Can Rats Make Pets Sick?

CDC states that leptospirosis "can affect people and animals, including pets, farm animals, rodents, wild animals," and that the bacteria can contaminate water or soil, "where it can survive for weeks to months." Dogs are considered broadly at risk — CDC's language is direct: "Almost every dog is at risk of leptospirosis, whether they live in the country, suburbs, or city." Cats are less commonly affected, but outdoor cats that hunt or encounter infected rodents face elevated risk.

Infected dogs may vomit, become dehydrated, or develop back pain associated with kidney involvement, but these signs are nonspecific and overlap with many other illnesses. A leptospirosis vaccine is available for dogs in the United States (none is currently available for cats), but it doesn't protect against every strain of the bacteria, so exposure control still matters even in vaccinated dogs. Because clinical signs can't reliably distinguish leptospirosis from other conditions on sight, the only responsible path is a veterinary evaluation — not a home checklist or wait-and-see approach.

Beyond leptospirosis, rats can carry rat-bite-fever bacteria and salmonella that can affect animals as well as people. It's also worth noting the reverse risk: it's rare but possible for a person to contract leptospirosis from an infected pet's urine, which is one more reason to wear gloves when cleaning up after a pet that may have been exposed and to see your own doctor if you develop symptoms.