Health officials are working to contain a measles outbreak in Christchurch.
Four teenagers at Christchurch Boys' High School have caught the potentially lethal infection, with a fifth case suspected.
The boys are all in isolation at home. Their family and friends have also been told by authorities to stay home
for several days unless they are immunised against the childhood disease.
Canterbury medical officer of health Cheryl Brunton is expecting more cases in the coming days.
"It is an outbreak of a highly contagious disease and we expect that there will be many more cases associated with this outbreak," she told Radio New Zealand.
"Just talking to the cases and their parents that we know about, we know that they've had contact with many other children."
There was a small measles outbreak at a Christchurch pre-school last year, prompting health authorities to remind parents of the importance of ensuring their children were fully immunised against the disease with the measles, mumps, rubella (MMR) vaccination.
Nationally, only 82 per cent of children are fully vaccinated against measles. Rates of 95 per cent are required to prevent outbreaks.
Measles can spread through the air by breathing, coughing and sneezing. It can cause a rash, high fever, a runny nose and sore, watery eyes. It can lead to pneumonia, ear infections, brain damage and can occasionally be fatal.
At the time of last year's outbreak, Canterbury medical officer of health Alistair Humphrey said many people had forgotten the potential severity of the illness.
"Measles is not like chickenpox where pretty much everybody survives. It does kill people."
The incubation period is seven to 18 days and people with the disease can be infectious for up to four days before the first symptoms occur.
- NZPA
