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Brucellosis (Bacterial Infection Caused by the Brucella Species Brucella Canis) in Dogs

Occurrence: rarer
Location of illness: Abdomen/pelvis, General/Whole body

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Brucellosis is a bacterial infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. caused by the bacterium Brucella canis. This infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. primarily affects dogs and can cause both reproductive problems and systemic diseases.

The most important facts at a glance

Brucellosis in dogs is caused by the bacterium Brucella canis, which belongs to the family Brucellaceae. These bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. are gram-negative, obligate parasites, and require a host for reproduction. The main transmission occurs through direct contact with infected bodily fluids, especially during mating. Indirect transmissions via contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. materials are less common. Signs of the disease include reduced fertilityFertility refers to the ability to conceive and bear offspring. In women, it refers to the ability to initiate and carry a pregnancy; in men, it refers to the ability to produce fertile sperm., Fever, and Swollen lymph nodes. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is complex and includes serological tests and the detection of bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. in blood cultures. Treatment is difficult, usually lengthy, and there is a high risk of relapse. A combination of antibiotics is often used, but complete cure is rare. PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. is crucial as there is no effective vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens.. Regular testing in breeding facilities and hygienic measures are important to prevent the spread. Research focuses on improved diagnostic tests, new antibiotics, and the development of a vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens.. Close collaboration between veterinarians and other professionals is essential to ensure the health of the animals and not to endanger breeding ability.

Causes

Brucella canis belongs to the family Brucellaceae, a group of gram-negative, non-spore-forming, and aerobic bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease.. They are obligate parasites and require a host for reproduction. Transmission occurs mainly through direct contact with infected bodily fluids, such as urine, saliva, or genital secretions. Transmission during mating plays a particularly important role, as the bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. are found in high concentrations in the reproductive organs.

The bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. can also be spread through contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. materials such as food, water, or kennel environments. However, indirect transmission via these routes is less common. Brucellosis can also be transmitted through transfusion of infected blood. The bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. enter the dog’s body and spread through the blood to various organs and tissues, including the spleen, lymph nodes, and reproductive organs.

Susceptibility to infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. can be influenced by factors such as age, sex, and the dog’s general health. Young and immunocompromised dogs are often more susceptible to infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. StressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. and poor housing conditions can also increase the risk of the disease.

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

The symptoms of a brucellosis infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. in dogs can be very variable and range from asymptomaticAsymptomatic means that there are no recognizable symptoms of a disease. An animal can have a disease or infection without showing visible signs, which can make diagnosis and treatment more difficult. cases to serious health impairments. A common symptom is Infertility in affected dogs, both in males and females. In pregnant bitches, Miscarriage can occur, usually in the last third of pregnancy, or the puppies are Stillbirth.

Other symptoms may include Fever, lethargy, Weight loss, and an enlarged spleen or lymph nodes. In male dogs, Inflammatory conditions of the testicles and epididymis can occur, which can lead to Infertility. ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. infections can also lead to arthritisArthritis is an inflammation of the joints that can cause pain, swelling, stiffness, and limited mobility. There are many forms of arthritis, including rheumatoid arthritis and osteoarthritis. or discospondylitis, a painful inflammation of the spine.

In some cases, the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. can also lead to systemic diseases that affect various organs, leading to a variety of clinical signs. Because the symptoms are non-specific, the disease is often overlooked or mistaken for other diseases.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of brucellosis is based on a combination of clinical symptoms, serological tests, and bacteriological cultures. Serological tests such as the Rapid Slide Agglutination Test (RSAT) or the Agar Gel Immunodiffusion (AGID) test are commonly used methods for detecting antibodies against Brucella canis. However, these tests are not always specific and can produce false-positive results, which is why confirmation by further tests is necessary.

A definitive diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. can be made by directly detecting the bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. in blood cultures or tissue samples, but this can be challenging because Brucella canis is a slow-growing bacterium. In some cases, molecular methods such as polymerase chain reaction (PCR) can be used to confirm the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients., especially when serological tests are not clear.

Since the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. can be complex, it is important that veterinarians take a careful historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. and correctly interpret the clinical signs to make an accurate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients..

Therapy

Treatment of brucellosis in dogs is difficult and often lengthy. Antibiotics can be used to combat the bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease., but complete eradication of the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. is rare. A combination of doxycycline and an aminoglycoside antibiotic such as gentamicin or enrofloxacin is often used to reduce the bacterial load and alleviate symptoms.

The duration of treatment can be several weeks to months, and there is a high risk of relapse because the bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. can persist in certain tissues. In addition to drug treatment, supportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. measures such as improved nutrition and stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. reduction can help strengthen the dog’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. and support recovery.

In severe cases or in dogs that do not respond to treatment, euthanasia may be considered to prevent further suffering and control the spread of the disease. Castration may also be considered to eliminate the reproductive organs as a reservoir for the bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease..

Prognosis and follow-up care

The prognosis for dogs with brucellosis varies greatly and depends on several factors, including the severity of the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., the age and general health of the dog, and the effectiveness of the treatment. In many cases, the symptoms can be controlled with appropriate treatment, but a complete cure is rare.

ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. infections can lead to permanent health impairments, especially if important organs are affected. Dogs that have been successfully treated may continue to carry the bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. and transmit the disease to other animals, which poses a particular challenge in controlling the disease.

The quality of life of the affected dog can be impaired by the disease, especially if it leads to recurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. infections or chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. pain. Close cooperation with a veterinarian is crucial to develop the best treatment plan and improve the dog’s quality of life.

Prevention

The preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of brucellosis in dogs is based on avoiding exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. to infected animals and controlling the spread in affected populations. Dogs used for breeding should be regularly tested for brucellosis to prevent transmission to offspring. Newly introduced dogs in breeding facilities should also be tested and observed during a quarantineQuarantine is the isolation of animals to prevent the spread of disease. This may be necessary if an infectious disease is suspected or after animals are imported from other countries. period.

Owners should ensure that their dogs do not have contact with infected animals and should follow hygienic measures to prevent the spread of the bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease.. This includes regular cleaning and disinfection of kennels and other areas where the dogs are kept.

Since there is currently no effective vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens. against Brucella canis, preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. is key to controlling the disease. Public education about the risks and signs of the disease can help minimize the spread of infection and raise awareness of the need for preventive measures.

Close collaboration with veterinarians and other professionals in the field of animal health can help monitor the disease and take appropriate measures to prevent its spread. Regular monitoring and testing in breeding facilities are crucial to ensure the health of the animals and not to endanger reproductive capacity.

Outlook on current research

Brucellosis, caused by the bacterium Brucella canis, is an important disease in dogs that occurs worldwide and can be a major problem, especially in breeding facilities. Current research focuses on the development of improved diagnostic tests to detect the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. earlier and more accurately. One focus is on molecular biological methods such as polymerase chain reaction (PCR), which enable rapid and accurate identification of Brucella canis. These methods could complement or even replace conventional serological tests in the future.

At the same time, intensive research is being carried out on vaccines, as there is currently no approved vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens. against Brucella canis. Various approaches are being investigated, including inactivated bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. and genetically modified strains that are intended to triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats. an immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens. without causing the disease. InitialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. results are promising, but comprehensive clinical studies are still needed to confirm the effectiveness and safety of these vaccines.

Another important area of research is antibiotic therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions.. Traditionally used antibiotics do not always show the desired effect, and there is a risk of developing resistantResistant means being insensitive to a substance, drug, or treatment. In dogs and cats, resistance can refer to the ineffectiveness of antibiotics against certain bacterial strains or the insensitivity of parasites to certain pesticides. bacterial strains. Therefore, research is being conducted on new active ingredients and treatment regimens that could be more effective and safer. The goal is to completely eliminate the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. to prevent relapses.

In addition, the epidemiology of brucellosis is being further researched to better understand the transmission routes and develop effective preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies. This involves investigating how the disease spreads within a populationIn veterinary medicine, the term population refers to a group of animals of a particular species living in a specific geographic area or environment. and which factors increase the risk of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. This information is crucial for the development of control measures, especially in breeding facilities and animal shelters.

In conclusion, collaboration between veterinarians, epidemiologists, and microbiologists is essential to find holistic solutions to combat brucellosis. The One Health Initiative, which emphasizes the connection between human, animal, and environmental health, plays an important role in current research. By sharing knowledge and resources, innovative approaches can be developed to improve not only the health of animals but also that of humans.

Frequently asked questions (FAQs)

What is brucellosis in dogs? Brucellosis in dogs is a bacterial infection caused by the bacterium Brucella canis. It often leads to reproductive problems such as Infertility and Abortions in pregnant bitches.
How is brucellosis transmitted to dogs? Transmission can occur through direct contact with infected animals or through contact with contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. materials such as urine, saliva, or genital secretions. Transmission during mating is also possible.
What symptoms occur in infected dogs? Symptoms may include fertilityFertility refers to the ability to conceive and bear offspring. In women, it refers to the ability to initiate and carry a pregnancy; in men, it refers to the ability to produce fertile sperm. disorders, Abortions, Inflammatory conditions of the testicles or prostate in males, lethargy, Weight loss, and Lameness. However, some dogs show no obvious symptoms.
How is brucellosis diagnosed in dogs? Diagnosis is usually made by serological tests that detect antibodies against Brucella canis, as well as by cultural or molecular biological methods such as PCR, which can directly identify the bacterium.
Can brucellosis be transmitted from dogs to humans? Brucella canis is less commonly transmitted to humans compared to other Brucella species, but zoonotic transmission is possible, especially in immunocompromised individuals. Precautions should always be taken.
What treatment options are available for infected dogs? Treatment usually involves long-term antibiotic therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. to reduce the bacterial count. A complete cure is difficult to achieve, and in some cases, castration may be recommended to control the spread of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..
How can the spread of brucellosis be prevented in breeding facilities? PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. measures include regular testing of breeding animals for brucellosis, quarantineQuarantine is the isolation of animals to prevent the spread of disease. This may be necessary if an infectious disease is suspected or after animals are imported from other countries. of new animals, strict hygiene measures, and avoidance of mating infected animals.
Is there a vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens. against brucellosis in dogs? There is currently no approved vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens. against Brucella canis. Research on potential vaccines is ongoing, but until an effective vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens. is available, preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. measures are crucial.
How long is the incubation periodThe incubation period is the time between infection with a pathogen and the appearance of the first symptoms. This period can vary depending on the pathogen and individual immune response. for brucellosis in dogs? The incubation periodThe incubation period is the time between infection with a pathogen and the appearance of the first symptoms. This period can vary depending on the pathogen and individual immune response. can vary but is typically between a few weeks to several months, depending on the individual and route of transmission.
What measures should pet owners take if their dog contracts brucellosis? Pet owners should isolate their dog to prevent transmission to other animals and closely follow the veterinarian’s instructions for treatment and further testing. It is important to take protective measures to minimize the risk of zoonotic transmission.