Canine Influenza Outbreak

The current strain is H3N2. We are carrying the H3N2 vaccine, as well as the Bivalent H3N2 and H3N8 vaccine. Both require a booster 3 weeks after the initial vaccination date. Then it is good for 1 year. Huntington recommends that all dogs be vaccinated, but most especially those dogs that are social (boarding, day care, dog beach/parks, etc) AND dogs owned by clinic/hospital/shelter employees as humans can transport the virus to their own dogs at home on their clothing, etc.


On August 3, 2017, Veterinary Public Health (VPH) was notified that a dog living in the San Gabriel Valley tested positive for canine influenza H3N2 by PCR. The dog developed a cough on July 29th after boarding at a kennel in the area. The veterinarian tested the dog for influenza when seen on July 31st, even though the symptoms were mild. VPH began efforts to contain the disease after learning from the boarding facility that at least 11 other dogs developed coughs after being at the facility during the last half of July.

The source of this outbreak is currently unknown. VPH investigated an outbreak of this virus among imported dogs and a single case in a dog rescued from San Bernardino County last spring. During those investigations, dogs were quarantined at 108 different sites around the county, which contained the disease spread. Since that time there were no additional reports of confirmed infection locally. However, there were reports nationally of the virus spreading in multiple states following various dog shows. Considering the spread of infection elsewhere in the nation and continued import of dogs from Asia, there is a risk that this virus will be repeatedly introduced into our area. Thus, Veterinary Public Health continues to recommend that dogs that interact frequently with other dogs should be vaccinated against canine influenza, including H3N2.

What is Veterinary Public Health doing to contain this outbreak?

* Contacting owners of dogs that were at the facility since mid-July to identify additional potential cases and institute quarantines to reduce disease spread

* Quarantining ill dogs for 40 days after onset
* Quarantining contact animals for 14 days after last potential exposure

* Reaching out to veterinarians, shelters and the public to encourage testing and reporting

What can you do?

Remember, dogs are most contagious during the incubation period (2-4 days post exposure) when they are not exhibiting clinical signs. Dogs that are infected with canine influenza H3N2 can be contagious for up to 30 days or more; therefore, dogs infected with H3N2 should be isolated for at least 40 days.

To help prevent the spread of canine influenza H3N2 virus we recommend that veterinarians:

• Test any coughing and sneezing dogs or cats for influenza, especially those that have recently been exposed to a suspected case or that have been in a highly social setting, such as a boarding facility, groomer, dog show, dog park, etc. VPH program is not providing free testing for canine influenza at this time. Contact your veterinary diagnostic laboratory for more information

  • PCR testing on nasopharyngeal swabs is best performed within the first week of illness, but some dogs may still test positive by PCR for 3 weeks or more because of prolonged shedding. Note that a negative PCR test does not rule out the disease.
  • Serologic testing can be performed on dogs starting 7-10 days past the onset of signs. Serologic tests should be performed twice, with the second sample being drawn 2-3 weeks later, to look for a rising titer.
  • Prevent spread in your lobby. Do not allow dogs or cats with respiratory signs to sit in the lobby of a veterinary hospital. Such animals should be taken directly into examination rooms.
  • Vaccinate highly social dogs against canine influenza, including H3N2
  • Keep dogs sick with, or exposed to, influenza at home. Advise pet owners of the importance of home isolation to prevent spread and protect the community
  • Frequently clean and disinfect all common areas, such as lobbies and treatment rooms. Create written protocols and policies for maintaining infection control. Advise pet boarding facilities, and grooming salons to do the same.
  • Perform frequent hand washing - wash hands after handing each animal.
  • Avoid sharing equipment or toys between healthy and sick animals.
  • Wash and disinfect medical or grooming equipment after use on animals
  • Handle sick animals last in group settings
  • Report confirmed and suspected cases of influenza to our program (see below)

To report a case of canine influenza:

Influenza in any animal species is legally reportable in Los Angeles County. To report a case, complete the Influenza Reporting Form ( <> ) and fax it in to our program.

Information about Los Angeles County cases of canine influenza H3N2 are available on our website and will be updated as reports are received: <>

Return to news