Agricultural Disaster Preparedness and Recovery May 23, 2011 Print Friendly and PDF

Brucellosis (contagious abortion) is an infectious disease of domestic livestock caused by the Brucella species of bacteria (B. abortus, B. melitensis, B. suis, B. ovis). The disease also effects dogs (B. canis) and the wild buffalo and elk populations of Yellowstone National Park. Brucellosis causes abortions in all species and may permanently reduce fertility in a herd. The bacteria is transmitted through direct contact with aborted fetuses, placenta, semen, milk, or vaginal secretions. The bacteria may also be transmitted by contact with contaminated clothing or equipment.

Brucellosis is highly zoonotic, meaning that it can be transmitted from animals to people. Transmission of the disease occurs most often in people such as veterinarians and abattoir employees in close contact with pregnant, lactating, or slaughtered animals. Brucellosis may also be contracted through consumption of unpasteurized milk, cheese, or ice cream, or through contact with the live form of the Brucella vaccine.

Brucellosis is considered by the Centers for Disease Control and Prevention to be a potential weapon of bioterrorism. If you suspect an outbreak of Brucellosis was intentional, contact local law enforcement or the FBI immediately.

Endemic Areas

Brucella species of bacteria are found worldwide but are mostly controlled. Areas still prone to Brucellosis outbreaks among livestock are Africa, the Middle East, and parts of Asia and South America.

Clinical Signs


  • Abortions
  • Stillbirths
  • Testicular abscesses
  • Reduced milk production


  • Abortion
  • Retained placenta
  • Impaired fertility
  • Testicular atrophy


  • Abortion
  • Sterility
  • Lameness


Brucellosis in dogs may be treated with antibiotics, but they should be considered lifelong carriers of the disease. Due to the highly contagious nature and economic impact of the disease, livestock with Brucellosis must be slaughtered to eradicate the disease. Any animal suspected of having Brucellosis should be reported to the State Veterinarians or USDA Area Veterinarian in Charge immediately.


Brucellosis vaccines are available for cattle. To prevent the spread of Brucellosis, basic biosecurity procedures must be followed, including the quarantine of animals of unknown vaccination status before they enter the herd. In addition, any aborted fetus should be brought to the attention of a veterinarian immediately.

Public Health

Brucellosis is a public health threat. The disease is highly zoonotic and can be transmitted to people through contact with bodily secretions of infected animals, consumption of unpasteurized milk, cheese, or ice cream, or accidental injection with Brucella vaccines.

Brucellosis infection in people, also known as undulant fever, typically causes flu-like symptoms, including fever, headache, backache, and weakness. Severe infections can lead to Endocarditis (inflammation of the heart) and chronic pain and fatigue. Brucellosis may be treated with antibiotics, but full recovery may be slow if at all.


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