Kaye Steinsapir said she thought she was feeding her cat, Lila, one of the healthiest, most nutritious cat foods available.

"Lila was a healthy, vibrant cat without any medical conditions," said the lawsuit filed Tuesday in Los Angeles Superior Court. But in recent weeks, Lila began vomiting, drinking an excessive amount of water and was eventually diagnosed with acute kidney failure, the lawsuit said.

Gregory Helmer, a Los Angeles attorney retained by Steinsapir and Lois Grady of Sacramento, California, who alleges her cat, Riley, also became ill after eating tainted cat food, filed the lawsuit "on behalf of themselves and all others similarly situated."

Menu Foods recalled on March 16 several brands of dog and cat food products nationwide. Scientists at the New York State Food Laboratory last week identified the rodent poison aminopterin as the likely culprit in a scare that prompted the recall of 95 brands of "cuts and gravy" style dog and cat food by Menu Foods of Ontario, Canada.

On Tuesday, a survey by the Veterinary Information Network, which counts 30,000 veterinarians and veterinary students as members, said the number of reported kidney failure cases had already grown to more than 471. The network's founder, Paul Pion, a California veterinarian, said 104 animals have died.

The company has so far confirmed the deaths of 15 cats and one dog. Other deaths have been reported anecdotally around the United States, but Menu Foods has not confirmed them.