There have been two diagnosed cases of rheumatic fever in Rotorua so far this year and those working closest with families affected want to see more people visiting the doctor for throat swabs.
In the past, the Lakes District Health Board has had a high incidence of rheumatic fever and has been delivering a prevention programme since 2012.
Between 2009 and 2012 the health board had 7.8 cases per 100,000 people, in 2017 that rate had dropped to 3.8 cases.
A Lakes District Health Board spokeswoman said the cases in the Lakes DHB area were spread over all seasons, not just in winter.
Māori and Pacific children and young adults (aged 4 to 19) have the highest rates of rheumatic fever and it is unevenly distributed in New Zealand, with most cases recorded in the North Island.
Toi Te Ora Public Health medical officer of health Dr Neil de Wet said rheumatic fever was a serious disease and could cause permanent heart damage.
Strep throat, a throat infection caused by a Group A Streptococcus (GAS) bacteria, can lead to rheumatic fever if left untreated.
"If your child has a sore throat it's important that they see a doctor or nurse to get it checked in case they have a strep throat that needs treatment with antibiotics," de Wet said.
Rheumatic fever can cause the heart, joints, brain and skin to become inflamed and swollen.
While the symptoms may disappear on their own, the inflammation can cause rheumatic heart disease, where there is scarring of the heart valves.