There’s a good chance the seven probable H1N1 cases in Iowa will come back positive, adding to one already-confirmed illness, health officials said Sunday.

“When we have probable cases, it’s highly likely they come back confirmed,” said Polly Carver-Kimm, spokeswoman for the Iowa Department of Public Health, noting that 99 percent of the cases sent to the Centers for Disease Control and Prevention come back positive.

It could be several days before the results come back because the testing site has a backup of unconfirmed specimens, Carver-Kimm said.

The new batch of those probably infected popped up on May 2, after national and state health officials confirmed the first H1N1 virus case in Iowa.

That same day, Gov. Chet Culver declared a public-health disaster.

But this doesn’t mean things are getting worse, said Doug Beardsley, the director of the Johnson County Public Health Department. It means state officials can more easily transport anti-viral medication and supplies, send out health teams to assist medical institutions, and quarantine individuals to help prevent the flu from spreading.

CDC officials said they are in the process of sending 25 percent of strategic national stockpile supplies — a national program that collects and ships medicine — to all 50 states. Nationally, 226 people have been infected with the new virus. Only one person has died from it in the United States.

“I don’t anticipate breaking into the stock,” Beardsley said. “It looks like local supplies are adequate.”

The only confirmed case, a southeastern Iowa female who recently returned from a trip to Mexico, has not been hospitalized. Because of her trip to Coralville, Johnson County has been confirmed as an area with probable exposure to the illness. Another previously suspected state case has come back negative.

The new probable sicknesses, reported in Marshall and Tama Counties, forced state health and education officials to close schools in the Marshalltown School District until May 10. The goal of this is to limit the exposure of the illness, health officials said.

“We know that there are people walking around who have not even been to a doctor,” Carver-Kimm said. “We want to stop people from transferring the virus.”

Many medical-supply store officials said they have seen an increase in the sale of face masks — and the flu panic is to blame, they said.

Face masks are almost out of stock at Community Medical Supply, 2901 Northgate Drive, a company that sells medical equipment and supplies to physicians, nursing homes, and the public, said Christiana Rasmussen, a respiratory therapist.

“All of the companies we order from are on back order,” she said, adding she believes people want to protect themselves from the virus.

But health officials said if individuals are healthy, there’s no need for the facial protection.

“It’s not recommended for general public unless you’re caring for someone ill at home,” Beardsley said. “There’s no plan or need to be distributing them to the public if you’re healthy.”