Brucella abortus

• Bovine brucellosis:
  • Caused by Brucella abortus
  • Eradicated in many countries including UK
  • Infection usually by ingestions but also venereal, skin abrasions, inhalation, transplacental
  • Abortion storms in susceptible herds
  • Abortion after fifth month of gestation due to placentitis
  • Brucellae excreted in foetal fluids for 2-4 weeks following abortion and at subsequent parturitions without abortion
  • Infection of mammary glands and lymph nodes persists for years
  • Excreted intermittently in milk for years
  • Seminal vesicles, ampullae, testicles and epididymus infected in bulls; necrotising orchitis
  • Decreased fertility in cows and bulls; decreased milk production
  • Localisation in spleen and lymphatic tissue of non-pregnant animals
  • Occasionally causes arthritis
• Isolated from closed cases of poll evil and fistulous withers in horses

• • Brucella abortus
    • Uncommonly localises in joints
    • Usually in carpal bursitis (hygroma) in cattle and bursitis in horses

Affects cattle, transmission is by ingestion and abortion occurs in last half of pregnancy. Placenta is covered by fibrinonecrotic tissue. Foetus often shows bronchopneumonia.