The main risk factor for Lyme disease is exposure to ticks that are infected with Lyme disease bacteria. In areas where Lyme disease is widespread, such as the northeastern United States and Canada, several factors may increase your risk, including:he main risk factor for Lyme disease is exposure to ticks that are infected with Lyme disease bacteria. In areas where Lyme disease is widespread, such as the northeastern United States and Canada, several factors may increase your risk, including: