Skip Navigation Menu
Government of Ontario Central Web Site Ontario Ministry of Health and Long-Term Care
Return to Home Page Government of Ontario Central Web Site Contact us for questions and comments Site map Version française de cette site web
Information Channels Public Information Health Care Providers News Media Text Only Version
Index Health Care Providers Section
DISEASES : Brucellosis

Brucellosis, or Undulant Fever, is a systemic bacterial disease caused by Brucella species, usually B. abortus (cattle), B. melitensis, B.ovis (sheep and goats), B. suis (pigs), and rarely B. canis (dogs).

Symptoms and Signs

The signs and symptoms are extremely variable. In the acute form (<8 weeks from illness onset) symptoms are nonspecific and "flu-like," including fever, sweats, malaise, anorexia, headache, myalgia, and back pain. In the undulant form (<1 year from illness onset), symptoms include undulant fevers, arthritis, and orchiepididymitis in males. Neurologic symptoms may occur acutely in up to 5% of cases. In the chronic form (>1 year from onset), symptoms may include chronic fatigue syndrome-like, depressive episodes, and arthritis.

Mode of Transmission

Common sources of infection occur by ingesting contaminated milk and dairy products, and entry of the bacteria through abrasions of the skin from handling infected mammals (i.e., contaminated tissues, blood, urine, vaginal discharges, aborted fetuses, and especially placentas). Occupations at greatest risk for the disease include abattoir workers, meat inspectors, animal handlers, veterinarians, and laboratory workers.

Brucellosis may be used in by bioterrorism. The most likely use would be through its use in food and drink.

Incubation Period

The incubation period is highly variable and difficult to ascertain. It is usually 5 to 60 days with 1 to 2 months being the most common. Occasionally the incubation period can last several months.

Laboratory Diagnosis

Laboratory diagnosis is made by appropriate isolation of the infectious agent from blood, bone marrow or other tissues, or from discharges of the patient. Serologic tests are valuable, especially when paired sera show a rise in antibody titre.

For sending specimens to the Central Public Health Laboratory, physicians must call (416) 235-6100 during work hours and (416) 605-3113 after work hours prior to submission.

Specimens should be handled according to universal precautions and packaged for transport to the Central Public Health Laboratory according to the Transportation of Dangerous Good regulation.


A combination of rifampin (600 to 900 mg daily) or streptomycin (1g daily), and doxycycline (200 mg daily) for at least 6 weeks is the treatment of choice. Relapses occur in about 5% of patients treated with rifampin and doxycycline.


No vaccine is available for humans.


Brucellosis is a reportable disease in Ontario under the Health Protection and Promotion Act and must be reported immediately to the local medical officer of health by telephone. The disease should be reported even if it is only suspected and has not yet been confirmed.

Brucellosis is also a reportable animal disease in Canada and suspect animal cases should be reported to the Canadian Food Inspection Agency.

For more information
Call the ministry INFOline at 1-800-268-1154
(Toll-free in Ontario only)
In Toronto, call 416-314-5518
TTY 1-800-387-5559
Hours of operation : 8:30am - 5:00pm
Go to top of page
|  return to main publications menu  |  return to program publications menu  |
|  home  |  central site  |  contact us  |  site map  |  français  |

This site maintained by the government of Ontario, Canada.