Since 2007, FDA has become aware of an increasing number of illnesses in pets associated with the consumption of jerky pet treats
... The reports involve more than 5,600 dogs, 24 cats, three people and include more than 1,000 canine deaths. About 60 percent of the reports are for gastrointestinal illness (with or without elevated liver enzymes) and about 30 percent relate to kidney or urinary signs. The remaining 10 percent of cases involve a variety of other signs, including convulsions, tremors, hives, and skin irritation.
The illnesses have been linked to many brands of jerky treats. The one common factor the cases share is consumption of a chicken or duck jerky treat or jerky-wrapped treat, mostly imported from China. [It also points out that the label won't note if the ingredients were imported from China, so this may explain the non-imported cases.]
The report goes on in interesting detail about the tests they're running with their findings thus far, and includes links to PDFs of the reports describing each case they've investigated. It also includes advice to pet owners [fda.gov] on handling the situation, including what to do if they believe one of their pets has been affected. (Hopefully nobody here has a pet sickened by the treats, so this can serve as a warning rather than an explanation.)