Brucellosis is an infection caused by bacteria. It can be passed from animals to people. It sometimes causes long-term illness.

Early in an infection, brucellosis can seem like the flu, with fever, weakness, and body aches. Brucellosis can get worse, especially if left untreated. The bacteria can attack many parts of the body, including the heart, liver, brain, and genitals.

Herd animals are most likely to have brucellosis infection. The bacteria can be shed by livestock, such as sheep, cows, goats, and pigs, and wild animals such as elk, bison, moose, wild boar, and caribou. Even pet dogs can spread the infection during breeding time. Sometimes miscarriage is an animal's only sign of infection.

Brucellosis is contagious.

• You can get infected by drinking or eating unpasteurized milk or cheese, or eating undercooked meat from an infected animal.
• You can inhale or ingest the bacteria when you handle an infected animal or its meat, hides, or wool. Hunters and people who work with animals tend to be most at risk for infection.
• If you are pregnant and have brucellosis, you can pass it to your baby before birth. You can also pass it after birth in your breast milk.

The infection can usually be cured if it's treated early with antibiotics. But some people go on to have long-term illness after treatment.