Scientists have taken an important step towards developing a blood test that could identify millions of people who unknowingly transmit tuberculosis.
A groundbreaking study has discovered a group of biological markers found at elevated levels among infectious patients.
Researchers hope the findings will pave the way for a simple test that can diagnose and stop the spread of the estimated 10 million cases a year.
Tuberculosis, or TB, is the world’s deadliest infectious disease, killing more than a million people each year, according to data from the World Health Organization.
Scientists at the University of Southampton, working with experts from around the world, carried out the most detailed analysis ever of blood markers for bacterial infection.
The study, published in the Insight Clinical Research Journalused a novel technique that identified a set of six proteins that are highly accurate in identifying tuberculosis.
Lead author Dr Hannah Schiff, a respiratory expert from Southampton, said up to three million cases were missed last year, mainly in developing countries.
He added: “Tuberculosis remains a global catastrophe because our efforts to control the spread are hampered by inadequate testing, which is slow and reliant on specialized equipment and laboratories.
“A third of people who become infected are not diagnosed and remain infectious.
“In our study, we combined a new measurement technique with deep mathematical analysis to identify these six new markers of tuberculosis disease.
“It could lead to a transformative alternative for diagnosing the disease: a simple test that detects proteins in the bloodstream whose levels differ between people with tuberculosis, healthy individuals and those suffering from other respiratory diseases.”
Tuberculosis is transmitted by inhaling small droplets from the coughs or sneezes of infected people, and while it primarily affects the lungs, it can devastate any part of the body.
Cases in the UK rose to around 5,000 last year and are expected to continue rising in 2024, according to the UK Health Security Agency.
The University of Southampton study was carried out with experts from the University of Cape Town in South Africa and the Cayetano Heredia University in Lima, Peru.
It was published on the occasion of World Tuberculosis Day on March 24, which is celebrated to raise awareness and intensify efforts to end the global tuberculosis pandemic.
The study was funded by the UK Medical Research Council and the National Institute for Health and Care Research (NIHR) Southampton Biomedical Research Centre.
The academics who led the research studied proteins found in the blood of people with active tuberculosis in Africa and South America.
They compared the biomarkers with those found in healthy people and patients with lung infections, identifying 118 proteins that differed significantly between the groups.
The experts then narrowed them down to six proteins that they said can be used to distinguish contagious tuberculosis patients from people in good health or with lung conditions.
The findings are a roadmap to developing a TB test that is as simple as the lateral flows used during Covid, said study co-leader Dr Diana Garay-Baquero, also from Southampton.
He added: “The new markers we discovered are really interesting, but the important work now is to turn them into tests that can be used for the millions of people who unknowingly transmit TB.
“As the Covid-19 pandemic confirmed, we ignore highly infectious airborne diseases at our own peril.”