What is leptospirosis?
Leptospirosis (lepto) is a disease caused by a bacteria called Leptospira interrogans. It can infect multiple species of mammals, including humans, dogs, rats, mice, raccoons, skunks, opossums, cows, and pigs. Lepto is occasionally diagnosed in dogs in LA County.

What are the symptoms of lepto?

In dogs: Symptoms are variable and are most commonly associated with kidney damage which may include fever, lethargy, low appetite, vomiting and increased or decreased urination and thirst.  Diarrhea and liver damage or yellowed mucus membranes (gums) may also be seen.

In humans: Symptoms are variable and may include fever, severe headache, and muscle aches. In severe cases, people may have yellowed mucus membranes, cause kidney damage and respiratory distress. Click here to learn more about lepto in people. 

How is lepto transmitted?
Infection occurs when the urine of an infected animal contacts the eyes, nose, mouth, or broken skin of another animal or a  person. Exposure to water or mud contaminated with urine may also spread it. In the United States, most human cases of lepto occur after recreational exposure to contaminated lakes or streams, not from dogs. The bacteria is shed in the urine of an infected dog. Therefore a person caring for a dog with lepto should wear gloves, especially when cleaning up urine.

Tracking lepto in dogs in LA County:

Leptospirosis Outbreak in Dogs in Los Angeles County in 2021

• 77 cases reported in dogs
• Case categorization based on LA County's leptospirosis case definition for dogs
  • 48% confirmed
  • 19% probable
  • 32%  suspected
• Vaccination history was available for 68 cases.  Of these, 81% had not been vaccinated against lepto.
• In 2014, laboratories were required to report cases and the total amount of total reported cases increased
• In 2020, one laboratory did not report as required and the total amount of reported cases was decreased.  In addition, the COVID-19 pandemic may have had an impact on pets being taken in for veterinary visits and pets being tested for this disease thus accounting for a decrease in reported cases.

• Modes of exposure
  • Most cases exposed to wildlife, or water contaminated by wildlife, in or near the dog's home environment (such as  backyard water bowls, fountains, and ponds)
  • The most common wildlife exposure in lepto cases in dogs included raccoons, rats or mice, opossums and skunks.

• Locations of cases

  • Areas throughout LA County, no clear geographic pattern

  • Due to the cost of testing, may be more likely to be diagnosed in dogs in higher income areas

What is the treatment for lepto in dogs?
Veterinarians treat infected pets by administering specific antibiotics that can kill the bacteria. Most dogs with lepto are seriously ill and should be treated in a veterinary hospital.

How can I protect my dog from lepto?

1. Wildlife Control. Do not attract wildlife to your yard. Do not leave your pet's food and water outside at night. If you have water outdoors for your pet during the day, wash and change your pet's water bowl daily in case it was contaminated by the urine of wild animals. If you suspect a rat or mouse infestation in your house, consult an exterminator.  

2. Consider vaccinating your dog for lepto. Local data suggest that a variety of Leptospira serotypes (strains) of bacteria may cause illness in dogs. Therefore the 4-way vaccines (protecting against 4 strains of the bacteria) are a better choice for protection than the 2-way vaccines. Canine Influenza and Leptospirosis Vaccine Providers in Los Angeles County and Neighboring Counties 12.6.21

Reporting Lepto Cases
VETERINARIANS: Report a case of leptospirosis disease by using this form and email it in to vet@ph.lacounty.gov or fax to 213-481-2375.