Dog-killing disease makes comeback in Connecticut

A disease that used to be prevented as part of routine dog vaccines but went dormant made a comeback and recently infected dogs in Easton and Monroe.

Easton Animal Control Officer Kelly Fitch is advising all dog owners to get their pets vaccinated for leptospirosis, also known as lepto.

“A 2-year-old dog passed away from lepto lost last week,” Fitch said. “There have been several other cases in Easton and also in Monroe. People can catch it from their pets or if they are outside with bare feet.”

The disease is spread through the urine of infected animals such as raccoons, opossums, rodents, other wildlife, or livestock. No direct contact is required.

Dogs running around off their property can catch it; even dogs that stay within their electric fence can catch it if an infected animal comes inside and urinates, Fitch said.

Leptospirosis is a bacterial disease that affects humans and animals, according to the U.S. Centers for Disease Control. It is caused by bacteria of the genus Leptospira.

In humans, it can cause a wide range of symptoms, some of which may be mistaken for other diseases. Some infected people, however, may have no symptoms at all.

Without treatment, leptospirosis can lead to kidney damage, meningitis, liver failure, respiratory distress, and even death.

To prevent leptospirosis infection, the CDC advises keeping rodent problems (rats, mice, or other animal pests) under control. Rodents can carry and spread the bacteria that cause the disease.

The CDC also advises people to get their pets vaccinated. The vaccine does not provide 100% protection. This is because there are many strains of Leptospira, and the vaccine does not provide immunity against all strains. It is important to have a pet revaccinated, even if it gets leptospirosis, because it can still get infected with a different strain of leptospirosis.

Pet owners should also take steps to prevent themselves and others from becoming infected with the disease due to an infected pet. The primary mode of transmission from pets to humans is through direct or indirect contact with contaminated animal tissues, organs, or urine, the CDC says.

The disease is nasty but treatable. In humans it can cause high fever, headache, chills, muscle aches, vomiting, jaundice, red eyes, abdominal pain, diarrhea, and rash. In addition to these symptoms, in dogs it can cause refusal to eat, severe weakness and depression, stiffness, severe muscle pain and inability to have puppies.

When dog owners take their pets for their annual vaccinations, they should be sure they to get DHPPL, which means distemper, hepatitis, parvo, parainfluenza, and leptospirosis. The “L” had been left out in recent years, Fitch said. If a dog has been recently vaccinated, she urges the pet owner to call the vet to make sure leptospirosis was included.

“We hadn’t seen cases of lepto in years, so drug companies stopped putting the vaccine in the melting pot of medicine people take their dogs to get in their yearly vaccine,” she said.

Fitch attributes the rise to diminishing forests and wildlife habitat.

“Building is closing in on wild animals, bringing them into contact with humans and pets,” she said.

For more information about lepto, visit