Swine flu cases jump by 30 percent

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.

Most of the new cases cropped up in Chicago, with 842 cases, and suburban Cook County, with 517 cases.

Slight increases were reported in DuPage County, with 82 cases, Kane with 57, and Lake with 149. McHenry held steady at four, and Will increased by 15 to 91.

Nationally, the U.S. Centers for Disease Control reports 60 percent of the cases have involved people between ages 5 and 24, and most hospitalizations involve those under 24 - unlike seasonal flus, in which the elderly are hit hardest.

The spread of the disease appears to have dropped off from its April peak in Mexico, where this new strain of the flu is believed to have originated.

Globally, because the southern hemisphere is entering its flu season, more cases have been reported recently there.