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Outbreak believed to have come from a feral cat colony 

LOS ANGELES — An outbreak of a fast-spreading mutant virus killed 15 cats in Los Angeles County this month, veterinary researchers said Friday. 

Humans are not threatened by the rare hemorrhagic calicivirus but can spread it among cats, the University of California, Davis, School of Veterinary Medicine said. 

Owners of healthy cats were urged to minimize contact with unknown cats. Owners of cats that develop fever or respiratory problems were urged to call their veterinarians before taking the animals anywhere. 

Janet Foley, director of Maddie’s Shelter Medicine Program at UC Davis, said past outbreaks ended quickly and the current outbreak appears to be fading due to precautions taken by veterinary practices. But she said owners should still be careful. 

“If the contact is not limited then more cats are going to get sick and die,” she said. 

The Southern California Veterinary Medical Association said it issued an advisory to its 1,200 members after the UC Davis investigators confimed the disease. 

First signs of the often-fatal illness appeared July 2 when cats believed to have the infection were brought to several Los Angeles-area veterinarians. 

Thirty illnesses were deemed “probable” cases of the virus and 15 of those cats had died as of Thursday. Another 10 to 20 cats were deemed “possible” cases. 

The deaths occurred at four locations. Foley said the identities of those locations were not being released because they are private practices. 

The Southern California veterinary association said in a statement that the outbreak was believed to have come from a feral cat colony and spread to three West Los Angeles veterinary hospitals and a cat foster care network. 

Most of the animals were healthy prior to the illness, and some were current on their vaccinations. 

Cats infected by the virus develop a high fever, become depressed, often have oral and nasal discharge, and often develop swellings on their face, trunk and lower extremities. Foley said swollen head and feet are key signs. 

Spreading appears to occur cat-to-cat or person-to-cat from contaminated clothes, hands and shoes. The virus is a mutant strain of a common calicivirus that is widespread among cats and does not usually cause disease. 

The current outbreak is only the fourth identified appearance of the virus. It was first identified in Northern California in 1998 and appeared twice last year on the East Coast, Foley said. It had never before been seen in Southern California. 

The infection was confirmed at the veterinary school’s Center for Companion Animal Health by laboratory personnel associated with the Maddie’s Shelter Medicine Program, which has been studying infections among cats living in animal shelters.