A severe flu strain has hit the US and is spreading to start the year 2013.
As of Dec. 29, 2012 the CDC categorized the illness as "widespread" in 41 states (see the map above and the list of states below), and 7 other states are seeing regional activity.
Influenza A H3N2 was the most commonly detected influenza subtype nationwide.
Influenza is more commonly known as "the flu" and is a contagious respiratory illness caused by viruses infecting the nose, throat and lungs.
States with widespread influenza:
Alabama, Alaska, Arkansas, Colorado, Connecticut, Florida, Georgia, Kentucky, Idaho, Illinois, Indiana, Iowa, Kansas, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, Rhode Island, Tennessee, Texas, Utah, Vermont, Virginia, West Virginia, Wisconsin, and Wyoming
Seven other states have regional influenza activity reported.
Arizona, California, Missouri, Montana, Oregon, South Dakota, and Washington all have regional influenza.
Washington, DC has local influenza while Hawaii reported sporadic influenza activity.
Delaware did not report.