Campylobacteriosis in Dogs and Cats

TL;DR. Campylobacteriosis is an uncommon bacterial gut infection in young or crowded dogs and cats that causes watery or mucus-filled diarrhea, but it typically resolves well with targeted antibiotic treatment.

Campylobacteriosis primarily targets the gastrointestinal tract of young or stressed dogs and cats.

What is it?

Campylobacteriosis is an infectious bacterial disease of the gastrointestinal tract that affects both dogs and cats. The culprit behind this condition is a group of spiral-shaped, motile bacteria belonging to the genus Campylobacter, most commonly Campylobacter jejuni or Campylobacter upsaliensis. While these bacteria can live harmlessly in the intestines of many healthy adult dogs and cats, they can cause severe, symptomatic infections in younger animals, stressed pets, or those with compromised immune systems.

When the bacteria colonize the digestive tract, they attach to and invade the lining of the small and large intestines. This invasion triggers a robust inflammatory response, leading to mucosal damage, decreased nutrient absorption, and a disruption in the normal fluid balance of the gut. The result is acute gastroenteritis, characterized by diarrhea that often contains mucus or blood. Because the bacteria can be shed in large numbers in the feces of infected animals, the disease is highly contagious among pets and, importantly, poses a zoonotic risk—meaning it can be transmitted from animals to humans, causing similar gastrointestinal distress in people.

Understanding campylobacteriosis is essential for pet owners, especially those with young puppies, kittens, or pets living in multi-animal environments. Recognizing the signs early and implementing proper hygiene practices can protect both your pet's health and the health of your human family members. Managing this disease in pets is not just about animal welfare, but also about protecting the human household, particularly young children, elderly individuals, or anyone with a compromised immune system.

Causes & risk factors

The primary cause of campylobacteriosis is the ingestion of Campylobacter bacteria. This transmission typically occurs via the fecal-oral route. Pets can contract the bacteria by:

• Ingesting food or water contaminated with infected feces.
• Eating raw or undercooked poultry, beef, or pork, which are common reservoirs for the bacteria.
• Consuming unpasteurized milk or contaminated surface water (such as puddles, ponds, or streams).
• Direct contact with an infected animal's stool or contaminated environment.

Several risk factors increase the likelihood of a pet developing clinical disease:

• Age: Young animals under six months of age are the most frequently affected. Their immune systems are still developing, and their gut microbiomes are less stable, making it easier for pathogenic bacteria to colonize.
• Crowded Environments: Kennels, animal shelters, pet shops, and breeding facilities provide ideal conditions for the rapid spread of the bacteria. High animal density and shared spaces increase the risk of exposure.
• Stress and Concurrent Infections: Stress from rehoming, dietary changes, or other infections (such as parvovirus, coronavirus, or intestinal parasites) can weaken a pet's local gut immunity, allowing Campylobacter to multiply and cause disease.
• Poor Sanitation: Inadequate cleaning of food bowls, water dishes, and living areas can facilitate the persistence of the bacteria in the environment. Campylobacter bacteria are sensitive to drying and acidic environments but can survive for weeks in cool, moist environments, such as damp soil, standing water, or feces.

There are no documented breed predispositions for campylobacteriosis in either dogs or cats; any breed can become infected if exposed under the right conditions.

Signs to watch for

The clinical signs of campylobacteriosis can vary from mild, self-limiting diarrhea to severe, life-threatening gastroenteritis. Owners should monitor their pets closely for the following symptoms:

• Diarrhea (Cardinal): This is the hallmark sign of the infection. The stool is typically loose, watery, or semi-formed. In severe cases, the diarrhea can be frequent and voluminous.
• Mucoid diarrhea (Common): The stool often contains visible mucus, which is a sign of large intestinal inflammation (colitis). It may also contain streaks of fresh, red blood.
• Fever (Common): An elevated body temperature is a frequent response to the systemic inflammatory reaction caused by the bacterial invasion of the gut wall.
• Anorexia (Common): Infected pets often lose their appetite entirely or show a marked decrease in food intake due to abdominal pain, nausea, and general malaise.
• Vomiting (Common): Vomiting can occur alongside diarrhea, further compounding fluid loss and increasing the risk of dehydration.
• Abdominal Pain (Common): Pets may show signs of abdominal discomfort, such as a tucked-up posture, whimpering when touched, or restlessness.
• Lethargy (Common): A general lack of energy and reluctance to play or interact, resulting from dehydration, fever, and nutrient depletion.

Loss of appetite (anorexia) and lethargy are common signs of campylobacteriosis in young pets.

How vets diagnose it

Diagnosing campylobacteriosis requires distinguishing it from other causes of gastroenteritis, such as viral infections, parasites, dietary indiscretion, or other bacterial pathogens. Because Campylobacter can be found in the feces of healthy, asymptomatic pets, finding the bacteria alone is not always proof that it is the cause of the illness. Your vet will perform a comprehensive diagnostic workup to confirm the diagnosis.

The diagnostic process typically involves:

1. Physical Examination and History: Your vet will assess your pet's hydration status, body temperature, and abdominal sensitivity, and gather information about their diet, environment, and onset of signs.
2. Fecal Smear Cytology: A rapid, in-clinic test where a small smear of feces is stained and examined under a microscope. As noted in a leading veterinary internal medicine reference:

   "Occasionally, classic Campylobacter forms may be found during cytologic examination of a fecal smear (i. e. , "commas," "seagull wings"). Such cytologic findings are suggestive of Campylobacter but are nonspecific and of uncertain sensitivity."

3. PCR Analysis of Feces: Polymerase Chain Reaction (PCR) testing is a highly sensitive and specific molecular test. It detects the genetic material of the bacteria in the stool sample. PCR is highly effective because it can differentiate between different species of Campylobacter, helping to identify the specific pathogen involved.
4. Fecal Culture: Culturing the bacteria involves growing them on specialized media in a laboratory. This is a complex process because Campylobacter requires specific microaerophilic (low oxygen) conditions to grow. According to veterinary literature:

   "Diagnosis can be made only by finding clinical disease consistent with a particular organism, evidence of the organism or its toxin, eliminating other causes of the clinical signs, and seeing the expected response to appropriate therapy. If the clinician cultures feces, it is crucial to call the laboratory ahead of time, tell staff members what is being sought through culture, and follow their ins[tructions]."

Treatment options

Treatment of campylobacteriosis involves a combination of targeted antimicrobial therapy and supportive care to address dehydration and intestinal inflammation.

First-Line Antibiotic Therapy

Antibiotics are indicated for pets showing moderate to severe clinical signs, those with confirmed zoonotic risk to vulnerable humans in the household, or young animals at risk of systemic spread.

• Erythromycin: This is a macrolide antibiotic and is widely considered the drug of choice for treating campylobacteriosis. It helps reduce the shedding of the bacteria and shortens the duration of clinical signs.
• Azithromycin: A macrolide antibiotic belonging to the azalide subclass, azithromycin is sometimes used as an alternative to erythromycin due to its convenient dosing schedule and favorable gastrointestinal tolerance.

Second-Line and Alternative Antibiotic Therapies

In cases where the bacteria are resistant to macrolides, or if the pet does not tolerate the first-line medications, alternative antibiotics may be prescribed:

• Neomycin: An aminoglycoside antibiotic that acts locally within the gastrointestinal tract to combat bacterial overgrowth.
• Orbifloxacin: A fluoroquinolone antibiotic that may be reserved for severe, systemic, or resistant infections.
• Chloramphenicol: A broad-spectrum antibiotic that can be highly effective but is typically reserved for cases where other options are not viable.

Supportive Care

In addition to antibiotics, supportive therapies are crucial:

• Fluid Therapy: Intravenous or subcutaneous fluids are administered to correct dehydration and electrolyte imbalances caused by vomiting and diarrhea.
• Dietary Management: A highly digestible, low-fat, or gastrointestinal-specific diet helps rest the gut and promotes mucosal healing.
• Probiotics: High-quality veterinary probiotics may be recommended to help restore a healthy balance to the gut microbiome after bacterial disruption and antibiotic use.

Prognosis

With appropriate antibiotic therapy and supportive care, the prognosis for recovery is good. Most pets show significant improvement within 24 to 48 hours of initiating treatment. However, completing the full course of prescribed antibiotics is critical to ensure the infection is completely cleared and to prevent the development of antibiotic-resistant bacterial strains.

In very young, severely debilitated, or immunocompromised pets, recovery may take longer, and intensive supportive care may be required. Long-term complications are rare, and most pets return to a normal, healthy life with no lasting gastrointestinal damage.

Prevention

Preventing campylobacteriosis involves practicing excellent hygiene and minimizing your pet's exposure to potential sources of the bacteria:

• Hygiene and Sanitation: Always wash your hands thoroughly with soap and water after handling your pet, cleaning up feces, or scooping litter boxes. Promptly remove and safely dispose of pet waste from your yard or litter box.
• Safe Feeding Practices: Do not feed raw or undercooked meats to your pets. Clean food and water bowls daily with hot, soapy water.
• Clean Water Access: Prevent your pets from drinking from outdoor water sources like puddles, ponds, or streams, which may be contaminated with wildlife feces. Provide fresh, clean drinking water at all times.
• Quarantine and Isolation: If you introduce a new pet to your household, keep them separate from your other pets until they have been cleared of any infectious diseases by a veterinarian, especially if they are showing signs of diarrhea.

When to call your vet

You should contact your veterinarian if your puppy, kitten, or adult pet develops persistent diarrhea, especially if it contains mucus or blood, or if they show a sudden loss of appetite.

Seek immediate emergency veterinary care if your pet exhibits severe lethargy, continuous vomiting, a high fever, or refuses to drink water, as these signs can quickly lead to life-threatening dehydration and shock.

Sources

• Internal Medicine, 5th Edition, pages 495, 1334.