enlarge Derek Davis/Staff Photographer

Dennis Nasto, a member of the department of infection control at Maine Medical Center, displays one of the masks the hospital is asking patients to wear if they are experiencing flu-like symptoms.

For all stories, links to the Centers for Disease Control and more, go to the Press Herald's complete coverage of Maine, national and international outbreaks of swine flu.

IF YOU THINK YOU HAVE SWINE FLU

• If you live in an area where swine flu has been identified and become ill with influenza-like symptoms, contact your own health care provider before going to your local emergency room. Your provider will determine whether you need testing or treatment.

• Limit your contact with people as much as possible. Do not go to school or work.

• Cover your mouth and nose with a tissue when coughing or sneezing, and put used tissue in a waste basket.

• If you do not have tissue, cover your cough or sneeze and then clean your hands.

• If you experience any of these warning signs, seek emergency medical care: difficulty breathing or shortness of breath; pain or pressure in the chest or abdomen; sudden dizziness; confusion; severe or persistent vomiting

• In children, emergency warning signs include: fast breathing or trouble breathing; bluish skin color; not drinking enough fluids; not waking up or not interacting; symptoms improve, but return with fever, worse cough; fever with a rash

Source: Maine Center for Disease Control and Prevention

The number of people in Maine believed to be infected by the swine flu virus rose to five Thursday, with the latest case appearing in Penobscot County, Maine's top health official said.

All of the cases are mild infections, and the patients are recovering well at home, said Dr. Dora Anne Mills of the Maine Center for Disease Control and Prevention.

Mills said she expects the number of cases to continue to rise during the next few days because Maine schools were closed last week for spring vacation, and families arrived home last weekend or early this week. Those who were exposed to the H1N1 virus in their travels have a two- to seven-day incubation period before exhibiting symptoms, Mills said.

"I suspect in the next few days we're going to see an increasing number of people with positive tests because of our travel history," she said.

Four of the cases in Maine have been linked to travel so far. Mills would not say exactly where the patients were exposed to the swine flu virus, but said none has been linked to Mexico, which is believed to be the source of the outbreak. That may change as more people are tested.

The number of tests conducted by the state is growing rapidly. The Maine CDC ran about a dozen tests Monday and about three dozen Tuesday. That number shot up to 100 tests Thursday.

Three of the five Maine swine flu cases involve youths under age 18, including the Penobscot case and two in York County, Mills said.

A York County school and a day-care center – Kennebunk Elementary School and the Crayon Academy in Arundel – were closed by health officials Wednesday for at least seven days. The youth in Penobscot County has not been in school for almost two weeks, Mills said, so the state is unlikely to recommend school closure in that area.

The Penobscot case, one adult case in Kennebec County and another adult case in York County have been labeled "probable" swine flu, meaning they have been confirmed by state testing but are still awaiting confirmation from the federal Centers for Disease Control and Prevention.

Mills said there's a "greater than 95 percent chance" the state test results will be confirmed by the national CDC, but the state can't wait for the federal results to come back before taking action.

"We want to take action now," she said. "We need to be conservative and aggressive on this."

The two York County youths who are apparently infected have cases that are considered "highly suspicious," meaning they are symptomatic and have had household contact with an infected individual, but there are no test results yet.

The numbers are "a moving target" from day to day, Mills said. A Kennebec County case that had been labeled as probable swine flu, for example, was retested late Wednesday and found to be ordinary seasonal influenza.

"The numbers mean less and less as time goes on," Mills said. "You cast a net and do a lot of tests to find out if you have the disease in the geographical area you're testing. Once you've got some probable cases, you stop doing the tests. It's not going to change your treatment."

Meanwhile, some hospitals and doctors' offices are reporting an increase in phone calls, office visits and trips to the emergency room as Mainers react to the outbreak.

It looks like midwinter at Mercy Hospital in Portland, where the number of patients coming into the emergency room rivals what's seen at the height of traditional flu season in mid-February, said Dr. John Southall. The hospital has sent 10 specimens to the state for swine flu testing, Southall said, but so far none has come back positive.

"Flu isn't an emergency department illness," Southall said. "If people are experiencing some of the symptoms of flu, they should really be going to their regular doctors and then come to the ER only if they're very sick."

About a dozen people with symptoms...