Parents need to keep children away from sick calves, health authorities warn.
Calves with diarrhoea are the most common carriers of the disease known as Verotoxin E coli, VTEC or Shiga-toxin producing E coli, STEC.
Children under the age of five are over 20 times more likely to get infected, and about half of the cases require hospitalisation.
Taranaki has one of the highest rates of the disease in the country, with ten cases confirmed last year and the region's medical officer of health Jonathan Jarman saying a one-year-old child has been hospitalised with the VTEC disease just this week.
Mr Jarman said the high rate was because of the large number of dairy cows in the region, and people needed to be more aware of it.
"Of the tummy bugs it's actually one of the worst. With our cases over half have blood in their diarrhoea, there's a severe abdominal pain that they suffer and I think it's potentially a very scary illness if you're sitting on a farm in the middle of nowhere."
Mr Jarman said through work with Massey University they have found that VTEC and STEC is an organism that is carried in the intestines of ruminant animals.
"With our 500,000 dairy cows in Taranaki it is really important that when kids have contact with animals they wash their hands.
"The best prevention is regular hand washing especially before eating, after helping out on a farm and after touching animals."
The Taranaki District Health Board has been working with rural communities to raise the awareness of VTEC and STEC, and Mr Jarman said hope the message is sinking in.
"The proof of the pudding will be what happens this year. We've only just developed resources and I've noticed quite a few rural schools have been sending information out to parents.
"Hopefully, ultimately we will see a decline in cases."