Brucellosis: How It Spreads, Symptoms, Prevention and Treatment

Brucellosis is an infectious disease caused by bacteria of the Brucella family. People catch it from infected animals or from animal products contaminated with the bacteria. Animals that most often carry it include cattle, sheep, goats, pigs, dogs, bison, elk, caribou, moose and wild hogs. It is treatable with antibiotics, and it almost never spreads from person to person.

How people get it

• eating undercooked meat such as sheep, beef, goat or camel, or undercooked game such as bison, elk, caribou, moose and wild hog;
• consuming unpasteurized (raw) milk or other dairy products made from contaminated milk;
• breathing in the bacteria;
• getting body fluids from infected animals in the eyes, nose or mouth;
• dressing meat or hides from infected animals after hunting;
• getting certain animal vaccines in the eyes, nose or mouth, or accidentally injecting oneself while vaccinating animals; and
• working in a laboratory with Brucella samples.

People with certain jobs and hobbies face more exposure: slaughterhouse workers, hunters, veterinarians and veterinary staff, animal breeders and shelter staff, and laboratory workers. In fact, brucellosis is the most commonly reported bacterial infection acquired in laboratories.

Symptoms

Anyone who thinks they have been exposed should contact a health care provider. Symptoms vary, and some can last a long time before brucellosis is diagnosed. The first symptoms can include fever, unusual tiredness, sweating, headache, pain in the muscles, joints or back, loss of appetite and a general feeling of being unwell.

Other problems can persist, or come and go, until the infection is treated:

• recurring fevers;
• arthritis;
• swelling of the testicles and scrotum;
• infection of the heart (endocarditis);
• memory loss, confusion and irritability;
• depression; and
• swelling of the liver or spleen.

Prevention

Food and drink. The best protection is to avoid undercooked meat and unpasteurized dairy products, including milk, cheese and ice cream. Pasteurization is a heating process that destroys harmful bacteria. If you are not sure whether a dairy product is pasteurized, don't eat or drink it.

Working with animals. Animal caretakers such as veterinarians, vet techs and shelter staff, as well as hunters, butchers and herders, are at higher risk. Anyone handling animal tissues should wear rubber gloves, goggles, gowns or aprons, and masks or respirators, which keep the bacteria out of the eyes and out of cuts and wounds.

Laboratory work. Laboratory staff should take precautions when handling samples. After an exposure, they should assess their risk and follow recommendations for symptom monitoring and, where advised, blood tests and preventive antibiotics.

Treatment and recovery

Once tests confirm brucellosis, treatment is with antibiotics, taken for at least 6 to 8 weeks. The doctor chooses the drugs, so tell your providers if you are pregnant, allergic to doxycycline or rifampin, or have a weakened immune system. One strain, Brucella RB51, which can be caught from contaminated animal products, is resistant to rifampin and needs other antibiotics.

Finishing all the medicine matters: without proper treatment, the infection can become chronic, bringing long-term problems such as arthritis, endocarditis, chronic fatigue, depression and swelling of the liver or spleen. Recovery can take a few weeks to several months, depending on how sick the person is and when treatment starts. Death is rare, occurring in fewer than 2% of people infected.

Sources

• Centers for Disease Control and Prevention, "About Brucellosis": https://www.cdc.gov/brucellosis/about/index.html