Tracking Lyme disease infections in dogs may help scientists predict possible outbreaks of the tick-borne illness in humans, government researchers report. Since dogs are also susceptible to Lyme disease, they can be a good indicator of the risk of human infection, the scientists from the U.S. Centers for Disease Control and Prevention said. When blood tests show that few dogs in a given area carry the bacteria, the risk to people is relatively low, they noted. Conversely, when more dogs test positive for Lyme, people may be at increased risk, they noted.