Rare Infection Kills 15 Cats, but Threat Eases

A recent outbreak of a rare feline respiratory infection has killed at least 15 cats in West Los Angeles but appears to be ending, veterinary officials said. The disease poses no threat to humans.

Since July 2, about 30 cats being treated for other illnesses at three animal hospitals and one cat foster care program have been infected with strains of calicivirus and half of them have died, said Janet Foley, director of UC Davis’ shelter veterinary medicine program, which is investigating the outbreak.

No new cases have been reported in the last week, according to Mark Nunez, president of the Southern California Veterinary Medical Assn.

Respiratory infection caused by calicivirus is common for cats, and veterinarians routinely vaccinate against it. However, these mutated forms of the virus have affected even healthy cats with up-to-date vaccinations.

This cluster of calicivirus is 30% to 50% fatal and can be transmitted between cats. People who handle infected animals can also give the disease to other cats, Foley said.

The mutant strain causes blood vessel inflammation. Symptoms include swollen head and paws, high fever, and bloody discharge from eyes, nose and rectum. Cats also show signs of respiratory infection, such as sneezing.

Those with mild symptoms usually recover within a few days. There is no treatment for more severe cases.

To prevent infection, Foley recommended that pet owners restrict their cats’ access to other cats by keeping them inside.

Foley, an infectious disease consultant, became aware of the cluster of infections July 2, when a West Los Angeles veterinarian told her about a sick cat at a clinic. A shelter medicine epidemiologist from UC Davis went to investigate and confirmed the virus.

After learning of the outbreak, hospitals isolated infected cats to avoid transmitting the disease and took other steps to halt its spread, officials said.

VCA West Los Angeles Animal Hospital had one confirmed case of hemorrhagic calicivirus, said Nunez, who is medical director at an affiliated clinic in Burbank.

The California Animal Hospital’s department of surgery did not accept cats the first week of July, to avoid infecting others, owner Scott Anderson said.

Nunez declined to identify the third clinic and the foster program, at their requests.

Veterinarians at Los Angeles County’s Department of Health Services said no cases had been reported at county animal shelters

The county’s Veterinary Public Health and Rabies Control Program learned of the outbreak when a pet owner whose three cats had died from the calicivirus reported it Monday, said Karen Ehnert, the program’s senior veterinarian.

Only two other outbreaks of hemorrhagic calicivirus have been reported.

It was first identified in 1998 by Niels C. Pederson, director of the Center for Companion Animal Health at UC Davis, when he found an infected kitten in a Northern California practice. Investigators believe that several cats in New York and Boston were subsequently infected. Each incident appeared to peter out.

“I don’t think that there is reason to panic at this point,” Pederson said.

If a pet owner suspects a cat is infected, veterinarians recommend calling a clinic before taking the animal in. That way, the office can properly prepare to isolate the cat.