It comes on suddenly, with fever and chills. Your aching body feels as though you've done 10 rounds with Mike Tyson after having run 25 miles uphill wearing a lead suit. Your head feels like Bugs Bunny dropped an anvil on it. Your sinuses are clogged and your throat feels like it was scoured with industrial-grade sandpaper.

You've got the seasonal flu. For whatever it's worth, you're not alone.

It's week nine of the 2011 flu season, and the illness is widespread in Pennsylvania. According to the state Department of Health's website, "there was an increase in flu cases, outbreaks of influenza and influenzalike illness (ILI) in Pennsylvania; the increase was more pronounced in the eastern part of the state. ILI is defined as patients presenting with fever over 100-degrees, cough and/or sore throat in the absence of a known cause other than influenza.

During week seven (the week ending Feb. 19 and the one for which the most recent figures were available), authorities reported 1,898 flu cases in the state, up from 1,632 in week six, according to the Department of Health. Also during week seven, 189 influenza hospitalizations were reported, most of them involving those 65 years and older, and people between 25-49 years of age.

Five flu deaths were reported during week sseven. Altogether, 39 flu deaths have been reported since October, including four deaths in children under 18 years and nearly half among those age 65 or older.

Local hospitals are seeing a significant increase in the numbers of people seeking treatment for flu symptoms.

Blue Mountain Health System spokeswoman Lisa Johnson said there has been a "definite increase in flu cases in the emergency rooms over the last two weeks." In January, there were 33 patients with "viral illness and flu positive" cases, although not all were tested for flu. In February, 53 patients were diagnosed with viral illness, with most testing positive for flu.

St. Luke's Miners Memorial Hospital, Coaldale, is also seeing a significant increase.

"Since January, St. Luke's Miners Memorial Hospital's emergency department, physician offices and health centers along with St. Luke's Urgent Care Center, Jim Thorpe, have seen a steady increase in visits for influenzalike illness," said Kathy Matika, RN, BSN, CIC, head of Infection Prevention/ Employee Health at St. Luke's.

"The number of patients with positive flu tests for influenza in February tripled that of January," she said.

Influenza activity is likely to continue increasing over the next few weeks, and the recent deaths show us that severe and fatal illness can occur in healthy people throughout the season. Most of the recent influenza hospitalizations and deaths are in people who have no recent history of influenza vaccination, according to the Department of Health.

Vaccination is the first line of defense.

"Statewide, flu is widespread, being identified in all age groups but slightly increased in the 25-49 age group. This age group is generally considered a healthy adult age group, but when it comes to flu vaccination they are the least likely age group to be vaccinated. The next group with a slightly increased number of cases is children under 18. The confirmed flu cases we are seeing in our community fit the statewide trend. According to the Pennsylvania Department of Health, most flu types that have been identified are a good match to the vaccine. Vaccination remains the best way to prevent the flu," Matika said.

While it would have been best to get the vaccine last fall, there are still some supplies left. Ask your family doctor for a flu shot, or call 1-877 PA HEALTH to find out where the vaccines are available.

However, cautions Johnson, "the flu vaccine takes 10 days to two weeks to become activated in your system."