Public health officials are bracing for more cases of measles after 20 students were struck down at an Auckland school.
Westlake Boys High School is telling students who have not been immunised to stay home to avoid the highly infectious illness spreading further.
Auckland Regional Public Health Services (ARPHS) confirmed there have now been 40 cases of measles in Auckland this year, half of which came from the North Shore school.
An ARPHS spokeswoman said they were also seeing a rise in cases spreading within the community.
"We are expecting more cases in Auckland including possibly more from Westlake Boys," she said.
More than 750 people have come into contact with people infected with measles during Auckland's latest outbreak.
ARPHS has contacted these people and asking that anyone who is not immune to quarantine themselves at home.
There have been 58 confirmed measles cases nationwide since the end of December, according to the Ministry of Health.
This includes 30 new cases in Auckland this month alone.
Outside of Auckland, there were 14 cases in the central North Island, three in Wellington and one in the Bay of Plenty since the end of December 2013.
The initial measles outbreak originated in the Philippines, arriving in New Zealand via a hip-hop dance competition in Sydney.
"There is no treatment, and complications can be severe, including hospitalisation," ARPHS health medical officer Richard Hoskins said.
"The only way to prevent measles is to be vaccinated with two doses of the MMR vaccine."
Public health officials are working with Westlake Boys High School to stop the spread.
The school has distributed information in letters to students, their parents, staff and the board of trustees.
Westlake Boys High School declined to talk to the media regarding the outbreak and referred inquiries on to the ARPHS.
In a letter to parents, principal David Ferguson asked that all students who were not immunised to stay at home until March 8.
Parents with children suffering measles symptoms were advised to avoid busy GP waiting rooms and to call a doctor instead.
In 2011, a measles outbreak lead to 600 people being infected nationwide including many who needed hospital care.
Measles symptoms start with a high fever, which in non-immune people develops about 10 days after exposure into the measles virus.
This is followed by one or more of the following: a runny nose, cough, red eyes and small white spots inside the mouth. A red blotchy rash on the neck and face appears three or four days later before spreading to the rest of the body.
One infected person is able to spread the disease to an average of 13 unimmunised people.
Just being in the same room as someone with measles can be enough to catch it.
There are currently measles outbreaks in overseas countries including the Philippines, Australia, Europe, the United Kingdom, Asia, India, and North America.
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