Causes

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. About 100 - 200 cases occur each year.

People working in jobs where they often come in contact with animals or meat -- such as slaughterhouse workers, farmers, and veterinarians -- are at higher risk.

Symptoms

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

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

High fever spikes usually occur every afternoon. The name "undulant" fever is because the fever rises and falls in waves.

Other symptoms that may occur with this disease:

• Muscle pain
• Swollen glands

The illness may be chronic and last for years.

Exams and Tests

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

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

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

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.

Outlook (Prognosis)

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

Possible Complications

• Bone and joint sores (lesions)
• Encephalitis
• Infective endocarditis
• Meningitis

When to Contact a Medical Professional

Call for an appointment with your health care provider if:

• You develop symptoms of brucellosis
• Your symptoms get worse or do not improve with treatment
• You develop new symptoms

Prevention

Drinking and eating only pasteurized milk and cheeses is the most important way to prevent brucellosis. 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.

Alternative Names

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

References

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

Young EJ. Brucella Species. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Disease. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009: chap 226.

Updated: 4/24/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.