Understanding Diarrhea in Dogs

by Cecilia Martinez- Southernwind Kennels

Why Early Stool Testing and Cultures Are Critical for Canine Health

One of the most common yet misunderstood health concerns dog owners face is diarrhea. While it may seem like a minor digestive upset, prolonged or recurrent diarrhea can be a sign of a deeper health issue. Left undiagnosed or untreated, it can lead to severe complications that affect your dog’s immune system, weight, energy levels, and long-term health. This article explores the common causes of diarrhea in dogs, the importance of early diagnostic testing, and the risk of bacterial infections, including spirochetes, which are commonly found in Florida.

Common Causes of Diarrhea in Dogs

Dogs can experience diarrhea for a variety of reasons, including:

• Sudden changes in diet

• Eating spoiled food or non-food items

• Parasites such as Giardia, hookworms, roundworms, and coccidia

• Stress or anxiety due to environmental changes

• Viral infections such as parvovirus or coronavirus

• Bacterial infections, which can be far more dangerous than many realize

  

  A Veterinarian checking the Stool sample

The Role of Fecal Float Tests

The fecal flotation test is a basic diagnostic tool that helps detect intestinal parasites. A small stool sample is examined for parasite eggs using a special solution. This test is often the first step when diarrhea is present, especially in puppies or newly adopted dogs. However, while this test is effective for parasites, it does not detect bacterial infections.

When the Float Test is Negative: The Importance of Stool Cultures

If a fecal float comes back clear and the diarrhea persists, your next step should be a complete stool culture and sensitivity test. A stool culture identifies harmful bacteria that may be causing gastrointestinal upset. These bacteria include:

Salmonella

Often contracted through contaminated raw food, soil, or feces from other animals. It can also be transmitted from contact with reptiles or birds. Symptoms may include fever, vomiting, and severe diarrhea.

Salmonella Bacteria

Clostridium perfringens

Common in dogs with poor diet changes or contaminated food exposure. This bacterium produces toxins that disrupt the intestinal lining. It can be part of a dog's normal flora but become pathogenic under stress or poor immunity.

Campylobacter

Frequently found in shelter dogs, boarding facilities, or multi-dog households. It is transmitted through contact with contaminated water, feces, or food. Puppies are particularly vulnerable.

E. coli

While some strains are naturally present in a healthy gut, pathogenic strains can cause bloody diarrhea and lethargy. Dogs can contract E. coli from raw meat, dirty water, or close contact with infected dogs.

Spirochetes (Spirochaetosis)

Common in warm and humid regions like Florida, spirochetes are spiral-shaped bacteria that can infect the gastrointestinal tract. They are often spread through contaminated water, feces, or infected prey. In some cases, spirochetes may remain undetected without a specialized culture. Symptoms can mimic those of viral or parasitic infections, leading to misdiagnosis if proper testing is not done.

How Dogs Contract These Bacteria

Dogs can pick up harmful bacteria from many common sources including:

• Drinking from puddles, lakes, or contaminated water bowls

• Eating spoiled food or garbage

• Contact with feces from other infected animals

• Unsanitary kennel or shelter conditions

• Close contact with infected dogs, especially in high-traffic areas like dog parks or daycares

  
  

  

  Dog eating Spoiled Food from a Trash Can

  
  

Treatment and Antibiotics

Once the specific bacteria is identified via culture, a veterinarian can prescribe the correct antibiotic. Here are some commonly used antibiotics, always administered under veterinary supervision:

• Metronidazole is frequently used for Giardia and Clostridium

• Amoxicillin or Clavamox for certain strains of E. coli and Salmonella

• Tylosin is used for chronic diarrhea and suspected bacterial overgrowth

• Doxycycline may be effective against certain spirochetes and other systemic infections

  
  

The exact treatment plan should always be determined by a veterinarian, especially since the misuse of antibiotics can worsen symptoms or promote resistance.

Why Early Testing is Critical

Delaying a full diagnostic workup can allow the problem to worsen. In some cases, ongoing diarrhea damages the gut lining, weakens the immune system, and leads to chronic inflammatory conditions. Puppies and older dogs are especially at risk of dehydration, malnutrition, and secondary infections if the root cause isn’t addressed early.

A comprehensive stool exam, including both float and culture tests, is essential in cases of persistent diarrhea. It helps not only to rule out common parasites but also to uncover hidden bacterial threats that require specific treatment.

Acting early can prevent complications that might become irreversible if left untreated.

Final Thoughts

As breeders and caretakers, we must remain vigilant and proactive when it comes to canine health. Diarrhea is not just a nuisance—it can be a warning sign.

At Southernwind, we encourage all dog owners to prioritize thorough diagnostic testing and work closely with trusted veterinarians to protect their dogs’ long-term health.