Beyond Acute Infection: A Conceptual Framework Linking Zoonotic Bacterial Pathogens to Pulmonary Fibrosis and Lung...

Zoonotic bacterial pathogens are transmitted through various routes and are traditionally associated with acute febrile illnesses that may include pulmonary complications. However, in some survivors, the disease extends beyond the acute phase, leading to the remodeling of pulmonary architecture and driving progressive fibrosis. Although no direct cases have been reported, these pathogens may plausibly predispose injured lungs to carcinogenesis, similar to the well-recognized phenomenon of tuberculosis-associated scar cancer. As such long-term sequelae remain largely overlooked in current clinical practice, their potential contribution to fibrotic and malignant lung disease represents a critical and underexplored knowledge gap. This review proposes a unified mechanistic framework linking acute pathogen-mediated alveolar damage to chronic pulmonary fibrosis and subsequent lung carcinogenesis. We delineate four convergent biological pillars driving this continuum: (1) pathogen persistence establishing chronic Interleukin-1β (IL-1β)/Tumor necrosis factor-α (TNF-α)-mediated inflammation; (2) sustained TGF-β signaling and mechanotransduction driving progressive extracellular matrix remodeling; (3) unresolved reactive oxygen species (ROS) generation causing profound oxidative DNA damage; and (4) aberrant epithelial-mesenchymal transition (EMT) that perpetuates fibrosis and generates pre-malignant cell populations. Together, these sequelae alter lung biomechanics, suppress local immune surveillance, and create a mutagenic environment that is highly conducive to malignant transformation. Although direct epidemiological data is still emerging, the significant mechanistic overlap with idiopathic pulmonary fibrosis (IPF) presents a compelling rationale for shared oncogenic risk. We advocate for a paradigm shift in clinical practice, emphasizing the potential value of long-term surveillance for survivors of severe pulmonary infections. By integrating infectious diseases, pulmonology, and oncology, this framework highlights a neglected cause of fibrotic lung disease and establishes a foundation for future translational research.