Nearly 600 pets have died and more than 3,600 have been sickened in an ongoing, mysterious outbreak of illnesses tied to jerky treats made in China, federal animal health officials said Tuesday. Most of the cases have been in dogs of all breeds, ages and sizes, although 10 cats have been sickened, too. The pace of the reported illnesses appears to have slowed, but federal Food and Drug Administration officials are now seeking extra help from veterinarians and pet owners in solving the ongoing puzzle.“To date, testing for contaminants in jerky treats has not revealed a cause for the illnesses,” Martine...