Health workers are on alert following an outbreak of the highly-contagious norovirus among Auckland's elderly population.
At least 160 people have been struck down with the acute viral gastroenteritis illness in three separate outbreaks in the past six weeks.
The norovirus is a highly contagious stomach bug with symptoms usually
including nausea, vomiting, diarrhoea, and stomach cramping.
In January, North Shore Hospital closed a ward for elderly patients to any new admissions after 20 patients fell ill, while at an unnamed Auckland rest home another 70 people were struck down by the bug.
The third outbreak affected 73 people aboard the QE11 when it berthed recently in Auckland.
In all three outbreaks, public health staff had to move fast and isolate all patients with the illness for 10 days. All medical staff tending them wore masks and gowns and were also not allowed to treat any other sick people while monitoring those with the virus. Once patients were well, the entire area where they were treated was disinfected with hypochloride to destroy the bug.
The norovirus kills on average one person a year in New Zealand, although the victims have often had health complications beforehand.
Early symptoms of the norovirus are nausea and abdominal cramps before extreme diarrhoea and vomiting. People are usually sick from two to five days.
Auckland medical officer of health Greg Simmons said the worrying element was though they had only confirmed three cases, it was probably more widespread in the community.
The virus is most dangerous for elderly people and those with compromised immune systems.
An outbreak last year caused delays to surgery at hospitals in Wellington, Porirua and Christchurch while patients were isolated and the wards were decontaminated.
Noroviruses
* A group of viruses that are known to cause gastroenteritis.
* Symptoms include nausea, vomiting, diarrhoea and stomach cramping.
* Not serious in most people, but can cause dehydration.
* Very contagious, but careful hygiene and regular handwashing can prevent its spread.
* No treatment or vaccine exists, but illness usually only lasts 2 to 5 days.
