Brucellosis in Pigs


Causal agent

Brucella suis biovars 1,2 and 3.  Biovar 4 occurs in Reindeer and Caribou, whereas Biovar 5 is in mice.  Brucella is a bacteria

Age group

All ages can be infected

Clinical signs


Generally no clinical signs exhibited by infected animals

Brucellosis suis in a testes


Can cause abortion, infertility and severe metritis


Can cause orchitis (infection of testes) and infertility

Piglets, Weaners

Posterior paralysis and lameness



The major route of infectivity is through contact with another pig.  Venereal transmission is possible.  Note many other mammals (wild and domestic) can carry and potentially transmit Brucella suis to pigs.  In Europe B. suis biovar 2 occurs in the Hare

Post-mortem Lesions


Generally none.  Many be abscessation sometime with necrosic foci in the liver.  Metritis and orchitis



Serological examination.    This has been a requirement for exporting pigs around Europe, but is now not required.  The UK is free of Brucella suis but it is endemic in the wild boars of Europe.

Note the relatively common organism Yersinia enterocolitica O:9 share a common antigen and this will cause false positive results.




This is a reportable disease.  Depopulation is the only viable option


Through good national and herd biosecurity measures

Zoonotic implications


Brucella is a serious zoonotic disease and causes ‘undulating fever’ in man.  This however, is primarily an occupational hazard.

Note Yersinia enterocolitica is also a zoonotic disease causing diarrhoea