Three cases of mumps have been confirmed in Hawke Bay.
Someone was a high school student at Hastings Boys, while the other two were adults.
Cases have prompted health officials to urge parents to check their children's immunization status.
The Hawke County Health Council spokesperson, Dr Rachel Eyre, said Hastings Boys' high school had worked fast with health officials after diagnosis.
Important health tips have been sent to all parents and carers and to wider school communities.
"Mumps is a very infectious viral infection that spreads from breathing, sneezing and coughing and can spread rapidly among those who are not immune, especially in schools," Eyre saide.
This epidemic was a timely reminder for parents and caregivers to check that their children were up-to-date with vaccinations.
"Know that if your child develops a fever or has swollen glands around the controls or the jaw, stay at home and call your doctor in the first phase or Heathline at 0800 611 116."
Eyre said it is important for people with mumps to stay away from school, work or community concentrations up to five days after the swelling develops or until well, whichever is the earlier.
"If you were born after 1981 and you have never had mumps or mumps / MMR immunization, you should see your family doctor," Eyre said. Two documented doses were required to demonstrate immunity.
"The sooner the free immunization is made, the more likely it is to protect you."
Non-vaccinated adolescents and adults are at greater risk and are more likely to develop severe mumps and complications.
Public health officials had advised the profession of doctor to be on alert for mumps.