A new strain of the norovirus stomach bug has hit Northland, causing one death and leaving medical officials worried.
The Sydney 2012 norovirus strain was identified in Sydney last year, and is a combination of two strains that originated in Holland and Japan in about 2007.
It is a new, highly infectious strain that can cause epidemics.
It has health officials around the world concerned and 17 outbreaks of the new strain have already been identified in Northland, including one death.
Northland medical officer of health Jonathan Jarman said the new strain had replaced the New Orleans strain that had been around since 2009.
Dr Jarman said of the five confirmed Sydney-strain norovirus cases reported in Northland between September and last month, all were in rest homes and affected residents and staff.
He confirmed the death was that of a rest-home patient.
There were 84 outbreaks of the new strain nationally and a total of 177 norovirus cases in Northland last year. "The feedback I have received from rest-home nurses is that the Sydney 2012 strain is similar to the New Orleans strain but perhaps causes more vomiting," Dr Jarman said.
It is likely that many more people have been affected than just those in these confirmed outbreaks, but most people are not tested as it usually only causes a couple of days' illness in healthy people.
Dr Jarman said there were two deaths in Northland in 2011 that were associated with outbreaks caused by the New Orleans 2009 strain so the death from the new strain was not out of the ordinary.
"Norovirus gastroenteritis is normally only a mild to moderate illness but the elderly and the very young can have more serious disease.
"In 2011 we had a large outbreak of norovirus in Northland rest homes.
"The final number of affected people with confirmed or suspected norovirus gastroenteritis was 288 with two associated deaths."
Deadly new bug in North
The Sydney 2012 strain is similar to the New Orleans strain but perhaps causes more vomiting.Jonathan Jarman, NDHB Medical Officer Dr Jarman said one of the unique features of norovirus was it could spread through the air as well as through the usual ways tummy bugs spread.
"Norovirus has been described as the Ferrari of the virus world because it is so infectious and can spread so quickly. I take my hat off to any rest home that can control an outbreak of norovirus," he said.
Norovirus symptoms are mainly vomiting and diarrhoea, stomach pains, aching muscles, feeling off colour and a headache that usually lasted for a couple of days. He said people with symptoms of gastroenteritis were advised to stay away from other people and see a doctor if the symptoms were severe or the illness did not ease after two days.
There was no treatment for norovirus other than to let the illness take its course and stay hydrated by drinking regularly.
The most important way of preventing spread was thorough hand hygiene after going to the toilet and before preparing food.
There were more than a million cases of the new strain in the UK last year.