What is a hallmark of chronic (latent) tuberculosis infection?

Granuloma formation is a hallmark of chronic (latent) tuberculosis infection. In response to tuberculosis bacteria, the immune system creates granulomas, which are small collections of immune cells that form to contain the infection and prevent its spread. These granulomas can remain viable for long periods, allowing the bacteria to persist in a dormant state within the host without causing active disease.

In latent tuberculosis, individuals typically show no symptoms and cannot transmit the infection, as the bacteria are contained. The formation of granulomas is a critical aspect of how the body attempts to control the tuberculosis bacteria, indicating a functioning immune response to the infection.

Other conditions associated with active tuberculosis, such as cavitary lesions, fever, chills, and productive cough, indicate the presence of active disease rather than a latent infection. In latent tuberculosis, none of these symptoms would generally be present, further reinforcing the distinction between latent and active disease.