University of Otago Global Health Institute researcher Prof Philip Hill is part of an international team working on the "groundbreaking" new study, which could potentially change the way the world tackles the disease.
The Asymptomatic Tb Transmission in Indonesia and South Africa Study recently received about $NZ34 million from the Gates Foundation and the Wellcome Trust, to address the critical gap in understanding transmission.
Prof Hill said asymptomatic Tb was one of the most complex issues hindering progress in the fight against the infection.
His role will be to co-lead the project’s epidemiological research component with Africa Health Research Institute (AHRI) and University of Alabama Birmingham researcher Prof Emily Wong.
For the study, he said researchers from AHRI and Padjadjaran University would recruit 90,000 adult volunteers from households with children, to take part in community-based Tb screening in South Africa and Indonesia.
Among volunteering households, children would be tested for immune responses to Mycobacterium tuberculosis complex — the bacteria that cause Tb — enabling the study team to assess whether asymptomatic Tb in adults was contributing to transmission within families.
Prof Hill said Tb was essentially uncontrolled in high-burden countries.
"When we do surveys in the community, we find that half the cases that are diagnosed, do not have symptoms of Tb.
"There is increasing evidence that these people, who don’t tend to go to the health facility unless they start to feel sick, are transmitting the pathogen to others.
"This study is trying to quantify the amount of Tb transmission from these asymptomatic people."
The project would also integrate innovative diagnostics and biological investigations.
These include testing of exhaled breath and biobanking of blood samples to support cutting-edge research to help grow understanding about asymptomatic Tb, and to detect the condition earlier.
Mathematical modelling studies would extrapolate the findings to the global situation, he said.
Prof Wong said at present, the disease was only detected when people sought care at clinics and hospitals when they felt sick.
"If the study shows that people who feel well have infectious asymptomatic Tb, then we might have to flip the paradigm of global Tb control away from clinics and screen people in their communities."
