Toxin Identified, But May Not Explain What Sickened and Killed Them


            There’s a new wrinkle in the tainted pet food investigation. Recent reports elsewhere in the media have indicated that melamine – not aminopterin – in tainted pet food is making pets sick and in some cases has killed them. It turns out that may not exactly be true. Melamine has been identified and linked to wheat gluten imported from China, which is used in some pet foods (Many brands were recalled by Menu Foods). Most importantly, from what little experts do know about melamine and its affects after being ingested, pets shouldn’t have died as a result. While melamine (used as a fertilizer in Asia) should certainly not be in pet foods, it’s not known to be lethal.

            So, then why have pets died after eating contaminated food? The truth is that no one knows. Dr. Richard Goldstein, an internal medicine specialists and assistant professor Small Animal Medicine at the Cornell University College of Veterinary Medicine, Ithaca, NY say he and his colleagues have been working hard on attempting to answer that question. According to the veterinary literature on melamine, even when it was fed to rats in massive quantities for weeks, their only adverse affects were occasional bladder stones.

            “Of course, rats are not cats and dogs, but still melamine shouldn’t be causing the problems we’re seeing,” says Goldstein. “We’re missing a piece of the puzzle.”

            The puzzle began when the original over 90 brands were recalled from Menu Foods. On March 23, the United States Food and Drug Administration announced The New York State Food Laboratory in Albany identified a foreign substance, a rodenticide called aminopterin, in the tainted food. Goldstein says as far as he knows the finding was real, although mysteriously his lab at Cornell and also the FDA could not reproduce the same finding. At a March 30 news conference, Dr. Stephen Sundlof, director of the Center for Veterinary Medicine at the FDA said aminopterin is no longer being considered the source of contamination in the recalled pet foods.

            It was at that same news conference that Sundlof and Dr. Donald Smith, dean of the College of Veterinary Medicine at Cornell, announced the identification of melamine in samples of the tainted food, and also in urine of sick pets who ate the tainted food, and in a kidney of a cat who died as a result of eating contaminated food. 

            Something else is definitely going on, there’s a real discrepancy,” according to Dr. Steven Hansen, a veterinary toxicologist and director of the ASPCA Animal Poison Control Center, Urbana, IL. He agrees that melamine in of itself should not be causing acute kidney failure and deaths (although he says ironically potently toxic aminopterin would have caused a similar result). He theorizes, “Perhaps, cats are uniquely sensitive to the melamine.” Hansen notes that far more cats than dogs after eating tainted food seem to have become sick (or have died), although his theory wouldn’t completely explain why at least some dogs are also being affected.

            Goldstein rattles off other possibilities to explain the impact of melamine, which he stresses are solely conjecture. There’s the possibility there’s still another yet identified toxin in the food; that the melamine somehow interacted with something in some pet foods which caused illness or death or that the pets who died or who became the most ill had diagnosed or undiagnosed previous conditions which caused them to react adversely to the melamine. Certainly, many dogs and cats ate the tainted food and have not become ill.

            At the March 30 press conference, Sundlof admitted a broker may have passed tainted imported wheat gluten to a pet food maker that manufactures dry food, yet he would not name the company. As a result pet owners have begun avoiding pet foods containing wheat gluten (some which have been voluntarily recalled by various manufacturers). “Staying away from foods with wheat gluten, at least for a time, makes sense,” says Goldstein. However, he adds that he sees no reason to avoid all dry foods.        

            As for home cooking for pets, he says, “It can be done, but understanding how to do it requires a real dedication of time and knowledge – pets have very different nutritional requirements compared to people. The manufactured pet foods truly are complete and balanced.”

            Meanwhile, there’s a concern that millions of pets have been fed dry food with wheat gluten over the past weeks. Some pets never exhibited symptoms at first when they ate brands affected by the original Menu Foods recall, and then became suddenly and violently ill.

            “If people are concerned about their pets, certainly a visit to the veterinarian makes sense,” says internal medicine specialist Dr. Sandy Willis of Seattle, WA. “All pets should see a veterinarian twice a year health for a screening anyway. So, if you haven’t been to the veterinarian for six months, especially if you believe your pet has eaten potentially tainted food – it’s a very good idea. We have identified pets without symptoms, but the blood work indicates there’s a problem. By concerned pet owners visiting veterinarians, we’ve also picked up early on other disease threats unrelated to pet foods – and we’ve saved lives as a result. So, in a sense, there has been some good news with all of this.”