Brucella canis: an infectious cause of prolonged fever of undetermined origin.

We have reported a case documenting the difficulties encountered in diagnosing and treating patients with brucellosis caused by Brucella canis, including the nonspecific clinical presentation, low level of intermittent bacteremias, the slow-growing, fastidious nature of the organism, and the lack of antigenic cross-reactivity with the antigens usually used in routine Brucella serology. Further, the predominant southeastern United States epidemiology of this organism and the importance of exposure to dogs are also demonstrated by this report. It is important that physicians caring for patients in this region of the country be aware of the epidemiologic, serologic, and microbiologic pitfalls encountered in diagnosing B canis infections.