Researchers say that the chemicals melamine and cyanuric acid worked together to cause health problems and even death in pets this past spring.
New studies show what many were guessing at the end of the months-long pet food recall that began this past March: When combined, melamine and cyanuric acid can produce deadly effects in pets.
One study found that cats fed food containing only one of those two chemicals experienced no problems whereas cats that ate pet food with both melamine and cyanuric acid “quickly experienced acute kidney failure.”
The study was led by veterinary toxicologist Birgit Puschner at the California Animal Health and Food Safety Laboratory in the University of California, Davis, School of Veterinary Medicine.
Results also showed that cats receiving the food with both chemicals present “developed fan-shaped crystals in their urinary tracts,” an abnormal development in healthy cats.
The study was published in the November issue of the Journal of Veterinary Diagnostic Investigation.
An additional study on 22 pigs, led by Steve Ensley of Iowa State’s veterinary lab, also concluded that a combination of melamine and cyanuric acid causes a more potent result on an animal’s kidney than if consumed individually.
Both studies were presented at the American Assn. of Veterinary Laboratory Diagnosticians’ annual meeting in Reno, Nev., in October.
The association also released preliminary results from its pet-food nephrotoxicity survey of veterinary labs, which began April 5 but is ongoing through its Web site.
Of the 347 usable cases analyzed and collected through June 6, 68 percent were cats and 32 percent were dogs. In addition, 61 percent of those cats and 74 percent of those dogs died; the rest were reported ill or recovered.
The top two food products responsible for the illnesses as reported by the survey were Iams and Special Kitty for U.S. cats and Alpo Prime foods followed by Ol’ Roy for U.S. dogs.
In Canada, 20 of 27 cases involved a cat. Special Kitty Canada and President’s Choice were the two foods most frequently associated with illness in Canada during the recall.
In descending order, the regions hardest hit with cases were:
The association also used five necropsy cases (four cats and one dog) to conduct a test study. More than one of the contaminants was found in four out of five of the animals and all of them had a history of eating the contaminated food.
The most common finding was the presence of yellow-brown crystals within the renal distal tubules and collecting ducts and, occasionally, in the urine sediment. All five pets had elevated blood urea and creatinine concentrations as well as other indications of renal problems.