A strange virus that began to spread rapidly after multiple waves of illegal immigrant children were shipped into the U.S. from Latin America last year has been shown in a new study to be directly related to the "polio-like illness" that's reportedly infected at least 112 children in 34 states, and killed nearly a dozen others. Known as enterovirus D68, or EV-D68, the mystery virus picked up speed dramatically last fall, with the U.S. Centers for Disease Control and Prevention reporting that the number of new cases reported in 2014 was significantly higher than in any previous recorded year.