Context
Tuberculosis (TB) remains one of the leading infectious causes of mortality worldwide, with an estimated nearly 10 million new cases each year and more than one million deaths. However, national prevalence surveys using chest radiography indicate that approximately half of TB cases are missed by current diagnostic methods.
These findings highlight the limitations of passive case detection strategies, which rely on identifying symptomatic patients and therefore fail to detect infected but asymptomatic individuals who may contribute to transmission and the persistence of the disease in the community. Among these patients, diagnostic confirmation tools show sub-optimal performance due to the absence of a reliable biological reference sample and the low bacterial load.
These limitations underline the need to develop new diagnostic tools capable of improving both the triage and confirmation of TB cases. In this context, the development of tests based on biomarkers detectable in non-sputum samples, which are easy to collect and suitable for point-of-care use, represents a promising approach to expand access to diagnosis and strengthen early case detection.
The Fondation Mérieux, in partnership with the Pasteur Institute of Madagascar (IPM), the Pasteur Center of Cameroon (CPC), IPBS/CNRS, and CIRI, is launching the LAM4RO project with the objective of evaluating the diagnostic performance of LipoArabinoMannan detection (a biomarker of the bacterium responsible for the disease) using non-invasive samples.
Objectives
Using air and saliva samples, the project aims to evaluate tools to:
- Improve community-based triage of pulmonary tuberculosis cases, particularly the identification of paucibacillary or subclinical forms in intra-domestic contacts of index cases
- Verify treatment effectiveness
- Conduct a cost-effectiveness analysis of these new approaches
Activities
This study will be implemented by the Pasteur Institute of Madagascar the Pasteur Center of Cameroon (CPC) in their respective countries, in close collaboration with the national tuberculosis control programmes.
In the intervention countries, patients identified as having pulmonary tuberculosis will be recruited from tuberculosis diagnosis and treatment centres located within health facilities: the University Hospital Centre for Care and Public Health of Analakely in Antananarivo and the University Hospital Centre of Fenoarivo in Madagascar, as well as Jamot Hospital in Yaoundé and the Efoulan District Hospital in Cameroon. These patients will be managed according to current national guidelines and will be followed throughout the entire duration of treatment, i.e. six months.
To assess the level of transmission risk from the index case (an individual with active tuberculosis disease) to their close contacts, a household investigation will be conducted to identify potential secondary cases. A full diagnostic assessment will be carried out before the initiation of any treatment, whether curative (for secondary TB cases) or preventive (for individuals at risk).
Household contacts who have not received any treatment will be regularly followed for 18 months and will receive appropriate care, according to national procedures in each country, if tuberculosis is confirmed.
The collection of exhaled breath condensate (EBC) and saliva samples will be performed at TB diagnostic and treatment centres for individuals receiving curative treatment (at treatment initiation), or at home for all other participants during each follow-up visit, in order to detect the presence of LAM in these samples.
The Mérieux Foundation is the research project’s promoter, providing scientific, methodological and organizational support for the project, working closely with national anti-tuberculosis actors. Through this commitment, the Foundation is contributing to the development of diagnostic innovations suitable for contexts with limited resources, and to the sustainable strengthening of health systems.
