Also known as undulant fever, Malta fever, Mediterranean fever and Bang’s disease, brucellosis is a disease with symptoms that can last from a few weeks to several years. It is characterised by fever and non-specific flu-like symptoms including myalgia, headache and arthralgia. Occasionally the infection may present with focal sepsis in bones or joints. Neurological symptoms appear in a minority of patients and can last for years leading to chronic fatigue syndrome.
Brucellosis is caused by bacteria of the genus Brucella, which can be transmitted from animals to humans by direct contact, or by the consumption of contaminated food and water. Veterinarians as well as people working on farms, in abattoirs and laboratories are more at risk of infection by inhalation of the bacteria or through contamination of open skin wounds. Although rare, cases of person-to-person contact have been reported via breast-feeding, child birth, sexual contact, transfusion and bone marrow transplants.
Five species of Brucella are known to be pathogenic to humans and each has a specific animal reservoir: B. abortus (cattle), B. melitensis (goats and sheep), B. suis (pigs), B. ceti and B. pinnipedialis in marine animals and very rarely B. canis (dogs). B. abortus is generally associated with cattle and is the most common species worldwide (Acha & Szyfres, 2003a). Control and eradication programmes for brucellosis have reduced its incidence in humans. Global incidence ranges from <1 case per 1,000,000 population (e.g. UK, USA, Australia), to 20-30 cases per 1,000,000 population (southern European countries, e.g. Greece and Spain), to over 70 cases per 1,000,000 population in Middle Eastern countries.