LOS ANGELES (CBSLA.com) — A dog in the San Gabriel Valley has tested positive for the highly contagious canine influenza H3N2.

Los Angeles County Veterinary Public Health says the dog contracted the disease after boarding at a kennel in the area. At least 11 other dogs developed coughs after also boarding at the facility during the last half of July.

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The source of the outbreak is unknown, but authorities say there’s a risk that the virus will be repeatedly introduced to Southern California because of the spread of the infection throughout the country and the continued import of dogs from Asia.

Symptoms include a soft, moist cough; nasal or ocular discharge; sneezing, lethargy, and fever. A small percentage of infected dogs may develop a severe pneumonia and require extensive hospitalization.

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The disease can cause pneumonia but is not contagious to humans, according to the Centers for Disease Control.

“If owners suspect their dog is infected, they should immediately seek veterinary medical attention and keep their pups away from other dogs,” Dr. Jeremy Prupas, L.A. Animal Services Chief Veterinarian, said in a statement.

LA Animal Services is vaccinating dogs against canine influenza, and there’s no indication at this time that the virus has spread to any L.A. County animal shelters, Prupas said.

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To prevent the spread of the virus, dogs should be vaccinated. Sick dogs should be isolated for at least 30 days, and not allowed to share equipment or toys with healthy animals. Handlers and owners should frequently wash their hands and keep pet facilities clean and disinfected.