UC Davis veterinary researchers have confirmed the identity of a viral disease that has caused an outbreak in Los Angeles County of a rare but often-fatal infection in cats.

The outbreak appeared during the week of July 2 when a number of cats with signs of the infection were brought into veterinary practices in the Los Angels area.

The virus, called hemorrhagic calicivirus (sounds like cuh-LEE-see virus) is not known to pose a threat to human health.

The common "parent" strains of this virus don't usually cause disease and are quite widespread among cats. The mutant strains, however, cause the infected cats to develop high fevers; depression; discharges from the mouth and nose; and often swelling around the face, trunk and lower extremities. Cats with mild signs of the disease usually recover within a few days, while cats with a severe form of the disease often die despite extensive treatment.

Outbreaks of this disease have been uncommon in the past, but when observed have tended to spread rapidly with high death rates among animals. Previous outbreaks usually remain localized to one or more veterinary practices or animal shelters.

The virus involved with this recent outbreak was confirmed at the School of Veterinary Medicine's Center for Companion Animal Health, through the Maddie's Shelter Medicine Program. Researchers in the program have been studying infections among cats living in animal shelters and have begun an investigation of the current outbreak. They hope to determine the scope of the problem, trace the course of infection and develop protocols to prevent further spread of disease.

Initial results from that study should be available in several weeks.