Increase in Brucella canis cases in the UK
Canine brucellosis is an infectious and zoonotic disease caused by Brucella canis, which is causing increasing concern for the animal health sector. Over the last three years, there have been an alarming number of dogs diagnosed with brucellosis infections in the UK.
Prior to 2020, incidents of Brucella canis infections were relatively sporadic and involved individual imported animals. The current increase in infection rates has been associated with an increased number of imported rescue dogs¹. Such dogs have usually been imported or have travelled to countries where Brucella canis is endemic². It is estimated by DEFRA that nearly 30,000 dogs were imported from these countries over the 2019-2020 period¹.
Dogs in kennels, rehoming centres and breeding establishments are at increased risk due to the close contact, mixing, and frequent movement of dogs in and out of the facilities. Outbreaks have been reported in kennels in Italy, Netherlands, Sweden, Switzerland, France, Portugal, and the UK³.
Pathogen characteristics, transmission, and outcome
Brucella canis are Gram-negative, aerobic, coccobacilli bacteria. They are facultative extracellular-intracellular pathogens that can overcome innate immunity at early times of infection and promote chronic infection⁴.
The predominant routes for dog-to-dog transmission are through coitus. Dogs can also become infected via contact with oronasal and conjunctival mucosa or broken skin and the secretions, excretions, and tissues (including blood) of infected dogs³.
The main clinical consequence of canine brucellosis are late abortion, stillbirth, and failure to conceive in female dogs. Infection in male dogs can lead to epididymitis, orchitis, prostatitis and infertility. Furthermore, puppies can be born, which have very high risk of perinatal mortality².
Treatment and management of Brucellosis
There is currently a lack of clear guidance on treating the infection. Since there are significant antimicrobial stewardship implications, costs, and impacts on the infected dog’s lifestyle and health that should be considered, euthanasia is unfortunately, the only option to eliminate all on-going risk of transmission to others³.
In situations where the owner will not euthanise, the following is recommended.
- Isolation of the infected dog from other dogs and susceptible humans for the remainder of their life; neutering of infected dogs¹.
- Antimicrobial therapy, although none have been proven to be totally successful³.
- Regular serological monitoring following diagnosis and treatment to identify and manage relapses of infection³.
Effective strategies to prevent transmission of Brucella canis
Currently, no vaccines against Brucella canis are available and instead prevention focuses on infection prevention strategies and improving awareness in veterinary staff, prospective owners, and breeders. Screening of dogs prior to importation from endemic regions and screening of dogs prior to breeding³ is recommended.
Brucella canis bacteria can survive in areas with high humidity and low temperatures with no sunlight for long periods of time. Therefore, dust, dirt, water, clothing, and other inanimate objects which have been contaminated with high-risk infectious fluids can pose a transmission risk for a prolonged period, potentially several months⁶. Disinfection of contaminated materials and the working environment with an effective surface disinfectant is therefore vital to brucellosis control.
To clean infectious, or potentially infectious material or environments it is advisable to:
- Avoid direct contact with materials freshly soiled with an infected dog’s urine or reproductive fluids though use of personal protective equipment (PPE).
- Clean the environment regularly using a disinfectant which demonstrates efficacy against Brucella canis to European veterinary standards EN 1656 and EN 14349.
- Full deep clean twice a week advised for area(s) where dogs are kept, to maintain cleanliness and reduce bacterial load, particularly in enclosed spaces and for infected dogs.
- Any contaminated clothing should be safely disposed of or washed at high temperatures (60°c or more). Any fabrics contaminated with high-risk materials should be safely disposed of.
- Care should be taken to minimise splashes or generation of aerosols (small airborne liquid droplets), to minimise the potential for infection via inhalation or via the mucus membrane of the eye as there is a risk these may contain Brucella canis.
ANIGENE Professional Surface Disinfectant Cleaner is effective against Brucella canis having been rigorously tested against Brucella spp. to the European veterinary disinfectant standards, EN 1656 and EN 14349, with efficacy at a 1% dilution within just 5 minutes.
Can Brucella canis be passed from animals to humans?
Whilst Brucella canis is known to be zoonotic, infection is infrequently reported in humans. This could be underdiagnosed due to often vague clinical signs and lack of testing.
Infected dogs can pose a significant risk to veterinary staff and laboratory staff processing pathology samples, rehoming charity staff as well as pet owners or breeder, particularly those individuals with underlying health conditions⁵. Symptoms of Brucellosis in humans are flu-like, including a high temperature, loss of appetite, headaches, or extreme fatigue⁷ but can become chronic or long-lasting in some cases⁶.
Signs of illness in humans can occur within one week but potentially up to six months after exposure. On average, signs and symptoms begin to occur three to four weeks after infection. Individuals who believe they have been exposed to Brucella canis should be made aware of the symptoms and should notify their GP accordingly⁶.
Sources
- Middlemiss C (2021) Brucella canis in dogs in the UK. Veterinary Record. Volume 188, Issue 4.
- Buhmann G et al. (2019) Canine Brucellosis: Insights into the Epidemiologic Situation in Europe. Front Vet Sci. 6 :151.
- Barker E and BSAVA Scientific Committee (2023) Brucella canis. British Small Animal Veterinary Association. DOI: 10.22233/9781910443514.1.9
- Chacón-Díaz C et al., (2015) Brucella canis Is an Intracellular Pathogen That Induces a Lower Proinflammatory Response than Smooth Zoonotic Counterparts. Infection and Immunity. Volume 83 no 1.
- Ornelas RF et al (2022) Zoonotic diseases in companion animals in the UK. Improve Veterinary Practice.
- APHA (2021) Canine Brucellosis: Summary Information Sheet. Version 1.
- Brucellosis – NHS (www.nhs.uk)