Leptospirosis in Dogs: A 2025 Veterinary Guide to Infection, Diagnosis, Treatment, and Prevention 🐶🦠

Hello, I’m Dr Duncan Houston BVSc. Leptospirosis is a serious bacterial infection that can affect a dog’s kidneys, liver, lungs—and even humans. It’s spreading in both rural and urban areas, and quick recognition is essential. This 2025 guide walks you through how dogs get infected, the signs to watch for, how to test and treat it, and how to prevent it. 🩺

🧬 What Is Leptospirosis?

Leptospirosis is caused by spiral-shaped bacteria called Leptospira. There are 250+ serovars (subtypes), but vaccines cover only 4:

• Canicola – linked to kidney disease; more common in Mexico and the southern U.S.
• Pomona – severe kidney and liver involvement; linked to livestock
• Grippotyphosa – common in U.S. dogs; found in wildlife
• Icterohaemorrhagiae – rat-linked; attacks the liver

Leptospires live in stagnant water and moist soil and can survive for months. 🦠

💧 How Dogs Get Infected

• 🐕 Walking or swimming through contaminated water
• 🥤 Drinking from puddles, ditches, or communal bowls
• 🩸 Exposure via broken skin, eyes, or mucous membranes
• 🐭 Exposure to wildlife urine—especially raccoons, rats, and skunks

Dogs can also get infected from bites or consuming infected tissues. Outbreaks have occurred in urban boarding and daycare facilities. 💥

⚠️ Symptoms of Leptospirosis

Symptoms vary by organ system affected:

🩺 Acute Signs

• 🌡️ Fever
• 🤕 Muscle pain, stiff walk
• 📉 Lethargy and poor appetite
• 🩸 Bruising or bleeding (including nosebleeds)

🧬 Organ Damage

• 🧪 Kidney failure (common): increased thirst, no urine output
• 🟡 Liver damage: jaundice (yellow gums, skin, eyes)
• 🫁 Lung involvement: pulmonary hemorrhage (70% mortality)
• 👀 Uveitis: cloudy or discolored eyes

Chronic forms can cause ongoing kidney/liver failure, eye inflammation, and weight loss. Puppies under 1 year old are at highest risk. 🚨

🧪 Diagnosing Leptospirosis

PCR Testing

• 🧬 Detects leptospiral DNA in blood (early) or urine (after 10 days)
• ✅ Rapid results, unaffected by vaccination history

MAT (Microscopic Agglutination Test)

• 🔬 Measures antibodies to specific serovars
• 📈 Titers >1:800 (or 1:3200 if vaccinated) = infection likely
• 🔁 Repeat test in 2–4 weeks for definitive diagnosis

In-House ELISA Tests

• 🕓 Fast but not strain-specific
• 💉 Can’t distinguish infection vs. vaccination

💊 Treatment

Treatment involves:

• 💊 Doxycycline – clears blood/urine infection
• 💧 IV fluids – essential for kidney support
• 🧼 Gloves & bleach (1:10) for urine cleanup
• 💉 Dialysis for severe kidney failure (limited access)

Dogs can shed bacteria in urine for weeks. Isolation is recommended for at least 2 weeks post-treatment. 🔬

📉 Prognosis

• ✅ 80–90% survive with early treatment
• ☠️ Lung involvement or Pomona strain = higher mortality
• 🐾 Some survivors have long-term kidney/liver damage

🛡️ Prevention

Vaccination

• 💉 Covers 2–4 strains (Canicola, Icterohaemorrhagiae, Pomona, Grippotyphosa)
• 📆 Given annually after an initial 2-shot series
• ⚠️ May not prevent infection but reduces symptoms and shedding

Environmental Prevention

• 🧼 Control rodents in your yard and home
• 🚫 Avoid letting dogs drink from puddles or slow water
• 👟 Wear gloves/boots for cleanup and disinfection

🧍‍♂️ Can Humans Get Leptospirosis?

Yes. Zoonotic risk comes from:

• 🧴 Cleaning up infected urine
• 🐀 Contact with infected wildlife or contaminated water
• 💧 Swimming, wading, or flood exposure

Symptoms in humans are flu-like—headache, fever, muscle aches—and may progress to kidney or liver disease. If you think you’ve been exposed, see a doctor. 🏥

📱 Ask A Vet: Lepto Help for Dog Owners

• 🧬 Help interpreting test results
• 💊 Treatment planning and side effect monitoring
• 📋 Vaccination scheduling
• 🧼 Household risk assessment

Visit AskAVet.com or download the app for 24/7 veterinary support. 🐾

✅ Summary: Leptospirosis in Dogs

• 🦠 Bacterial infection spread via water, soil, or wildlife urine
• 🩺 Causes kidney, liver, or lung damage—sometimes fatal
• 🧪 Diagnosed with PCR and antibody testing
• 💊 Treatable with antibiotics and supportive care
• 💉 Vaccine recommended for all dogs, especially in humid or urban areas
• 🧍 Human infection possible—clean carefully and wear gloves

Leptospirosis is more common than you think—and often preventable with vaccines and awareness. Stay alert and proactive to keep your pet safe. 🐶🛡️

— Dr Duncan Houston BVSc