Alabama, California, Idaho, Texas, Utah and Wyoming experienced low influenza-like illness activity levels for the week ending March 31, officials said.
A report on the Centers for Disease Control and Prevention found influenza-like illness activity levels were minimal in Alaska, Arizona, Arkansas, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Vermont, Virginia, Washington, West Virginia and Wisconsin.
Activity levels are based on the percentage of outpatient visits in a state due to influenza-like illness and are compared to the average percentage of such visits that occur during spring and fall weeks with little or no influenza virus circulation.
Of the 4,551 specimens tested by U.S. World Health Organization and National Respiratory and Enteric Virus Surveillance System collaborating laboratories and reported to CDC/Influenza Division, 20.5 percent were positive for influenza.
Nationally, seasonal influenza A (H3) viruses have predominated since the start of the 2011-12 season and continue to remain overwhelmingly predominant in Regions 3: Delaware, Maryland, Pennsylvania, Virginia and West Virginia; Region 5: Illinois, Indiana, Michigan, Minnesota, Ohio and Wisconsin and Region 7: Iowa, Kansas, Missouri and Nebraska.
However, 2009 H1N1 viruses continue to circulate in several regions.
