Although a “One Health” approach has been successfully implemented for emerging infectious zoonotic diseases with pandemic potential, we still lack a conceptual framework to address enzootic diseases like brucellosis. The vast majority of published brucellosis studies in the developing world rely solely on serology. An important shortcoming of brucellosis serology is the impossibility to infer which (smooth) Brucella spp. induced antibodies in the host. In this respect, mixed farming and especially raising small ruminants along with cattle, a common practice in the developing world, is reported to be a risk factor and a central question that has to be answered is whether cattle are infected with B. melitensis or with B. abortus or with both Brucella species. Therefore the isolation, identification and molecular characterization of Brucella spp. in human and the different livestock species needs to be undertaken to define a sound conceptual framework, identify the source of infection and plan appropriate control measures.