Health Encyclopedia

Brucellosis

Definition

Brucellosis is a bacterial infection that occurs from contact with animals carrying brucella bacteria.

Alternative Names

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

Causes

Brucella can infect cattle, goats, camels, dogs, and pigs. The bacteria can spread to humans by:

Coming in contact with infected meat or the placenta of infected animals
Eating unpasteurized cheese
Drinking unpasteurized milk

Brucellosis is rare in the United States. About 100 to 200 cases occur each year. Most cases are caused by the Brucella melitensis bacteria.

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

Brucella is found in many countries worldwide including:

Egypt
Iraq
Iran
Jordan
Saudi Arabia
Chad
Greece
Mexico

Symptoms

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

Abdominal pain
Back pain
Fever and chills
Excessive sweating
Fatigue
Headache
Joint and muscle pain
Loss of appetite
Swollen glands
Weakness
Weight loss

High fever spikes often occur every afternoon. The name undulant fever is often used to describe this disease because the fever rises and falls in waves.

The illness may be chronic and last for years.

Exams and Tests

Your health care provider will examine you and ask about your symptoms. You'll also be asked if you've been in contact with animals or possibly eaten dairy products that were not pasteurized.

Tests that may be done include:

Blood test for brucellosis
Blood culture
Bone marrow culture
Urine culture
CSF (spinal fluid) culture
Biopsy and culture of specimen from affected organ

Treatment

Antibiotics are used to treat the infection and prevent it from coming back. These include:

Doxycycline
Streptomycin
Gentamicin
Rifampin

Often, you need to take antibiotics for 6 weeks. If there are complications from brucellosis, you will likely need to take the medicines for a longer period.

Outlook (Prognosis)

Symptoms may come and go for years. Also, the illness can come back after a long period of not having symptoms.

Possible Complications

Health problems that may result from brucellosis include:

Bone and joint infection and damage
Encephalitis (swelling or inflammation of the brain)
Infective endocarditis (inflammation of the inside lining of the heart chambers and heart valves)
Meningitis (infection of the membranes covering the brain and spinal cord)

When to Contact a Medical Professional

Contact your provider for an appointment if:

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

Prevention

Drinking and eating only pasteurized dairy products, such as milk and cheeses, is the most important way to reduce the risk for brucellosis. People who handle meat should wear protective eyewear 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

Gotuzzo E, Ryan ET. Brucellosis. In: Ryan ET, Hill DR, Solomon T, Aronson NE, Endy TP, eds. Hunter's Tropical Medicine and Emerging Infectious Diseases. 10th ed. Philadelphia, PA: Elsevier; 2020:chap 75.

Gul HC, Erdem H. Brucellosis (Brucella species). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 226.

Review Date:8/26/2023
Reviewed By:Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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