This 2009 image taken through a microscope and provided by the Center for Disease Control and Prevention, shows the H1N1 strain of the swine flu virus.
Doctors are treating a child for a suspected case of swine flu, officials in Middlefield said.
The child is taking medication and improving, Dr. Matthew Huddleston, health director for Middlefield, said.
He said the federal Centers For Disease Control and Prevention would have to decide if it's a confirmed case of swine flu.
State health officials are also looking at two other probable cases of swine flu involving adults in Stratford and Southbury who recently returned from Mexico. Both are recovering and neither was hospitalized. Officials are awaiting test results from the CDC.
East Haddam closed its schools after two students recently returned from a family trip to Cancun, Mexico and became ill. One child attends the town's elementary school while the second attends the middle school. A third, younger child also became sick. East Haddam is holding a news conference at 4 p.m. regarding the incidences.
Classes are also canceled in the Wethersfield School District, as well as several magnet schools, Wednesday because an employee at Silas Deane Middle School recently traveled to Mexico and now has flu-like symptoms. The district had not decided as of Wednesday afternoon if schools will open Thursday.
Late Wednesday, the Rotella School in Waterbury announced it would close Thursday and Friday as a precaution, after a student who had just been to Mexico reported being sick. The district pointed out that that "while the symptoms may not be that of the swine flu," the school will be sanitized as a precaution.
The World Health Organization has set the pandemic alert to Phase 4, which means "sustained human to human transmission." Phase 4 is one step below the level reserved for widespread human infection.
Dr. Matthew Carter, chief epidemiologist for the state Department of Public Health said he expects to see travel-related cases.
"It's just a matter of time before we all have travel related cases that are confirmed and we soon will be moving past this stage. Right now we're focused on travel-related cases, but the real issue will be when we start to see community transmission," Carter said.
The state Department of Public Health has established a panel of infectious disease experts and has reached out to emergency rooms and doctors across the state to step up monitoring of flu-like symptoms.