DES MOINES — Iowa has confirmed its first case of the H1N1 virus, commonly known as the swine flu, prompting Gov. Chet Culver on Saturday to declare a public health emergency as the state awaits results on a string of new probable cases.

Culver aides said the Centers for Disease Control and Prevention confirmed the swine flu diagnoses in a southeast Iowa woman who became ill last week after returning from Mexico.

“As I have said all along, it was only a matter of time before Iowa saw its first case of this flu and today the CDC has confirmed that an individual in eastern Iowa does in fact have the H1N1 infection,” Culver said in a statement.

After returning to the U.S., the woman traveled through Johnson, Des Moines and Muscatine counties, health officials said.

The results of testing on a second probable case — the case in which the sick person was known to have been in Clinton County — was negative, Culver said.

No other cases have been reported in Clinton County.

But state health officials on Saturday reported seven new probable cases of the flu, six in Marshall County and one in Tama County.

As a precautionary measure, schools in the Marshalltown Community School District will be closed until at least May 10.

Phil Roeder, a spokesman for Culver, says officials made the move because most of the new cases reported in Marshall County involved school-age children.

Officials have said in the past that they anticipated more than 90 percent of probable cases will eventually be diagnosed as swine flu. Definitive testing must be done at the CDC labs, though state officials are working to develop that testing ability at the University of Iowa.

After the first case was confirmed, Culver signed a public health disaster declaration at the governor's mansion at Terrace Hill.

That declaration gives Culver the authority to obtain additional medication and take steps to control the spread of the disease. That could include quarantines of individuals or groups of people, though state health officials have said that probably won't be necessary.

The declaration also allows Culver to deploy public health "response teams" to assist local health providers, who officials say are facing the greatest stress in the current health crisis.

The Iowa Department of Public Health has established an emergency coordination center in the state Capitol complex. Culver aides said the state has received a shipment of anti-viral medication, and officials expect to have about 750,000 courses on hand. Each course includes several doses.

Officials have said that should be enough to treat the level of disease anticipated.

The supplies the state has received also include personal protective gear.

"On the state level, we are taking every precaution to help prevent the spread of this disease," said Culver. "We continue to monitor the situation both in Iowa and around the country."

State health officials have conceded that since the disease has been introduced into the state, its spread is virtually certain. They continue to urge people to take basic safety precautions, such as washing hands frequently and using tissues when coughing and sneezing.

They also urged those experiencing symptoms of the disease to stay home and contact a health care provider. Symptoms include a fever above 100 degrees, sore throat and coughing.

None of the cases reported in Iowa have been life threatening, and public health officials have said the initial victims are well on the road to recovery. None of the victims to date have been hospitalized, in sharp contrast to the situation in Mexico where the disease has proved deadly.

Department of Public Safety staffers have been assigned to protect the anti-viral medication as it is stored and moved around the state as needed.

Some states have activated National Guard troops to guard the medication. Culver has said he considered that step, but decided it wasn't necessary at this point. He has put the National Guard command center at Camp Dodge outside of Des Moines on alert should it be needed.

Nationally, the U.S. count Saturday morning was 161 confirmed cases. There were 705 confirmed swine flu cases worldwide, although the real number is believed to be much higher.

Roeder said Marshall Community School System will close for the next week, that most new cases reported today were school-age children and that's why it was decided to close schools.

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