Update 3 on Melamine, Cause of Pet Death

First, the pet death toll is rising, from 16 to possibly over 4000:

"The FDA said Friday it had received more than 17,000 consumer complaints about the tainted pet food, including the deaths of 1,950 cats and 2,200 dogs."
- Mix Of Chemicals May Be Key To Pet-Food Deaths

Now, more info on how these animals may be falling ill. A university in Canada (Canada?) conducted some experiments:

"... if you take cat urine and you add melamine to it and cyanuric acid, the crystals will form in the cat urine in a test tube as we're watching them." ... "The crystals are suspected of contributing to kidney failure in pets." ... "I think we've identified what we feel is an important and likely underlying positive agent of why the animals are getting sick."
- Mix Of Chemicals May Be Key To Pet-Food Deaths

Cyuranic acid is a metabolite of melamine, that is, our body can produce cyuranic acid from melamine during digestion. Cyuranic acid could also be present in tainted food.

As Russ said in comments this association is still circumstantial. Nowhere have I read that melamine and/or its derivatives were the cause of pet death. As I've said, there seems to be a disconnect between ingestion of what's described as a "not-particularly toxic" chemical and kidney failure.

Still, the evidence from experiments such as the one above indicate there may be greater risk to consuming melamine than was previously believed.

There's a question of amounts that I don't see being addressed. The government said that the likelihood of illness after eating pork or chicken fed melamine is low. That addresses an acute situation. What is the effect of chronic low-level ingestion for humans? And if melamine from one source may not contain enough to do damage, can the intake of melamine consumed simultaneously from numerous sources (contaminated meat, contaminated vegetable protein, environment, etc.) do damage?
________Photo and caption from FabCats.org.