A world-first study has revealed that household overcrowding and sugary drinks raise the risk of acute rheumatic fever.
It also found a strong link between skin infections and the disease, and doctors are calling it a "major breakthrough".
Porirua GP Dr Katie Shillito sees at least one case of rheumatic fever every year. The serious chronic illness can last a lifetime and result in heart problems, as it did for a recent patient.
"The young person presented with heart failure, which is usually something we see in the elderly. It's upsetting to see young people deal with this."
About 160 New Zealanders deal with rheumatic fever every year. Aotearoa has one of the highest rates in the world, with Māori and Pasifika disproportionately affected
But Epidemiologist Professor Michael Baker hopes their latest discovery will change that.
"Basically if you are living in a crowded house, you are more exposed to the streptococcal bacteria that causes rheumatic fever and starts it off. That's a risk factor for getting these skin infections."
A situation the housing crisis has exacerbated in some areas.
"It wouldn't be uncommon for us to have 15 people in a house," Dr Shillito said.
GPs like College of GPs director Dr Bryan Betty are calling the research a gamechanger because it clearly links skin infections and not just strep throat to rheumatic fever.
"This is incredibly important in the treatment of rheumatic fever in New Zealand, I think a major breakthrough."
Which will impact the way doctors operate work.
"Having to extend our thinking to skin infection as well will change the way we approach prevention of rheumatic fever, which is so so important."
The study also found sugary drinks increase the risk of disease.
"It has to live off something and it loves sugar," said Prof Baker.
The study authors are calling for Health New Zealand to act on the study and investigate whether intensive skin infection treatments can reduce rheumatic fever.
