Applying One Health to understand brucellosis biology
Guzmán Verri, Caterina
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Members of the Brucella genus, are facultative extracellular intracellular zoonotic bacteria that cause reproductive disease in animals. The different species show strong host preference in spite of sharing 96-98% similarity at genome level. An integrated effort to understand brucellosis is taking place in Costa Rica, a tropical country of 51 000 km2 located in Central America. A total of 545 277 bovines were sampled between 2012-2016 from 8 672 herds. Sheep, goats, pigs, water buffaloes, horses and stranded cetaceans were also sampled between 1999-2016. Human and dog reported cases were documented. Seroprevalence data and the implications for the control of the disease will be presented. WGS and MLVA analysis of Brucella abortus isolated from bovines and humans indicated the presence of several clusters, some in specific areas and others widely distributed in the country. Interestingly, the human isolates constituted an unique cluster. The first two human cases worldwide of Brucella neotomae were also reported. By the same means, elements of genetic variation were described, and in Brucella from marine mammals worldwide, they are related to oceanic distribution and preferred host. Extensive pseudogenization was found in these isolates as compared to terrestrial ones. In B. ceti isolates from wildlife dolphins further degradation of specific metabolic pathways was observed. Thus, gene loss through pseudogenization is a source of genetic variation in Brucella that relates to host preference. These findings are important to understand the natural history of brucellosis, its zoonotic potential and the impact of human interventions such as vaccination and domestication.