Researchers show how fungal infections can cause TB-like illness, highlighting the need for improved testing to ensure accurate diagnosis and appropriate treatment.
A new study by researchers at MRC Unit The Gambia at the London School of Hygiene & Tropical Medicine has identified important fungal infections among patients with symptoms commonly associated with tuberculosis (TB), but who had tested negative for TB.
Published in PLOS one, the study found evidence of Aspergillus DNA in five samples and Pneumocystis jirovecii DNA in three samples.
The most reported symptoms among participants with positive results were cough and weight loss. These findings represent the first molecular identification of Aspergillus species and Pneumocystis jirovecii in adults in The Gambia and suggest that fungal infections may be present in a small number of patients who present with TB-like symptoms.
Dr Karen Forrest, Head of Clinical Services Department said; “This work adds to the growing list of molecular diagnostic assays that support patient management within our Clinical Services Department.
It has important implications for antimicrobial stewardship, as confirmed fungal infections can help prevent inappropriate antibiotic use, while also strengthening our expanding capacity in molecular diagnostics.
Furthermore, access to anti-fungal agents remains difficult and evidence that fungi are making people ill helps make the case that this should be addressed.” The research focused on three fungal pathogens classified as priority threats by the World Health Organization: Aspergillus species, Histoplasma species, and Pneumocystis jirovecii.
These fungal infections can cause serious illnesses, particularly in areas where access to specialised diagnostic tools is limited. In The Gambia, where tuberculosis remains a significant public health challenge, fungal infections can easily be mistaken for TB because they often present with similar symptoms such as persistent cough, weight loss and shortness of breath.
To better understand whether these infections are present in The Gambia, MRCG researchers developed a new multiplex Polymerization Chain Reaction (PCR) testing tool capable of detecting all three fungal pathogens simultaneously from a single sputum sample.
The molecular assay was designed to support faster and more efficient screening, especially in vulnerable communities. The newly developed test also showed high accuracy and sensitivity, detecting very small amounts of fungal DNA.
This makes it a promising tool for future fungal disease surveillance and could help strengthen diagnostic capacity. Dr Sheikh Jarju, Molecular Diagnostic Laboratory Manager at MRCG at LSHTM said; “These findings are important because they show that these fungal pathogens could be associated with patients that present TB-like symptoms.
This highlights the need to include fungal testing in our diagnostic approach to improve patient care and avoid misdiagnosis.” The team analysed more than 250 stored sputum samples collected from adults between 2017 and 2021.
All participants had symptoms suggestive of tuberculosis and were recruited from the Greater Banjul area, but their samples had tested negative.
While the study confirms the presence of these fungal pathogens, the researchers note that more work is needed to better understand how common these infections are, how they affect patients, and how they should best be managed. Dr. Zackary Salem-Bango, from University of California, Los Angeles and the University of Washington who worked with the MDx lab team, Mary Basiru Njai and Zainab Tambajang, highlighted: “These findings demonstrate the importance of improving access to diagnostic testing and strengthening the case for broader availability of antifungal therapies.
They highlight an important, though often underrecognized role of these pathogens in patients presenting with upper respiratory symptoms in the broader region, while also laying the groundwork for future research in this area.” Overall, the study provides critical early evidence that fungal infections should be considered when assessing patients with symptoms suggestive of TB. Improving awareness and access to testing could help ensure patients receive more accurate diagnoses and better care.
