Tis the season ... for germs and bugs, that is.

From the merely icky to the truly frightening, the list of illnesses school-age children share with one another is lengthy and nasty -- everything from lice and conjunctivitis to strep throat and meningitis.

When illness spreads rapidly through a school, administrators face a number of concerns. Chief among those are how to contain the infection and how to keep parents informed.

Officials in the Cornell School District understand those concerns all too well. In the spring, the district found itself in the spotlight after an outbreak of gastrointestinal illness, later traced to the norovirus, sickened 130 pupils and 16 staff members and forced the district to close its single school building for more than a week. Ultimately, the district spent more than $150,000 on rigorous decontamination measures.

Cornell's situation was extreme, but "in theory, it could happen anywhere," said LuAnne Brink, Allegheny County Health Department epidemiology manager.

And while norovirus is high on the list of communicable illnesses that plague school districts, they also must combat any number of other infections -- and those illnesses don't have to strike large numbers of pupils to be worrisome.

This school year, for instance, attention has turned to a handful of local districts, including North Allegheny, Mt. Lebanon and Baldwin-Whitehall, with confirmed cases of a drug-resistant staph infection typically seen in hospitals rather than community settings. The Allegheny County Health Department has asked school districts to voluntarily report cases of the infection, called methicillin-resistant Staphylococcus aureus, or MRSA.

Attendance tipoff
Keeping tabs on the spread of communicable illnesses often starts with a district's daily attendance numbers.

"The district watches attendance trends carefully," said Dr. Mary S. Todora, assistant superintendent of secondary education. "Our current average daily attendance is 96 percent. If numbers in a particular school or across the district drop significantly, we will look into the reasons."

The Allegheny County Health Department asks that schools notify the department when an absentee rate is more than 20 percent above normal.

The school nurse's office is another key spot where illness trends are carefully monitored. School nurses in many districts said the first thing they do when illness is on the rise is head into the classrooms to reinforce good hygiene, particularly with younger students.

"Hand washing, hand washing, hand washing. I think that's my middle name," said Lynn Fey, an elementary school nurse in the Mars Area School District.

During last year's norovirus outbreak, Cornell instituted strict measures, including installing washing stations outside restrooms, to prevent further spread of the infection.

"We're still following a lot of those guidelines, and we're prepared to handle a situation if it should arise again," said district business manager Patrick Berdine.

Joanne Dimattia, school nurse at McClellan Elementary in the West Jefferson Hills School District, sometimes has students swab everyday classroom objects, such as the doorknob, and put the specimens on a petri dish.

"Then we examine what grows so they can see and understand," she said.

The school nurse is usually a district's first line of defense against outbreaks.

"Our nurses are good judges of the health climate in the schools, said Peters Township School District spokeswoman Cara Zanella. "A couple of kids with stomachaches would be one thing, but 15 or 20 would send up red flags."

Sounding the alarm
Many school nurses said they rely on their county health departments to help decide what is cause for concern. Health departments may, for instance, send alerts when an infection is appearing in larger-than-usual numbers.

Sometimes, what is rumored to be an "outbreak" really isn't.

When the Keystone Oaks School District had a number of mononucleosis cases at the high school last year, officials called the county Health Department.

"We found there was a spike countywide, and our number of cases was not unusually high. So we sent home a letter explaining that our numbers were very much in line with what the department was seeing in other school districts," said district spokesman Jim Cromie.

With other infections, such as MRSA, just a few cases are cause for concern. When the rate or type of infection is troublesome, county health departments frequently work hand in hand with school districts to contain the illness.

Sharon Silvestri, chief of the Allegheny County Health Department's infectious diseases program, said the department averages one to two inquiries a week from school districts during the school year, with lice and norovirus being the most common complaints.

Stopping the spread
What steps are taken to contain the illness depends upon its cause.

"We follow the specifications of the Allegheny County Health Department. ... We always use a strong disinfectant anyhow, but if there is a problem, we use a different cleaning protocol," said Idessa Hricisak, director of special services for Bethel Park School District.

"It's very particular to the infectious agent. For example, with norovirus, we stress hand washing, not the use of a hand sanitizer. But for MRSA, we recommend the hand sanitizer," said Ms. Brink, of the Allegheny County Health Department.

To combat MRSA, the Mt. Lebanon School District installed hospital-grade soap dispensers in the showers, and custodians fog the locker rooms daily with disinfectant after students leave.

When illness strikes, administrators also must make decisions about whether, when and what to tell the school community.

"If we notice a pattern, we'll notify the school principals, and they make a decision about whether to send a letter to parents," said Susan Eshleman, school nurse at Chartiers Valley High School.

Just because the rumor mill reports an illness doesn't mean an alert to parents is necessary.

"People will say things like, 'Oh, I hear you have a lot of mono at the high school.' When we investigate, in nearly every case, we find not nearly as many people have it as has been reported. You have to investigate before you send out a letter and get people in a panic -- because they will panic," said Karen Thomas, health services coordinator for Hampton School District.

"You have to be careful to get the correct information out there. If you're sending a letter, does it say what you want it to say and is it really necessary," cautioned Donna Wagner, school nurse at Edgewood Primary in the Woodland Hills School District.

Often the decision to alert parents is based more on the seriousness of the infection rather than the extent of its spread.

For example, the Mt. Lebanon School District opted to send a letter to all district parents in September notifying them that one MRSA case had been confirmed.

"It was because of the fears, because people had a lot of questions. You can't educate unless you inform," said district spokeswoman Cissy Bowman.

Ellen Dickson, school nurse coordinator for the Baldwin-Whitehall School District, said her district has sent letters notifying parents of meningitis and strep throat infections because those illnesses can have serious consequences.

A well-drafted alert educates rather than panics parents and includes information about the symptoms, complications and management of an illness. In addition to letters, many districts use e-mail, newsletters and their Web sites to convey information. Alerts are a critical part of containment efforts.

Nowhere is that more evident than the "lice letter." Head lice, while not a public health threat, is a nuisance, and it tops the list of conditions for which districts send alerts. Those alerts usually include stringent protocol for eradicating the infestation.

Ms. Silvestri said she thinks school districts are less reluctant than they used to be to send such letters.

"I think we're in an age now where people want to know," she said.