The severe respiratory virus believed to have sickened hundreds of U.S. children in Midwestern and Western states has now spread to the Northeast, health officials report. The New York State Department of Health confirmed on Friday more than a dozen cases of infection with Enterovirus D68, which sometimes requires hospitalization, especially for children with asthma. And on Saturday, the Connecticut Department of Public Health said it had received reports from two hospitals in different parts of the state of clusters of severe respiratory illness among young children that could be due to Enterovirus D68.