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Chapter 8 - Reportable diseases
8.2 Brucellosis

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8.2.1 Etiology and distribution

Brucellosis is an infectious bacterial disease caused by various species of the family Brucellaceae. They arefound worldwide and can affect many mammalian species, including humans. In livestock, infection and subsequent production losses can cause a significant economic impact. In animals, the disease may be asymptomatic or may be characterized by reproductive issues, for example, infertility, late term abortions, weak offspring, and inflammatory lesions in the male reproductive system.

In Canada, brucellosis is listed as a reportable disease in the Reportable Diseases Regulations. Brucella abortus, B. melitensis, and B. suis are listed by the World Organisation for Animal Health (WOAH; founded as Office International des Épizooties (OIE)) and are considered foreign animal diseases in Canada's farmed and captive animal populations.

Brucella abortus, also known as bovine brucellosis, is the main causative agent of brucellosis in cattle, bison and elk. Canada declared itself free of bovine brucellosis to the World Organization of Animal Health (WOAH) in 1985 after a long-standing eradication program. Canada's wildlife reservoir of B. abortus is limited to wild bison in and near Wood Buffalo National Park (WBNP). There has never been a detected transmission event from wild bison to livestock in a 400km area around WBNP, despite heightened surveillance.

Brucella suis biovars 1-3 is known as swine brucellosis. Canada has never reported a case of swine brucellosis. B. suis biovar 4 is associated with brucellosis in caribou and muskoxen and is known to exist in Northern Canada.

Brucella melitensis commonly infects sheep and goats and is the most pathogenic zoonotic species of brucellosis. Canada has never reported a case of B. melitensis.

Producers and private veterinarians must remain vigilant as despite risk mitigation measures in place, wildlife reservoirs and imported animals can still serve as potential sources of introduction into domestic livestock populations. Some Brucella spp. are considered potential agents for bioterrorism. An outbreak of brucellosis in Canadian domestic livestock would have significant repercussions for animal health, public health, and international trade.

More information regarding brucellosis in Canada can be found on CFIA's Brucellosis page.

8.2.2  Surveillance

Ongoing surveillance activities allow Canada to claim freedom from brucellosisFootnote 1, supporting trade and allowing for early detection of disease incursions in livestock.

Active brucellosis surveillance for cattle, swine, cervids and bison continues at federal slaughter establishments and provincial abattoirs through routine post mortem inspection and the collection of blood samples from mature, sexually intact animals.

Another component of brucellosis surveillance comes from the testing of animals for export and entry into artificial insemination centers. There is also ongoing collection and testing of blood samples from cattle in community pastures in northern Alberta, within 400km of WBNP.

Disease reporting by producers and veterinary practitioners remains an important element of brucellosis surveillance.  Veterinary practitioners are encouraged to discuss instances of unexplained bovine abortions with a CFIA district veterinarian.

More information on CFIA's surveillance programs can be found on CFIA's Brucellosis page.         

8.2.3  Testing

Accredited veterinarians may submit samples for export certification (to satisfy USA federal / state or Mexico federal testing requirements) or through the Artificial Insemination Program. These samples are sent either to external laboratories approved for brucellosis testing (BPAT) or CFIA laboratories depending on the reason for testing and / or type of test required.  This information can be found in the applicable sections of this manual specific to the activity being conducted. Further information about sample collection, packaging, shipping and forms can also be found in Section 3.2 - Serologic Testing.

Reactors on preliminary testing will be handled as per the applicable program requirements and must be reported to a CFIA veterinarian for appropriate follow up.

Samples may not be submitted by accredited veterinarians to approved laboratories if brucellosis is suspected. If brucellosis is suspected by an accredited veterinarian, a CFIA district office must be contacted.

8.2.4  Public Health

Brucellosis is a zoonotic disease, transmissible from animals to humans. Whenever brucellosis is confirmed in an animal, public health officials are to be notified.

When investigating an undetermined outbreak of abortion, practitioners should employ appropriate PPE and biosecurity practices. Anyone who has been in contact with suspect animals, potentially contaminated material (for example, aborted fetuses, placenta, birthing fluids) or who have consumed unpasteurized milk or milk products should be made aware of this zoonotic potential and seek medical attention if they subsequently become ill.

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