of bovine tuberculosis in the state of Minas Gerais, Brazil, in 2013. The state was divided into seven regions, and a preset number of herds was randomly sampled in each region. From each farm, female cattle aged 24 months or older were randomly sampled and subjected to the comparative cervical tuberculin test (CCTT). Animals with inconclusive test results were re-tested with the same diagnostic procedure after a minimum interval of 60 days. A total of 31 832 animals were tested from 2 182 farms. An epidemiological questionnaire was administered in the farms to identify risk factors associated with bovine tuberculosis. Prevalence in the state was estimated at 4.25% (95% CI: 3.36% -5.15%) for herds and at 0.56% (95% CI: 0.46% -0.66%) for animals. Data on herd prevalence for bovine tuberculosis for each stratum showed the highest prevalences at region Sul e Sudoeste (stratum 5) and region Central (stratum 3) which were significantly different from the lowest prevalences found at regions Noroeste, Norte e Nordeste (stratum 1) and region Leste (stratum 2). The highest animal prevalences observed for the region Sul e Sudoeste (stratum 5), region Zona da Mata (stratum 4) and region Central (stratum 3) were significantly different from the lowest ones at region Triângulo Mineiro (stratum 7), region Noroeste, Norte, e Nordeste (stratum 1) and region Leste (stratum 2). The presence of bovine tuberculosis was associated with animal purchase from cattle traders ResumoFoi realizado um estudo transversal para avaliar a situação epidemiológica da tuberculose bovina no estado de Minas Gerais em 2013. O Estado foi dividido em sete regiões e um número predefinido de fazendas foi amostrado aleatoriamente em cada região. Dentro de cada propriedade, fêmeas com idade igual ou superior a 24 meses foram escolhidas aleatoriamente e submetidas ao Teste Tuberculínico Cervical Comparativo (CCTT). Os animais com resultados inconclusivos foram retestados com o mesmo procedimento diagnóstico após um intervalo mínimo de 60 dias. Um total de 31832 animais foram testados provenientes de 2182 propriedades. Um questionário epidemiológico foi aplicado em cada fazenda para identificar fatores de risco associados à tuberculose bovina. A prevalência de focos no estado foi de 4,25% (IC 95%: 3,36 -5,15) e 0,56% (IC 95%: 0,46 -0,66) de animais. Em relação a prevalência de rebanho com tuberculose bovina para cada estrato, as maiores prevalências foram observadas nas regiões Sul e Sudoeste (estrato 5) e Central (estrato 3), que foram significativamente diferentes das menores prevalências encontradas nas regiões Noroeste, Norte e Nordeste (estrato 1) e Leste (estrato 2). As maiores prevalências de animais observadas nas regiões Sul e Sudoeste (estrato 5), Zona da Mata (estrato 4) e Central (estrato 3) foram significativamente diferentes das menores encontradas nas regiões do Triângulo Mineiro (estrato 7), Noroeste, Norte, e Nordeste (estrato 1) e Leste (estrato 2). A prese...

The aim of this study was to evaluate the Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR) as a tool for molecular typing of C. pseudotuberculosis isolates from eight different hosts in twelve countries. Ninety-nine C. pseudotuberculosis field strains, one type strain (ATCC 19410T) and one vaccine strain (1002) were fingerprinted using the ERIC-1R and ERIC-2 primers, and the ERIC-1R+ERIC-2 primer pair. Twenty-nine different genotypes were generated by ERIC 1-PCR, 28 by ERIC 2-PCR and 35 by ERIC 1+2-PCR. The discriminatory index calculated for ERIC 1, ERIC 2, and ERIC 1+2-PCR was 0.89, 0.86, and 0.92, respectively. Epidemiological concordance was established for all ERIC-PCR assays. ERIC 1+2-PCR was defined as the best method based on suitability of the amplification patterns and discriminatory index. Minimal spanning tree for ERIC 1+2-PCR revealed three major clonal complexes and clustering around nitrate-positive (biovar Equi) and nitrate-negative (biovar Ovis) strains. Therefore, ERIC 1+2-PCR proved to be the best technique evaluated in this study for genotyping C. pseudotuberculosis strains, due to its usefulness for molecular epidemiology investigations.

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Brucellosis is a neglected zoonotic disease of remarkable importance worldwide. The focus of this systematic review was to investigate occupational brucellosis and to identify the main infection risks for each group exposed to the pathogen. Seven databases were used to identify papers related to occupational brucellosis: CABI, Cochrane, Pubmed, Scielo, Science Direct, Scopus and Web of Science. The search resulted in 6123 studies, of which 63 were selected using the quality assessment tools guided from National Institutes of Health (NIH) and Case Report Guidelines (CARE). Five different job-related groups were considered greatly exposed to the disease: rural workers, abattoir workers, veterinarians and veterinary assistants, laboratory workers and hunters. The main risk factors and exposure sources involved in the occupational infection observed from the analysis of the articles were direct contact with animal fluids, failure to comply with the use of personal protective equipment, accidental exposure to live attenuated anti-brucellosis vaccines and non-compliance with biosafety standards. Brucella species frequently isolated from job-related infection were Brucella melitensis, Brucella abortus, Brucella suis and Brucella canis. In addition, a metaanalysis was performed using the case-control studies and demonstrated that animal breeders, laboratory workers and abattoir workers have 3.47 [95% confidence interval (CI); 1.47-8.19] times more chance to become infected with Brucella spp. than others individuals that have no contact with the possible sources of infection. This systematic review improved the understanding of the epidemiology of brucellosis as an occupational disease. Rural workers, abattoir workers, veterinarians, laboratory workers and hunters were the groups more exposed to occupational Brucella spp. infection. Moreover, it was observed that the lack of knowledge about brucellosis among frequently exposed professionals, in addition to some behaviors, such as negligence in the use of individual and collective protective measures, increases the probability of infection.

Brucella abortus S19 and RB51 strains have been successfully used to control bovine brucellosis worldwide; however, currently, most of our understanding of the protective immune response induced by vaccination comes from studies in mice. The aim of this study was to characterize and compare the immune responses induced in cattle prime-immunized with B. abortus S19 or RB51 and revaccinated with RB51. Female calves, aged 4 to 8 months, were vaccinated with either vaccine S19 (0.6–1.2 x 1011 CFU) or RB51 (1.3 x 1010 CFU) on day 0, and revaccinated with RB51 (1.3 x 1010 CFU) on day 365 of the experiment. Characterization of the immune response was performed using serum and peripheral blood mononuclear cells. Blood samples were collected on days 0, 28, 210, 365, 393 and 575 post-immunization. Results showed that S19 and RB51 vaccination induced an immune response characterized by proliferation of CD4+ and CD8+ T-cells; IFN-ɣ and IL-17A production by CD4+ T-cells; cytotoxic CD8+ T-cells; IL-6 secretion; CD4+ and CD8+ memory cells; antibodies of IgG1 class; and expression of the phenotypes of activation in T-cells. However, the immune response stimulated by S19 compared to RB51 showed higher persistency of IFN-ɣ and CD4+ memory cells, induction of CD21+ memory cells and higher secretion of IL-6. After RB51 revaccination, the immune response was chiefly characterized by increase in IFN-ɣ expression, proliferation of antigen-specific CD4+ and CD8+ T-cells, cytotoxic CD8+ T-cells and decrease of IL-6 production in both groups. Nevertheless, a different polarization of the immune response, CD4+- or CD8+-dominant, was observed after the booster with RB51 for S19 and RB51 prime-vaccinated animals, respectively. Our results indicate that after prime vaccination both vaccine strains induce a strong and complex Th1 immune response, although after RB51 revaccination the differences between immune profiles induced by prime-vaccination become accentuated.

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