Leptospirosis in Dogs

How Dogs Get Leptospirosis

• Contaminated water: puddles, ponds, streams and standing water, the most common source^2,1
• Urine-soaked soil and grass, where the bacteria can survive for weeks to months, including in backyards visited by rodents or wildlife^4,14
• Direct contact with the urine of infected animals, bites or eating infected carcasses^3,8
• Places where dogs gather, such as dog parks, boarding kennels, daycare and training facilities^4,13

Rats are the most common source in New York City, and worldwide about 30% of rats carry the bacteria.^6,14 Cases often rise after heavy rain and flooding.^8,15 In the Northeast, lepto is most common in the fall, while in the South it occurs year-round.¹⁴

Symptoms of Leptospirosis in Dogs

Some dogs have no signs, while others become severely ill.^3,4 Signs include:

• Fever, lethargy, poor appetite, vomiting and diarrhea^8,1
• Increased or decreased thirst and urination, from kidney injury, the most common form of lepto in dogs^9,8
• Muscle pain, stiffness, back pain or belly pain^5,3
• Jaundice from liver involvement^9,3
• Coughing or breathing difficulty from bleeding in the lungs^9,8
• Bleeding, and eye inflammation⁹

Diagnosis

Bloodwork often shows sudden kidney changes, liver changes and low platelets.⁹ Vets confirm lepto with a combination of tests:^7,8

• PCR on blood and urine, ideally collected before antibiotics are given⁷
• Antibody tests (MAT), often repeated 1 to 2 weeks apart, because results can be negative in the first week^8,7
• Rapid in-clinic tests, some of which can be positive in vaccinated dogs⁸

A single negative test doesn't rule lepto out.⁷

Treatment

Dogs are treated with antibiotics, usually a tetracycline-class antibiotic for 2 weeks, or a penicillin-class antibiotic given by IV if the dog is vomiting.^7,9,2 Most need hospital care with IV fluids, anti-nausea medicine, pain relief and close monitoring of urine output.^7,3 Dogs whose kidneys stop producing urine may need dialysis at a specialty center.^9,7 Other dogs in the home may be given preventive antibiotics.⁷

Can a Dog Recover From Leptospirosis?

Yes, and the chances are good when it's treated early.^4,2 In a German study of 99 dogs with lepto, about two thirds survived. In small studies of dogs with severe kidney injury treated with dialysis, 73% to over 80% survived.^16,12,7 Lung bleeding is the most dangerous form, with death rates of up to 70%.⁷ Some survivors are left with chronic kidney disease. In one study, half of long-term survivors of dialysis developed it.^10,3 See kidney disease in dogs.

Can Humans Get Leptospirosis From Dogs?

It's possible but uncommon. Most US human cases come from water recreation or rodents, and New York City has found no dog-to-human transmission in 19 years of surveillance.^4,6 If your dog has lepto:^7,3,5

• Wear gloves to clean up urine, and wash your hands after handling your dog.
• Clean urine spots with a household disinfectant or a solution of 1 part household bleach to 10 parts water.
• Use a separate toileting area away from where people and children play or garden.
• Take extra care until 48 hours of antibiotics are done, and see your doctor if you're ill, pregnant or have a weak immune system.

Dogs can keep shedding bacteria in urine for months after recovery if not fully treated.^8,9

Prevention

• Vaccinate yearly. The vaccine covers the four most common types and is recommended for all dogs from 12 weeks of age. See the lepto vaccine.^7,3
• Keep dogs from drinking standing water, puddles and ponds.^2,15
• Control rodents around your home.^6,4
• Choose boarding and daycare facilities that require the lepto vaccine.¹⁷

Frequently Asked Questions

Can my dog get lepto from my backyard?

Yes, if rodents or wildlife urinate there. The bacteria can survive in damp soil for weeks to months.

What are the first signs of leptospirosis in a dog?

Fever, lethargy, poor appetite, vomiting and changes in drinking or urination.

How long does leptospirosis take to show up?

Usually 2 to 14 days after exposure.

Can vaccinated dogs get lepto?

Rarely. The vaccine covers the most common types but not all of them.

What kills leptospirosis?

Common household disinfectants and diluted household bleach kill the bacteria on surfaces. Infected dogs need antibiotics.