LANSING, Mich. (AP) — State and federal agencies are investigating an unknown illness that’s sickened dogs in northern Michigan and killed at least 30 canines in one county after they exhibited signs of a parvo-like illness. The Michigan Department of Agriculture and Rural Development says it’s working with local animal control shelters, veterinarians, the Michigan State University’s veterinary laboratory, the U.S. Department of Agriculture and other partners on testing to determine the illness’ cause. The state agency said “several dogs” have fallen ill with the same symptoms in the state’s northern Lower Peninsula with an illness similar to canine parvovirus.