A measles outbreak in Auckland is worsening, with concerns new cases are spreading among plane passengers who travelled with an infected person.
Auckland Regional Public Health Service today said the number of confirmed cases of measles in the city had risen to 39.
Though infections were originally thought to be mainly limited to a school in Oratia, at least nine cases had now been detected in other places including several early childhood centres, it said.
Its medical officer of health Richard Hoskins said a measles-infected person had also entered Auckland on a Thai Airways flight from Bangkok on June 19.
The person was in the early stages of the disease and may have infected fellow passengers, he said.
"All passengers onboard the flight who have not had the right number of measles immunisations for their age, or are unsure, should be vigilant if they suspect they could have measles.
"We will be trying to contact a number of passengers who were sitting close to the passenger with measles."
Measles is potentially serious, with many of those infected so far needing hospital treatment.
Symptoms start as a runny nose, cough, sore eyes and fever, then develop into a raised red rash that starts on the face and moves to cover the rest of the body.
Dr Hoskins said the focus of battling the disease must now be on immunisation rather than containment.
"Given the level of community spread, this is the only option remaining to try to limit the spread of measles. Immunisation is the only way to avoid getting measles."
"These new cases have been in several early childhood centres and we are now working with those centres to quarantine susceptible contacts at home in case they develop measles,"
Those who suspect they have measles have been urged to contact Healthline on 0800 611 116 or a local doctor.