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Brucellosis, also known as undulant fever or Mediterranean fever, is caused by the organism Brucella melitensis. The organism infects all domestic and wild animals. Human infections arise through direct contact with infected animals or their milk. 

Human infections usually arise from direct contact with infected animals (cattle, swine, goats, sheep and dogs) or their milk.
Infection is through ingestion (unpasteurised milk and milk products), inhalation (aerosols) or direct inoculation (usually in those with an occupational exposure such as veterinarians or farmers).

Incubation period
Incubation is variable, typically 5-30 days, but may be up to 6 months. The infection may persist for several months without causing any symptoms.

Signs and Symptoms

  • Continued, intermittent or irregular fever of variable duration
  • Headache
  • Weakness
  • Profuse sweating
  • Chills
  • Arthralgia
  • Depression
  • Weight loss
  • Generalized aching
  • Localized suppurative infections of organs
  • Osteo-articular complications are common


  • History of exposure
  • Clinical features
  • Laboratory findings (blood tests)

Brucellosis is usually treated with a combination therapy of doxycycline and rifampicin for a minimum of six weeks. Follow-up for a minimum period of a year is essential to encourage patient adherence to treatment and to detect relapse.

Control and Prevention

  • Educate the public against drinking untreated/unpasteurised milk or eating dairy products produced from such milk. Boiling milk is effective when pasteurisation is not available.
  • Educate farmers and handlers of potentially infected animals to reduce exposure and exercise care in handling placentae, discharges and foetuses.
  • Search for and investigate livestock at risk of infection.
  • No vaccine available for humans

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