E. coli O157:H7, also known  as VTEC or STEC, causes serious illness (occasionally fatal) by producing powerful toxins. E. coli is a bacteria which lives in the intestines of people and animals. Most strains are harmless however some strains such as the O157:H7 strain can cause illness. Internationally there have been widespread outbreaks of this illness.

Doctors are legally required to notify the Public Health Service of cases of E Coli disease under the Health Act 1956.

In the Nelson Marlborough district around 5 cases of E. coli disease are notified to the Medical Officer of Health each year.


The disease may cause an acute illness that includes symptoms of mild to severe diarrhoea (may be bloody), severe stomach cramps and vomiting. Some people may display no symptoms. People usually get sick within 3-9 days of ingesting the bacteria. Symptoms are generally mild in healthy people; however, they can be severe in children, the elderly, and people with reduced immunity.

Contact your GP or Healthline (0800 611 116) for further advice.

How is it spread?

Illness is usually due to eating contaminated raw food, drinking unpasteurized (raw) milk or contaminated water, contact with the faeces of infected people or animals.

People are infected with E. coli O157:H7 by consuming the bacteria. Common methods include:

  • Contact with some farm animals or their faeces, mainly calves and cows
  • Consuming unpasteurised/raw milk and dairy products
  • Drinking contaminated water e.g. stream or roof water
  • Eating meat (especially minced meat) that has not been properly cooked
  • Infection can be spread from person to person – so wash and dry hands thoroughly after going to the toilet.


Always wash and dry hands thoroughly after going to the toilet, changing a child’s nappy, before and after preparing food and after touching animals.

Be careful:

  • With food preparation and storage. Keep raw meat separate from cooked foods during storage and preparation
  • Always thoroughly cook meat, especially minced meat
  • Wash all raw fruit and vegetables thoroughly before eating
  • Avoid drinking water directly from rivers, streams and creeks

People should remain away from work or school for 48 hours after symptoms have gone. Food handlers, early childhood workers and children attending early childhood centres must not return to work or Early Childhood Centres until they have had 2 negative faeces (poo) specimens at least 2 days apart.