Mycobacteria are a group of pathogenic bacteria that cause diseases like leprosy and tuberculosis in humans. Now, a new study finds that mycobacteria are associated with red blood cells at lung infection sites, an interaction that has escaped scientific notice for 140 years since the discovery of the organism causing tuberculosis. The new research, published in Microbiology Spectrum, illuminated the interaction of mycobacteria with red blood cells and its role in lung disease.