Campylobacter in dogs – symptoms, testing and treatment

Overview

Campylobacters are bacteria, only some of which cause disease in animals or people. When Campylobacter causes intestinal inflammation in a dog, the condition is called campylobacteriosis.

Campylobacter jejuni is a common cause of symptomatic campylobacteriosis in companion animals. The dog-adapted C. upsaliensis, meanwhile, is also often found as part of the normal intestinal microbiota.

A dog can carry the bacterium and shed it in faeces without looking ill. In one study from northern Europe involving 36 dogs, 56% had at least one positive faecal sample.

These dogs were Staffordshire Bull Terriers from 30 households, so the figure does not describe disease prevalence in all dogs. C. coli and C. helveticus can also be found in dogs.

Both individual cases and clusters of campylobacteriosis have been reported in dogs.

Causes

Infection spreads through faeces, food or water

Dogs acquire the bacterium orally through contaminated food, water or faecal contact. Raw or undercooked poultry and unpasteurised milk can transmit infection to a dog.

Contaminated drinking water can also be a source, even when food is cooked. A faecally contaminated environment can sustain exposure between animals.

The bacterium can survive particularly well in cool conditions close to 4°C. Campylobacters can remain alive in lake and river water for weeks or months.

The bacterial species and the dog's immunity influence intestinal disease

Stomach acidity forms part of the body's defence before bacteria reach the intestines. Multiplication and the development of intestinal disease can occur in both the small and large intestine.

Toxins produced by the bacterium also contribute to disease caused by C. jejuni. Disease-causing C. jejuni can cross the mucus layer, attach to intestinal surface cells and invade them.

The dog's defences and the characteristics of the bacterial strain influence disease severity. More than one Campylobacter species can occur in the same dog.

Risk factors

Infection and bacterial shedding are identified more often in animals under 6 months old than in older animals. High dog density, for example in a shelter, can increase infection pressure.

Another intestinal disease or concurrent parasite infection may be associated with increased Campylobacter risk. Stress and other concurrent infections can contribute to whether a dog develops signs.

An immunocompromised dog may need more careful treatment when infection causes symptoms. Raw food carries a greater microbiological risk than heat-treated food.

However, a small feeding study from northern Europe found no statistically significant association between diet type and Campylobacter carriage. Among the 33 dogs that followed the feeding plan, C. upsaliensis was found in 39.4% initially and 30.3% after the feeding period.

The feeding period lasted 4–5 months. Three dogs whose agreed diet was not followed were excluded from the feeding comparison.

Typical symptoms

Symptomatic campylobacteriosis most commonly appears as an acute intestinal upset in dogs.

• Stools become loose or clearly watery, often with a rapid onset of diarrhoea.

• Diarrhoea may contain mucus, blood or both mixed with the faeces.

• Your dog may have a fever while intestinal signs are present.

• Your dog seems more tired than usual and is less active during the illness.

• Abdominal pain may accompany inflammatory diarrhoea.

• Vomiting can occur intermittently, even if it is not the main sign.

Acute diarrhoea has been described as lasting 5–15 days. Sometimes it recurs or becomes chronic.

However, some dogs carrying C. jejuni pass entirely normal-looking stools.

Complications and consequences

Mild, uncomplicated campylobacteriosis often resolves on its own. However, diarrhoea-related fluid loss can significantly impair general condition and circulation.

In severe intestinal inflammation, bacterial entry into the bloodstream and sepsis are assessed as serious possibilities. Rare canine cases have also involved inflammation of the liver and biliary tract or pregnancy loss.

Bacterial shedding can continue even when diarrhoea is no longer visible. Improvement in symptoms and a complete end to transmission risk are therefore different things.

Shedding of dog-adapted C. upsaliensis may last longer and be more consistent than shedding of C. jejuni.

Diagnosis at the vet

Results are considered alongside symptoms and the bacterial species

The vet assesses general condition, dehydration and possible systemic infection before interpreting the result as the cause of illness. In severe intestinal inflammation, a blood count and the inflammatory marker CRP can support assessment of systemic signs.

Faeces can be tested for Campylobacter by culture or PCR. Culture requires a special low-oxygen growth environment, making it more demanding than routine bacterial culture.

PCR looks directly for bacterial genetic material in a faecal sample. For identifying C. jejuni, PCR may be more sensitive than culture.

Culture needs live bacteria, so transport conditions affect its success. A fresh sample should reach the laboratory preferably the same day and within 2 days at the latest.

If transport is delayed, suitable transport medium and storage at around 4°C improve bacterial survival. Drying, oxygen, sunlight and warmth can reduce the viability of bacteria in the sample.

During prolonged transport, other microbes in the sample may outgrow Campylobacter and make isolation harder. A swab sample needs a transport tube and suitable medium that support bacterial survival.

A cultured strain can undergo susceptibility testing to help select an appropriate antibiotic. Species-specific testing distinguishes C. jejuni, for example, from other campylobacters whose significance may differ.

Intermittent or transient bacterial shedding also affects the result from a single sample. In a particular transmission-risk situation, follow-up samples can assess whether the dog is still shedding after treatment.

Routine Campylobacter screening of healthy animals is not recommended.

Treatment

Supportive care and monitoring general condition are the foundation

Your vet prescribes treatment according to symptom severity, your dog's immunity and test findings. Supportive care may be needed in an uncomplicated infection even when no antibiotic is used.

Fluid therapy corrects dehydration and reduced circulating blood volume associated with diarrhoea. A dog in good general condition with mild acute diarrhoea does not usually benefit from starting an antibiotic.

Blood in the faeces does not automatically require an antibiotic either if the illness is otherwise mild. Moderate acute diarrhoea responding well to fluid therapy also does not usually require an antibiotic.

A positive PCR result does not change this treatment principle without clinical illness that fits the finding.

Severe infection may need a targeted antimicrobial

Antibiotics are considered particularly for dogs with severe signs or impaired immunity. Severe systemic disease is suspected if poor condition persists despite adequate fluid treatment.

Where possible, the medicine is selected using susceptibility testing. Macrolides such as erythromycin or tylosin may be used for campylobacteriosis when needed.

Antibiotic-resistant Campylobacter strains occur, so previous treatment history influences drug choice. Susceptibility to penicillins and trimethoprim can differ between Campylobacter species.

Enrofloxacin is avoided in puppies because of its risk of cartilage damage, although it may be considered for some adult dogs.

In hospital, the vet reviews the need for antibiotic treatment daily according to the dog's response. Antimicrobial treatment is not continued unnecessarily after clinical signs have resolved.

Medication does not necessarily eliminate bacterial shedding, so transmission prevention does not rely on antibiotics alone. Probiotic use is assessed individually, as there is no clear recommendation for or against their use in acute diarrhoea.

Prevention

Campylobacter can spread from dogs to people. Infection occurs when bacteria reach the mouth, for example through hands or objects contaminated with faeces.

Wash hands after handling an animal, its faeces, bedding or food. Remove faeces promptly so they do not contaminate gardens and paths.

Clean food and water bowls and contact surfaces regularly. Avoiding raw feeding reduces the associated exposure through food and the dog's faeces.

If raw pet food is handled at home, use utensils and chopping boards separate from those for human food. Wash metal or ceramic dishes used for raw food immediately in water above 70°C.

Store raw pet food in its packaging or a covered container so that it does not contact human food. Use thawed raw food as soon as possible after defrosting.

Do not refreeze raw food that has already been thawed for later use. Avoid wooden utensils when handling raw food because they are difficult to clean thoroughly.

Keep young children away from dog food and faeces, including outdoors. A pregnant person should avoid handling raw food and the faeces of an animal with diarrhoea.

During pregnancy, another household member should clean up faeces where possible. In kennels or shelters, animals with infectious diarrhoea are separated from others.

Important for dog owners

Record when diarrhoea began, stool wateriness, blood and mucus, and your dog's drinking, vomiting and energy levels. Tell the vet about raw feeding, possible drinking from natural water sources, and similar signs in other animals or people at home.

Follow the laboratory's collection and transport instructions. When discussing results, ask which bacterial species was sought and how the finding fits your dog's particular signs. Do not start an antibiotic prescribed for another animal or change current treatment yourself.

Keep cleaning equipment and food bowls separate from human food preparation. If a family member develops diarrhoea, tell their healthcare professional about the dog's signs and laboratory finding too. Agree on reassessment with the vet if diarrhoea fails to settle, returns or your dog's general condition deteriorates.

Frequently asked questions

Does a positive faecal sample mean my dog is ill?

Not necessarily: campylobacters are also found in dogs with normal-looking stools and no signs of disease. Results are interpreted according to bacterial species and symptoms. Routine Campylobacter screening of healthy dogs is generally considered unnecessary.

Does every dog need an antibiotic?

Uncomplicated campylobacteriosis is often mild and self-limiting, so antibiotics are usually unnecessary. Severe systemic signs or impaired immunity may change treatment needs. Where possible, the vet selects any required antimicrobial according to the susceptibility result for the bacterial strain identified.

How long can diarrhoea last?

Acute Campylobacter diarrhoea has been described as lasting 5–15 days. However, some dogs may carry the bacterium without any symptoms. Diarrhoea can also recur or become prolonged. Deterioration in general condition and dehydration determine urgency, rather than the number of days alone.

Can Campylobacter spread from a dog to a person?

Faecal transmission is possible even from a dog without symptoms. Wash hands after handling your dog, faeces and food. Contaminated raw food can also expose people directly, so infection in a household does not always identify the dog as the original source.

Can dogs only catch it from raw food?

The bacterium can also spread through contaminated water and faecal contact. Raw food is one exposure to consider, but the source for an individual dog may remain unknown. In cool lake and river water, campylobacters can survive for several weeks or even months.