ATLANTA, Dec. 21 (UPI) -- For the week ending Dec. 14, U.S. influenza increased nationwide, but Texas was hard hit with more than a dozen critically ill and six dead, officials say.
The influenza strain H1N1 -- the same strain that caused the 2009 pandemic -- killed six people and left 14 critically ill in the Greater Houston area, KHOU-TV in Houston reported.
The Harris County Health Department said at least three people died from the H1N1 flu virus -- all middle-age men, two with underlying health issues, including cardiovascular disease and obesity.
H1N1 is also suspected in at least nine other deaths in eight regional hospitals, health officials said.
The Texas Public Health Association issued an influenza health alert Friday and urged all in Texas age 6 months and older to get a flu vaccine immediately because it takes about two weeks for the vaccine to become effective.
Most of the flu cases in Texas are H1N1, which is included in this year's influenza vaccine.
Those with flu-like symptoms should see a doctor within the first 48 hours to be given Tamiflu, officials said.
Of 7,294 specimens nationally tested and reported by U.S. World Health Organization and National Respiratory and Enteric Virus Surveillance System collaborating laboratories 17.8 percent tested positive for influenza. One influenza-associated pediatric death was reported.
Alabama, Louisiana, Mississippi and Texas reported high levels of influenza-like illness; Oklahoma reported moderate influenza-like illness activity; while Colorado, Illinois, Missouri, Nevada, Utah, Virginia and New York City experienced low influenza-like illness activity.
Thirty-seven states experienced minimal influenza-like illness activity: Alaska, Arizona, Arkansas, California, Connecticut, Delaware, Florida, Georgia, Hawaii, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Montana, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Washington, West Virginia, Wisconsin, and Wyoming.
Widespread influenza activity was reported by four states: Alabama, Louisiana, New York and Texas.
Regional influenza activity was reported by: Arkansas, Colorado, Florida, Georgia, Illinois, Indiana, Kentucky, Maine, Massachusetts, Mississippi, Nevada, New Hampshire, New Jersey, North Carolina, Oklahoma, South Carolina, Tennessee, Utah and Virginia.
Local influenza activity was reported by 17 states: Arizona, California, Connecticut, Idaho, Iowa, Kansas, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, Ohio, Oregon, Washington, Wisconsin and Wyoming.
Sporadic influenza activity was reported by Delaware, Hawaii, New Mexico, North Dakota, Pennsylvania, Rhode Island, South Dakota and West Virginia. Vermont reported no influenza activity.