OKLAHOMA CITY (AP) — A woman who began showing flu-like symptoms after a trip to Mexico has become the first person in Oklahoma to have a confirmed case of swine flu, state health officials said Tuesday.

The woman, who lives in Pontotoc County in southeast Oklahoma, did not require hospitalization and has recovered, State Epidemiologist Dr. Kristy Bradley said.

Meanwhile, health officials are waiting for results of four “probable” cases that have been sent to the Centers for Disease Control for confirmation. School officials in the Deer Creek School District in Edmond said Monday one of those cases involves a student there.

“They were not able to tell us the age, grade level or school,” said Deer Creek Superintendent Rebecca Wilkinson. “We have notified all schools to be under precaution.”

for any students or staff members who might be exhibiting flu-like symptoms.

School officials have followed recommendations from the health department and not closed any of the schools, but Wilkinson added, “If our parents feel like they need to take their children home, we certainly understand that.

“We’re going to wait until we have a documented case and then make the best decision possible. It is our intent to safeguard our children.”

After the government last week advised schools to shut down for two weeks if there were suspected cases of swine flu, U.S. health officials now are no longer recommending that schools close.

Health and Human Services Secretary Kathleen Sebelius said Tuesday that the swine flu virus had turned out to be milder than initially feared and that the government is changing its advice on closing schools.

Sebelius says parents should still make sure to keep sick children at home.

In the confirmed Pontotoc County case, the woman stayed home from work while ill, and it is thought that she did not transmit the disease to others in the community, Bradley said. She began showing symptoms on April 25 after a trip to Puerto Vallarta. She was given antiviral treatment.

“This announcement should not cause any interruption in the day-to-day activity of Oklahomans,” Bradley said. “There is no reason for anybody to have an unnecessary anxiety level.”

She said swine flu in the United States has been no more severe than seasonal flu. Bradley said health officials estimate as many as 300 Oklahomans can die each year from influenza-related complications.

But Bradley predicted the emergence of a new strain could lead to a more severe flu season in the fall.

“It is a little too early to tell, but we have concerns whenever you have the emergence of a brand-new flu strain late in the flu season,” she said. “It tends to wane and be very inactive and quiet in the summer and then resurges and causes quite a bit of increased activity in the fall and early winter. That is what we are preparing for.”

Since the swine flu outbreak first was detected on April 24, Bradley says state health officials have received 346 specimens for testing and conducted 258 tests. Of those, six have been sent to the CDC for further testing. One of those came back negative, one tested positive and four were “probable” cases.

Oklahoma health officials have received equipment to begin testing samples in Oklahoma for swine flu, but Bradley says the state will use the CDC for confirmation of the first five positive tests.

Oklahoma joins 38 other states with cases of swine flu confirmed through the Centers for Disease Control and Prevention. More than 400 cases have been reported nationally, and two deaths, both in Texas.

Oklahoma doctors are routinely sending in samples from patients with flu-like symptoms, and several of those have been sent on to the Centers for Disease Control and Prevention for further testing.

Bradley said four other probable positive samples for swine flu from Oklahoma have also been sent to the CDC, and state health officials are awaiting confirmation.

She declined to release further details about the woman.

State health officials have been predicting Oklahoma would join the many other states in which swine flu cases have been confirmed, and have been urging residents to wash hands frequently and stay home from work or school if sick.

“The confirmation of a case in the state means citizens should be cautious, but not fearful,” Gov. Brad Henry said in a statement. “It simply means that Oklahomans should continue to take commonsense measures to avoid getting the virus, and to see a doctor if they experience flu-like symptoms.”