Two of the nation’s leading manufacturers have withdrawn their top-selling brands after New York state agriculture officials found illegal drug residues of unapproved antibiotics on the popular pet treats.

Wednesday’s announcement that Nestle Purina PetCare Co. is recalling their troubled chicken jerky Waggin’ Train and Canyon Creek Ranch brand dog treats “until further notice”, while Del Monte officials, which owns the Milo’s Kitchen brand, also announced Wednesday they are recalling their Chicken Jerky and Chicken Grillers home-style dog treats from shelves nationwide. A lesser known company, IMS Pet Industries, whose Cadet brand of chicken jerky treats were also found to be contaminated with the same drug residues, according to the New York State Department of Agriculture this week.

I Heart New York

The move came after the New York State Department of Agriculture and Marketing (NYSDAM) told federal Food and Drug Administration (FDA) veterinary officials this week that trace amounts of residual the antibiotics sulfaclozine, tilmicosin, trimethoprim, enrofloxacin and sulfaquinoxaline were found in the brands of jerky treat products imported from China.

But it’s Legal in China

Nestle Purina sidesteps the issue of a contaminated product with excuses of “regulatory inconsistencies“ and that although the products are “technically considered an adulteration” in the U.S. Nestle Purina insists that the finding, “does not pose a safety risk to pets“.

Despite the discovery of at least five different unapproved drug residues found on the imported treats, officials at Nestle-Purina and Del Monte claim there is no cause for alarm. They say that the trace amounts of these drugs would not cause the symptoms that have long been associated with the pet treats since problems associated with the treats began to emerge in 2007.

The FDA released a statement Wednesday updating the ongoing chicken jerky treat investigation into the cause of the reported illness and death of dogs that consumed the chicken jerky pet treats. The agency stated that based on their review of the NYSDAM results, “there is no evidence that raises health concerns, and these results are highly unlikely to be related to the reports of illnesses the FDA has received related to jerky pet treats.“

3243 Dogs and 9 Cats

From January 1, 2012 to December 17, 2012 the agency has received 2674 jerky pet treat reports involving 3243 dogs, 9 cats, of which 501 dogs died, and 1 cat died. 112 of the reports included dogs diagnosed with acquired Fanconi syndrome – cases which were confirmed by veterinary diagnosis and/or laboratory work.

Multiple Drug Residues

Sulfaclozine is an antibacterial sulfonamide and an antiprotozoal agent against coccidiosis used in veterinary medicine. However, the FDA revoked all approved subtherapeutic (increased rate of gain, disease prevention. etc.) uses of sulfonamide drugs in animal feed in 1975.

Tilmicosin is a macrolide antibiotic used in veterinary medicine for the treatment of bovine respiratory disease and ovine respiratory disease. It is a FDA approved antimicrobial drug for use in medicated feeds for the control of bovine respiratory disease in groups of beef and nonlactating dairy cattle, sheep, and in swine for the prevention of pneumonia.

Trimethoprim is a sulfadiazine used for control of bacterial infections during treatment of acute strangles, respiratory tract infections, acute urogenital infections, wound infections, and abscesses. This an FDA drug approved for use in horses, which are non-food animals. The drug is not intended for use in food-producing animals. The FDA revoked all approved subtherapeutic uses of sulfonamide drugs in animal feed.

Enrofloxacin is an antimicrobial known as a fluoroquinolone. In 2005, the FDA withdrew approval of its use in poultry, as this practice was noted to promote the evolution of fluoroquinolone-resistant strains of the bacterium Campylobacter, a human pathogen.

Sulfaquinoxaline is an antibacterial sulfonamide FDA approved veterinary medicine which can be given to animals as an antimicrobial used as an aid in preventing outbreaks of coccidiosis. The subtherapeutic use of sulfonamide drugs in animal feed is not approved by the FDA.

In general, the illegal and indiscriminate use of antibacterial and antiviral drugs in the absence of a susceptible bacterial infection is, not only, unlikely to provide benefit to treated animals, but will likely cause the increased risk of the development of drug-resistant pathogenic bacteria. The danger exists, not just for poultry ingesting the drugs, but for the humans and pets that consume meat laced with these unapproved drugs.

Link to Fanconi Syndrome

What do the presence of sulfonamide drugs have to do with dogs that are fed pet treats? What explanation is there of the dogs that have been diagnosed with acquired Fanconi Syndrome with sulfonamide antimicrobials? Further, why are some dogs affected and others are not?

All these questions can be answered with one simple explanation: The dogs that are affected by the treats are dogs that are experiencing an allergic reaction to sulfonamide drugs. More specifically, they are hypersensitive to sulfonamites. In particular, acquired Fanconi Syndrome can be due to an allergic reaction to drugs known as sulfonamide-associated renal tubular necrosis.

Approximately 3% of the general population have adverse reactions when treated with sulfonamide antimicrobials. Dogs in particular are equally predisposed to allergic reactions to sulfonamide antimicrobials.

Exposure to sulfonamides can result in tubulointerstitial nephritis, a problem associated with Fanconi syndrome. The acute form is most often due to allergic drug reactions or to infections. In fact, over 95% of cases result from infection or an allergic drug reaction. Causes of acute tubulointerstitial nephritis include an allergic reaction to the antibiotic sulfonmaides.

Renal tubular acidosis, another problem associated with Fanconi syndrome. In particular, Type 2 Renal tubular acidosis (RTA) is very rare and most often occurs in patients who have one of the following: Fanconi syndrome and/or various drug exposures, among them sulfonamide drugs.

Sulfonamide Hypersensitivity

Sulfonamide antimicrobials have been associated in humans with hypersensitivity reactions. These reactions also occur in dogs, the only non-human species known to develop a similar spectrum of sulfonamide hypersensitivity.

Many of the commonly used sulphonamides used in veterinary medicine are associated with idiosyncratic drug reactions in dogs. Idiosyncratic toxicosis is believed to be caused either by an immune-mediated syndrome or by an idiosyncratic reaction in dogs, perhaps due to toxic metabolites of the sulfonamide. A large majority of the animals in which idiosyncratic toxicosis occurs when they have had a previous exposure to a sulfonamide. Most cases involve a trimethoprim and sulfonamide combination (two of the drugs found on the chicken jerky treats).

Species Specific Sensitivity to Sulfonamides

An idiosyncratic sulfonamide toxicosis can occur in any breed of dog. In particular, dogs are considered to be unable to acetylate sulfonamides to any significant degree. What is acetylation? In layman’s terms according to Dr. Cathy Alinovi, “In order to break down sulfa drugs, the body needs to add an acetate molecule to the sulfa. Then, the liver says – Oh, I know what to do with this – it can detoxify, break down and excrete the sulfa. Dogs cannot do that, so the liver says what the heck is this and the sulfa drug will not break down, so it isn’t removed from the body.“

Note: A great big super special thanks to Susan Thixton, of Truth About Pet Food, with whom I worked closely with in developing this important story.

For More Information:
FDA Update on Jerky Treats
FDA Report Regarding Jerky Pet Treats and Illnesses
FDA investigates animal illnesses linked to jerky pet treats
FDA Information on reports of illnesses and the ongoing investigation into jerky pet treats
FDA CVM jerky pet treat reports: 2010
FDA CVM jerky pet treat reports: 2011 Reports
FDA CVM jerky pet treat reports: January – April 2012
FDA CVM jerky pet treat reports: April – August 2012
Milo’s Kitchen notice
Nestle-Purina notice