Cary, N.C. — Wake County health officials said Thursday that the number of confirmed cases of swine flu in the county has doubled, to four.

Meanwhile, the woman who was the county's first confirmed case said she believes a Cary school was the source of the virus locally.

Dr. Elizabeth Tilson, interim Wake County community health director, said a 39-year-old and an 11-year-old are the latest residents who tested positive for the H1N1 virus.

Tilson said the new cases are unrelated and have no link to Reedy Creek Middle School, which was tied to the first two cases. The 11-year-old attends a school that isn't in session now, she said, declining to identify the school.

On Monday, tests confirmed a 42-year-old mother had contracted swine flu, and public health officials said Wednesday that a Reedy Creek Middle student was the county's second confirmed case of the illness.

"I believe that there have been a lot of kids at the school with the same symptoms over the past few weeks. I just happen to be the first one to get tested," the woman, who asked that her name be withheld, told WRAL News Thursday in a phone interview.

She said she believes she picked up the virus from her son, who is a student at Reedy Creek Middle.

Her son was tested for H1N1 this week after she tested positive for the virus, but his tests came back negative. Public health officials told her he might have already recovered from the illness by then, she said.

He was recently in contact with the Reedy Creek Middle student who tested positive for the virus, she said.

"I believe it is coming from the school, and my concern is that parents were not aware of what was going on," the woman said. "They were continuing to send their kids to school. We had (end-of-grade tests and) exams, and they're wanting to get their kids in for the review dates. But in the meantime, their kids are either spreading it unknowingly or catching it."

Officials said the student is recovering at home and that people who were in close contact with him or her have been alerted to watch for flu-like symptoms.

Principal Lawrence Jackson ordered Reedy Creek Middle staff Wednesday to disinfect the entire school. He said cleaning crews had been working since the first H1N1 case was reported in North Carolina last month to make sure doors and handles in the school were kept clean to limit the spread of germs.

Parents said Thursday that they were confident the school is safe for students.

"I have much confidence in Lawrence Jackson – he's been a great principal – so if he's assured us they've cleaned (the school) ... I'm pretty confident they'll be safe," parent Toi Abbate said.

About 20 percent of students were absent Thursday, which was above normal, Jackson said.

The H1N1 patient said the principal responded promptly to the H1N1 threat, but she still wants parents to be aware of the risks of sending their children to Reedy Creek Middle until the outbreak subsides.

"This (student) is not an isolated case," she said. "If your children are sick or if you're feeling sick, don't even go. Don't send them to school. It's not worth it."

Another parent, who asked to remain anonymous because her son has friends who attend Reedy Creek Middle, said her child got sick with flu-like symptoms 10 days before the confirmed case at Reedy Creek was made public.

"If I'd known he was potentially a case because it was in the community, I could have gotten him Relenza or Tamiflu earlier and prevented him from getting sick," the parent said.

North Carolina has 35 confirmed cases of swine flu, with a dozen reported in the past two days.

In addition to the Wake County student, the new cases include a Johnston County teenager, an officer at Seymour Johnson Air Force Base in Wayne County and a Cumberland County resident who was diagnosed while traveling out of state.

Tilson said she believes there are likely numerous unreported cases of swine flu locally. Most physicians aren't testing for the H1N1 virus unless a patient is sick enough to be hospitalized or is in a position where an infection could spread rapidly, such as a health care worker or a teacher, she said.

The H1N1 patient said more testing for the virus needs to be done.

"I think it's being downplayed in doctor's offices," she said. "These doctors and these clinics need to have testing supplies."

Officials have confirmed more than 11,000 cases of swine flu across the country, and 17 people have died from the disease in the U.S., according to the Centers for Disease Control and Prevention.

The number of swine flu cases worldwide has surpassed 19,000, the World Health Organization reported.