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Nov. 29, 2007

MSU survey determines that more than 300 pets may have died from contaminated pet food; culprit may be lethal combination of contaminants

EAST LANSING, Mich. — A survey, commissioned by the American Association of Veterinary Laboratory Diagnosticians and designed and implemented by Michigan State University toxicologists, has found that more than 300 dogs and cats may have died earlier this year as a result of eating contaminated pet food.

In addition, the survey also determined that the cause of death may have been related to two food contaminants which, separately, are relatively harmless, but together can be deadly.

On March 30, the Food and Drug Administration announced that the pet food in question had been contaminated with a substance called melamine. It was later determined that other contaminants – cyanuric acid, ammelide and ammeline – were also in the food. However, the focus was placed on melamine and cyanuric acid.

“Separately, those two compounds are pretty harmless,” said Wilson Rumbeiha, an associate professor in MSU’s Diagnostic Center for Population and Animal Health. “But when combined, they form crystals which can block the kidneys.

“And, unfortunately, these crystals don’t dissolve easily. They go away slowly, if at all, so there is the potential for chronic toxicity.”

It was earlier this year that Rumbeiha and colleagues designed a questionnaire to determine how many animals had become ill or died from eating bad food. The contamination led to a massive recall of tainted pet food.

Collecting data from veterinarians, veterinary technicians and pathologists from April 5 through June 6, Rumbeiha found that 348 cases met the criteria for what he called “pet food-induced nephrotoxicity.” The cases involved 236 cats and 112 dogs.

“Two-thirds of the animals affected were cats, but proportionally, more dogs died from it than cats,” Rumbeiha said.

He theorized that more cats got sick than dogs because of their smaller size. He also found that smaller-breed dogs were more susceptible.

Among some other findings:

  • Nearly 98 percent of the 348 cases reported were in the United States, with the other 2 percent from Canada.
  • In the United States, Texas recorded the most cases, followed by Illinois and Michigan.
  • An equal number of male and female animals were affected.
  • The average age of an affected animal was 8 years. The ages ranged from two months to 18 years.
  • About 25 percent of the affected animals had a pre-existing condition that made them more susceptible. Most of the conditions were kidney or cardiovascular disease.

“What this does,” said Rumbeiha, “is provide a snapshot of this disease. It helps us to better characterize the disease. The good news is we are not seeing any new cases.”

MSU partnered with the American Association of Veterinary Laboratory Diagnosticians and pathologists from the University of Guelph and Colorado State University.

The findings were presented at a recent American Association of Veterinary Laboratory Diagnosticians meeting in Reno, Nev.


Michigan State University has been advancing knowledge and transforming lives through innovative teaching, research and outreach for more than 150 years. MSU is known internationally as a major public university with global reach and extraordinary impact. Its 17 degree-granting colleges attract scholars worldwide who are interested in combining education with practical problem solving.

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