NCCID Disease Debriefs provide Canadian public health practitioners and clinicians with up-to-date reviews of essential information on prominent infectious diseases for Canadian public health practice. While not a formal literature review, information is gathered from key sources including the Public Health Agency of Canada (PHAC), the USA Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO) and peer-reviewed literature.

This disease debrief was prepared by Beamlak Manyaz. Questions, comments, and suggestions regarding this debrief are most welcome and can be sent to

What are Disease Debriefs? To find out more about how information is collected, see our page dedicated to the Disease Debriefs.

Questions Addressed in this debrief:

  1. What are important characteristics of Brucellosis disease?
  2. What is happening with current outbreaks of Brucellosis?
  3. What is the current risk for Canadians from Brucellosis?
  4. What measures should be taken for a suspected Brucellosis case or contact?

What are important characteristics of Brucellosis?


Brucellosis is a disease the bacterial genus Brucella. These bacteria are gram negative, non-motile cocci/small rods that are able to produce urease. Brucellos melitensis, B. abortus, and B. suis are the three species that are pathogenic to humans, but other species are able to infect a range of other hosts. This includes, but is not limited to, dogs(B. canis) and marine mammal species (B. ceti and B. pinnipediae) where there have also been a few human cases identified with neurobrucellosis.The disease is also known as Mediterranean fever, Malta fever, Bang’s disease or Undulant fever. Brucellosis is caused by eating or drinking raw (unpasteurized) dairy products or coming into contact with the bodily fluids of infected animals. Some instances of airborne transmission have also been identified in animal pens, slaughterhouses, and labs.

Sign and Symptoms:

A person with brucellosis typically initially shows symptoms such as fever, headaches, chills, profuse sweating, and weakness. Initial symptoms could also progress to depression, weight loss and body aches. It is possible for symptoms to disappear for weeks to months, only to reoccur later. Some may also persist for a long period of time while others might not even go away. If the infection persists, there can also be swelling of the liver or spleen, testicle or scrotum area, and the heart (endocarditis). It could also result in recurrent fever, arthritis, chronic fatigue, or even neurological symptoms in up to 5% of the cases.

Severity and Complications:

If left untreated, these symptoms and may worsen and affect other areas of the body such as the bones, joints, as well as genital and urinary tracts. It has been reported that brucellosis has a fatality rate of 2%.



Brucellosis occurs commonly in areas without effective public health and domestic animal health programs. The areas with the highest risk include the Mediterranean area (Portugal, Spain, Southern France, Italy, Greece, Turkey, North Africa), Eastern Europe, Africa, the Middle East, Asia, Mexico, and South and Central America. The biggest risk, as mentioned before, comes from consuming unpasteurized milk and milk products, which tends to be more common outside of the U.S.A but is also becoming more common all-over North America as well.


Slaughterhouse workers, meat-packing employees, veterinarians, laboratory workers, as well as hunters, face an increased risk of exposure due to the amount of contact with animals, their tissues, or their bodily fluids.

Incubation Period:

The incubation period of Brucella bacteria can range anywhere from 5 to 60 days and occasionally, up to several months as well.

Reservoir and Transmission:

Common reservoirs of the Brucella genus include animals such as sheep, goats, cows, camels, bison, elk, caribou, moose, wild hogs, and even coyotes. There are no vectors that have been identified for these bacteria, but they are still able to survive outside of the host. They can survive for up to 135 days on carcasses and organs, 125 days in soil, 32 days on paper, and 180 days in blood that is 4ºC.

Infection can be acquired through ingestion, direct contact via skin abrasions and mucous membranes, and inhalation. Person-to-person transmission is extremely rare. However, it is possible for infected mothers who are breast-feeding to pass the infection on to their infants. Though it is uncommon, transmission may also occur through tissue transplantation of blood transfusions. Additionally, sexually transmitted infections of brucellosis are also rarely reported.

When animals like sheep, goats, cows, and camels get infected, their milk also becomes contaminated. If it is not pasteurized, the infection will get transmitted to people who consume the milk and its respective products. Other risk factors include coming into contact with infected tissues, blood, urine, vaginal discharge, and aborted fetuses. The bacteria can also enter the body through wounds in skin or mucous membranes when a person comes into contact with infected animals. This becomes a big problem for people working in close contact with animals who exposed to their bodily secretions.

The most common places for humans to be exposed and infected include laboratories, slaughterhouses, meat-packing factories (and similar workplaces where there is a high exposure to animals), and during hunting. Hunters are also at risk as exposure could come through skin wounds, accidental ingestion of undercooked meat or inhaling bacteria while dressing game. It is also more common to get infected via inhalation of the bacteria in workplaces such as the laboratories as these cases are most likely due to aerosolization.

Laboratory Diagnosis:

Brucellosis is diagnosed by identifying the microorganism in the blood, tissue or bodily discharge of the infected person. Serological tests can also be done to identify antibodies in blood serum, such as the Brucella Microagglutination Test (BMAT), which is a modified serum agglutination test (SAT) which detects antibodies to Brucella species (B. melitensis, B. abortus or B. suis). There are no tests available yet to detect antibodies of B. canis.

Prevention and Control:

Pasteurization is when raw milk is heated to high temperature for a short period of time, to destroy any harmful bacteria which may make milk unsafe to consume. Thus, to avoid infection, consumption of unpasteurized dairy products and raw meat must be avoided.

For people who work in the environments described above, protective equipment such as rubber gloves, goggles, gowns, and aprons must always be worn while handling animals, wild or domestic carcasses, and animal tissues. When assisting the birth of animals as well, wear protective equipment and be aware of the risk of inhaling bacteria. Additionally, the World Health Organization recommends vaccination of cattle to control bovine, sheep, and goat brucellosis. In areas where the occurrence of brucellosis is low, eradication by testing and culling is recommended to eliminate the infection. Furthermore, if you choose to adopt or import dogs from another country, be aware of the risk of brucellosis and take it immediately to the veterinarian for examination and testing. The veterinarian staff should also wear protective equipment when working with potentially infected animals.

Brucella microbes are also easily killed by common disinfectants and heat. So, places like laboratories and hospitals that come into contact with suspected brucellosis cases, should take the necessary precautions to clean areas that may have come into contacted with the bacteria.


There are currently no vaccines against brucellosis for humans, however multiple have been developed to vaccinate cattle. The species, B. abortus, is the main cause for brucellosis infection in cattle. B. abortus RB51 is a strain that is developed specifically for cattle immunization. Additionally, this strain can also help with differentiating between naturally infected and vaccinated cattle through serology. Though this is the main vaccine used B. abortus S19 has been developed for vaccines for cattle, and B. melitensis Rev-1 was developed for sheep and goats.

When humans are exposed accidentally to all three of these strains, they can still develop symptoms that are consistent with a brucellosis infection. Veterinarians and medical staff who provide these vaccinations should also be aware of the risks of being exposed and how to respond in that situation.

These vaccines were developed to prevent the symptoms (abortion, infertility, etc.) of brucellosis in animals. However, they do not necessarily prevent animals from becoming infected. Additionally, the vaccines from the B. abortus S19 and B. melitensis Rev-1 strains could interfere with diagnostic tests because the resulting antibodies produced cannot be differentiated from those produced from a natural infection.

Though vaccination of cattle against brucellosis is commonly practiced in the United States, it is not permitted in Canada.


Recovery from the infection may take a few weeks to several months and is usually treated with antibiotics. Brucella microbes are susceptible to tetracyclines and streptomycin or trimethoprim-sulfamethoxazole (TMP-SMX) and are resistant to penicillin and cephalosporins. Generally, a combination of the antibiotics doxycycline and rifampin or streptomycin is recommended for minimum 6-8 weeks to treat the infection. This is unless the patient is pregnant, allergic to either antibiotic or immunosuppressed make sure to let doctor know if this is the case). For expecting mothers, post-exposure prophylaxis may be recommended as well. The RB51 strain is resistant to the antibiotics that are normally used to prevent infections, so it is recommended that that if exposed to this particular strain, one must receive antibiotics to prevent infection.

These microbes are also susceptible to heat as well as 1% sodium hypochlorite, 70% ethanol, iodine/alcohol solutions, glutaraldehyde, and formaldehyde disinfectants. These can be used to clean areas that may have been exposed to Brucella.

What is happening with current outbreak of Brucellosis?

There has recently been an outbreak of brucellosis in China due to a factory leakage. As of September 17, 2020, 1401 people have tested positive due to this outbreak and more are currently being tested.


In the United States, brucellosis occurs more often near the border along Mexico. More recently, there had been an outbreak in Dallas, Texas, where 20 confirmed cases and 5 probable cases of brucellosis in 2016. The unexpected increase in cases during 2016-2017 were confirmed to be from the species B. melitensis. This outbreak was caused by the consumption of imported unpasteurized cheese.


Brucellosis is quite rare in Canada, with 288 cases being confirmed from 1991-2018. However, there has been a noted increase in the rate of cases in recent years.


In 2018, 10 cases of brucellosis were confirmed in Manitoba.


In Ontario. 10 cases of brucellosis infections were reported in 2018 and 5 cases were reported in 2019.

British Columbia

There have only been 5 reported cases in British Columbia in the last 10 years, so it is not a common disease in this region.

What is the current risk for Canadian from Brucellosis?

Brucellosis is quite rare in Canada, with a total of 288 cases being confirmed from 1991-2018. However, there has been a noted increase in the rate of cases in recent years.

What measures should be taken for a suspected Brucellosis case or contact?

Human infections occur most frequently among people who have traveled to or who live in areas where the disease is endemic in animals (mainly cattle, sheep, and goats).  Brucellosis is endemic in many parts of the world particularly in high-risk areas like Mexico, South and Central America, Eastern Europe, Asia, Africa, the Caribbean, the Middle East, and the Mediterranean Basin (Portugal, Spain, Southern France, Italy, Greece, Turkey, and North Africa). When traveling to these areas, be cautious of and avoid contact with livestock and consumption of raw animal products. Consumption of raw or undercooked meat, as well as raw or unpasteurized dairy products, can result in transmission of Brucella and potentially lead to illness.

Although it is not commonly reported in travelers, clinicians should also be aware of the possibility of B. suis or (in feral swine and caribou/reindeer) B. canis (in canines) infection, as these Brucella species are present in animal populations that certain travelers may contact.

Case and Contact Management

Case Definitions

A case is confirmed when Brucella is isolated from the appropriate clinical specimen or if there is a rise observed in Brucella agglutination titre between acute and convalescent serum specimens obtained 2 or more weeks apart and tested at the same laboratory. A probable case, on the other hand, is identified when clinical illness (which is defined as acute or insidious onset of the symptoms of Brucellosis) is observed in a person who has been epidemiology linked to a confirmed case or displays clinical illness with the supportive serology. Lastly, since person-to-person transmission is rare, there is no need to isolate or quarantine patient once their case is confirmed or deemed probable, they need to just proceed with the treatment.

Identifying and Reporting

Brucellosis is a reportable disease in all 57 states and territories. If a disease case is confirmed by a health provider, hospital, or laboratory, it is mandatory to report it to the respective state and territorial jurisdictions. Reporting requirements vary by jurisdiction. Brucellosis is also a nationally notifiable condition.

Brucellosis is a reportable disease in Canada as well. This means that anyone who suspects that an animal has brucellosis must immediately report to a Canadian Food Inspection Agency veterinarian.