An outbreak of E. coli has led to the closure of a crèche in north Co Galway.

The Health Service Executive says the temporary closure happened after three children were diagnosed with a serious form of gastroenteritis last week. A further four cases have been detected this week.

Two of the children involved are being treated in hospital in Dublin.

The HSE says an investigation into the cause of the outbreak is continuing.

It is understood that both staff and children at the facility have taken ill. All are being monitored and will not be allowed into other childcare centres until tests show they are completely free of infection and pose no risk to others.

The strain of gastroenteritis detected - Verotoxigenic Escherichia coli (VTEC) - can cause diarrhoea, vomiting, nausea, and high temperature. It can be spread in a number of ways, through contact with animals, contaminated soil, water or certain foods.

VTEC bacteria can also transfer between toddlers who are not toilet trained.

The HSE says that in the majority of cases, patients recover without treatment, but in some instances the bacteria in question can cause anaemia or kidney failure.

There has been an increase in the number of cases of VTEC identified here in recent years, with over 900 reported last year.

Careful hand washing is one of the key ways to prevent the spread of infection.