The Kansas Department of Health and Environment (KDHE) identified the first influenza cases of the 2011-2012 flu season in Kansas this week.

On Dec. 21, the Kansas Health and Environmental Laboratories confirmed influenza in specimens from two adults from the same workplace in northwest Kansas. Five coworkers were also ill with symptoms of influenza.

Symptoms of influenza include fever, headache, extreme tiredness, dry cough, and muscle aches. Complications can include pneumonia, ear and sinus infections, and dehydration; influenza may also worsen other chronic conditions.

“Flu has arrived once again in the state. Although flu activity is now low, it normally rises during the holidays before peaking around February. Influenza can continue to circulate through spring, and the flu can be unpredictable,” said KDHE Secretary and State Health Officer Robert Moser, MD.

On average, five to 20 percent of the U.S. population contracts influenza yearly and more than 200,000 people are hospitalized with complications.

Influenza was documented as a cause of death for 31 Kansans in the 2009-2010 influenza season; in the 2010-2011 flu season, there were 14 documented deaths from influenza. However, influenza is often not listed on death certificates because laboratory tests may not show influenza by the time pneumonia or other complications develop, said State Epidemiologist Charles Hunt. “The actual numbers of influenza-related deaths are likely much higher and can vary substantially from year to year,” said Hunt.

The Centers for Disease Control and Prevention (CDC) estimates that as many as 3,300 to nearly 49,000 influenza-associated deaths occurred during influenza seasons between 1976-1977 and 2006-2007, depending on the severity of the season.