Clostridium difficile in Pets and People 🦠🐾

By Dr Duncan Houston, BVSc

Clostridium difficile (C. difficile or C. diff) is a toxin-producing bacterium that causes diarrhea in humans—and possibly in pets. While rare in healthy cats and dogs, C. difficile is becoming more common across North America. Learn how to protect yourself, your family, and your pets in this 2025 zoonotic health update. 🧴

🔬 What Is Clostridium difficile?

C. difficile is a bacterium found in the intestines of people, animals, and the environment. It produces toxins that cause disease, and it can form tough spores that survive for years on surfaces and resist many disinfectants. 😷

Infection usually occurs when spores are ingested—typically through contaminated hands or surfaces. 🧽

📈 Why Is It Becoming More Common?

In humans, C. difficile is now the leading cause of hospital-associated diarrhea. It’s also appearing more often in people outside of hospitals. Risk factors include:

• 💊 Antibiotic use
• 🎂 Older age
• 🏥 Long hospital stays
• 🧪 Acid-suppressive medications
• 🔬 Certain cancer therapies

The hyper-virulent strain ribotype 027/NAP1 has emerged in North America, Europe, and Japan, causing severe illness in previously healthy individuals. 🚨

🐶🐱 Can Pets Carry C. difficile?

Yes. Studies show that up to 4% of healthy cats and dogs carry it—but that rate can climb to 30% in young animals, breeding colonies, or pets exposed to healthcare environments. 🧬

Dogs visiting hospitals or living with children are more likely to shed C. difficile. 🦠

🤧 Symptoms of C. difficile Infection (CDI)

In Humans:

• 💩 Mild to severe diarrhea
• 🌡️ Fever and abdominal pain
• 🛏️ Potential complications and death in vulnerable patients

In Pets:

• 💩 Diarrhea—usually mild, but can be severe
• 🩺 Usually linked to prior antibiotic use
• 📊 Most pets carry the bacteria without symptoms

🧪 How Is It Diagnosed?

• 🔍 Simply finding C. difficile is not enough—toxin detection is key
• 📊 Stool must be tested for toxin presence (not just bacterial culture)
• ⚠️ Healthy animals should not be tested unless symptomatic

💊 How Is CDI Treated?

In Humans:

• 💊 Stopping current antibiotics may help
• 🦠 Severe cases treated with targeted antibiotics
• ❌ Probiotics are not proven effective for CDI

In Pets:

• 💊 Most recover without medication
• 💧 Fluids may be needed for diarrhea
• ⚠️ No vaccine available for any species

🧼 If Your Pet Has C. difficile…

• 🧼 Wash hands thoroughly with soap and water after contact
• 🚫 Avoid alcohol-based sanitizers—they don’t kill spores
• 🐾 Limit exposure to other pets (no parks or kennels)
• 🧽 Clean contaminated areas ASAP with diluted bleach (1:10)
• 🧤 Wear gloves during cleanup
• 💨 Steam-clean rugs and upholstery

🏥 Special Notes for Therapy Animals

Dogs visiting hospitals are at increased risk. Prevention tips:

• 🚽 Don’t let pets drink from toilets
• 🚫 Patients should not feed therapy animals

👩‍⚕️ Should You Test Your Pet If You Have C. difficile?

No. Even if your pet is shedding C. difficile, it may not be the same strain. Testing is not helpful in most cases. Just wash hands thoroughly and keep toilets closed. 🚽

⚠️ High-Risk Groups

• 👶 Infants under 12 months: not affected by C. difficile
• 👵 Older adults and those with weakened immune systems: higher risk
• 👧 Young children: more likely to interact closely with pets, less likely to wash hands

Precautions:

• 🧼 Supervise hand washing after pet interaction
• 🚿 Avoid close contact when pets have diarrhea

📱 Ask A Vet App Support

If your cat or dog has diarrhea while on antibiotics, or if C. difficile is suspected, the Ask A Vet app is here to help:

• 📸 Share stool photos or cleanup concerns
• 🧪 Review test results and treatment options
• 📋 Get disinfection and isolation tips
• 💬 Talk with a licensed vet for peace of mind

🏁 Final Takeaway

C. difficile is serious and increasingly common in people—and occasionally in pets. While pets are rarely affected, they can carry the bacteria. Prioritize hygiene, avoid unnecessary antibiotics, and use bleach to clean up after sick pets. For guidance, consult your vet or use the Ask A Vet app to stay protected. 🐶🐱🧼❤️