Human brucellosis is one of the world's most common zoonoses, with an incidence in certain countries exceeding 10 per 100,000 population, particularly in poor rural settings.
Rarely fatal, but relapse can occur with debilitating and economically devastating effects. It is considered a class B bioterrorist agent, is easily spread by aerosol, and is a significant hazard in microbiology laboratories.
The 4 main human pathogens causing disease are Brucella melitensis , B abortus , B suis , and B canis .
Most cases of brucellosis in Northern Europe and North America are acquired overseas and/or from consuming unpasteurized milk products including cheese.
The disease can affect any organ system and therefore presents in a variety of ways, especially as a prolonged fever of unknown origin, with associated rheumatic features in about 50% of cases. Diagnosis is based on clinical presentation and laboratory tests.
Combination antibiotic therapy is the mainstay of treatment and should be used for prolonged periods to prevent relapse of symptoms. There is disagreement about the optimum treatment regimen.
Brucellosis is a zoonotic disease that can affect various organs, tissues, and systems.  In humans it is caused by Brucella species including B melitensis , B abortus , B suis , and B canis (and more rarely by B pinnipediae , B cetaceae , and B inopinata BO1 ), which are pleomorphic gram-negative bacteria transmitted to humans from animal reservoirs. Most cases of brucellosis in Northern Europe and North America are acquired overseas and/or from consuming unpasteurized milk products including cheese. The disease tends to relapse and can rarely become chronic, although the definition and classification of chronic brucellosis remains controversial.   Brucella species are considered class B bioterrorist agents, due to the ease of infection through the inhalation of organisms.
Senior Lecturer (Honorary Consultant)
Liverpool School of Tropical Medicine and Royal Liverpool University Hospital
NJB is an author of several references cited in this monograph. NJB is partially supported by the National Institute of Health Research Health Protection Unit in Emerging and Zoonotic Infections at the University of Liverpool and Public Health England. He is affiliated with the Liverpool School of Tropical Medicine. Views expressed in this monograph are those of the contributor and do not necessarily represent the official position of the National Health Service, the National Institute for Health Research, the Department of Health, or Public Health England.
Specialist Trainee in Clinical Microbiology
Royal Liverpool University Hospital
AG is an author of several references cited in this monograph.
Consultant in Infectious Diseases
Whipps Cross Hospital
ST declares that she has no competing interests.
Infectious Diseases Consultant
Unit of Infectious Diseases
Rabin Medical Center
MP declares that she has no competing interests.
Professor of Medicine
Section of Infectious Diseases
Department of Medicine
Baylor College of Medicine
EJY declares that he has no competing interests.
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