Pet Food Recall: Updated Information for Veterinarians
Courtesy of ACVIM
As the pet food recall continues to develop, we want to keep veterinarians as current as possible.
A comprehensive AVMA Pet Food Recall List is available at
The AVMA Pet Food Recall List contains all recall information that has come to the attention of the AVMA, but it is not guaranteed to be complete. The AVMA encourages all concerned owners to contact the specific manufacturer regarding the status of any particular pet food or treat.
Current Thoughts on the Causative Agent
Dr. Neal Bataller, director of the Division of Compliance, FDA Center for Veterinary Medicine, characterized the problem as resulting from a triazene- or melamine-related compound. The current thinking is that a combination of chemicals-each alone, seemingly nontoxic-forms polymers in the animal, and the resulting crystals do physical or other damage, primarily to the kidneys. Analysis of the crystals in the kidneys of affected animals have revealed that they are approximately 50 percent cyanuric acid and 50 percent melamine. They are extremely insoluble. Furthermore, tests mixing melamine and cyanuric acid in samples of cat urine resulted in almost immediate formation of crystals that were identical to crystals found by Veterinarians in the kidneys of affected animals. Two other melamine- related substances-ammelide and ammelin may also play roles and are under investigation. Veterinarians can view images of the melamine-cyanuric acid crystals on the University of Guelph Laboratory Services website at www.labservices.uoguelph.ca/urgent.cfm#crystals. Melamine-cyanuric acid crystals most resemble xanthine crystals in appearance.
Current Thoughts on Treatment
Recently, several dozen epidemiologists, laboratory diagnosticians, clinical nutritionists, toxicologists, pathologists, and other veterinary specialists held a conference call arranged by the AVMA to provide a forum for discussion of the animal health aspects of the pet food adulteration and recall. The Food and Drug Administration, ACVIM, American Association of Veterinary Laboratory Diagnostics, and the Veterinary Information Network were represented. Although no new treatment protocols were recommended, several important points were underscored for communication to veterinary practitioners. In particular, the participants agreed that the standard treatment for renal failure, consisting of fluid therapy and supportive care, seems still to be the most effective treatment. Also, there currently is no evidence that acidifying or alkalinizing the urine will help to dissolve the crystals in vivo. The long term effects of the adulterated food on renal function are still unknown. Veterinarians should consider periodic monitoring of renal function including urinalysis as deemed appropriate in the individual patient.
Acute renal failure remains the primary problem being treated in response to consumption of the recalled food. Clinical presentation varies. Some of these pets are quite azotemic and ill whereas others may present only with polyuria and polydipsia, dilute urine and blood work which shows mild azotemia or no significant changes. Some pets that have consumed recalled food remain asymptomatic but in fact have significant changes on their blood work and/or urinalysis. Therefore, the best recommendation for pet owners remains to consult with a veterinarian if a pet has eaten the recalled food in all cases, but particularly if the pet is showing any illness including anorexia, lethargy, vomiting, diarrhea, polyuria, or polydipsia. Recommendations still include doing a general blood test (CBC, biochemistry panel) and urinalysis. Crystalluria is being found in many of these cases and veterinarians should request a urine review for crystal morphology from their diagnostic laboratory. Veterinarians should contact their diagnostic veterinary laboratory if they have further questions. Fluid therapy and symptomatic treatment tailored to the individual pet, the existing protocols of treating pets affected by the recalled food, are still the best courses of action. Many pets are responding well to treatment. Recheck blood work in 3 - 4 weeks may be advisable when minor disease is present.
Veterinarians should be aware that formalin dissolves these crystals. Therefore, formalin may not be the best fixative for samples collected from affected animals if transit time to a laboratory involves several days. However, preservation of tissues in formalin for overnight delivery to a laboratory appears to be acceptable and some samples should be preserved in formalin for other pathologic studies. The AAVLD provides suggestions for sample collection on its web site; go to www.aavld.org, click on News and then "Protocol for suspected pet food associated nephrotoxicity." Veterinarians should also consult with their diagnostic laboratory for more specific recommendations.
Veterinarians are encouraged to participate in the AAVLD online survey on cases related to adulterated pet food. The survey is accessible to AAVLD laboratories on the members-only area of the Web site. Nonmembers can enter case data via the public area by going to www.aavld.org; click on News and then on AAVLD Pet Food Toxicity Survey.
Veterinarians with animals that were exposed to the suspect food and subsequently died from kidney failure should perform complete postmortem examinations. A full complement of tissues (not just kidney) should be fixed as described above and submitted to a veterinary diagnostic laboratory for complete histopathology evaluation. Please include any pertinent history including any history of consumption of the recalled foods. Also, a full complement of fresh tissues should be collected, frozen and held in the clinic for possible future toxicological analysis (serum, blood, urine, liver, kidney, stomach content [vomitus], brain, fat, etc.) when the causative agent is definitively identified. In live pets, urine and serum can be collected and frozen for future toxicological testing. Opened cans of suspect food should be put in plastic bags and frozen and can be held by the owner. The Toxicology Laboratory of the California Animal Health and Food Safety Laboratory (CAHFS) has assisted the FDA with the analysis of pet food related to the recall. If a veterinarian feels that a pet fits the case definition for illness due to consumption of recalled food as provided by the FDA, the CAHFS Toxicology Laboratory can be contacted at 503-752-6322 for testing
options. Please see www.cahfs.ucdavis.edu for more information.