A groundbreaking study in Western Australia's remote Kimberley region has uncovered a silent and concerning health issue: more than half of the local Aboriginal children tested were found to be carrying the potentially deadly Group A Streptococcus bacteria without showing any symptoms.
High Rates of Asymptomatic Carriage Revealed
The research, led by the Wesfarmers Centre of Vaccines and Infectious Diseases at the Telethon Kids Institute, involved testing 234 Aboriginal children aged between 5 and 14 years across four Kimberley communities. The findings were stark. Fifty-six per cent of the children tested positive for Strep A in their throats, yet displayed no signs of illness. This high rate of asymptomatic carriage creates a hidden reservoir for the bacteria, facilitating its silent spread through communities.
Professor Jonathan Carapetis, the study's senior author, emphasised the gravity of the discovery. "We were surprised by the high number of kids who were carrying the bug without knowing it," he stated. This silent transmission is a critical factor in the region's persistently high rates of serious Strep A complications.
A Driving Force Behind Devastating Complications
The Kimberley has some of the highest documented rates of rheumatic heart disease (RHD) in the world, a severe and lifelong heart condition caused by the body's immune response to repeated Strep A infections. The study, published in the Medical Journal of Australia, directly links the widespread asymptomatic carriage to this crisis.
"This high level of carriage is likely a major contributor to the high rates of infection and, consequently, the high rates of rheumatic heart disease we see in the region," explained Professor Carapetis. The bacteria spreads easily through respiratory droplets, and carriers without symptoms can unknowingly infect others, including vulnerable individuals who may develop severe disease.
Urgent Call for New Prevention Strategies
The research team is now advocating for a fundamental shift in public health strategy for the Kimberley. Current approaches often focus on treating symptomatic infections. However, these new findings highlight the need for broader, community-wide prevention measures to tackle the silent spread.
Potential strategies under consideration could include:
- Regular screening programs in high-risk communities to identify carriers.
- Investigating the use of antibiotics in a targeted way to reduce carriage rates and interrupt transmission cycles.
- Accelerated development and deployment of a Strep A vaccine, which Professor Carapetis describes as "the ultimate game-changer" for regions like the Kimberley.
The study was conducted between August 2020 and April 2021, with funding from the National Health and Medical Research Council. It provides the strongest evidence to date that asymptomatic carriage is a key, and previously underappreciated, driver of the Strep A disease burden in remote Aboriginal communities. Health authorities now face the challenge of translating this critical research into actionable policies that can protect children and reduce the devastating impact of rheumatic heart disease.
