Hazel Guinn, who was a nursery pupil at Marsh School in High Wycombe, died following a short illness which was identified as the influenza A virus, a spokesman for Buckinghamshire County Council said.

On Wednesday the school, which has 180 pupils aged between three and seven, was closed as a precaution.

The spokesman said health experts said the virus "was not particularly virulent" but the exact cause of Hazel's death "has not yet been established".

Marion Clayton, the council's portfolio holder for schools, said: "When we took the decision to close the school on Wednesday evening we did not know what the virus was.

We have taken the decision to close Marsh School because of the particular circumstances and these parents' concerns Marion Clayton

"We have since been informed by the Health Protection Unit that it is influenza A.

"Two members of staff have shown symptoms this week and we are aware of four other children who may well have this flu bug, although these children are on the mend."

She said parents were obviously concerned over the girl's death and most had agreed it was better to have their children at home so they could be monitored.

"I must stress that pupils throughout the country get this particular bug every winter and schools do not normally need to close," Ms Clayton said.

"We have taken the decision to close Marsh School because of the particular circumstances and these parents' concerns.

Neighbouring schools

"I would like to extend my sympathies to the family. I know the school has been offering them every support and will continue to do so."

Health Protection staff have written to parents and visited the school to advise staff and identify whether there are vulnerable people who might benefit from a flu vaccine.

They will be writing to parents again on Thursday to update them on the situation.

Neighbouring schools have also been informed of the situation.

The school is expected to reopen next week.