Why does brucellosis cause fever?

Brucellosis is an infection caused by Brucella bacteria. The immune system reacts to the bacteria and can produce fever, sweating, tiredness, headache, muscle aches or joint pain. Symptoms may develop gradually and can fluctuate, which can make the illness harder to recognise without a medical history and appropriate testing.

Fever is a common presentation of Brucellosis. Fever has many other causes, so it does not on its own identify brucellosis. Exposure history is particularly useful, including contact with farm animals or animal tissues and eating unpasteurised dairy products.

Arrange a clinical assessment if brucellosis is a possibility, particularly after a relevant animal or food exposure. Tell the clinician about the timing of symptoms, recent travel, work with animals, consumption of unpasteurised dairy foods and any worsening joint, back or testicular pain. Testing and treatment need to be chosen by a clinician.

Rest, drink fluids if you can, and record fever patterns and other symptoms. Do not take leftover antibiotics or share medicines, as unsuitable treatment can complicate assessment and may not clear the infection.

Seek urgent medical care for confusion, severe headache with a stiff neck, trouble breathing, fainting, severe chest pain, persistent vomiting, or signs of severe dehydration. Get prompt assessment for fever with marked weakness, worsening localised joint or back pain, swelling or pain in a testicle, or symptoms during pregnancy.

Ask whether your exposures and symptoms fit brucellosis, which tests are appropriate, and how long treatment may need to be taken if infection is confirmed. Ask which symptoms could suggest an infection affecting a joint, the spine, the nervous system or another organ.