Inflammation, immune dysfunction and viral disease: could micro- and nanoplastics be the missing link?

The ubiquity of Micro- and nanoplastics (MP/NPs) pollution has reached a critical point, with these synthetic particles now detected across all environmental compartments and within human systemic circulation. As the global landscape faces an escalating frequency of viral outbreaks, there is an urgent need to understand how persistent xenobiotics modulate host-pathogen dynamics. This review posits that MP/NPs represent the “missing link” between environmental degradation and the rising severity of infectious diseases. By synthesizing recent toxicological and immunological data, here we delineate how MP/NPs function as biological “Trojan horses.” By forming a complex “chemical corona,” MP/NPs stabilize viral particles, enhancing their persistence and facilitating their translocation across compromised mucosal barriers. At the cellular level, internalized MP/NPs trigger chronic immune dysfunction by overactivating the NLRP3 inflammasome and inducing mitochondrial oxidative stress, while paradoxically suppressing essential antiviral signaling pathways, such as the type I interferon response. Furthermore, we highlight novel mechanisms of MP/NPs-mediated viral dissemination via migrasomes and hypothesize their potential to exacerbate chronic viral infections like HIV. Our findings redefine MP/NPs not merely as inert contaminants but as potent immunological modifiers that heighten host susceptibility and alter viral pathogenicity. This paradigm shift is vital for advancing One Health strategies and refining risk assessments in an increasingly plastic-polluted world.