The first reported cases were at Caereinion High School

Newtown's Ysgol Dafydd Llwyd acts as a feeder school for Caereinion High school, where the outbreak was first reported last week.

The suspected viral infection has struck down 200 at the high school and 30 at a nearby primary.

Symptoms include gastric upsets, high temperatures and headaches.

On Friday, Powys Council said 60 children from the 127-pupil Welsh-medium primary, Ysgol Dafydd Llwyd, were now ill.

A council spokesman said the bug was probably passed on to children in Newtown from siblings who attended Caereinion High School in Llanfair Caereinion, near Welshpool.

Leaflets have been sent home to advise parents with children at all three schools about the illness. Advice includes keeping children at home 48 hours after symptoms have cleared up.

Ysgol Dafydd Llwyd is some 15 miles from Llanfair Caereinion.

'Airborne'

Head teacher, Sian Davies, said a "significant number" of pupils were absent with high temperatures, vomiting and sore throats.

Meanwhile, environmental health chiefs said hygiene standards at Caereinion High School were not to blame for the outbreak. Test results at the school show that the infection is "airborne".

Officials added that children were starting to return to classes more than a week after the first reported cases.

They also explained that illnesses at both high and primary schools in Llanfair seemed to be linked because the pattern of symptoms were the same.