EAST LANSING, Mich. (AP) -- A Michigan State University veterinary professor is launching a survey to better estimate how many cats and dogs died after eating tainted food and what, specifically, killed them.
Federal officials have not said how many animals have died. More than 100 brands of pet food have been recalled because of contamination since March 16, when Menu Foods, citing the deaths of 10 cats and dogs, announced a North American pet food recall.
Wilson Rumbeiha, professor of veterinary clinical toxicology, is coordinating the survey. He began April 4 and is to present findings in October in Reno, Nev. at a convention of the American Association of Veterinary Laboratory Diagnosticians.
The group is funding the survey.
The survey asks U.S. and Canadian veterinarians and lab workers 17 questions, such as what food a dog or cat ate, the animal's age and breed and how the pet's illness was diagnosed.
"We want to find the common denominators," Rumbeiha told the Detroit Free Press for a Sunday story.
Animals became sick or died after eating pet food with ingredients imported from China that were tainted with the chemical melamine and related nitrogen-rich compounds. Melamine is typically used to make resins that go into plastic kitchenware and countertops.
The chemical has also contaminated feed given to farmed fish, about 20 million chickens and thousands of hogs. Federal officials say the risk to human health is very low.
The Michigan Veterinary Medical Association said that it questioned 157 members and reported last month that 35 cats and 17 dogs in Michigan were suspected of having died from consuming the tainted food.