Three more confirmed cases of measles in Northland in about as many days have taken the total to nine.
The latest patients, all unimmunised and living in Whangārei, are aged from 25 to 58.
Medical Officer of Health Dr Catherine Jackson said contact tracing had revealed that people had unwittingly visited Whangārei Hospital while they were infectious, and before the rash had appeared, which highlighted the extreme care everyone needed to be taking.
"We know that measles is circulating in Northland, and is well and truly here now, so we need everyone in the community to be vigilant around the signs and symptoms and know what to do if they have been exposed or are exhibiting symptoms of measles," she said. The first sign of infection was a high fever followed by a cough, runny nose and sore, red eyes. After three or four days a rash appeared on the face, then spread to the body.
Measles was infectious for five days before the rash appeared until five days after it had gone, and spread very easily.
"It is really important to stay at home until you feel better, and for at least five days after the rash appears," Dr Jackson said.
"If you get a rash then call Healthline on 0800 611-116 for advice and information in the first instance. Some people get very unwell with measles, and if you need to see a doctor please call ahead to your GP or the emergency department so they can prepare for your arrival."
All three new cases had been very unwell, one being admitted to the ICU, while 30 people were in isolation because they are at high risk.
If there was a case of measles at a school, early childhood centre or workplace, the Northland Public Health Unit would request that unimmunised adults and/or children do not attend the facility for up to two weeks if they had been exposed to someone with the infection.
"We are aware of the impact that isolation for a week or more has on family and working lives, but we have to balance this with the need to prevent the further spread of measles, and to protect infants, those most at risk of complications if they contract the disease, and the wider community," Dr Jackson said.
"We do want to thank people for staying in isolation, and for being immunised, because this is really helping stop the spread of measles."
Anyone who was feeling unwell was asked not to visit hospital patients.
One complicating factor at this time of year, she added, was the presence of influenza, which had similar signs and symptoms to measles in its early stages.