By NewsDesk  @infectiousdiseasenews

Los Angeles County health officials are reporting dog outbreaks of canine influenza H3N2 and leptospirosis in recent months.

Canine influenza

Between July and August 18, 2021 a total of 10 confirmed cases and 46 suspected cases of CIV H3N2 in dogs have been reported in LA County.  Most of the cases were associated with staying in several boarding kennels or dog day care settings.

To date, this is the largest outbreak of CIV H3N2 reported in Los Angeles County.

The canine influenza virus H3N2 (CIV H3N2) usually causes mild to moderate disease in dogs and on rare occasions can also infect cats. This strain of canine influenza was first found in the US in 2015 when it was detected in Chicago and spread to other parts of the country.

The Veterinary Public Health Program (VPH) recommends that dogs be vaccinated against CIV H3N2 before they enter boarding kennels, dog day care, dog parks, or engage in dog group activities.  This vaccine is also advisable for dogs that may occasionally encounter other dogs.

To date, there is no evidence that humans can become sick with canine influenza H3N2.


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 may have been exposed at a boarding facility in Santa Monica, 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.

From April to August 18, 80 total leptospirosis cases (56 lab-confirmed and 24 suspect) have been reported.

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, it is believed to be likely underdiagnosed and underreported, so the true local incidence in dogs is unknown.

The bacteria, Leptospira,  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.