Why does Wisconsin lead nation in H1N1 cases?

Wisconsin continues to report more H1N1 influenza cases than any other state in the country. As of this morning, the state has reported at least 2,200 confirmed and probable cases of the virus, with one death.

That's 500 more cases than in Texas, one of the states where the outbreak began. And it's significantly higher than Minnesota's 96 cases.

Wisconsin public health officials have been fielding a lot of calls lately from people who are wondering why the state has so many cases of the new influenza.

There are a couple of explanations for the high numbers, according to Seth Boffeli with the Wisconsin Department of Health Services.

In Wisconsin, 75 percent to 80 percent of the H1N1 cases have been individuals under the age of 19.

"Part of the reason why we're higher is we've just simply been testing more. Another factor is that we have really the equivalent of five full-time labs processing cases here. So we have virtually no backlog at all," said Boffeli.

Some states reportedly have thousands of flu samples waiting to be tested. Minnesota has kept up with its samples, but there is only one full-time state lab. So a few weeks ago, the agency decided it would stop testing every suspicious case of the flu.

Boffeli says if Wisconsin was a hot spot for the virus, the Centers for Disease Control and Prevention wouldn't have classified the state's outbreak as only sporadic.

By contrast, flu is considered widespread in California and Arizona, even though those states have reported far fewer cases to the CDC than Wisconsin. One advantage to Wisconsin's fast processing of samples is that the state has been able to see a strong pattern emerge in terms of who's most vulnerable to the virus.

Boffeli says so far, H1N1 influenza is infecting young people the most. He said 75 percent to 80 percent of the cases have been individuals under the age of 19.

That could be due in large part to the way kids congregate in groups.

A few weeks ago, schools in the small town of Lodi, Wis., shut down for a week after a handful of kids got sick and quickly spread the virus to as much as one-quarter of the school population.

"On a Thursday or a Friday there were five confirmed cases within the school district, and by Monday or Tuesday one of the schools had 26 percent of the students out sick with the flu," said Boffeli. "So if we've seen one particular community where it can spread quickly, it's in school-aged children."

Minnesota has also detected numerous potential flu outbreaks in schools. Most recently, dozens of kids in several metro-area schools have been absent due to flu-like systems. A few of the cases have been confirmed as H1N1 influenza.

But the Minnesota Health Department has been cautious about taking much action with the outbreaks, and is only releasing the location of flu cases -- not the ages or gender of the patients. So it's unclear if the state is seeing as many infections in young people as Wisconsin.

Minnesota Health Department spokesman Buddy Ferguson says the illnesses are expected, and health officials don't want to give people the impression that they need to avoid certain places to stay healthy.

"The fact that you might have more reported cases say, in a particular school, doesn't mean that you're at greater risk than people in other places," said Ferguson. "The fact that you don't have as many reported cases doesn't mean that you should take assurance from that, and assume that you have nothing to be concerned about."

In other words, Ferguson says Minnesotans should assume they can get H1N1 influenza at any time, in any place, and they should take steps to protect themselves.

Officially, Minnesota has reported 96 cases of H1N1 influenza. But Ferguson says that number doesn't mean much at this point.

"This is most likely the tip of the iceberg," said Ferguson. "We believe the novel influenza virus, H1N1 is pretty much ubiquitous. It's circulating everywhere statewide. And that's really been the case for several weeks now."

The Health Department says flu cases continue to be relatively mild, much like seasonal flu.

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