He said many cases probably are a result of students either catching swine flu in their communities or places they traveled during the summer, then bringing the virus with them to campus.
For different reasons, other regions have been less affected.
Dr. Christian Sandrock, an assistant professor of pulmonary and critical care medicine at the University of California, Davis, works in a region that has seen perhaps the fewest cases this season.
"We haven't really seen it hit the emergency departments and clinics in hospitals yet," he said. "We definitely weren't untouched in June and July."
Weather, he said, may account for the difference.
"We tend to have less humid, much dryer air," he said. That often accounts for less respiratory illness.
He also noted the heavy rains that have led to flooding in some areas of the South, which also brought more people from the outdoors, and California has had relatively nice weather.
Sandrock said California tends to see later ends to summer weather, and therefore, later starts to flu season.
"It might be we're just going to catch up a week or two later than the rest of the country," he said. "I don't want to catch up, but we might."
Catching up may be what the South is doing now.
"Back in May, we were at a much smaller problem with H1N1 than most of the United States, and it's not because we weren't looking," said English.
Schools closing earlier may have had something to do with that, although English said schools being in session probably would not account for all of the differences in flu rates.
"We're accustomed to the same sort of thing happening every year in the winter," he said, noting that rates rise until the Christmas holiday, then drop off, rising when schools return in January.
Of the current spike, English said, "We all knew that might happen when schools started back this fall."
While swine flu has been widespread in several areas, doctors noted that most cases can be dealt with without hospitalization.
"Most of those children are not severely ill, and [are] not admitted to the hospital," said English of the patients who have come to Le Bonheur.
He said that 100 children have been admitted to the hospital for swine flu, with about 15 needing to go to the intensive care unit.
Turner added that the disease has been mild among college students, despite the number of infections it has caused.
Turner said he expects that swine flu cases will drop, and that public health officials should take advantage of the opportunity that will provide.
The disease has caused 21,000 infections in college students nationwide, he said, but only 37 hospitalizations and no deaths thus far.
"I think as we've got into it, more people are comfortable with the fact it's a mild disease," said Turner. However, he warned, complacency may present a problem.
"This is technically the second wave," he said, the first coming last spring.
"For this wave, I would imagine that college campuses will have new cases appearing for anywhere from four to six weeks," he added. "By November, we'll probably be through this wave, which will give us the opportunity to get students vaccinated for H1N1."
And that will be important to prevent spread of the illness.
"It hasn't spread to the community yet where the most vulnerable people may be," said Turner. "I suspect that we will see it go out in the community, into teenagers and to schoolchildren."
And while only a minority of children with swine flu need hospitalization, parents should remain vigilant, said English.
"We've seen otherwise healthy children develop complications of the flu," he said, because of secondary infections.
"While it is true that most patients are not having severe complications, some of them are," said English. "We just don't know yet [what] the total number of patients with life-threatening disease will be."
For more information on the web: CDC H1N1 Map