Brucellosis

Definition

Brucellosis is an infectious disease caused by contact with animals carrying bacteria called Brucella.

Alternative Names

Rock fever; Cyprus fever; Undulant fever; Gibraltar fever; Malta fever; Mediterranean fever

Causes, incidence, and risk factors

Brucella can infect cattle, goats, camels, dogs, and pigs. The bacteria can spread to humans if you come in contact with infected meat or the placenta of infected animals, or if you eat or drink unpasteurized milk or cheese.

Brucellosis is rare in the United States, with approximately 100 - 200 cases each year.

People working in jobs requiring frequent contact with animals or meat -- such as slaughterhouse workers, farmers, and veterinarians -- are at high risk.

Symptoms

Acute brucellosis may begin with mild flu-like symptoms or symptoms such as:

• Fever
• Abdominal pain
• Back pain
• Chills
• Excessive sweating
• Fatigue
• Headache
• Loss of appetite
• Joint pain
• Weakness
• Weight loss

Classically, high fever spikes occur every afternoon. "Undulant" fever derives its name from this up-and-down fever.

Additional symptoms that may be associated with this disease:

• Muscle pain
• Swollen glands

The illness may be chronic and persist for years.

Signs and tests

• Blood culture
• Clean catch urine culture
• CSF culture
• Bone marrow culture
• Serology detecting brucellosis antigen

This disease may also alter the results of the following tests:

• Quantitative immunoglobulins (nephelometry)
• Serum immunoelectrophoresis
• Febrile/cold agglutinins

Treatment

Antibiotics are used to treat the infection and prevent it from coming back. Longer courses of therapy may be needed if there are complications.

Expectations (prognosis)

Relapse may occur, and symptoms may continue for years. As with tuberculosis, the illness can come back after a long period of time.

Complications

• Bone and joint lesions
• Chronic fatigue syndrome
• Encephalitis
• Infective endocarditis
• Meningitis

Calling your health care provider

Call for an appointment with your health care provider if you develop symptoms of brucellosis.

Also, call if your symptoms worsen or do not improve with treatment, or if new symptoms develop.

Prevention

Drinking and eating only pasteurized milk and cheeses is the most important preventative measure. People who handle meat should wear protective glasses and clothing and protect skin breaks from infection. Detecting infected animals controls the infection at its source. Vaccination is available for cattle, but not humans.

References

Franco MP, Mulder M, Gilman RH, Smits HL. Human brucellosis. Lancet Infect Dis. 2007;7:775-86.

Salata RA. Brucellosis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier. 2007: chap 331.