NORTHWOOD - Though Coe-Brown Academy shut down Friday after hundreds of students were out sick with flu-like symptoms, the school is expected to be open Monday.

About 200 of the school's 700 students stayed home Friday with some form of a respiratory illness. The number of people out sick had been rising, from 40 to 50 over the last couple of days, and at least 10 educators were affected, according Dr. Jose Montero, the state epidemiologist monitoring the situation.

The state did not confirm an actual flu outbreak, and "the expectation is that we have a different kind of respiratory illness with a mix of several different things at the same time," Montero said. "Some of them may have the flu, but most of them may not."

Whatever the precise cause, all of the students were complaining of a cough, fever, sore throat, headache, congested chest and general malaise, he said.

"What we know today is nobody has any severe illness that requires hospitalization or intensive care," Montero said Friday night. "I can't tell you that that will not happen. That's why we emphasize that people who are sick should not go to school."

The outbreak wasn't causing problems at K-8 Northwood School or at Wentworth-Douglass Hospital in Dover.

"We haven't seen anything at all," said Kenneth Darsney, the school's assistant principal.

"I have not admitted any young people with the flu," said Susan Stocklan, nursing supervisor at Wentworth-Douglass.

Coe-Brown issued an "influenza alert," sending parents a letter saying the state's communicable disease control division was assisting with the outbreak.

"Colds and influenza-like symptoms are not uncommon in a school setting during this time of the year. Influenza-like (flu-like) illness is currently circulating throughout the state and the country," wrote Darlene Morse, the state's public health nurse program manager.

The illnesses come as flu activity has been dropping across the state for the last three weeks, Montero said. The timing of flu season typically varies - sometimes arriving in October or November or, like this cycle, in late January, he said, adding the season can last a few weeks or up to three months.

Flu-like symptoms typically fester in people for 24 to 48 hours before becoming a full-blown illness, Montero said. The sickness can spread especially fast - at school or elsewhere - when people are shaking hands, coughing or sneezing without following what Montero called proper etiquette.

For example, don't cough in to your hand - cough into your elbow, he advised.

Coe-Brown didn't have to take any special steps to sanitize the academy - just open some doors to improve air circulation, Montero said.

Montero said school will open Monday after the rare closure, and the state will work with officials to track students' health.

"It is not frequent that you have all of these people sick at the same time," he said.

The state offered these tips to stay healthy from the flu or similar illnesses:

- Wash hands frequently with soap and water

- Use an antibacterial hand gel when soap and water are not available for hand washing

- Use a tissue to cover the nose and mouth when coughing or sneezing

- Stay home from work or school if experiencing flu-like symptoms until 48 hours after symptoms stop

- Eat right, exercise and get plenty of rest

- Do not share utensils, such as silverware