CHICAGO | The head of the Illinois Department of Public Health says the state has logged nine probable cases of swine flu, all in the Chicago-area.

Dr. Damon Arnold says five of the probable cases are in Chicago, while two are in Kane County and single cases are being reported in both Lake and DuPage counties. The people diagnosed range in age from 2 to 57.

Arnold says all of the cases so far have been mild and nobody has been hospitalized.

MORE: Read more on the swine flu.

Arnold appeared at a news conference Wednesday called in the wake of Chicago's decision to close an elementary school after one student there was found to have a probable case of swine flu.

Arnold, Chicago Mayor Richard Daley, Gov. Pat Quinn and other officials all stressed that the state is working hard to prevent further illnesses.

The news came as Chicago school officials shut down an elementary school after one child contracted a probable case of swine flu, and the Illinois Department of Public Health said other cases are suspected in the state.

The cases are Illinois' first in a swine-flu outbreak that's suspected of killing more than 150 in Mexico and has spread across the U.S. and other parts of the world. The first U.S. swine flu death in the current outbreak was confirmed Wednesday, a 23-month-old child in Texas.

In Chicago, attendance dropped at Joyce Kilmer Elementary School before test results from one sick student indicated swine flu, school officials said. Officials decided to close the school out of caution for at least two days because of a rise in absences.

Chicago Department of Public Health Commissioner Terry Mason said the child is recovering at home.

"Parents should not be alarmed but they should be prepared," he said. "If children are sick, keep them home."

Jenelle Barrett, whose daughter attends Kilmer, arrived at the school Wednesday morning after learning about the probable case of swine flu. She said she wanted to know whether the sick child was in her daughter's second-grade classroom.

Her daughter, 7-year-old Destiny Cruickshank, said students have been coughing and sneezing.

Her teacher told them "when you are coughing and stuff that you should go wash your hands," the girl said.

Chicago Public School officials said to protect the family's privacy, they aren't releasing any information about the student with the probable swine flu case, including how the child may have contracted the illness. A specimen from the child has been sent to the federal Centers for Disease Control and Prevention to test for swine flu, said IDPH spokeswoman Kelly Jakubek.

Jakubek said she didn't know if Illinois had yet received its own testing kits.

Alderman Joe Moore said school officials told him the child is "in the upper grades" of the school, which serves students in preschool through eighth grades.

Arlette Crawford, 40, learned about the probable case of swine flu when she arrived at the school with her 5-year-old daughter, Aaliyah.

"I am pretty nervous," she said, recalling how on Tuesday she ate breakfast at the school with her daughter and they sat near another girl who "was sneezing nonstop," had a flushed face and raspy voice. Crawford said she and a teacher persuaded the mother to take that child home.

Principal Marsha Engquist of the nearby private Lake Shore School noted that it's allergy season and allergies cause some symptoms similar to flu. She said her school hasn't seen an unusual number of absences and remains open.

CPS chief executive officer Ron Huberman said state health officials alerted him Tuesday night that a student at the North Side elementary school had a probable case of swine flu. He said the district informed families about the school closure through automated phone messages.

The Chicago closing came as President Barack Obama urged school districts with confirmed cases of swine flu to consider closing to help control spread of the illness.

"Parents should also think about contingencies if schools in their areas should shut down ... . Just sending a (sick) child from a school to a day care center would not be a good solution," Obama said.

State officials are calling the case "probable" until their test results are confirmed at the federal level. Officials said the CDC will make the final determination on whether Illinois' cases match the swine flu outbreak in Mexico.

As of 2008, Hispanic students made up 59.9 percent of Kilmer's population, according to CPS, but Mason cautioned against drawing conclusions or stereotyping. Determining whether the child had traveled recently to Mexico will be part of the investigation, Mason said.

Several parents who had not heard about the school closure arrived with their children Wednesday morning and were met by school staff on the sidewalk distributing a one-page flu information sheet in English and Spanish.

Mason said the school would be cleaned, but emphasized that the flu spreads through contact between people.

"It's not doorknobs and water faucets, it's children coughing and sneezing," he said. "We want to emphasize that the building is not a problem."

Associated Press writers Deanna Bellandi and Karen Hawkins contributed to this report.