Brucellosis in Swine

VIVO Infectious Diseases

Brucellosis in Swine

Swine brucellosis is widely distributed in populations of both domestic and feral swine, although the responsible biovars of B. suis vary geographically. Brucellosis in domestic swine has been well controlled in many countries, but wild boar and feral swine remain as distinct threats not only to domestic swine but to humans that harvest them for food.

There are multiple similarities between brucellosis in ruminants and swine. In both cases, infection frequently occurs by exposure through mucous membranes and the infecting bacteria colonize multiple tissues in the animal. Brucellosis in swine also results in reproductive losses from abortions, stillbirths and reduced litter size. Having said that, brucellosis in swine due to infection with B. suis shows some distinct differences from what is observed for brucellosis in ruminants:

Infected swine develop a prolonged viremia that can persist for many months or even years. There is also prolonged shedding of the bacteria from mucosal surfaces and in urine.
Venereal transmission of B. suis occurs commonly within populations of swine. Infected males appear to play a much greater role in transmission that is the case in ruminants and B. suis is commonly found in semen of infected boars.
Infected males and non-pregnant females contribute to transmission, which is generally not observed in ruminants.
Abortion does occurs in varying percentages of pregnant sows, but is generally not a major feature of swine brucellosis.
Processing swine in abattoirs poses a significant risk of zoonotic transmission to workers, which is not typical of what is seen with slaughter of infected ruminants.

There are no commercial vaccines for immunizing swine against brucellosis.

References

Chitradevi S, Rathnapraba S, Jagatheesan PNR. Swine brucellosis: A mini review. Int J Vet Sci Anim Husbandry 2024; 9:424-427.

Olsen SC, Tatum FM. Swine brucellosis: current perspectives. Vet Med (Auckl). 2016; 8:1-12.

Ruano ZM, Mateus TL, Vieira-Pinto M. An insight into brucellosis in wild boar and domestic pigs in Europe: A systematic review. J Infect Public Health. 2025; 18:102691.

Brucellosis in Ruminants

Brucellosis in Dogs

Updated February 2026. Send comments to Richard Bowen: rabowendvm@gmail.com