Whanganui parents are being encouraged to immunise their children against the measles following a recent outbreak of the disease in nearby areas.
Measles cases have been confirmed in places around New Zealand, including Levin.
Whanganui District Health Board head paediatrician David Montgomery said measles, one of the most infectious diseases in the world, was a serious illness.
"In 90 per cent of cases, measles causes high fevers, misery, cough, red eyes and rashes, and lasts about a week," Dr Montgomery said.
"In 10 per cent of cases it is more serious. Measles frequently causes pneumonia, croup, diarrhoea, and ear infections. For one in 1000 cases, measles causes encephalitis (brain inflammation), resulting in convulsions, paralysis, permanent brain damage, or death."
In large developed countries, between one and three children out of every 1000 with measles will die, Dr Montgomery said. The mortality rate is higher in children who also have other illnesses, poor immune systems, or are malnourished.
"Measles can be prevented by immunisation, with routine measles immunisation usually given at 15 months and at 4 years of age.
"If anyone is exposed to measles, they should discuss their situation with a health professional as soon as possible. They may require immediate measles vaccination, or they may need hospital treatment with immunoglobin in certain circumstances."
Children under 15-months-old, pregnant women who have not been immunised, and people with low immunity are particularly vulnerable to the disease.
Dr Montgomery strongly advised parents to make sure all immunisations are given on time, and to seek medical advice immediately if their child is exposed to measles and has not had two doses of MMR vaccine.