Reporting Obligations

Suspected cases must be reported immediately by phone to the Thunder Bay District Health Unit at 625-5930 or toll-free 1-888-294-6630, ext. 5930 (Monday-Friday, 8:30am to 4:30pm). After hours and on weekends/holidays call Thunder Bay Answering Service at (807) 624-1280.



Aetiologic Agent:

Brucellosis is caused by the bacterium Brucella. Brucella species are small, nonmotile, gram-negative coccobacilli. The species that infect humans include B. suis, B. abortus, B. melitensis, and rarely B. canis.

Brucellosis is a potential bioterrorism agent.

Clinical Presentation:

Onset of symptoms may be acute or insidious; it is a systemic infection characterized by continued, intermittent or irregular fever, headache, weakness, sweating, chills, arthralgia, depression, weight loss or generalized aching. Localized infections of organs, including the liver and spleen may be present. Physical findings include lymphadenopathy, hepatosplenomegaly, and occasionally arthritis. Serious complications include meningitis, endocarditis and osteomyelitis

Modes of Transmission:

Transmission occurs through ingestion of raw milk and unpasteurized dairy products from infected animals, through direct contact of breaks in the skin and mucous membrane with infected animal tissue and their discharges and from fetuses and placentas. Airborne inhalation in laboratories and abattoirs has also been reported.

Incubation Period:

The incubation period is variable, and difficult to ascertain; usually 5 - 60 days, commonly 1-2 months, occasionally several months

Period of Communicability:

There is no evidence of person to person communicability.


Risk Factors/Susceptibility

  • Consumption of raw/unpasteurized milk or milk products
  • Animal contact (pets, farm animals, petting zoo)
  • Contact with aborted animal fetuses or birth products (i.e. placenta)
  • Occupational (laboratory workers, veterinarians, animal or animal product handler)
  • Travel outside province in the last 60 days


Diagnosis & Laboratory Testing

Any of the following will constitute a confirmed case of Brucellosis with clinically compatible signs and symptoms:

  • Isolation of Brucella sp. from an appropriate clinical specimen (e.g., blood, tissue, bone marrow)
  • A significant (i.e., fourfold or greater) rise in Brucella agglutination titre between acute and convalescent serum specimens obtained 2 or more weeks apart and tested at the same laboratory

Testing Information & Requisition


Treatment & Case Management

Treatment is under the direction of the attending physician and depends on clinical symptoms and age of the case; antibiotics are usually prescribed for six weeks to prevent recurring infection. For hospitalized cases, routine practices are recommended and contact precautions are indicated for people with draining wounds and or lesions.

Public Health staff will be involved to investigate cases of brucellosis to determine the source of infection.


Patient Information

Patient Fact Sheet



1. Ministry of Health and Long Term Care, Infectious Diseases Protocol - Appendix 1 (2022) Brucellosis.


Additional Resources

Heymann, D.L. Control of Communicable Disease Manual (20th Ed.). Washington, American Public Health Association, 2015.

CFIA. Fact Sheet "Brucellosis".



Last Updated: