A notorious strain of flu is starting to fill doctors' waiting rooms in Central Florida.
The H1N1 strain, otherwise known as swine flu, has accounted for most of the flu cases walking into the Centra Care clinics run by Florida Hospital.
"Right now, we're seeing at Centra Care about double the amount of cases we saw last week," said Dr. Timothy Hendrix, Centra Care's medical director.
So far this week, doctors have seen about 300 patients with flu symptoms.
Doctors send samples taken from each patient to the labs at the Centers for Disease Control and Prevention and the Florida Department of Health. Hendrix says most results are coming back having tested positive for H1N1.
The strain first made headlines in 2009, causing a pandemic that the CDC says infected millions of people.
It killed hundreds of thousands worldwide, according to the CDC.
Nowadays, Hendrix and doctors with the CDC say H1N1 is treatable and preventable.
"Every formulation of vaccine that you can get this year will protect against H1N1," said CDC Medical Officer Dr. Michael Jhung. "It will also protect against other influenza viruses that we think are circulating."
Hendrix says in addition to a flu shot, washing your hands, covering your mouth when you cough or sneeze and staying home when you are sick will greatly help curb the number of people who are infected.