Leptospirosis Vaccine for Dogs

What Is Leptospirosis?

Leptospirosis is a bacterial infection caused by spiral-shaped bacteria called Leptospira. It is a zoonotic disease — meaning it can spread from animals to humans — making it a genuine public health concern. Leptospira bacteria infect a wide range of wild animals (rats, raccoons, opossums, deer, skunks) that carry and shed the bacteria in their urine without becoming ill themselves. Dogs become infected through contact with contaminated water, soil, or the urine of infected wildlife.

In dogs, leptospirosis can cause severe liver and kidney damage, leading to acute kidney failure, liver failure, bleeding disorders, and death if not treated aggressively. Survival depends on early diagnosis and intensive care. Even dogs that recover may have permanent organ damage.

Which Dogs Are at Risk?

Any dog with exposure to outdoor environments can encounter leptospirosis, but risk is highest in dogs that:

Swim in or drink from rivers, lakes, ponds, streams, or puddles
Spend time in rural, wooded, or agricultural areas
Hunt or track wildlife
Roam off-leash in areas with wildlife presence
Live in urban areas with high rodent populations
Are exposed to flooding (floodwater concentrates contaminated runoff)

Leptospirosis is no longer just a rural disease — increasing urban wildlife and flooding events have made it a risk in suburban and urban environments too. Talk to your vet about local prevalence. Book a vet appointment at Happy Paws to discuss whether your dog should receive this vaccine.

The Leptospirosis Vaccine

The lepto vaccine is a non-core vaccine, meaning it is given based on individual risk assessment rather than universally. Modern vaccines protect against the four serovars most commonly responsible for disease in dogs: Canicola, Icterohaemorrhagiae, Grippotyphosa, and Pomona. This four-serovar (tetravalent) product offers significantly broader protection than older two-serovar formulas.

The vaccine is given as a subcutaneous injection, typically combined with the annual DA2PP booster visit. It requires an initial two-dose series spaced 2–4 weeks apart, then annual boosters. The annual booster is important because leptospirosis immunity wanes more quickly than many viral vaccines.

Vaccination Schedule

First dose: As early as 8–9 weeks in high-risk puppies, or at the 10–12 week puppy visit for average-risk dogs
Second dose: 2–4 weeks after the first dose
Annual booster: Required every year to maintain protection

Do not miss the annual booster — unlike core viral vaccines that can be extended to every 3 years in adults, leptospirosis immunity is shorter-lived and annual vaccination is essential for at-risk dogs.

Signs of Leptospirosis and When to Act

Signs typically appear 5–14 days after exposure and include:

Sudden fever, shivering, and muscle tenderness
Vomiting, diarrhea, and loss of appetite
Increased or decreased urination
Yellowing of the skin and eyes (jaundice) — indicates liver involvement
Bleeding from gums, in urine, or under the skin

This is a medical emergency. If your dog shows these signs, seek immediate veterinary care. Use the TailRounds AI Triage tool for rapid guidance. Leptospirosis is also a risk to human household members — practice careful hygiene (gloves, handwashing) if your dog is diagnosed or suspected to be infected.