A MUM-of-five died after breathing in a rare airborne bug, an inquest heard.
She was taken to Southampton General Hospital after colleagues noticed she had a fever.
But during the night her condition worsened and she died the following morning.
Specialists found she had been overwhelmed by the bacterial infection pneumococcal sepsis, leading to organ failure, the court heard.
Pathologist Dr Adrian Bateman said: “It is very unusual. I suspect she breathed it in and the organism got into her blood. It may not be too obvious where you got it from, without any obvious contact.”
Southampton deputy coroner Gordon Denson, who recorded a verdict of death by natural causes, said: “It amazed me how quickly she deteriorated for somebody to all intents and purposes a fit woman.”
Mrs Cook, of Bridgemary Avenue, Gosport, was a teaching assistant at Newton Primary School.