The number of swine flu cases in Illinois jumped by 35 percent over the weekend - but health officials maintain it's nothing to be alarmed about.
Total cases of the H1N1 virus, probable and confirmed, rose from 1,357 on Friday to 1,828 on Monday, an increase of 471 cases.
While the number of new cases had risen fairly steadily at a pace averaging 217 a week in the previous month, the rate tripled in the past week.
Kelly Jakubek, spokeswoman for the Illinois Department of Public Health, said such a rise is not surprising.
"It's taking its course," Jakubek said. "It spreads person to person, so we will see it continue to spread."
But like seasonal flu, with warmer weather, schools letting out, and fewer people concentrated indoors, health officials expect to see the numbers taper off soon.
The state recommends that only those severely ill with flu symptoms get tested, but most of the samples it has received continue to be for mild or moderate cases.
