The Food and Drug Administration is asking for the help of pet owners, after it was unable to pinpoint why thousands of animals were getting sick from eating jerky treats, mainly manufactured in China.
The agency has spent years trying to find out why 3,600 dogs and 10 cats in the U.S. were sickened by different brands of the treats since the agency first started getting complaints in 2007.
Of the thousands affected, approximately 580 animals died.
"This is one of the most elusive and mysterious outbreaks we've encountered," says FDA Center for Veterinary Medicine Director Bernadette Dunham. "Our beloved four-legged companions deserve our best effort, and we are giving it."
Some pets developed symptoms after ingesting the jerky treats and the severe cases included kidney failure, gastrointestinal bleeding, and a rare kidney disorder.
According to the FDA, 60 percent of cases involved gastrointestinal illness, and about 30 percent involved kidney and urinary systems. After eating treats made from chicken, duck, sweet potatoes and/or dried fruit some of the animals started to exhibit symptoms including decreased appetite, vomiting, diarrhea or increased urination.
In spite of the years of ongoing investigation into what has caused the infection, the FDA remains unable to pinpoint the exact cause.
The agency has conducted more than 1,200 tests including checks for Salmonella, metals, pesticides and other poisonous compounds in different brands of the treats but has been unable to decipher what is causing the infection. The FDA even visited plants in China where the jerky treats were made, trying to uncover the cause, but were unsuccessful.
Last year Nestle Purina and Del Monte pulled treats made in China from the shelves after New York officials said they found trace amounts of a banned antibiotic in Del Monte's Milo's Kitchen products and in Nestle Purina's Waggin' Train and Canyon Creek Ranch treats.
The FDA said the amount of drugs found in these products were so low they're unlikely to have caused the illnesses. Although inspections at the Chinese factories were inconclusive, the FDA said it would also look at the ingredient supply chain to try to find a cause.
Additionally, the agency is reaching out to pet owners and asks that any pet owner who suspects that their pet became sick after eating tainted jerky to contact the FDA immediately.