Submitted to: Veterinary Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 28, 2014
Publication Date: June 30, 2014
Citation: Olsen, S.C., Palmer, M.V. 2014. Advancement of knowledge of Brucella over the past 50 years. Veterinary Pathology. DOI: 10.1177/0300985814540545. Interpretive Summary: Brucella spp are intracellular pathogens that cause reproductive losses in domestic livestock and which also cause zoonotic infections in people. Regulatory programs in domestic livestock, which include vaccination of livestock, are the most cost-efficient way to control brucellosis and prevent human infection. In this manuscript, we describe advances in knowledge over the past 50 years regarding the pathogen, pathogenesis of infection and disease, and clinical disease and lesions associated with infection. This information will be of interest to scientists, regulatory personnel, people with responsibilities related to brucellosis, livestock owners, and other parties with interests regarding intracellular diseases of livestock.
Technical Abstract: Fifty years ago, bacteria in the genus Brucella were known to cause infertility and reproductive losses. The genus was considered to contain only three species, B. abortus, B. melitensis and B. suis. Since the early 1960’s, at least seven new species have been identified as belonging to the Brucella genus (B. canis, B. ceti, B. inopinata, B. microti, B. neotomae, B. ovis, and B. pennipedalis) with several additional new species under consideration for inclusion. Although molecular studies have found such high homology that some authors have proposed that all Brucella were actually one species, the epidemiologic and diagnostic benefits for separating the genus based on phenotypic characteristics is more compelling. Although pathogenic Brucella spps have preferred reservoir hosts, their ability to infect numerous mammalian hosts has been increasingly documented. The maintenance of infection in new reservoir hosts, such as wildlife, has become an issue for both public health and animal health regulatory personnel. Since the 1960’s new information on how Brucella enters host cells and modifies their intracellular environment has been gained. Although the pathogenesis and histologic lesions of B. abortus, B. melitensis, and B. suis in their preferred hosts hasn’t changed, additional knowledge on pathology of these brucellae in new hosts, or of new species of Brucella in their preferred hosts, has been obtained. To this day, Brucella remains a significant human zoonoses that is emerging or re-emerging in many parts of the world.