Pathogenesis and pathobiology of brucellosis in livestock.

Brucellaspecies are facultative, intracellular, Gram-negative bacteria with marked tropism for the pregnant reproductive tract of domestic animals. All Brucella species establish persistent infection in the reticuloendothelial system of their natural hosts. The mechanisms of placenta localisation, trophoblast tropism and abortion are poorly understood. A complete picture of the molecular determinants and mechanisms of the cell internalisation process began to emerge only recently. Cyclic beta-1,2-glucan is a molecule secreted into the periplasm of Brucella and is required for intracellular Brucella to avoid fusion of the phagosome with lysosomes. The type IV secretion system translocates Brucella effector proteins into host cells and is critical for both survival and replication of Brucella in infected host cells. Some aspects of the pathogenesis and pathobiology of brucellosis in productive domestic animals are discussed in this section.

Estudos de prevalência da brucelose bovina no âmbito do Programa Nacional de Controle e Erradicação de Brucelose e Tuberculose: Introdução / Prevalence studies on bovine brucelosis according to Brazilian National Program for the Control and Eradication of Bovine Brucellosis and Tuberculosis: Introduction

As estratégias de combate à brucelose bovina são bastante conhecidas e, até o momento, os resultados são divergentes. No Brasil, o Ministério da Agricultura, Pecuária e Abastecimento (MAPA) implementou, em 2001, o Programa Nacional de Controle e Erradicação da Brucelose e Tuberculose. Conhecer a situação epidemiológica da brucelose no início de um programa de controle permite: 1 - escolher as melhores estratégias de controle em função da frequência e padrão de distribuição da doença na população e 2 - acompanhar o programa com a finalidade de promover correções e evitar o desperdício de tempo e de recursos. Em razão disso, é necessário realizar estudos para dar suporte à escolha das melhores estratégias para os vários estados e regiões brasileiras e criar um mecanismo racional de verificação da efetividade das ações implementadas. Para tanto, o MAPA estabeleceu um Termo de Cooperação Técnica com a Faculdade de Medicina Veterinária da Universidade de São Paulo e envolveu também a Faculdade de Agronomia e Veterinária da Universidade de Brasília. Até o momento, foram concluídos os estudos de 15 unidades federativas, cujos resultados são apresentados nos artigos subsequentes. Além disso, há um 16º artigo que explora o impacto da vacinação de bezerras com a B19 na redução da prevalência da brucelose.

Although strategies for controlling and eradicating of bovine brucellosis are well known, the achievements vary widely. In 2001, the Brazilian Ministry of Agriculture, Livestock, and Food Supply (MAPA) started a new National Program for the Control and Eradication of Brucellosis and Tuberculosis (NPCEBT). In the beginning of a brucellosis control program, it is of utmost importance to gain insights into the epidemiological status of the disease in order to: (1) determine the sanitary measures according to the frequency and distribution patterns of the disease in the population; (2) monitor the development of the program and decide when to make adjustments, avoiding the waist of time and resources. As the epidemiological status of bovine brucellosis is not adequately known in Brazil, there was a case for undertaking cross-sectional studies targeted at identifying the best strategies for each state and region, as well as providing a basis for future appraisal of the NPCEBT. For this purpose, MAPA established a collaborative project with FMVZ-Universidade de São Paulo, which also included FAV-Universidade de Brasília. So far, 15 states completed the survey, whose results are described in the following papers. In addition, it is presented a paper that deals with modeling the impact of vaccination of heifers with strain 19 upon the reduction of brucellosis prevalence.

Estudos de prevalência da brucelose bovina no âmbito do Programa Nacional de Controle e Erradicação de Brucelose e Tuberculose: Introdução / Prevalence studies on bovine brucelosis according to Brazilian National Program for the Control and Eradication of Bovine Brucellosis and Tuberculosis: Introduction

As estratégias de combate à brucelose bovina são bastante conhecidas e, até o momento, os resultados são divergentes. No Brasil, o Ministério da Agricultura, Pecuária e Abastecimento (MAPA) implementou, em 2001, o Programa Nacional de Controle e Erradicação da Brucelose e Tuberculose. Conhecer a situação epidemiológica da brucelose no início de um programa de controle permite: 1 - escolher as melhores estratégias de controle em função da frequência e padrão de distribuição da doença na população e 2 - acompanhar o programa com a finalidade de promover correções e evitar o desperdício de tempo e de recursos. Em razão disso, é necessário realizar estudos para dar suporte à escolha das melhores estratégias para os vários estados e regiões brasileiras e criar um mecanismo racional de verificação da efetividade das ações implementadas. Para tanto, o MAPA estabeleceu um Termo de Cooperação Técnica com a Faculdade de Medicina Veterinária da Universidade de São Paulo e envolveu também a Faculdade de Agronomia e Veterinária da Universidade de Brasília. Até o momento, foram concluídos os estudos de 15 unidades federativas, cujos resultados são apresentados nos artigos subsequentes. Além disso, há um 16º artigo que explora o impacto da vacinação de bezerras com a B19 na redução da prevalência da brucelose.

Although strategies for controlling and eradicating of bovine brucellosis are well known, the achievements vary widely. In 2001, the Brazilian Ministry of Agriculture, Livestock, and Food Supply (MAPA) started a new National Program for the Control and Eradication of Brucellosis and Tuberculosis (NPCEBT). In the beginning of a brucellosis control program, it is of utmost importance to gain insights into the epidemiological status of the disease in order to: (1) determine the sanitary measures according to the frequency and distribution patterns of the disease in the population; (2) monitor the development of the program and decide when to make adjustments, avoiding the waist of time and resources. As the epidemiological status of bovine brucellosis is not adequately known in Brazil, there was a case for undertaking cross-sectional studies targeted at identifying the best strategies for each state and region, as well as providing a basis for future appraisal of the NPCEBT. For this purpose, MAPA established a collaborative project with FMVZ-Universidade de São Paulo, which also included FAV-Universidade de Brasília. So far, 15 states completed the survey, whose results are described in the following papers. In addition, it is presented a paper that deals with modeling the impact of vaccination of heifers with strain 19 upon the reduction of brucellosis prevalence.

Pathological, immunohistochemical and bacteriological study of tissues and milk of cows and fetuses experimentally infected with Brucella abortus.

This report describes a pathological, immunohistochemical and bacteriological study of 42 cows and their progeny (aborted fetuses, weak premature calves, and healthy full-term calves) infected at 6-7 months of gestation by conjunctival inoculation with Brucella abortus. Samples were collected at necropsy within 48 h of abortion or parturition. The most significant lesions were necrotizing and suppurative placentitis and lymphohistiocytic mastitis in cows, and fibrinous pleuritis, fibrinous pericarditis and bronchopneumonia in aborted fetuses. B. abortus was isolated more frequently from milk samples than from mammary tissues, and milk samples from cows with mastitis were often infected. Organisms were often demonstrated immunohistochemically and by culture in tissues showing moderate to severe histological changes.