A new strain of norovirus has circulated in Auckland hospitals.
The antibiotic resistant intestinal bug - clostridium difficile - can cause mild to severe diarrhoea depending on the strain.
Treatments for the bug include faecal transplants - which involve a sick person receiving a healthy person's waste via different methods.
Auckland scientists confirmed the presence of a new strain of the virus, commonly known as C. diff, here last November.
Up to 10 people had been infected with the bug in Auckland between November and May, Dr Sally Roberts from the Health Quality and Safety Commission said.
However, the real number is likely to be larger because doctors do not routinely screen for C. diff.
The strain was equal to a similar Australian strain, but not as severe as the one in the Northern Hemisphere, she said.
''It's not like in the UK where people are dying from it, we haven't hit that situation yet but that's what we need to prevent.''
The Ministry of Health was considering a surveillance programme to better monitor the superbug, she said.
Hand hygiene and spotless cleaning at hospitals was highly important in preventing the bug spreading.
- © Fairfax NZ News
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