http://abcnews.go.com/US/story?id=29...page=1&US=true

EXCLUSIVE: Rat Poison to Blame for Some Pet Food Contamination


March 23, 2007 � ABC News has learned that investigators have determined that a rodent-killing chemical is the toxin in the tainted pet food that has killed several animals.�


A source close to the investigation tells ABC News that the rodenticide, which the source says is illegal to use in the United States, was on wheat that was imported from China and used by Menu Foods in nearly 100 brands of dog and cat food.�


A news conference is scheduled for this afternoon by experts in Albany, N.Y., where scientists at the state's food laboratory made the discovery a week after a massive recall of 60 million cans and pouches was issued.�


The chemical is called aminopterin.�


What investigators can't say so far is whether this is the only contaminant, if it is in all of the recalled food, or if it's in enough quantity in to sicken more animals.


There is some good news according to the source. Knowing the chemical should aid veterinarians who are treating animals that have been sickened by the pet food.�


Aminopterin is used in the United States in, of all things, a cancer drug, according to the source.�


For a week, investigators have been looking for a cause behind the 15 confirmed pet food deaths tied to contaminated pet food. Many animal doctors, including those at New York's Animal Medical Center, suspect there will be a much larger rash of cases after they learned about an additional 200 reported cases of kidney failure in animals.�


Doctors at the hospital, which is considered the Mayo Clinic of veterinary medicine, say they noticed the kidney failure while studying sick animals from last Friday to Monday, and traced the cases back to the 60 million cans and pouches of recalled food from Menu Food.�


"I was shocked and surprised � acute kidney failure is not a common problem," veterinarian Cathy Langston told ABC News. "I've already heard about 200 cases, and so I bet that there are probably going to be thousands."�


So far, the government and the pet food maker, which sells food under 91 brand names, have confirmed 15 deaths. But the investigation to locate the toxic contaminant that caused the kidney failure in animals had not pointed to a cause until today.�


"This is very much like finding a needle in a haystack," Don Smith of the Cornell Veterinary School said earlier this week. "We're going to keep working at this until we find the cause."�


Investigators had already begun looking at the possibility that a pesticide or chemical may have been on the wheat used to produce the Menu Foods dog and cat food.�


The Food and Drug Administration, which was notified of the tainted food one day before the recall, said it's frustrated and realizes the growing crisis is an emotional one.�


"This is tragic," said Stephen Sundolf of the FDA's Veterinary Medicine group. "It is certainly uncommon. We expect pet food to be safe."�


And it's a crisis, if the New York hospital is right, that may not end for weeks.�


"I'm worried that there are more deaths to come from chronic renal failure over the next several months," Langston said. "It's not over."�