Seasonal flu activity appears to be picking up in the United States but it is still relatively low nationwide, federal health officials said. Officials at the Centers for Disease Control and Prevention said the percentage of respiratory specimens that were positive for seasonal flu inched higher to 4.9 percent for the week of Jan. 21 from 4.3 percent reported the week before, while doctor visits for flu-like illness are below national and regional baselines. The H3N2 virus has dominated national flu activity so far this season. Colorado, Kentucky, Missouri and Virginia reported regional flu activity -- but no state has reported widespread flu activity. CDC Region 5: Illinois, Indiana, Missouri, Ohio and Wisconsin reported the highest percent -- 14 percent -- of respiratory specimens that tested positive for flu. However, CDC officials said for the past three weeks the 2009 H1N1 virus dominated CDC\'s Region 6 that includes Arkansas, Louisiana, New Mexico, Oklahoma and Texas, the Center for Infectious Disease Research and Policy at the University of Minnesota reported. However, these states are seeing little overall flu activity. Federal health officials said they expect the levels of seasonal flu to increase over the coming weeks and continuing until the end of April.