You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
This week, the Canterbury District Health Board advised two more cases of measles had now been confirmed, one in Nelson and the other in Christchurch.
They were linked to three cases notified late last week, reported in Queenstown, Wanaka and Christchurch.
Four of the five people, who range in age from 13 months to 46 years, had not been immunised.
Investigations were continuing as to whether the fifth person, in Nelson, had been.
Given the geographical spread of those affected, Public Health officials across the South Island have urged anyone with symptoms suggestive of measles to phone for health advice in the first instance.
Canterbury DHB medical officer of health Dr Ramon Pink said it was important people who thought they might have symptoms did not visit GP rooms or after-hours clinics.
''Instead, please phone your family doctor/general practice team first for advice, to limit further exposure to other people.''
Measles was a notifiable, highly infectious viral illness, spread through coughing and sneezing.
Those who had not been immunised and exposed to measles first developed a respiratory type of illness with dry cough, runny nose, temperature over 38.5degC and would feel ''very unwell'', Dr Pink said.
A rash would present on the fourth or fifth day of the illness, usually spreading from the face to the chest and arms.
Public Health staff had not been able to trace the source of the outbreak and said they might have had a relatively mild illness and were now fully recovered.
However, they had determined the first three confirmed cases all visited Queenstown Airport on March 22 and those cases - and others infected since - had travelled on domestic flights within the South Island.
They may also have visited supermarkets, restaurants, camping grounds, recreational facilities and other public spaces.
Investigations were continuing and ''close contacts'' were being identified for follow-up.
Dr Pink said people were infectious from five days before the rash appeared to five days after it started and ''should stay in isolation during this time''.
''This means staying home from school or work and having no contact with unimmunised people.''