Guidance

Brucella canis: information for the public and dog owners

Published 26 September 2023

About Brucella canis

This document contains information on Brucella canis (or B. canis), a type of bacterial species which causes an infection known as brucellosis. B. canis can be transmitted from dogs to humans. In the UK, it is mainly found in dogs imported from Eastern Europe. Human-to-human transmission of B. canis is extremely rare.

The risk of most people catching B. canis is very low. Dog breeders and owners of imported dogs may be at a higher risk and should take steps to reduce the risk of infection.

B. canis in dogs

There has recently been an increase in the number of dogs being diagnosed with B. canis in the UK with 3 diagnoses pre-2020 and 97 diagnoses in 2023 (to June 2023). Most cases have been in dogs imported into the UK from Eastern Europe, or linked to imported dogs from Eastern Europe.

All UK cases have been in dogs that have either been imported, have mated with an imported dog, have had contact with the birthing products of an imported dog, or are the offspring (puppy) of an imported dog.

B. canis in humans

There have been a small number of human B. canis cases in the UK. All cases identified to date reported contact with an infected dog.

The Human Animal Infections and Risk Surveillance group (HAIRS) has recently published an expert assessment of the risk to public health from B. canis in dogs. This assessment shows that the risk to the general population in the UK from B. canis is very low.

For people who work with or own infected dogs, who are more likely to be exposed to reproductive or birthing products, such as breeders of imported dogs, or vets spaying and neutering infected dogs, the risk is low. However, the assessment highlighted that the risk to certain groups, such as people who have a weaker immune system (immunosuppressed) or young children, may be higher.

B. canis causes less serious effects in humans compared to other species of Brucella bacteria.

Symptoms of B. canis

Symptoms of B. canis in humans

In humans, B. canis does not always immediately cause symptoms. The time from getting infected with B. canis to developing symptoms in humans can vary from weeks to years.

If symptoms do occur, these can include:

• fever
• loss of appetite and weight loss
• sweating
• headaches
• tiredness (fatigue)
• back and joint pain

It is thought that people who are immunosuppressed and young children may be at higher risk of developing symptoms and severe illness after infection with B. canis.

There is very little evidence available to understand the health risk of B. canis during pregnancy. Evidence from infections caused by other types of Brucella bacteria suggests that pregnant women infected with Brucella bacteria may have a higher rate of adverse outcomes than healthy pregnant women. Treatment of brucellosis (of any cause) is more difficult in pregnancy.

Infection with B. canis is rarely fatal in humans and most people make a full recovery with antibiotics. If it is not treated, B. canis can lead to complications such as inflammation of the lining of the heart (endocarditis) or inflammation of the protective membrane around the brain and spinal cord (meningitis).

If you have had contact with an infected dog (particularly their reproductive or birthing products), or a dog that has tested positive for B. canis, and you feel unwell, you should inform your GP or NHS 111.

Signs of B. canis in dogs

Like humans, dogs can also be infected but appear well and not have any obvious clinical signs.

B. canis often affects the reproductive system in dogs and can cause infertility and miscarriages.

Dogs can also have other signs, such as:

• tiredness
• swelling of lymph nodes in the neck, armpit, or groin (lymphadenopathy)
• back and/or joint problems (including lameness)

How B. canis spreads

B. canis is a zoonotic disease which means that it can spread from animals to humans.

Dog-to-human transmission

Most contact with an infected dog will not cause a person to become unwell, but direct contact with reproductive and birthing products from an infected dog, especially reproductive secretions and birthing products, may increase the risk of infection spreading.

Some dogs without symptoms still appear to be able to spread B. canis, so it is important to practise good hand hygiene and minimise contact with birthing products and reproductive secretions of all imported dogs.

It’s extremely rare for a person infected with B. canis to spread the disease to other people.

Dog-to-dog transmission

Infected dogs can spread B. canis to other dogs by mating with other dogs via their reproductive and birthing products, and to their puppies (congenital infection).

Dogs that live in the same home as an infected dog may be more likely to become infected themselves.

How B. canis is diagnosed

In humans, the diagnosis is usually made through testing a blood sample which will be sent to a national laboratory for specialist testing.

In dogs, blood may be taken and tested (plus other samples such as birthing material, semen, fluid from joints, or fluid from lymph nodes).

Vet practices may use a lateral flow test (LFT) to test dogs initially, but this is not as accurate as the tests that can be done in a laboratory environment so confirmatory testing and interpretation by specialist national teams is recommended before irreversible decisions are made about the management of the apparently infected dog.

In dogs, the specialist test that is used assesses if the dog’s body has responded to becoming infected (antibodies against B. canis).

A negative test result does not always mean that the dog does not have the infection (its immune system may not have had enough time to make antibodies at the time of testing).

A positive test means that the dog is, or has previously been, infected with B. canis. B. canis infection can persist for many years without any clinical signs of infection so the specialists reviewing the test results will take this into consideration.

How B. canis is treated

People who are diagnosed with B. canis are usually treated with antibiotics. They may require several courses of treatment and repeated blood tests to check that the infection is gone.

In dogs, antibiotic treatment is not recommended because infection often continues despite this treatment. Vets will be able to advise on the best management approach for a dog that has B. canis, which will depend on a number of factors both relating to the dog and the people and other animals living with it. Management approaches may include euthanasia, neutering, or other treatment options to reduce the risk of onward transmission. Further information is available from the Animal and Plant Health Agency (APHA).

Protecting yourself from B. canis

The general population is at very low risk of getting infected with B. canis, but you should still continue to practise good hygiene around animals.

For any dog (imported or born in the UK), make sure that you minimise contact with the dog’s reproductive or birthing products, blood, and urine. If you have any contact with these products, always wash your hands thoroughly for a minimum of 20 seconds with soap and hot water before doing any other activity. If your hands are not visibly dirty and there are no hand washing facilities available, you can use alcohol hand sanitiser.

How to protect yourself from B. canis as a dog breeder

Breeders are at higher risk from B. canis than the general population. This is because of an increased chance of contact with infected reproductive or birthing products.

You should always practise good hand hygiene after any interaction with your dog and try to minimise your contact with reproductive and birthing products. When washing your hands, use soap and hot water for a minimum of 20 seconds. If your hands are not visibly dirty and there are no hand washing facilities available, you can use alcohol hand sanitiser. You may wish to consider wearing surgical gloves, a face mask, and eye protection when interacting with your dog or cleaning up after them for additional protection, especially if they are giving birth or suckling.

You can dispose of birthing or reproductive products in the normal way if these products did not come from a dog with confirmed B. canis. If the products are from a dog that has B. canis, you should discuss with your commercial waste contractor or contact your local environmental health team at the council to make sure that the products are disposed of safely.

Any hard surfaces where there have been reproductive or birthing products, blood, or urine from an imported dog should be thoroughly disinfected with a strong bleach solution. Soft furnishings should be disposed of or, where this is not possible (such as carpets), then these should be steam cleaned.

You should always check the country of origin of any dogs that you mate your dogs with and consider the risks of mating UK-born dogs with imported dogs. We advise that you check the history of any dogs that mate with your UK-born dog prior to any interaction taking place.

How to protect yourself from B. canis as an owner of an imported dog

We advise that all imported dogs are tested for B. canis before coming to the UK. Personal hand hygiene and other precautions outlined in this document, plus neutering your dog are the best ways to protect yourself and your family from B. canis if you already have a dog that has been imported from overseas.

Owners of imported dogs are likely to have a higher risk of getting B. canis than the general population. This risk increases if you are involved in birthing of puppies from an infected mother or have contact with reproductive or birthing products, blood, or urine from an infected dog.

You should wash your hands after any interaction with your dog and minimise your contact with birthing and reproductive products by wearing gloves and other protective clothing if you think you are going to have extensive exposure to these products. Even if you have worn gloves, hands should be thoroughly washed with soap and hot water, even when gloves have been worn, for a minimum of 20 seconds. If your hands are not visibly dirty and there are no hand washing facilities available, you can use alcohol hand sanitiser. You may wish to consider using surgical gloves, eye protection, and/or face mask when interacting with your dog (especially if they are giving birth) for additional protection.

What to do if your dog has been diagnosed with B. canis

If your dog has been diagnosed with B. canis, you will be contacted by your local health protection team who will ask about how you interact with your dog, where you acquired your dog, and any other people and animals in your household so that they can provide you with further advice.

If you feel unwell, contact your GP or 111 and tell them that you may have been exposed to B. canis infection in a dog.

You should not give blood until 6 months after the date of your last contact with a dog infected with B. canis.

It is important to discuss your dog’s B. canis diagnosis with your vet. Your vet will be able to advise on the best management approach for your pet, which will depend on a number of factors both relating to your pet, and the people and other pets living with it. Management approaches may include euthanasia, neutering, or other treatment options. Veterinarians and veterinary practices will also make their own decisions as to how they interact with your dog.

Wash your hands after every interaction with your dog. Hands should be washed with soap and hot water for a minimum of 20 seconds. If your hands are not visibly dirty and there are no hand washing facilities available, you can use alcohol hand sanitiser. You may wish to consider using surgical gloves, eye protection, and/or face mask when interacting with your dog for additional protection, especially if they are giving birth or weaning.

If you, or a member of your household, is pregnant, immunosuppressed, or a young child, you (or they) may wish to consider limiting interactions with the infected dog. This is because these groups are likely to be at greater risk of developing severe disease if they become infected.

Any hard surfaces where there have been birthing, reproductive products or urine should be thoroughly disinfected with a strong bleach solution. Soft furnishings should be disposed of or, where this is not possible (such as carpets), then these should be steam cleaned.

Any reproductive or birthing products from your dog can be thrown away in your normal household waste. Place the waste in a black bag and securely tie it prior to disposal. If there are large quantities of waste, contact your local environmental health team at the council who will be able to advise you on how to dispose of this safely.

There is a risk that any puppies from your dog, dogs that they have mated with, or other dogs in the household may also have B. canis. Please discuss with your vet who will be able to advise on appropriate testing.

Glossary

Reproductive and birthing products

Reproductive and birthing products are any material from a dog associated with reproduction and/or birth. This includes placenta/afterbirth, semen, vaginal secretions, any fluids released in the birthing process, and stillborn pups.