A second child has tested positive for the H1N1 flu virus at a Regina elementary school, officials with the health region reported Friday.

Another 140 to 150 students remained at home with illnesses that could yet turn out to be the same flu.

So far, officials said, the outbreak seemed to be contained to the one school, Massey Elementary, on the city's south side.

Saskatchewan's chief medical health officers told CBC News on Friday that she was not aware of any other schools experiencing high absenteeism due to a flu outbreak, however Dr. Moira McKinnon added it could happen in the next week.

About one-third of Massey's enrolment has been away from school after experiencing flu-like symptoms.

"We're not really surprised," McKinnon said. "Although we had hoped that we wouldn't have any school clusters, school clusters are occurring across Canada."

In Ontario, she noted, over 100 schools have experienced significant absenteeism, with 35 per cent of a school's population typically reporting sickness.

While many are likely mild cases of swine flu, McKinnon said some parents are keeping children at home with only a minor cough.

"There's a number of that absenteeism that is due to just people being concerned and keeping their children at home."

McKinnon added that health authorities did not have plans to institute any comprehensive testing of children. Authorities are confident they are properly dealing with H1N1, she said.

"We're not, actually, actively testing because it's so probable that we're pretty sure that that's what it is: H1N1," McKinnon said. "It's likely that all the other kids that have influenza-like illness have that particular virus."

Parents are being advised to keep children with flu symptoms at home for seven days. Fewer than three weeks remain in Regina's elementary school year.

Too late to close schools

McKinnon said authorities have so far rejected the notion of closing an entire school.

"School closures have been the subject of discussion right from the beginning," McKinnon said. "It's really only worth closing schools if you do it very early in the spread of the virus."

In order for the move to be successful, other measures would also have to be implemented, McKinnon added, including putting all people who had contact with a coughing person under quarantine for seven days.

Massey elementary was the only school in the province with a cluster of flu illness, she noted. Other schools in the same neighbourhood have not reported any problems.

However, McKinnon said, that could change as early as next week.

Nevertheless, McKinnon said parents should not be too concerned about their child's health.

"It's a mild illness in almost all cases," she said.

On Friday, McKinnon's ministry updated provincial numbers on confirmed cases of H1N1. The number rose again, from a total of 153 earlier in the week to 179 on Friday.