What is brucellosis? 

Brucellosis in horses is caused by Brucella abortus or Brucella suis bacteria. The infection is rare, especially in the United States and other countries that have control programs. The infection affects the supraspinal and atlantal bursae.

Clinical Signs: Brucellosis in horses causes fistulous withers in the supraspinous bursa or at the poll (poll evil). 

  • Initially the withers is swollen and painful 
  • Subsequent drainage is persistent
  • Prolonged infections can result in bone infection of the vertebral spines. 

Diagnosis: Aspiration of the bursal fluid is used to culture the organism. Once the infected bursa 

Treatment: If antibiotic therapy is not successful, surgery is often needed to remove the bursal lining.