Jonathan says young children with STEC are more likely to get a severe complication called haemolytic uraemic syndrome which can damage kidneys.
"On average we get a child with this complication once a year in Taranaki.
"We've already had one case in April where a very sick child ended up needing further treatment in Auckland," Jonathan says.
He says the main source for these toxin producing bacteria was animal waste, but can also be found in places contaminated with animal waste such as muddy puddles near farm animals or animals drinking troughs, farm clothing and footwear, and in dogs and other farm animals going inside a house.
"Children under 5 living on or visiting farms with cattle and calves are most at risk from STEC illness. Anyone showing signs of the STEC infection should seek advice from their doctor or call Healthline before taking any medication for this illness as some may even make it worse."
Jonathan says one of the best ways to prevent infection is regular hand washing before eating, after helping out on a farm and after touching animals.