Veterinary Guide to Canine Leptospirosis 2025 🩺🐕

By Dr. Duncan Houston BVSc

🧬 What Is Leptospirosis?

Leptospirosis is a zoonotic bacterial infection caused by spirochetes of the genus Leptospira, transmitted via urine from infected wildlife or domestic animals into water, soil, or food, entering through mucous membranes or broken skin.

👥 Who’s at Risk?

• Any age, breed, lifestyle or location—dogs everywhere can be infected.
• Greater risk for dogs exposed to stagnant water—ponds, puddles, slow-moving streams—or contaminated soil, bedding, or food.
• Wildlife reservoirs include rodents, raccoons, skunks, opossums, and farm animals.
• Climate impacts: warm, rainy locations and flood-prone areas increase leptospirosis risk.

⚠️ Clinical Signs to Watch For

Leptospirosis can present in many forms, from subclinical to life-threatening.

Kidney & Liver Involvement

• Elevated thirst/urination, vomiting, anorexia, lethargy.
• Icterus (jaundice), abdominal pain, hepatomegaly—the liver is commonly affected.
• Azotemia, metabolic acidosis, and electrolyte imbalances on bloodwork.

Systemic Signs

• Fever, muscle pain, stiffness, and limping due to vasculitis/myositis.
• Bleeding tendencies—petechiae, nosebleeds, melena, hematemesis due to coagulopathy.
• Respiratory distress—coughing, dyspnea, pulmonary hemorrhage in severe cases.
• Neurological or ocular issues—rare uveitis, meningitis cases.

🔍 Diagnostic Approach

1. History & physical: focus on water/animal exposure and systemic signs.
2. Bloodwork: CBC, chemistry panel—look for azotemia, liver enzyme elevations, thrombocytopenia, acidosis.
3. Urinalysis: Proteinuria, glucosuria, casts, hematuria, dilution abnormalities.
4. Serology & PCR: MAT paired titers plus PCR on blood/urine give a reliable diagnosis.
5. Imaging: Chest X-rays (pulmonary signs) and abdominal US for renal/hepatic changes.

🛠️ Treatment Protocols

• Hospital Care

• Initiate IV fluids and correct electrolytes/acidosis immediately.
• Start parenteral penicillin or ampicillin to clear leptospirosis.

• Oral Antibiotics

• Doxycycline for 2–4 weeks helps eliminate leptospires from the kidneys/urine, reducing zoonotic risk.

• Supportive Measures

• Antiemetics, antacids, nutrition support, and kidney-friendly diets.
• Manage coagulopathy and respiratory symptoms as needed.
• Dialysis can rescue dogs with severe kidney injury.

📈 Prognosis

• With prompt and aggressive treatment, 80%+ survive; prognosis is poorer with pulmonary hemorrhage.
• Chronic kidney or liver damage can occur; survivors may develop CKD.
• Zoonotic cases are rare; humans should reduce exposure until the dog is no longer shedding bacteria.

🏡 Prevention Strategies

• Vaccinate annually—covers common serovars like Canicola, Icterohaemorrhagiae, Pomona, and Grippotyphosa.
• Eliminate stagnant water, rodent control, and avoid wildlife urine exposure.
• Use protective equipment during the cleanup of contaminated areas and isolate infected dogs until cleared.

📱 Ask A Vet Telehealth Support

• 📸 Share bloodwork, imaging, PCR/MAT results for specialist interpretation.
• 🔔 Get medication reminders for antibiotics, fluids, and follow-up labs.
• 🩺 Video consults to assess hydration, bleeding signs, feeding, and respiratory effort.

🎓 Case Spotlight: “Riley” the Retriever

Riley, a 5-year-old outdoor Labrador, presented with lethargy, vomiting, polyuria, and mild jaundice after swimming in a local pond. Bloodwork showed azotemia and thrombocytopenia; PCR confirmed leptospirosis. He received IV fluids, ampicillin, followed by doxycycline. With telehealth support from Ask A Vet, Riley’s urine output, appetite, and labs were monitored, and rodent-proofing and vaccination reminders were provided. Riley made a full recovery and recommenced normal outdoor walks. 🐾

🔚 Key Takeaways

1. Leptospirosis is a potentially fatal but treatable zoonotic disease affecting the liver, kidneys, lungs, and blood clotting.
2. Suspect in any dog with systemic signs and exposure to stagnant water or wildlife, even urban dogs.
3. Diagnosis relies on serology (MAT), PCR, bloodwork, urinalysis, and imaging.
4. Prompt treatment with antibiotics and supportive care is critical; dialysis may be lifesaving.
5. Prevention through annual vaccination, environmental control, rodent management, and hygiene.
6. Ask A Vet telehealth advances treatment—specialist review, medication coordination, symptom tracking & education 📲🐾

Dr Duncan Houston BVSc, founder of Ask A Vet. Download the Ask A Vet app to support your dog’s leptospirosis prevention and treatment—from exposure assessment to diagnostics, home care, telehealth follow-ups, vaccine reminders, and recovery tracking 🐶📲