About 1,000 dog deaths and three human illnesses are being investigated after being linked to chicken, duck and sweet potato pet jerky imported from China. The U.S. Food and Drug Administration and the Centers for Disease Control and Prevention are researching about 4,800 complaints of illness, involving 5,600 dogs, 24 cats and three people.

FDA officials say they still can't identify a specific cause for the reported illnesses or deaths, despite seven years of testing and investigation.

According to the FDA's latest report, about 60 percent of the cases were tied to gastrointestinal and liver disease, 30 percent kidney or urinary disease, and 10 percent included neurologic, dermatologic, and immunologic symptoms. About 15 percent of kidney and urinary cases also tested positive for Fanconi syndrome, a rare kidney disease tied to reported cases of pet and human illnesses.

The FDA and CDC are tracking food consumed by sick dogs reported to the agency compared to what healthy dogs ate. Researchers hope the analysis will be able to tell what type of food (human or pet food) is making pets and people sick.

Overall, the jerky treat illnesses and deaths have been associated with many different product brands, officials said. As the FDA continues to investigate, it cautions pet owners that jerky pet treats are not required for a balanced diet, and pet owners should consult with veterinarians if they notice symptoms in their pets.

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