There are now 79 confirmed cases of whooping cough in McHenry County and health officials say the disease has moved from the schoolyard to the general population.
It is the county's worst outbreak since 2004 when 191 cases were recorded.
Debra Quackenbush, the McHenry County Department of Health community information coordinator, said ages range from 3 months to 35 years with additional cases awaiting testing.
"It is countywide at this point," Quackenbush said. "Each outbreak is uniquely different with no predicted trajectory. We had expected that it would grow and intensify, and it certainly has."
The initial outbreak of whooping cough -- also known as pertussis -- was recorded in mid-October at Cary-Grove High School. The number of cases in Cary stands at 35 but has spread to at least a dozen other communities from Algonquin to Woodstock. Quackenbush said no one has been hospitalized and patients typically respond to a five-day course of antibiotics.
"It is about education and getting the message out to health care providers, schools and students so they know what we are dealing with," Quackenbush said.
Quackenbush said whooping cough is usually active during the summer and continues through the fall as students return to school.
In an effort to prevent further cases, McHenry County Department of Health will hold a third walk-in vaccination clinic from 2:30 to 7 p.m., Wednesday, Nov. 16, at the department's office at 100 N. Virginia St, Crystal Lake.
Initial symptoms are similar to those of a common cold but after a week or two can develop into bursts of numerous, rapid coughs with a distinctive "whooping" sound.
While it can be mild in some cases, it poses a greater risk to infants who are not fully immunized, those with compromised immune systems and older people.
Health authorities recommend that if you live with someone with whooping cough that you also take antibiotics to halt its spread.
For details, visit www.mcdh.info or call MCDH's Communicable Disease Division at (815) 334-4500.