Can humans catch leptospirosis from dogs?

Leptospirosis is a zoonosis, a disease that can pass between animals and people. The US CDC says people catch it through contact with water or soil containing the urine or body fluids of infected animals, by touching an infected animal's body fluids, or from contaminated food or water. It advises covering cuts and scratches with waterproof dressings. It is rare for people to pass leptospirosis to other people.

Dogs catch it the same way, most often from water contaminated with urine, such as puddles and ponds, according to Cornell's Riney Canine Health Center. ACVIM notes that an infected dog usually does not start passing the bacteria in its urine until 7 to 10 days after infection.

How long a dog stays infectious is where sources differ. The Merck Veterinary Manual says a dog that becomes a carrier may shed the bacteria in its urine for months or even years. The CDC says a dog that is not fully treated may shed them for up to 3 months. Both point the same way: finish the treatment your vet prescribes and keep up the precautions until your vet says they can stop.

The 2023 consensus statement of the American College of Veterinary Internal Medicine reviewed the evidence. It found that the few reports suggesting transmission from pet dogs to people had not been confirmed with molecular methods, described one documented case of a sick dog passing it to a child in the household, likely through handling contaminated urine, and noted that surveys found no antibodies in vets and veterinary students. Its conclusion: the risk appears low, especially when basic precautions are taken, and treated dogs returned home are a low risk to the family.

In India the bigger exposure is the environment. The Health Ministry's advisory of 23 June 2026 says the disease is spread through the urine of infected rats, mice and other rodents, and that cases rise in the monsoon in endemic states. NCDC's programme covers 181 districts in 12 states and 2 union territories, including Kerala, Tamil Nadu, Karnataka, Maharashtra, Gujarat, Goa and West Bengal.

Vaccinating dogs also lowers the risk of people being exposed, Cornell notes. The vaccines cover the four most common types of Leptospira but not every strain, so a vaccinated dog can still be infected. Merck says it is usually recommended every year. WSAVA's 2024 guidelines treat it as core wherever the disease occurs and a suitable vaccine is available. Petym's glossary page on leptospirosis covers the vaccine and the signs in dogs in more depth, and the monsoon guide covers floodwater, paws and drying off after walks.