Nearly 600 dogs have died and 3,600 have been sickened since January after eating jerky, but no one has been able to pin down what has been causing the illness. Ten cats have been sickened as well. Dogs of all breeds, ages, and sizes have been affected, although the pace of the illness has slowed in the past few weeks due to an unrelated recall of jerky treats. The dogs appear to all have eaten chicken, duck, and sweet potato jerky treats, but what ingredient has caused the illness has not been discovered. To determine what is causing the illnesses, the FDA is now asking veterinarians to create to track and send detailed information about any animals who sickened by the jerky treats, including results of blood and urine tests.