Intracellular Passage Triggers a Molecular Response in Brucella abortus That Increases Its Infectiousness.

Brucella abortus is a facultatively extracellular-intracellular pathogen that encounters a diversity of environments within the host cell. We report that bacteria extracted from infected cells at late stages (48 h postinfection) of the intracellular life cycle significantly increase their ability to multiply in new target cells. This increase depends on early interaction with the cell surface, since the bacteria become more adherent and penetrate more efficiently than in vitro-grown bacteria. At this late stage of infection, the bacterium locates within an autophagosome-like compartment, facing starvation and acidic conditions. At this point, the BvrR/BvrS two-component system becomes activated, and the expression of the transcriptional regulator VjbR and the type IV secretion system component VirB increases. Using bafilomycin to inhibit BvrR/BvrS activation and using specific inhibitors for VjbR and VirB, we showed that the BvrR/BvrS and VjbR systems correlate with increased interaction with new host cells, while the VirB system does not. Bacteria released from infected cells under natural conditions displayed the same phenotype as intracellular bacteria. We propose a model in which the B. abortus BvrR/BvrS system senses the transition from its replicative niche at the endoplasmic reticulum to the autophagosome-like exit compartment. This activation leads to the expression of VirB, which participates in the release of the bacterium from the cells, and an increase in VjbR expression that results in a more efficient interaction with new host cells.

Levantamento epidemiológico visando à comparação das prevalências de Brucelose bovina através de “Ring Test” no município de Carmo-RJ, após 9 anos de vacinação de bezerras de 3 a 8 meses de idade / Epidemiological survey to compare the prevalence of bovine Brucellosis through a Ring Test in the city of Carmo-RJ, after 9 years of vaccination of heifers from 3 to 8 months of age

A equipe técnica do Centro Estadual de Pesquisa em Sanidade Animal Geraldo Manhães Carneiro (CEPGM), da Empresa de Pesquisa Agropecuária do Estado do Rio de Janeiro (PESAGRO-RIO), realizou em 2009, levantamento epidemiológico para Brucelose através do teste de triagem Teste do Anel do Leite (TAL) no município de Carmo. Foram testados 30 tanques de expansão, entre eles, comunitários, da Cooperativa e Laticínio local e tanques individuais. Como resultado do teste realizado no CEPGM, observou-se a prevalência de 38% para Brucelose bovina no município, indicando expressiva necessidade de aplicação de medidas de profilaxia e controle. Assim, foi instituída vacinação gratuita no município, em março de 2009. Durante 9 anos e 6 meses ininterruptos, foram vacinadas 18.777 bezerras. Em agosto de 2018, um novo levantamento epidemiológico foi realizado, procurando atingir os mesmos pontos de coleta do levantamento de 2009. Foi observada a prevalência de 6,6% para Brucelose, representando a expressiva redução de 83% na prevalência da doença nos rebanhos do município em questão.

Immunogenicity of adenovirus and DNA vaccines co-expressing P39 and lumazine synthase proteins of Brucella abortus in BALB/c mice.

Brucella poses a great threat to animal and human health. Vaccination is the most promising strategy in the effort to control Brucella abortus (B. abortus) infection, but the currently used live vaccines interfere with diagnostic tests and could potentially result in disease outbreak. Therefore, new subunit vaccines and combined immunization strategies are currently under investigation. In this study, immunogenicity and protection ability of a recombinant adenovirus and plasmid DNA vaccine co-expressing P39 and lumazine synthase proteins of B. abortus were evaluated based on the construction of the two molecular vaccines. Four immunization strategies (single adenovirus, single DNA, adenovirus/DNA, DNA/adenovirus) were investigated. The results showed that the immunization strategy of DNA priming followed by adenovirus boosting induced robust humoral and cellular immune responses, and it significantly reduced the numbers of B. abortus in a mouse model. These results suggest that it could be a potential antigen candidate for development of a new subunit vaccine against B. abortus infection.

Occurrence of oxidative stress in dairy cows seropositives for Brucella abortus.

Bovine brucellosis is an important zoonotic disease caused by the bacterium Brucella abortus that leads to economic losses due to animal discard and commercial restrictions. Since positive animals for brucellosis are culled, little is known about the pathogenesis of this disease. Therefore, the aims of this study were to evaluate possible changes in the activity of deaminase adenosine (ADA) and the oxidative stress in cows seropositives for brucellosis (Experiment I), and to evaluate the seroprevalence of B. abortus in dairy cows from the Western state of Santa Catarina, Southern Brazil (Experiment II). The Experiment I evaluated 20 pregnant cows: ten seropositives for B. abortus and ten seronegatives that were used as controls. The ADA activity and markers of oxidative stress (TBARS, catalase (CAT) and superoxide dismutase (SOD)) were evaluated in these animals. A reduction in the activity of ADA and catalase enzymes in seropositive animals was observed (p < 0.001). Conversely, there was an increase in TBARS levels and superoxide dismutase activity in cows infected by B. abortus (p < 0.001). The presence of oxidative stress and a reduction of ADA might be related to the modulation of the inflammatory response. The experiment II was performed due to a high number of herds with restrictions imposed by cases of brucellosis in the state of Santa Catarina in the last two years, and thus, the seroprevalence for B. abortus was evaluated in 1242 serum samples of cows of 69 herds. The serodiagnosis was performed using two tests: buffered acidified antigen and 2-mercaptoethanol. However, none of the serum samples were positive for B. abortus. Although we did not find seropositive animals for brucellosis in our study, the disease still requires continued surveillance, due to its economic impact, and to the oxidative stress caused by it, which may have contributed to cases of abortion in three seropositive cows (Experiment I) in the final third of the gestation.

Brucella abortus mutants lacking ATP-binding cassette transporter proteins are highly attenuated in virulence and confer protective immunity against virulent B. abortus challenge in BALB/c mice.

Brucella abortus RB51 is an attenuated vaccine strain that has been most frequently used for bovine brucellosis. Although it is known to provide good protection in cattle, it still has some drawbacks including resistance to rifampicin, residual virulence and pathogenicity in humans. Thus, there has been a continuous interest on new safe and effective bovine vaccine candidates. In the present study, we have constructed unmarked mutants by deleting singly cydD and cydC genes, which encode ATP-binding cassette transporter proteins, from the chromosome of the virulent Brucella abortus isolate from Korean cow (referred to as IVK15). Both IVK15ΔcydD and ΔcydC mutants showed increased sensitivity to metal ions, hydrogen peroxide and acidic pH, which are mimic to intracellular environment during host infection. Additionally, the mutants exhibited a significant growth defect in RAW264.7 cells and greatly attenuated in mice. Vaccination of mice with either IVK15ΔcydC or IVK15ΔcydD mutant could elicit an anti-Brucella specific immunoglobulin G (IgG) and IgG subclass responses as well as enhance the secretion of interferon-gamma, and provided better protection against challenge with B. abortus strain 2308 than with the commercial B. abortus strain RB51 vaccine. Collectively, these results suggest that both IVK15ΔcydC and IVK15ΔcydD mutants could be an attenuated vaccine candidate against B. abortus.

Monocyte-derived macrophages from Zebu (Bos taurus indicus) are more efficient to control Brucella abortus intracellular survival than macrophages from European cattle (Bos taurus taurus).

Brucellosis is one of the most important zoonotic diseases in the world. Considering its strict zoonotic nature, understanding of the pathogenesis and immunity of Brucella spp. in natural animal hosts is essential to prevent human infections. Natural resistance against brucellosis has been demonstrated in cattle, and it is associated with the ability of macrophages to prevent intracellular replication of Brucella abortus. Identification of breeds that are resistant to B. abortus may contribute for controlling and eradicating brucellosis in cattle. This study aimed to compare macrophages from Nelore (Bos taurus indicus) or Holstein (Bos taurus taurus) regarding their resistance to B. abortus infection. Macrophages from Nelore were significantly more efficient in controlling intracellular growth of B. abortus when compared to Holstein macrophages even under intralysosomal iron restricting conditions. Furthermore, Nelore macrophages had higher transcription levels of inducible nitric oxide synthase (iNOS) and TNF-α at 12h post-infection (hpi) and higher levels of IL-12 at 24 hpi when compared to Holstein macrophages. Conversely, Holstein macrophages had higher levels of IL-10 transcripts at 24 hpi. Macrohages from Nelore also generated more nitric oxide (NO) in response to B. abortus infection when compared to Holstein macrophages. In conclusion, cultured Nelore macrophages are more effective in controlling intracellular replication of B. abortus, suggesting that Nelore cattle is likely to have a higher degree of natural resistance to brucellosis than Holstein.

Avaliação genética das vacinas contra a brucelose bovina comercializadas no Brasil / Genetic evaluation of vaccine against bovine brucellosis marketed in Brazil

A prevenção contra infecções causadas por Brucella abortus em bovinos é realizada por meio da administração das amostras vacinais B19 e RB51. Existem relatos de que estas vacinas podem causar aborto em fêmeas vacinadas. Portanto, toda a ocorrência de aborto em animais vacinados merece um estudo aprofundado sobre a causa. No Brasil, não há registro sobre a origem das amostras B19 e RB51 utilizadas na produção das vacinas comerciais. Assim, um estudo para verificar possíveis mutações em relação às amostras referência USDA B19 e USDA RB51 de B. abortus se faz necessário, devido às amostras vacinais poderem reverter a sua virulência. Objetivou-se com este estudo caracterizar genotipicamente as amostras vacinais B19 e RB51 comercializadas no Brasil. A metodologia utilizada foi a genotipagem de genes marcadores destas amostras vacinais, por meio da amplificação pela reação em cadeia da polimerase. Os resultados obtidos permitiram a identificação do genótipo das vacinas comerciais B19 e RB51 disponíveis e utilizadas em bovinos no Brasil. A ausência de mutações nas vacinas testadas corrobora com a qualidade genética das mesmas, quanto à estabilidade dos genes analisados.

Vaccine strains B19 and RB51 are administered to cattle for prevention against infection by Brucella abortus. However, there are reports that these vaccines can cause miscarriages. Thus, every miscarriage among vaccinated animals should be thoroughly studied to determine the cause. In Brazil, there are no records on the origin of B19 and RB51 samples used in the preparation of commercial vaccines. Therefore, a study is needed to determine possible mutations in relation to the USDA reference samples of B. abortus due to the fact that vaccine samples could revert to the virulence of the disease. The aim of the present study was to perform a genotype analysis of vaccine strains B19 and RB51 used in Brazil. The methodology was based on the genotyping of marker genes of these vaccine strains by amplification using polymerase chain reaction. The results allowed the identification of the genotype of the B19 and RB51 commercial vaccine available for use on cattle in Brazil. The absence of mutations in the samples tested confirmed the genetic quality of the vaccines and stability of genes analyzed.

Immunoproteomics of Brucella abortus reveals differential antibody profiles between S19-vaccinated and naturally infected cattle.

Brucella abortus is a Gram-negative intracellular bacterium that causes infectious abortion in food-producing animals and chronic infection in humans. This study aimed to characterize a B. abortus S19 antigen preparation obtained by Triton X-114 (TX-114) extraction through immunoproteomics to differentiate infected from vaccinated cattle. Three groups of bovine sera were studied: GI, 30 naturally infected cows; GII, 30 S19-vaccinated heifers; and GIII, 30 nonvaccinated seronegative cows. One-dimensional (1D) and two-dimensional electrophoretic profiles of TX-114 hydrophilic phase antigen revealed a broad spectrum of polypeptides (10-79 kDa). 1D immunoblot showed widespread seroreactivity profile in GI compared with restricted profile in GII. Three antigenic components (10, 12, 17 kDa) were recognized exclusively by GI sera, representing potential markers of infection and excluding vaccinal response. The proteomic characterization revealed 56 protein spots, 27 of which were antigenic spots showing differential seroreactivity profile between GI and GII, especially polypeptides <20 kDa that were recognized exclusively by GI. MS/MS analysis identified five B. abortus S19 proteins (Invasion protein B, Sod, Dps, Ndk, and Bfr), which were related with antigenicity in naturally infected cattle. In conclusion, immunoproteomics of this new antigen preparation enabled the characterization of proteins that could be used as tools to develop sensitive and specific immunoassays for serodiagnosis of bovine brucellosis, with emphasis on differentiation between S19 vaccinated and infected cattle.

Murine and bovine γδ T cells enhance innate immunity against Brucella abortus infections.

γδ T cells have been postulated to act as a first line of defense against infectious agents, particularly intracellular pathogens, representing an important link between the innate and adaptive immune responses. Human γδ T cells expand in the blood of brucellosis patients and are active against Brucella in vitro. However, the role of γδ T cells in vivo during experimental brucellosis has not been studied. Here we report TCRδ(-/-) mice are more susceptible to B. abortus infection than C57BL/6 mice at one week post-infection as measured by splenic colonization and splenomegaly. An increase in TCRγδ cells was observed in the spleens of B. abortus-infected C57BL/6 mice, which peaked at two weeks post-infection and occurred concomitantly with diminished brucellae. γδ T cells were the major source of IL-17 following infection and also produced IFN-γ. Depletion of γδ T cells from C57BL/6, IL-17Rα(-/-), and GMCSF(-/-) mice enhanced susceptibility to B. abortus infection although this susceptibility was unaltered in the mutant mice; however, when γδ T cells were depleted from IFN-γ(-/-) mice, enhanced susceptibility was observed. Neutralization of γδ T cells in the absence of TNF-α did not further impair immunity. In the absence of TNF-α or γδ T cells, B. abortus-infected mice showed enhanced IFN-γ, suggesting that they augmented production to compensate for the loss of γδ T cells and/or TNF-α. While the protective role of γδ T cells was TNF-α-dependent, γδ T cells were not the major source of TNF-α and activation of γδ T cells following B. abortus infection was TNF-α-independent. Additionally, bovine TCRγδ cells were found to respond rapidly to B. abortus infection upon co-culture with autologous macrophages and could impair the intramacrophage replication of B. abortus via IFN-γ. Collectively, these results demonstrate γδ T cells are important for early protection to B. abortus infections.

Comparative analysis of the early transcriptome of Brucella abortus--infected monocyte-derived macrophages from cattle naturally resistant or susceptible to brucellosis.

Brucellosis is a worldwide zoonotic infectious disease that has a significant economic impact on animal production and human public health. We characterized the gene expression profile of B. abortus-infected monocyte-derived macrophages (MDMs) from naïve cattle naturally resistant (R) or susceptible (S) to brucellosis using a cDNA microarray technology. Our data indicate that (1) B. abortus induced a slightly increased genome activation in R MDMs and a down-regulated transcriptome in S MDMs, during the onset of infection, (2) R MDMs had the ability to mount a type 1 immune response against B. abortus infection which was impaired in S cells, and (3) the host cell activity was not altered after 12 h post-B. abortus infection in R MDMs while the cell cycle was largely arrested in infected S MDMs at 12 h p.i. These results contribute to an improved understanding of how host responses may be manipulated to prevent infection by brucellae.

Live Brucella abortus rough vaccine strain RB51 stimulates enhanced innate immune response in vitro compared to rough vaccine strain RB51SOD and virulent smooth strain 2308 in murine bone marrow-derived dendritic cells.

Brucella spp. are Gram-negative, coccobacillary, facultative intracellular pathogens. B. abortus strain 2308 is a pathogenic strain affecting cattle and humans. Rough B. abortus strain RB51, which lacks the O-side chain of lipopolysaccharide (LPS), is the live attenuated USDA approved vaccine for cattle in the United States. Strain RB51SOD, which overexpresses Cu-Zn superoxide dismutase (SOD), has been shown to confer better protection than strain RB51 in a murine model. Protection against brucellosis is mediated by a strong CD4+ Th(1) and CD8+ Tc(1) adaptive immune response. In order to stimulate a robust adaptive response, a solid innate immune response, including that mediated by dendritic cells, is essential. As dendritic cells (DCs) are highly susceptible to Brucella infection, it is possible that pathogenic strains could limit the innate and thereby adaptive immune response. By contrast, vaccine strains could limit or bolster the innate and subsequent adaptive immune response. Identifying how Brucella vaccines stimulate innate and adaptive immunity is critical for enhancing vaccine efficacy. The ability of rough vaccine strains RB51 and RB51SOD to stimulate DC function has not been characterized. We report that live rough vaccine strain RB51 induced significantly better (p ≤ 0.05) DC maturation and function compared to either strain RB51SOD or smooth virulent strain 2308, based on costimulatory marker expression and cytokine production.

Situação epidemiológica da brucelose bovina no Estado da Bahia / Epidemiological situation of bovine brucellosis in the State of Bahia, Brazil

O trabalho consistiu em estratificar o Estado da Bahia em quatro regiões com características homogêneas (circuitos produtores) para que fossem amostradas aleatoriamente, em cada uma delas, 300 propriedades. Em cada propriedade foram escolhidas, de forma aleatória, 10 a 15 fêmeas bovinas adultas, das quais foi obtida uma amostra de sangue. No total, foram amostrados 10.816 animais, provenientes de 1.413 propriedades. O protocolo de testes utilizado foi o da triagem com o teste do antígeno acidificado tamponado (Rosa Bengala) e a confirmação dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo se pelo menos um animal reagiu às duas provas sorológicas. As prevalências de focos e a de fêmeas adultas soropositivas do Estado foram de 4,2 por cento [3,1-5,3 por cento] e 0,66 por cento [0,41-0,93 por cento], respectivamente. Para os circuitos produtores foram: circuito 1, 5,8 por cento [3,6-8,7 por cento] e 0,86 por cento [0,41-1,3 por cento]; circuito 2, 3,1 por cento [1,5-5,6 por cento] e 1,2 por cento [0,25-2,1 por cento]; circuito 3, 6,3 por cento [4,0-9,3 por cento] e 1,7 por cento [0,66-2,7 por cento]; e circuito 4, 0,60 por cento [0,07-2,2 por cento] e 0,07 [0,00-0,21 por cento]. Para a análise de fatores de riscos associados à doença foi aplicado um questionário epidemiológico em cada propriedade visitada. Os fatores de risco (odds ratio, OR) associados à condição de foco foram: compra de reprodutores (OR= 2,27) e presença de áreas alagadiças (OR= 1,76). A vacinação de fêmeas de três até oito meses de idade foi um fator de proteção (OR= 0,53).

A study to characterize the epidemiological situation of bovine brucellosis in the State of Bahia was carried out in 2004. The State was divided into four similar production regions, 300 herds were randomly sampled in each region, and 10 to 15 adult bovine females were sampled in each of these herds. A total of 10,816 serum samples from 1,413 herds were collected. The serum samples were screened for antibodies to Brucella spp. by the Rose-Bengal Test (RBT), and all RBT-positive sera were re-tested by the 2-mercaptoethanol test (2-ME) for confirmation. A herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. The prevalence of infected herds and seropositive adult bovine females in Bahia State were: 4.2 percent [3.1-5.3 percent] and 0.66 percent [0.41-0.93 percent], respectively. In the production regions, prevalence of infected herds and animals were, respectively: region 1, 5.8 percent [3.6-8.7 percent] and 0.86 percent [0.41-1.3 percent]; region 2, 3.1 percent [1.5-5.6 percent] and 1.2 percent [0.25-2.1 percent]; region 3, 6.3 percent [4.0-9.3 percent] and 1.7 percent [0.66-2.7 percent]; and region 4, 0.60 percent [0.07-2.2 percent] and 0.07 percent[0.00-0.2 percent]. In each herd, an epidemiological questionnaire was applied. The risk factors (odds ratio, OR) associated with the presence of the infection were: purchase of breeding animals (OR = 2.27) and presence of flood areas (OR= 1.76). Vaccination of heifers from three to eight months of age was a protective factor (OR=0.53).

Situação epidemiológica da brucelose bovina no Distrito Federal / Epidemiological status of bovine brucellosis in the Federal District, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose bovina no Distrito Federal (DF). No total foram amostrados 2.019 animais, provenientes de 278 propriedades. Em cada propriedade visitada aplicou-se um questionário epidemiológico para verificar o tipo de exploração e as práticas de criação e sanitárias que poderiam estar associadas ao risco de infecção pela doença. O protocolo utilizado foi o da triagem com o teste do antígeno acidificado tamponado e a confirmação dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo quando pelo menos um animal foi reagente às duas provas sorológicas. A prevalência no DF foi de 2,5 por cento [1,0-5,1 por cento] para propriedades e de 0,16 por cento [0,04-0,28 por cento] para animais. Em razão dos resultados encontrados, que permitem pensar em estratégias de erradicação, recomenda-se que o DF intensifique o diagnóstico de brucelose, tanto na forma de testes sorológicos sistemáticos como pela introdução de mecanismos de detecção rápida em laticínios, em ambos os casos a fim de aumentar o número de propriedades certificadas como livres da doença e melhorar a sensibilidade do sistema de vigilância ativa.

A study to characterize the epidemiological status of brucellosis was carried out in the Federal District of Brazil. A total of 2,019 serum samples from 278 herds were collected. In each herd, it was applied an epidemiological questionnaire focused on herd traits as well as husbandry and sanitary practices that could be associated with the risk of infection. The serum samples were screened for antibodies against Brucella spp. by the Rose-Bengal Test (RBT), and all positive sera were re-tested by the 2-mercaptoethanol test (2-ME). The herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. Herd prevalence was estimated as 2.5 percent [1.0-5.1 percent] whereas animal prevalence was 0.16 percent [0.04-0.28 percent]. Given these results, that may warrant the implementation of eradication strategies, there is a case for intensifying the serological testing in the Federal District, coupled with the introduction of rapid detection methods by the dairy industries, with a view to increasing the number of accredited free herds and improving the sensitivity of the surveillance system..

Situação epidemiológica da brucelose bovina no Estado do Espírito Santo / Epidemiological situation of bovine brucellosis in the State of Espírito Santo, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose bovina no Estado do Espírito Santo. O Estado foi dividido em dois circuitos produtores. Em cada circuito foram amostradas aleatoriamente cerca de 300 propriedades e, dentro dessas, foi escolhido de forma aleatória um número pré-estabelecido de animais, dos quais foi obtida uma amostra de sangue. No total, foram amostrados 5.351 animais, provenientes de 622 propriedades. Em cada propriedade amostrada foi aplicado um questionário epidemiológico para verificar o tipo de exploração e as práticas de criação e sanitárias que poderiam estar associadas ao risco de infecção pela doença. O protocolo de testes utilizado foi o da triagem com o teste do antígeno acidificado tamponado e o reteste dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo quando pelo menos um animal foi reagente às duas provas sorológicas. Para o Estado, as prevalências de focos e de animais infectados foram, respectivamente, de 9,0 por cento [7,0-11,6 por cento] e 3,5 por cento [1,9-6,4 por cento]. Para os circuitos, as prevalências de focos e de animais infectados foram, respectivamente, de: circuito 1, 6,8 por cento [4,5-10,2 por cento] e 3,4 por cento [1,3-8,6 por cento]; circuito 2, 10,9 por cento [7,9 por cento-14,8 por cento] e 3,7 por cento [2,1-6,3 por cento]. Os fatores de risco (odds ratio, OR) associados à condição de foco foram: utilização de inseminação artificial (OR = 7,05 [2,51-19,82]) e confinamento/semiconfinamento dos animais (OR = 2,98 [1,22-7,26]). A vacinação de fêmeas entre três e oito meses de idade foi um fator protetor (OR = 0,03 [0,01-0,1]).

A study to characterize the epidemiological status of brucellosis was carried out in the State of Espírito Santo. The State was divided in two regions. Three hundred herds were randomly sampled in each region and a pre-established number of animals were sampled in each of these herds. A total of 5,351 serum samples from 622 herds were collected. In each herd, it was applied an epidemiological questionnaire focused on herd traits as well as husbandry and sanitary practices that could be associated with the risk of infection. The serum samples were screened for antibodies against Brucella spp. by the Rose-Bengal Test (RBT), and all positive sera were re-tested by the 2-mercaptoethanol test (2-ME). The herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. The prevalence of infected herds and animals in the State were, respectively, 9.0 percent [7.0-11.6 percent] and 3.5 percent [1.9-6.4 percent]. The prevalence of infected herds and animals in the regions were, respectively: region 1, 6.8 percent [4.5-10.2 percent] and 3.4 percent [1.3-8.6 percent]; and region 2, 10.9 percent [7.9-14.8 percent] and 3.7 percent [2.1-6.3 percent]. The risk factors (odds ratio, OR) associated with the presence of the infection were: use of artificial insemination (OR = 7.05 [2.51-19.82]) and intensive/semi-intensive management systems (OR = 2.98 [1.22-7.26]). Vaccination of heifers from three to eight months of age was a protective factor (OR = 0.03 [0.01-0.1]).

Situação epidemiológica da brucelose bovina no Estado de Goiás / Epidemiological status of bovine brucellosis in the State of Goiás, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose no Estado de Goiás. O Estado foi estratificado em três circuitos produtores. Em cada circuito foram amostradas aleatoriamente 300 propriedades e, dentro dessas, foi escolhido de forma aleatória um número pré-estabelecido de animais, dos quais foi obtida uma amostra de sangue. No total, foram amostrados 10.744 animais, provenientes de 900 propriedades. Em cada propriedade visitada aplicou-se um questionário epidemiológico para verificar o tipo de exploração e as práticas de criação e sanitárias que poderiam estar associadas ao risco de infecção pela doença. O protocolo de testes utilizado foi o da triagem com o teste do antígeno acidificado tamponado e a confirmação dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo quando pelo menos um animal foi reagente às duas provas sorológicas. No estrato 1, a prevalência foi de 7,7 por cento [4,7-10,7 por cento] para propriedades, e de 1,4 por cento [0,99-1,7 por cento] para animais. No estrato 2, foi de 19,5 por cento [15,0-24,0 por cento] para propriedades e de 2,6 por cento [2,0-3,1 por cento] para animais. No estrato 3, foi de 21,4 por cento [16,7-26,1] para propriedades e 4,3 por cento [3,7-5,0 por cento] para animais. A prevalência obtida para o Estado foi de 17,5 por cento [14,9-20,2 por cento] para propriedades e de 3,0 por cento [2,7-3,3 por cento] para animais. Os fatores de risco (odds ratio, OR) associados à condição de foco, segundo a análise multivariada, foram: compra de reprodutores a comerciantes de gado (OR = 2,06 [1,12-3,52]), ocorrência de abortos nos últimos 12 meses (OR = 5,83 [3,86-8,8]) e prática de vacinação contra brucelose (OR = 2,07 [1,38-3,09]). Tanto a ocorrência de aborto quanto a vacinação são, neste caso, consequência da presença de brucelose no rebanho.

A study to characterize the epidemiological status of brucellosis in the State of Goiás was carried out. The State was divided in three regions. Three hundred herds were randomly sampled in each region and a pre-established number of animals was sampled in each of these herds. A total of 10,744 serum samples from 900 herds were collected. In each herd, it was applied an epidemiological questionnaire focused on herd traits as well as husbandry and sanitary practices that could be associated with the risk of infection. The serum samples were screened for antibodies against Brucella spp. by the Rose-Bengal Test (RBT), and all positive sera were re-tested by the 2-Mercaptoethanol test (2-ME). The herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. For region 1, the herd prevalence was 7.7 percent [4.7-10.7 percent] and the animal prevalence was 1.4 percent [0.99-1.7 percent]. For region 2, the herd prevalence was 19.5 percent [15.0-24.0 percent] and the animal prevalence was 2.6 percent [2.0-3.1 percent]. For region 3, the herd prevalence was 21.4 percent [16.8-26.1 percent] and the animal prevalence was 4.3 percent [3.7-5.0 percent]. For the whole state, the herd prevalence was 17.5 percent [14.9-20.2 percent] and the animal prevalence was 3.0 percent [2.7-3.3 percent]. The multivariate analysis identified the following risk factors (odds ratio, OR) associated with positive herds: purchase of breeding stock from cattle traders (OR = 2.06 [1.12-3.52]), occurrence of abortions over the last 12 months (OR = 5.83 [3.86-8.8]), and vaccination against brucellosis (OR = 2.07 [1.38-3.09]). Both the abortions and the vaccination are, in this case, a consequence of the herd being infected with brucellosis.

Situação epidemiológica da brucelose bovina no Estado de Minas Gerais / Epidemiological status of bovine brucellosis in the State of Minas Gerais, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose bovina no Estado de Minas Gerais. O Estado foi estratificado em sete circuitos produtores. Em cada circuito foram amostradas aleatoriamente cerca de 300 propriedades e, dentro dessas, foi escolhido, de forma aleatória, um número pré-estabelecido de animais, dos quais foi obtida uma amostra de sangue. No total, foram amostrados 20.643 animais, provenientes de 2.204 propriedades. Em cada propriedade visitada aplicou-se um questionário epidemiológico para verificar o tipo de exploração e as práticas zootécnicas e sanitárias que poderiam estar associadas ao risco de infecção pela doença. O protocolo de testes utilizado foi o da triagem com o teste do antígeno acidificado tamponado e a confirmação dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo, se pelo menos um animal foi reagente às duas provas sorológicas. As prevalências de focos e de animais infectados do Estado foram de 6,0 por cento [5,0-7,1 por cento] e 1,1 por cento [0,78-1,4 por cento], respectivamente. Os resultados para os circuitos pecuários da prevalência de focos e de animais foram: circuito 1, 4,7 por cento [2,7-7,7 por cento] e 0,82 por cento [0,06-1,6 por cento]; circuito 2, 7,2 por cento [4,6-10,6 por cento] e 1,2 por cento [0,53-1,8 por cento]; circuito 3, 6,8 por cento [4,3-10,0 por cento] e 1,5 por cento [0,47-2,4 por cento]; circuito 4, 6,5 por cento [4,1-9,8 por cento] e 1,1 por cento [0,39-1,7 por cento]; circuito 5, 3,8 por cento [2,0-6,5 por cento] e 0,40 por cento [0,11-0,69 por cento]; circuito 6, 6,2 por cento [3,8-9,6 por cento] e 0,66 por cento [0,29-1,0 por cento]; circuito 7, 11,0 por cento [7,7-15,0 por cento] e 1,7 por cento [0,92-2,6 por cento], respectivamente. Os fatores de risco (odds ratio, OR) associados à condição de foco foram: compra de reprodutores (OR = 1,66 [1,13-2,44]), ocorrência de aborto nos últimos 12 meses (OR = 1,81 [1,26-2,60]) ...

A study to characterize the epidemiological status of brucellosis was carried out in the State of Minas Gerais. The State was divided in seven regions. Three hundred herds were randomly sampled in each region and a pre-established number of animals was sampled in each of these herds. A total of 20,643 serum samples from 2,204 herds were collected. In each herd, it was applied an epidemiological questionnaire focused on herd traits as well as husbandry and sanitary practices that could be associated with the risk of infection. The serum samples were screened for antibodies against Brucella spp. by the Rose-Bengal Test (RBT), and all positive sera were re-tested by the 2-mercaptoethanol test (2-ME). The herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. The prevalence of infected herds and animals in the State were, respectively, 6.0 percent [5.0-7.1 percent] and 1.1 percent [0.78-1.4 percent]. In the productive regions, the prevalence of infected herds and animals were, respectively: regions 1, 4.7 percent [2.7-7.7 percent] and 0.82 percent [0.06-1.6 percent]; region 2, 7.2 percent [4.6-10.6 percent] and 1.2 percent [0.53-1.8 percent]; region 3, 6.8 percent [4.3-10.0 percent] and 1.5 percent [0.47-2.4 percent]; region 4, 6.5 percent [4.1-9.8 percent] and 1.1 percent [0.39-1.7 percent]; region 5, 3.8 percent [2.0-6.5 percent] and 0.40 percent [0.11-0.69 percent]; region 6, 6.2 percent [3.8-9.6 percent] and 0.66 percent [0.29-1.0 percent]; and region 7, 11.0 percent [7.7-15.0 percent] and 1.7 percent [0.92-2.6 percent]. The risk factors (odds ratio, OR) associated with positive herds were: purchase of breeding stock (OR = 1.66 [1.13-2.44]), occurrence of abortions over the last 12 months (OR = 1.81 [1.26-2.60]), and the presence of deer in the farm (OR = 1.56 [1.08-2.27]). Vaccination against brucellosis was a protective factor (OR = 0.38 [0.19-0.79]). It can be concluded that the compulsory vaccination ...

Situação epidemiológica da brucelose bovina no Estado do Mato Grosso do Sul / Epidemiological situation of bovine brucellosis in the State of Mato Grosso do Sul, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose bovina no Estado de Mato Grosso do Sul. Foram definidos três estratos (regiões): Pantanal-corte, Planalto-corte e Planalto-leite, este último subdividido em Bolsão, Campo Grande e Dourados. Em cada estrato foram amostradas aleatoriamente propriedades e, dentro dessas, foi escolhido, de forma aleatória, um número pré-estabelecido de animais, dos quais foi obtida uma amostra de sangue. No total, foram amostrados 14.849 animais, provenientes de 1.004 propriedades. Em cada propriedade amostrada foi aplicado um questionário epidemiológico para verificar suas características e também para detectar transtornos reprodutivos que poderiam estar associados à infecção brucélica. O teste utilizado foi o do antígeno acidificado tamponado. O rebanho foi considerado positivo se pelo menos um animal foi reagente à prova sorológica. Para o Estado, a prevalência de focos foi de 41,5 por cento [36,5-44,7 por cento]. As prevalências de focos e de animais infectados por estrato foram, respectivamente, de: 59,0 por cento [52,8-64,9 por cento] e 12,6 por cento [9,1-17,2 por cento] para o estrato Pantanal-corte, e 40,6 por cento [35,8-45,5 por cento] e 4,5 por cento [2,1-9,0 por cento] para Planalto-corte. No estrato Planalto-leite, a prevalência de focos foi de 33,1 por cento [28,4-38,1 por cento]. Os fatores de risco (odds ratios, OR) associados à condição de foco foram: ter ≥500 vacas (OR = 2,46 [1,81-3,34]), ocorrência de bezerros fracos (OR = 1,20 [0,87-1,65]) e uso da inseminação artificial (OR = 0,71 [0,50-1,01]).

A study to characterize the epidemiological status of bovine brucellosis in the State of Mato Grosso do Sul was carried out. The State was divided in three regions: beef cattle Pantanal, beef cattle Plateau, and dairy cattle Plateau. Herds were randomly sampled in each region and a pre-established number of animals were sampled in each of these herds. A total of 14,849 serum samples from 1,004 herds were collected. In each herd, it was applied an epidemiological questionnaire focused on herd traits as well as clinical signs that could be associated with the brucellosis infection. The serum samples were tested for antibodies against Brucella spp. by the Rose-Bengal test. The herd was considered positive if at least one animal was positive. The prevalence of infected herds in the State was 41.5 percent [36.5-44.7 percent]. The prevalence of infected herds in the regions were, respectively: 40.6 percent [35.8-45.5 percent] for beef cattle Plateau, 59.0 percent [52.8-64.9 percent] for beef cattle Pantanal, and 33.1 percent [28.4-38.1 percent] for dairy cattle Plateau. The risk factors (odds ratio, OR) associated with the presence of the infection were: herd size larger than 500 cows (OR = 2.46 [1.81-3.34]), birth of weak calf (OR = 1.20 [0.87-1.65]), and use of artificial insemination (OR = 0.71 [0.50-1.01]).

Situação epidemiológica da brucelose bovina no Estado do Paraná / Epidemiological situation of bovine brucellosis in the State of Paraná, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose bovina no Estado do Paraná. O Estado foi estratificado em sete circuitos produtores ou regiões. Em cada circuito foram amostradas aleatoriamente cerca de 300 propriedades e, dentro dessas, foi escolhido de forma aleatória um número pré-estabelecido de animais, dos quais foi obtida uma amostra de sangue. No total, foram amostrados 14.857 animais, provenientes de 2.098 propriedades. Em cada propriedade amostrada foi aplicado um questionário epidemiológico para verificar o tipo de exploração e as práticas zootécnicas e sanitárias que poderiam estar associadas ao risco de infecção pela doença. O protocolo de testes utilizado foi o da triagem com o teste do antígeno acidificado tamponado e o reteste dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo se pelo menos um animal foi reagente às duas provas sorológicas. Para o Estado, os resultados de prevalências de focos e de animais infectados foram, respectivamente, de 4,0 por cento [3,2-4,8 por cento] e 1,7 por cento [1,1-2,4 por cento]. Para os circuitos, a prevalência de focos e a de animais foram, respectivamente: circuito 1, 14,7 por cento [10,9-19,2 por cento] e 2,8 por cento [1,2-4,4 por cento]; circuito 2, 8,8 por cento [5,9-12,6 por cento] e 2,4 por cento [1,0-3,8 por cento]; circuito 3, 3,4 por cento [1,6-6,1 por cento] e 0,85 por cento [0,21-1,5 por cento]; circuito 4, 2,3 por cento [0,94-4,8 por cento] e 0,83 por cento [0,02-1,6 por cento]; circuito 5, 2,3 por cento [0,94-4,7 por cento] e 1,6 por cento [0,06-3,3 por cento]; circuito 6, 0,3 por cento [0-1,9 por cento] e 0,09 por cento [0-0,27 por cento]; circuito 7, 1,0 por cento [0,21-2,9 por cento] e 2,2 por cento [0-6,0 por cento]. Os fatores de risco (odds ratio, OR) associados à condição de foco foram: compra de reprodutores (OR= 2,20 [1,42-3,40]) e prática de aluguel de pasto (OR= 2,45 [1,54-3,90]).

A study to characterize the epidemiological situation of bovine brucellosis in the State of Paraná was carried out. In this study, the State was divided into seven regions. Three hundred herds were randomly sampled in each region and a pre-established number of animals were sampled in each of these herds. A total of 1,4857 serum samples from 2,098 herds were collected. In each herd, it was applied an epidemiological questionnaire regarding herd features and also husbandry and sanitary practices that could be associated with risk of infection. The serum samples were screened for antibodies against Brucella spp. by the Rose-Bengal test (RBT), and all RBT-positive sera were re-tested by the 2-mercaptoethanol test (2-ME). A herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. The prevalences of infected herds and infected animals in Paraná State were 4.0 percent [3.2-4.8 percent] and 1.7 percent [1.1-2.4 percent], respectively. In the regions, the prevalences of infected herds and animals were: region 1, 14.7 percent [10.9-19.2 percent] and 2.8 percent [1.2-4.4 percent]; region 2, 8.8 percent [5.9-12.6 percent] and 2.4 percent [1.0-3.8 percent]; region 3, 3.4 percent [1.6-6.1 percent] and 0.85 percent [0.21-1.5 percent]; region 4, 2.3 percent [0.94-4.8 percent] and 0.83 percent [0.02-1.6 percent]; region 5, 2.3 percent [0.94-4.7 percent] and 1.7 percent [0.06-3.3 percent]; region 6, 0.34 percent [0-1.9 percent] and 0.09 percent [0-0.27 percent]; and region 7, 1.0 percent [0.21-2.9 percent] and 2.2 percent [0-6,0 percent]. The risck factors (odds ratio, OR) associated with the presence of the infection were: purchase of animals for breeding (OR= 2.20 [1.42-3.40]) and pasture rental practice (OR=2.45 [1.54-3.90]).

Situação epidemiológica da brucelose bovina no Estado do Rio de Janeiro / Epidemiological situation of bovine brucellosis in the State of Rio de Janeiro, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose bovina no Estado do Rio de Janeiro. O Estado foi dividido em três circuitos produtores. Em cada circuito foram amostradas aleatoriamente cerca de 300 propriedades e, dentro dessas, foi escolhido, de forma aleatória, um número pré-estabelecido de animais, dos quais foi obtida uma amostra de sangue. No total foram amostrados 8239 animais, provenientes de 945 propriedades. Em cada propriedade amostrada foi aplicado um questionário epidemiológico para verificar o tipo de exploração e as práticas zootécnicas e sanitárias que poderiam estar associadas ao risco de infecção pela doença. O protocolo de testes utilizado foi o da triagem com o teste do antígeno acidificado tamponado e reteste dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo se pelo menos um animal foi reagente às duas provas sorológicas. Para o Estado, as prevalências de focos e de animais infectados foram, respectivamente, de 15,4 por cento [12,9-17,9 por cento] e de 4,1 por cento [2,8-5,3 por cento]. Para os circuitos, as prevalências de focos e de animais infectados foram, respectivamente: circuito 1, 13,8 por cento [10,2-18,2 por cento] e 3,0 por cento [1,9-4,1 por cento]; circuito 2, 15,7 por cento [11,9-20,2 por cento] e 2,3 por cento [1,4-3,2 por cento]; circuito 3, 19,6 por cento [15,4-24,4 por cento] e 9,3 por cento [4,5-14,1 por cento]. Os fatores de risco (odds ratio, OR) associados à condição de foco foram: ter mais que 30 fêmeas com idade de 24 meses ou acima (OR=2,33 [1,51-3,07]), compra de reprodutores (OR= 1,95 [1,13-2,45]) e prática de aluguel de pasto (OR= 1,74 [1,03-2,74]).

A study to characterize the epidemiological status of bovine brucellosis in the State of Rio de Janeiro was carried out. The State was divided in three regions. Three hundred herds were randomly sampled in each region and a pre-established number of animals were sampled in each herd. A total of 8,239 serum samples from 945 herds were collected. In each herd, it was applied an epidemiological questionnaire focused on herd traits as well as husbandry and sanitary practices that could be associated with the risk of infection. The serum samples were screened for antibodies against Brucella spp. by the Rose-Bengal Test (RBT), and all positive sera were re-tested by the 2-mercaptoethanol test (2-ME). The herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. The prevalences of infected herds and animals in the State were, respectively: 15.4 percent [12.9-17.9 percent] and 4.1 percent [2.8-5.3 percent]. The prevalences of infected herds and animals in the regions were, respectively: region 1, 13.8 percent [10.2-18.2 percent] and 3.0 percent [1.9-4.1 percent]; region 2, 15.7 percent [11.9-20.2 percent] and 2.3 percent [1.4-3.2 percent]; and region 3, 19.6 percent [15.4-24.4 percent] and 9.3 percent [4.5-14.1 percent]. The risk factors (odds ratio, OR) associated with the presence of the infection were: herd size larger than 30 cows (OR=2.33 [1.51-3.07]), purchase of animals for breeding (OR= 1.95 [1.13-2.45), and pasture rental practice (R= 1.74 [1.03-2.74]).

Situação epidemiológica da brucelose bovina no Estado de Rondônia / Epidemiological situation of bovine brucellosis in the State of Rondônia, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da doença no Estado de Rondônia. O Estado foi estratificado em três circuitos produtores. Em cada circuito produtor foram amostradas aleatoriamente cerca de 300 propriedades e, dentro dessas, foi escolhido, de forma aleatória, um número pré-estabelecido de animais, dos quais foi obtida uma amostra de sangue. No total, foram amostrados 9.717 animais, provenientes de 927 propriedades. Em cada propriedade amostrada foi aplicado um questionário epidemiológico para verificar o tipo de exploração e as práticas zootécnicas e sanitárias que poderiam estar associadas ao risco de infecção pela doença. O protocolo de testes utilizado foi o da triagem com o teste do antígeno acidificado tamponado e o reteste dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo, se pelo menos um animal foi reagente às duas provas sorológicas. As prevalências de focos e de animais infectados do Estado foram de 35,2 por cento [32,1-38,4 por cento] e 6,2 por cento [4,9-7,6 por cento], respectivamente. Os resultados para os circuitos pecuários foram: circuito 1, 41,9 por cento [36,3-47,6 por cento] e 8,3 por cento [5,9-10,8 por cento]; circuito 2, 31,7 por cento [26,5-37,2 por cento] e 5,9 por cento [4,3-7,6 por cento]; circuito 3, 31,9 por cento [26,7-37,4 por cento] e 4,6 por cento [2,5-6,6 por cento]. Os fatores de risco (odds ratio, OR) associados à condição de foco foram: histórico de aborto (OR= 1,42 [1,04-1,95]) e exploração de corte (OR= 1,75 [1,30-2,38]).

A study to characterize the brucellosis epidemiological situation in the State of Rondônia was carried out. The State was divided into three regions. Three hundred herds were randomly sampled in each region. A pre-established number of animals were sampled in each of these herds. From 927 herds and 9,717 serum samples were collected. In each herd, it was applied an epidemiological questionnaire regarding herd features and also husbandry and sanitary practices that could be associated with risk of infection. The serum samples were screened for antibodies to Brucella spp. by the Rose-Bengal Test (RBT), and all RBT-positive sera were re-tested by the 2-mercaptoethanol test (2-ME). The herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. The prevalences of infected herds and animals in Rondônia State were 35.2 percent [32.1-38.4 percent] and 6.2 percent [4.9-7.6 percent], respectively. In the regions, the prevalences of infected herds and animals were, respectively: region 1, 41.9 percent [36.3-47.6 percent] and 8.3 percent [5.9-10.8 percent]; region 2, 31.7 percent [26.5-37.2 percent] and 5.9 percent [4.3-7.6 percent]; and region 3, 31.9 percent [26.7-37.4 percent] and 4.6 percent [2.5-6.6 percent]. The risk factors (odds ratio, OR) associated with the presence of the infection were: recent history of abortion (OR= 1.42 [1.04-1.95]) and beef herd (OR=1.75 [1.30-2.38]).