By Christie Keith
March 4, 2008
It seems that last year’s massive pet food recall wasn’t the first time thousands of pets suffered renal failure due to melamine and cyanuric acid contamination of pet food.
A recent article in the Journal of Veterinary Diagnostic Investigation says that a similar outbreak in 2004 was caused by the contaminants, and that “Findings in tissues from animals affected in the United States in 2007 were identical to those observed in the dogs from Asia that died in 2004.”
The 2004 outbreak sickened and killed thousands of dogs and cats and led to the recall of Pedigree dog foods and Whiskas cat foods in a number of Asian countries including the Philippines, Japan, South Korea, and Hong Kong. From a newspaper report dated March 15, 2004:
Taiwan veterinarians have reportedly said hundreds of dogs fed Pedigree Dry dog food have developed kidney failure and died in recent months.
But the company said that numerous scientific tests conducted by the Taiwan government and by its own experts have found no problems, and noted that since its dry dog food is the most popular brand in Taiwan and has major market shares in other affected countries, “we would expect a majority of dogs with any condition to have been fed our product.”
Renal disease, it said, is a common condition diagnosed in up to 100,000 dogs every year in Taiwan. Besides food and drink, it said, possible causes include infectious diseases, old age, natural or man-made toxins, and overall genetic susceptibility.
The Journal of Veterinary Investigative Diagnosis reported that the Asian cases were initially attributed to contamination with mycotoxin, and that “an estimated 6,000 dogs and a smaller number of cats developed nephrotoxic renal failure in 2004.” But their own research, working with tissue samples from animals from both years discovered characteristic crystals and kidney damage typical of melamine-associated renal failure (MARF) caused by the ingestion of melamine and cyanuric acid:
This study provides compelling evidence that the pet foodâ€“associated renal failure outbreaks in 2004 and 2007 share causation. In particular, the outbreaks share identical clinical, histologic, and toxicologic findings. Given the unique nature of the histologic features and the specificity of the toxicologic tests in this study, it is reasonable to conclude that both are examples of MARF. Although the source of melamine and cyanuric acid responsible for the 2007 MARF outbreak has been identified as vegetable protein concentrates imported from China, the source in the 2004 outbreak remains undetermined.
The addition of melamine, cyanuric acid, or both to enhance apparent protein content of vegetable concentrates is reportedly commonplace in some regions. Because chronic interstitial fibrosis is a self-perpetuating process and a common finding in animals with chronic kidney disease, sublethal MARF could represent an important, previously unrecognized cause of chronic kidney disease in dogs and cats. Interestingly, the contaminated wheat gluten in the 2007 outbreak was a human foodâ€“grade product. The potential effects of ingestion of similarly contaminated material by people are unknown.
With the one year anniversary of the first recalls almost on us, the issues raised by this study are both troubling and intriguing.
First is the reference to what it calls “chronic MARF,” or lingering effects of having eaten the contaminated foods. What happened to the affected animals in 2004? What will happen to the animals who survived in 2007 as they age? Can the fate of the animals from the earlier outbreak help us understand what’s happening to the survivors today?
Second is the fact that at least one previous massive pet food recall was attributed to mycotoxin contamination, calling into question any other pet food recalls — or human food problems, for that matter — previously thought to have been caused by mycotoxins.
Third is the question as to whether this has happened not only twice, but many times over the years. Certainly once the extent of melamine and cyanuric acid adulteration of protein concentrates in China was discovered it seemed fairly obvious the 2007 outbreak wasn’t the first one; it was just the first one we noticed. This study confirms that suspicion.
The study goes over the history of the 2007 recall, and brings up a question Pet Connection has been wrestling with since the beginning — the numbers. It has some for the 2004 incident:
The 2 outbreaks described in this study were widespread and catastrophic. It has been estimated that over 6,000 animals were affected in the 2004 incident and although the number of animals affected in 2007 is currently undetermined, the FDA has received over 10,000 complaints related to this outbreak.
The 2004 newspaper article contained some words that sound eerily familiar to all of us who followed the 2007 pet food recalls. About the dog and cat food recalls in Asia:
“We are taking this action out of an abundance of caution…This is the right thing to do to eliminate any concerns about the quality and safety of these products, and to ensure the health of our customers’ pets,” regional scientific affairs manager of Effem Foods Duncan Hall said in [a] statement.
The company advised customers to stop feeding products covered by the recall to their pets and said they should consult with their veterinarian if they have any concerns. It said it will offer a full refund for any unused product.
Let’s hope this never happens again, but if it does, the pet food companies can do better than that.
The study abstract is online here.