People infected with dengue fever could be able to take a test to determine if they are at high risk of death after scientists discovered a way to assess patients' likelihood of progressing to life-threatening disease.
There are up to 400 million cases every year of dengue fever, which spreads from mosquitoes to humans.
About half of the world's population is at risk of infection, and southeast Asian countries in particular face hospitals becoming overwhelmed as patients are admitted for observation.
Doctors have been in the dark about who is most at risk of dying from dengue, but researchers have discovered cell populations indicating whether an infected person is likely to progress to life-threatening severe disease.
The discovery paves the way for patients to be better managed, health systems to save money and for a biomarker test - like a COVID-19 rapid antigen test - to be developed for dengue fever, researchers say.
Melbourne and Indonesia-based researchers made the discovery.
"This will enable doctors to triage patients at an early stage, instead of referring all those diagnosed with dengue virus disease on to hospital," lead researcher and Monash University Diana Hansen said.
"Dengue virus is one of tropical medicine's big challenges as there is no highly effective vaccine and no available treatment for severe cases."
People infected with dengue fever for a second time usually have a more severe reaction.
Scientists looked at that group and found some people had an immune cell response, which reduced the impact of the disease.
"The other group, who didn't have this specific response, have instead an innate immune system response, characterised by a strong inflammatory attack to control the virus," Professor Hansen said.
"Those people get really sick, likely needing hospital care."
It was difficult to pinpoint cell types and their subtypes, but scientists used a technique called "mass cytometry", tagging cell types with rare earth materials to identify specific cell types within complex blood samples.
Researchers are starting on a second clinical study in Indonesia to bring a test for dengue fever patients a step closer.
Dengue fever can cause symptoms of high fever, headache, body aches, rash and nausea, and in rare cases it can lead to death, according to the World Health Organisation.
Non-fatal dengue fever hospital cases each cost an estimated $2085, according to Monash.
The research was published in the Journal of Biomedical Science.
