Flu season heightens precautions

At the downtown Crystal Lake yoga studio "cleaning everything down," such as disinfecting mats before and after classes, is the protocol in all seasons, Waring said. But the flu season has heightened sensitivity about spreading the virus to others.

"Attendance has been low recently," Waring said. "And nobody's coming in with obvious symptoms. Previously, there might have been some who would show up with lingering coughs. It seems like more recently, they would stay away. That's been my experience."

But practicing yoga, she said, "does boost the immune system, it clears it out too, so we have that going for us."

Influenza, or flu, is a contagious respiratory illness that can be spread by poor hygiene habits.

Public campaigns and announcements repeatedly urge people to get flu vaccinations, wash hands often with soap, and cover coughs and sneezes with a tissue or with their arms, not hands. The national Centers for Disease Control and Prevention recommends vaccinations for almost everyone over the age of 6 months, and especially for at-risk populations such as young children, the elderly and people with weakened immune systems.

Historically, the flu this season has been a more severe strain, causing more hospitalizations and deaths, according to the Illinois Department of Public Health.

From late December through Jan. 19, the state health department has documented 534 flu-related admissions to hospital intensive care units. Of those, 58 resulted in death, and officials expect those numbers to rise as the agency collects more reports from health care providers.

Flu season can arrive as early as October, typically peaks in January and February, and can continue through May.

The McHenry County Department of Health - through its "Please Don't Bring the Flu Here!" campaign poster - advises those with flulike symptoms to stay home and away from others.

Beginning in October, McHenry County saw a steady rise of rapid test-positive influenza cases, peaking in late December, officials said. There were no cases as early as October in 2011, a comparison of data shows.