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Veterinary Public Health Program
313 N Figueroa St. Rm 1127
Los Angeles, CA 90012
Tel (213) 288-7060
Fax (213) 481-2375
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Leptospirosis in Dogs in Los Angeles County in 2021


What is leptospirosis? dog walking in a park on a leash with an owner
Leptospirosis (lepto) is a disease caused by a bacteria called Leptospira interrogans.  These bacteria can infect multiple species of mammals, including humans, dogs, rats, mice, raccoons, skunks, opossums, cows and pigs.  Both animals and people may have a wide variety of symptoms, from no symptoms at all to liver and kidney damage and even death.  There are vaccines for dogs that may provide protection against this potentially serious infection.  Contact your veterinarian if you have questions about your pet and leptospirosis.  

Leptospirosis in dogs in Los Angeles County in 2021
In July 2021, Veterinary Public Health noted a large increase in reported confirmed and suspected canine leptospirosis cases.  Most of the affected dogs either live in or had exposures in locations on the west side of the county or the San Fernando Valley.  A number of dogs were exposed at dog daycare/boarding facilities but others may have been exposed at dog parks or beaches.  Many infected pets required hospitalization and extensive care.  At this time, there have been no reports of people becoming ill after exposure to the infected dogs.  The leptospira serovar canicola is the likely cause of this outbreak.  Dogs are the primary reservoir for the canicola serovar, not wildlife or rats.  As a result, this outbreak is driven by dog-to-dog transmission of the bacteria in group settings such as boarding kennels or dog daycare, leading to a higher number of cases than what has been seen in recent years.  With this recent increase in canine cases, it is very important for veterinarians to consider leptospirosis as a possible cause when dogs are seen at their veterinary facility with lethargy, loss of appetite, reluctance to move, increased thirst, increased urination, vomiting, or evidence of kidney or liver damage on bloodwork.  Vaccination against leptospirosis is very important to protect the health of dogs in LA County.   As of today this outbreak is considered to be concluded.

Summary of the outbreak

  • 201 cases resulting in 13 deaths

  • Of the cases with data available:

    • 55% (91/164) of dogs were hospitalized

    • 66% (101/154) of dogs had exposures at dog daycare or boarding facilities

    • There were clusters of cases (over 30 dogs each) at two separate daycare/boarding facilities

    • 49% (51/105) of cases reported going to dog parks

    • Pet owners also reported hiking, going to beaches and walks around the neighborhood as potential routes of exposure


Is it still recommended to get my dog vaccinated against Leptospirosis?
Yes.  Following this outbreak, the Leptospira vaccine should be considered a core vaccine for dogs in Los Angeles County.  Dogs were the primary reservoir for the serovar suspected in causing this outbreak, but wildlife and rodent exposures pose a continuous risk of infection as well.  Vaccination with the 4-serovar vaccine is recommended, even after a dog has had natural infection, as cross-protection against the various serovars after natural infection is not well documented.  The vaccine should be boostered annually thereafter.  Dogs should be fully vaccinated prior to attending places where other dogs gather such as daycare, boarding, dog parks, training, groomers, etc.). 


The epidemic curve for this outbreak with information about daycare/boarding status is below:

                 chart showing reported cases of leptospirosis in dogs in Los Angeles County from March 28, 2021 to February 6, 2022

*This chart includes cases reported to Veterinary Public Health with onset date available.  If onset date was not available, lab confirmed date is used.  There are 5 additional cases without a reported onset date or lab confirmed date.  These cases are pending investigation and are not included in this chart.  Six asymptomatic cases are included, the lab confirmed date is used for those.

Findings on reported cases of leptospirosis in dogs in Los Angeles County from March 28, 2021 - February 6, 2022 (n=198)*:
Number of cases (total reported to VPH = 201)
Lab-confirmed 184
Probable 10
Suspect 7
Missing data 0
Deaths 13
Asymptomatic 6
Symptomatic 172
Missing data 23
Any boarding/daycare reported 101
No boarding/daycare reported 53
Missing data 47
Dog park visit reported 51 (28 of these also went to boarding/daycare)
No dog park visit reported 54 (26 went to boarding/daycare)
Missing data 96
 *Although the outbreak is over, we are still investigating cases.  As such, this data is subject to change.



How common is leptospirosis in pets and animals Los Angeles County?

From 2008-2020, 88 cases of leptospirosis in dogs were reported in Los Angeles County.  However, since some dogs may be asymptomatic or have mild symptoms and may not be tested, we believe it is likely underdiagnosed and underreported, so the true local incidence in dogs is unknown.  We believe most cases in Los Angeles County are contracted due to contact with infected wildlife or rodents, however other forms of transmission may be more likely when there is an increased incidence of disease.  For example, dogs that are in congregate settings and exposed to large numbers of other dogs (boarding, daycare, training, dog parks, beaches, grooming, etc.), may be at increased risk of contracting the bacteria through direct contact or through contact with urine-contaminated surfaces or water sources.


How do dogs and other animals get lepto?

The bacteria are spread through the urine of infected animals which gets into water or soil and can survive there for weeks to months.  Animals and humans become infected when they come into direct contact with the contaminated water or soil.  The bacteria enters through cuts in the skin or through the eyes, nose or mouth (drinking contaminated water) or through inhalation.  If your pet has become infected, it most likely came into contact with the bacteria in the environment or was exposed to infected animals including other dogs or wildlife.  Your pet may have been drinking, swimming or walking through contaminated water.  Since wildlife and rodent exposure is possible to pets even in suburban or urban environments, this means that pets in Los Angeles County could be exposed to infected wildlife or their urine from their backyards or around their residence, even without visiting a congregate setting such as a dog park or daycare.   Cats are more resistant to infection but may show mild disease when infected.


How soon after exposure to lepto would my dog develop symptoms?

The time between exposure to the bacteria and the development of disease is usually 5 to 14 days, but can be as short as a few days or as long as 30 days or more.


What are the signs of lepto in pets?

Contact your veterinarian if you suspect your pet may be showing signs of leptospirosis.  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.  Sometimes pets do not have any symptoms.  Your veterinarian can perform tests to determine whether your pet has the disease.


Is lepto treatable in dogs?

Lepto is treatable with antibiotics.  If an animal is treated early, it may recover more rapidly and any organ damage may be less severe.  Other treatment methods such as hospitalization, fluids, or dialysis may be required.


Is there a vaccine available for leptospirosis?

Yes there are lepto vaccines available for dogs, however the vaccine does not provide 100% protection.  This is because there are many strains (serovars) of lepto and the vaccines available do not provide immunity against all strains.  Local data suggest that a variety of lepto strains 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.  The 4-way Leptospira vaccine is recommended for dogs living in Los Angeles County.  2 doses of the vaccine are normally given 3-4 weeks apart, and should be boostered again every year.  Schedule with your veterinarian to have your pet vaccinated against lepto. 


If my dog had a lepto infection in the past, are they considered immune for life?

No.  Infection with lepto does not guarantee that a pet is immune for life.  It is important to get your pet vaccinated even if they become sick with lepto because your pet can be reinfected with a different strain of lepto later.  Discuss with your veterinarian when your pet should be vaccinated after recovering from a recent infection.


Are vaccine reactions to the leptospirosis vaccine common?

Previously there has been concern about vaccine reactions from the Leptospira vaccine.  However, current vaccines containing leptospiral antigen have not been shown to be more reactive than other vaccines for dogs.  Speak to your veterinarian for more information about whether the lepto vaccine is recommended for your dog.


How do I prevent my dog from contracting lepto?

  • Vaccinate your dog against lepto (especially before entering a congregate facility such as daycare/boarding)

  • Keep dogs away from wildlife

  • Do not attract wildlife to yards by keeping bushes and shrubbery trimmed and closing off outdoor crawl spaces

  • Do not leave pet food or water bowls outside and routinely clean food and water bowls that may have been contaminated by wildlife

  • Keep rodent problems under control; call an exterminator if needed

  • Do not allow pets to drink from or enter contaminated bodies of water


If my dog had lepto, when can they return to their normal activities?

It is important to keep your dog at home and not go out to public areas until they have been treated with antibiotics.  Generally, once your pet has completed the recommended antibiotic course and is no longer symptomatic, they are much less likely to release lepto in their urine and be contagious to others.  However, some dogs may still release lepto in their urine intermittently for weeks to months.  We recommend consulting with your veterinarian after your dog has been diagnosed and treated for lepto for their recommendation on when it is safe to resume normal activities or return to congregate facilities (daycare, boarding, grooming, dog parks, beaches, etc.).



Can humans contract leptospirosis?

Lepto is considered a zoonotic disease which means that it can be transmitted between people and animals.  Humans are infected in similar ways as animals, such as through contact with contaminated urine (or other bodily fluids, except saliva), water, or soil.  The bacteria can enter the body through the eyes, nose, mouth or skin, especially if the skin is broken from a cut or scratch.  Normal daily activities with your pet will not put you at high risk for lepto infection.  For humans, the most likely exposure to lepto is when a pet is sick and pet owners or veterinary staff have direct contact with their urine. It is especially important to practice good hand hygiene around a dog that is sick or recovering from lepto.  Use gloves when cleaning up urine, spray the area with a disinfectant, and wash your hands immediately after removing gloves or after having contact with a pet you are caring for.


What are the signs of lepto in humans?

Symptoms are variable and may include fever, severe headache, and muscle aches. In severe cases, people may have yellowed mucous membranes (gums), kidney damage and respiratory distress. Click here to learn more about lepto in people.  If you develop symptoms of lepto after exposure to an infected pet, see your physician immediately and discuss your exposure.  Tests can be performed to see if you have this disease.   


How do I stay safe around my dog if they have been diagnosed with lepto?

  • Make sure that your infected pet takes all of their medicine and follow up with your veterinarian as needed

  • Wear gloves when cleaning up waste, especially urine, or any contaminated bedding from your pet

  • Wash your hands after removing your gloves and after any handling of your pet

  • To disinfect a surface that was contaminated by pet waste or urine, use an antibacterial cleaning solution or a solution of 1 part household bleach in 9 parts water

  • Consider having your pet urinate in sunny areas or areas that will dry completely rather than urinating in areas that will always stay wet

  • Do not pressure wash areas where animals have urinated as this may cause the bacteria to aerosolize and it can then be inhaled

  • As some dogs can release the bacteria in their urine intermittently for weeks to months after recovery, it is important to follow these precautions whenever you clean up pet waste and urine



  • Educate clients about leptospirosis and steps that may be taken to reduce risk, especially to rodents and wildlife

  • Discuss vaccination with each client and remind clients about recommended boosters

  • Educate clients and veterinary staff about the zoonotic potential of leptospirosis and the recommended ways to reduce exposure

    • Practice good hand hygiene around a dog that is sick or recovering from leptospirosis

    • Always use gloves when cleaning up urine

    • Veterinary staff should wear proper PPE when handling dogs suspected of having lepto and use good hygiene when disinfecting areas that may have had contact with urine

    • Properly disinfect areas inside and outside of the veterinary facility where infected dogs have urinated

    • Do not use pressure washing to clean urine contaminated areas as this may create aerosols

  • Report all cases of confirmed or suspected leptospirosis in LA County to Veterinary Public Health using this reporting form.


If you have questions about leptospirosis or wish to report a case, please call 213-288-7060 or email


Additional resources for leptospirosis:

Vaccinate Dogs for Canine Flu H3N2 and Leptospirosis - Help Stop Both Outbreaks in LA County 9.22.21

Los Angeles County Veterinary Public Health - Leptospirosis in Animals

Center for Food Security and Public Health Fast Facts Sheet for Clients - Leptospirosis

2010 ACVIM Small Animal Consensus Statement on Leptospirosis

Leptospirosis - CDC


Last updated: March 11, 2022

Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.
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