ISSN 2398-2993      

Brucella abortus


Veronica Fowler

Tammy Hassel




  • Kingdom: bacteria.
  • Phylum: proteobacteria.
  • Class: alphaproteobacteria.
  • Order: rhizobiales.
  • Family: brucellaceae.
  • Genus: brucella.
  • Species: brucella abortus.


  • Named after Sir David Bruce who discovered this organism.

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Clinical Effects



  • Brucellae are found in reproductive organs. Infected animals can become persistently infected acting as resevoirs of infection.


  • Infection normally occurs through ingestion of contaminated fetal tissue/fluids or being directly exposed to an aborting cow. 
  • Occasionally infection occurs through veneral contact, skin abrasions, inhalation or transplacental transmission.
  • Can also be transmitted through the conjunctiva, skin and respiratory tract.
  • Humans can become infected by handling contaminated tissues.

Pathological effects

  • Multiplication occurs within host phagocytes and lymph nodes.
  • Proliferates massively at midgestation in the reproductive tract leading to abortion around 5 months.
  • Early embryonic death → apparent infertility.
  • Abortion, fetuses partially autolyzed.
  • Epididymitis Epididymitis → loss of fertility.


Control via animal

  • Direct treatment of infected animals is ineffective.
  • Infected cattle should be slaughtered.

Control via environment

  • Rapid removal of aborted fetuses.


  • Vaccination has been used historically.
  • Two vaccines are currently available S19 and RB51.
Vets, or other personnel, administering live Brucella vaccines should take great care to avoid needle-stick injuries.  It is possible for humans to develop clinical brucellosis following such exposure and this debilitating condition will usually necessitate months of intensive antibiotic therapy with a high risk of relapse.


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Further Reading


Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Carvalho Neta A V, Mol J P, Xavier M N, Paixão T A, Lage A P & Santos R L (2010) Pathogenesis of bovine brucellosis. Vet J 184 (2), 146-55
  • Bercovich Z (2000) The use of skin delayed-type hypersensitivity as an adjunct test to diagnose brucellosis in cattle: a review. Vet Q 22 (3), 123-30 PubMed.
  • Bercovich Z. (1998) Maintenance of Brucella abortus-free herds: a review with
    emphasis on the epidemiology and the problems in diagnosing brucellosis in areas of low prevalence.
    Vet Q 20 (3), 81-8 PubMed.
  • Corbel M J (1997) Brucellosis - an overview. Emerg Infec Dis 3 (2), 1-12
  • Samartino L E & Enright F M (1993) Pathogenesis of abortion of bovine brucellosis. Comp Immunol Microbiol Infect Dis 16 (2), 95-101
  • ter Huurne A A, Meijer M & Dijkerman N A (1993) Latency of Brucella abortus causes problems in oriented control: a review. Tijdschr Diergeneeskd 118 (21), 679-83 PubMed.
  • Strausbaugh and Berkelman. (2003). Human Illness Associated with Use of Veterinary Vaccines. Clin Inf Dis 37 (3). PP 407-414.

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