Trying to help solve a puzzle that has baffled federal investigators for years, a veterinary toxicology and pathology team at the Veterinary Information Network (VIN) is collecting information on dogs that have become ill after eating jerky treats.

On the premise that less is more, the project team is asking only veterinarians to submit cases — and preferably cases for which laboratory data is available. Pet owners who wish for their pets’ information to be included are asked to talk with their veterinarians about participating.

Dr. Kendal Harr, a veterinary clinical pathologist who is spearheading the effort, said, “We’re trying to establish a database that is only inputted by veterinarians to try to weed out cases that are really caused by other diseases, which is a real complicating factor in the FDA database.”

The U.S. Food and Drug Administration (FDA) has received more than 2,500 reports since 2007 of dogs that became sick after eating jerky treats, predominantly chicken jerky made in China. Its ongoing investigation has turned up no identifiable contaminants.

Last week, four companies producing five brands of chicken treats for dogs recalled the products following a discovery by the New York State Department of Agriculture and Markets of trace residues of several antibiotics.

However, the FDA stated that the finding is “highly unlikely to be related to the reports of illnesses” it has received.

The brands affected by the recalls are: Waggin’ Train and Canyon Creek Ranch dog treats marketed by Nestle Purina; Milo’s Kitchen Chicken Jerky and Chicken Grillers marketed by Del Monte Corp.; Publix Chicken Tenders Dog Chew Treats sold by the grocery chain Publix Super Markets; and Cadet chicken jerky sold by IMS Pet Industries, Inc.

At least some of the brands have been named in “adverse event” reports made to the FDA.

In a posting about jerky pet treats and illnesses dated Jan. 9, the FDA Center for Veterinary Medicine (CVM) speaks to confounding aspects of the jerky treat illness reports it’s received:

It is possible that other food or drug exposures caused the signs and symptoms reported in these reports; thus, there is no certainty that the reported jerky treat caused the adverse event. There may be one or more concomitant diseases, conditions, medications or other foods that can better explain the clinical signs seen. Sometimes a significant amount of time elapses between the date the problem occurred and the date the problem is reported and the reporter does not remember specific details (which can include the brand name or the names of other brands fed at the same time or prior to the report), so the report may contain erroneous information. Reporting bias also may exist in passive reporting systems. For example, increased media attention to specific products may cause increased reporting for those products for some period of time, causing an apparent sudden increase in the number of reports received. CVM Updates were publicly released September 26, 2007, December 19, 2008, and November 18, 2011, and all were followed by increased reporting activity after the update was issued.

Harr, who has reviewed many of the case reports posted online by the FDA, agreed that some are tenuously related to jerky treat consumption, if at all. “There are cases where a dog was hit by a car but the owner believes it died from chicken jerky treats,” she said.

Siobhan DeLancey, a spokeswoman in the FDA Office of Foods and Veterinary Medicine, said the reports received by the agency also are “highly variable in the amount of information they contain," adding that “complete reports containing objective measurements (such as lab reports) are definitely helpful. ... We welcome any addition information we can gain from VIN members on existing and new cases.”

VIN is an online international community for the profession with nearly 50,000 members. The VIN News Service is the news media operation of VIN.

Dr. Sharon Gwaltney-Brant, a VIN toxicology consultant and a former vice president and medical director of the ASPCA Animal Poison Control Center, testified to the variable quality of reports made to public databases.

“People make associations all the time with things that are totally unrelated,” she said.

Gwaltney-Brant recalled that the Animal Poison Control Center between 2007 and 2009 received close to 100 jerky-related illness reports. Of those, she remembers only one in which the link between jerky consumption and illness seemed clear.

The case involved a bull mastiff who helped himself to an entire 5-pound bag of jerky. Previously healthy, she said, the mastiff promptly developed excessive thirst and urination (polydipsia and polyuria), telltale signs of a kidney condition known as Fanconi-like syndrome that has become the hallmark condition associated with eating jerky pet treats.

The Fanconi-like signs are attention-catching because Fanconi syndrome usually is an inherited disease, and rare. It occurs in people as well as dogs. Until the jerky treats problem surfaced, the syndrome in dogs was found most often in basenjis.

Besides increased thirst and urination, clinical signs include loss of appetite, lethargy, vomiting and diarrhea.

Gwaltney-Brant said the signs should be evident within four days of jerky consumption to be considered viable cases for the purposes of VIN’s survey.

Harr, the survey team pathologist, said she particularly is interested in cases in which laboratory workup results show electrolyte abnormalities in the blood and/or urinalysis showing glucosuria and proteinuria.

Harr said she also would like any of the following:

• Samples of suspect jerky, provided the package lot number is available
• Frozen tissue samples from necropsies
• Urine from active cases when samples are collected within 24 hours of jerky treat ingestion

Veterinarians who are members of VIN may access the online survey here.

Veterinarians who are not members of VIN may call toll-free (800) 700-4636 to obtain a temporary login and password to access the survey.

Harr said she is hopeful the survey will bring a turning point in the investigation. “The cases that would be added into the VIN database could be critical to define a causal link between jerky treats and the Fanconi syndrome that has been associated with it,” she said.