Michael Dennis hates it when people call influenza “the flu.”

Dennis, an associate biology professor at Montana State University Billings, thinks the nickname minimizes influenza’s impact on society.

A true case of influenza can be serious, even deadly. Some 36,000 Americans die every year from the virus, and 200,000 are hospitalized, some for weeks.

Somehow “the flu” has become a catch-all term for many ailments, including colds and intestinal troubles. But someone who catches influenza will know it is the real thing, said Dr. Steve Helgerson, the state medical officer.

“People who are sick with influenza do not consider themselves mildly ill,” Helgerson said. “People can often remember — ‘I got sick at 10 o’clock.’ ”

Influenza is a respiratory disease characterized by fever, coughing, sneezing and body aches. It is unusual to have a case of the flu without a fever or with an upset stomach.

Anywhere from 5 to 20 percent of the population will get influenza in a typical flu season. In the United States, flu seasons usually begin in December or January and last through March or April.