The Minnesota Department of Health confirmed the state's first case of swine flu on Thursday, leading school officials to keep a central Minnesota middle school closed through Tuesday.
The Minnesota Department of Health said the U.S. Centers for Disease Control and Prevention confirmed the case in a person with ties to Rocori Middle School in Cold Spring.
The middle school and a private elementary school next to it closed for a second day on Thursday.
Rocori Superintendent Scott Staska said health officials told him the case is confined to the middle school, and there were no immediate plans to close other schools in the district. For now, St. Boniface School will also remain closed.
State Health Commissioner Sanne Magnan said officials are continuing to interview anyone who had contact with the sick individual. They want to know where those people live, who they've been in contact with and where they've traveled -- particularly if they've recently gone to Mexico.
Investigators will also ask them if they've had any flu symptoms, such as fever, muscle aches, cough, or gastrointestinal problems.
The Health Department may test some of them for the new strain of flu if they suspect they had sufficient exposure to the virus.
In announcing the probable case a day earlier, health officials said the person was expected to make a full recovery. They have not identified the person.
More than 100 people in the U.S. had been confirmed with swine flu in more than a dozen states. It has also made people sick in Mexico and several other countries.
Magnan said officials were looking at the current case to get a better idea of how the virus behaves, but she said there are many unanswered questions about whether it will remain a threat.
"This is the unpredictability of the influenza," she said.
As of Thursday morning the state public health lab had completed tests on 126 patient specimens. Out of all of those samples, there is still only the one confirmed case of H1N1 in Minnesota. The Health Department has another 23 samples that they are still testing.
The state had to send the probable sample to the CDC n Atlanta for confirmation of the H1N1 virus. But as soon as tomorrow, those tests will be able to be done in Minnesota.
The CDC is providing states with the laboratory materials for H1N1 flu testing, that will allow them run their own tests for the illness.
Once Minnesota receives the materials, the state will no longer have to ship samples to CDC headquarters in Atlanta for testing. That should cut a day off of the process of confirming probable cases. The state will be able to conduct its own testing as early as Friday.
Minnesota health officials continue to recommend that people take commonsense steps to protect themselves and others: Wash your hands frequently, cough and sneeze into your sleeve, avoid sick people. If you feel fluish, stay home.
While the regular flu season is winding down, heath department spokesman Buddy Ferguson said that might not be the case with a new virus.
"If you have a completely new influenza virus like this, it will typically not follow the regular flu seasonal pattern," he said.
Gov. Tim Pawlenty urged Minnesotans to take certain precautions, but he said the state is prepared to handle the illness if it spreads.
"It is a cause for concern but not a cause for panic," Pawlenty said.
Pawlenty and his advisers have refrained from calling the suspected illness swine flu and instead referred to it as "H1N1 novel flu" - a distinction of importance in a major pork-producing state.
Though there is no vaccine for this strain of the flu, Magnan said antiviral drugs have been effective and Minnesota is expecting additional stockpiles of those from the CDC. Some of the 400,000 doses the state currently has will be distributed to regional hospitals in case of immediate need, health officials said.
(The Associated Press contributed to this report)