Brucellosis is caused by the gram-negative, aerobic and intracellular bacillus of Brucella spp.

• It is an important cause of Pyrexia of Unknown Origin (PUO) in a returning traveller, with fevers that are classically remittent (temperature remains normal throughout the day and fluctuates more than 1 degree over 24 hours).

Epidemiology

• The disease is endemic worldwide, but particularly in areas with high levels of animal farming or animal-to-human contact.
• Animals affected include cattle, goats, sheep, camels, foxes, and dogs.
• The Middle East and North Africa are particularly high risk, as well as parts of Europe including Portugal, Spain, Greece and Turkey.

Transmission

• In travellers, this is commonly via consumption of untreated milk/dairy (especially unpasteurized) products, as well as raw meat or liver.
• Abbatoir workers, meat packers, vets, and hunters can also acquire it through the skin or mucous membrane contact (e.g. conjunctiva from eye splashes, or needlestick injury).
• The most common mode of transmission in farmers is via inhalation.
• It is very important to inquire about animal exposure and consumption of unpasteurized dairy products in any returning traveller with possible signs/symptoms consistent with brucellosis.

PC

• The presentation is often non-specific, with fever, weight loss, night sweats, lymphadenopathy and joint pain/myalgia or spinal tenderness.
• The incubation period is about 5-30 days or longer (can be many months).

Signs:

• Hepatosplenomegaly occurs in about 1/3 of patients, and patients often look pale and unwell on presentation.
• Other less common signs include:
  • Testicular pain due to orchitis
  • Respiratory signs: consolidation, hilar lymphadenopathy, pleural effusions, lung nodules. These are often associated with a dry cough.
  • Focal brain or cranial nerve lesions
  • Uveitis/conjunctivitis
  • Skin rashes