KEY POINTS:
A contagious stomach bug is doing the rounds of Auckland schools, affecting students sitting exams.
Avondale College principal Brent Lewis said the bug had struck several schools in the city and "it's particularly bad timing".
But not all schools have been hit - with the country's biggest, Rangitoto College, unscathed.
A New Zealand Qualifications Authority spokeswoman said it was too soon to know if there had been an increase in the number of students missing exams because of illness in Auckland this year.
Balmoral School principal Malcolm Milner said two illnesses hit staff and students one after the other.
An influenza hit the school this month, and up to 54 students a day were off sick. Last week, the stomach bug took hold.
Caretaker Peter Maurice ended up bedridden after he contracted it cleaning up after a child had been sick.
"He lost 2kg and another couple of staff had it as well," said Mr Milner. "It's particularly vehement."
One parent told the Herald the flu virus had been was "really nasty" - with symptoms including a severe cough, fever and listlessness - and it took about a fortnight for full recovery.
In some families it had spread to babies at home or parents, who, like their children, needed up to a full week off work.
At Clayton Park School in Manurewa, principal Paul Wright says using a sterilising hand gel in classes, dispensed by teachers, has led to a drop in sickness among pupils. The gel is used in every class - at a cost of about $2000 a year.
