Microplastics as emerging viral vectors: Nexus, mechanisms, ecological implications and health risks

Microplastics (MPs) have emerged as pervasive environmental pollutants with complex implications for ecological and human health. Beyond their chemical toxicity and persistence, MPs act as dynamic microhabitats supporting microbial colonization and viral adsorption. This review provides a comprehensive overview of the physicochemical characteristics, environmental distribution, and degradation pathways of the most common polymeric MPs, including polystyrene, polyethylene, polypropylene, polyvinyl chloride, polyurethane, polyethylene terephthalate, polydimethylsiloxane, and biobased polyesters. Particular attention is given to the virus-microplastic interface, highlighting how MPs serve as vectors that enhance viral persistence, transport, and infectivity. Experimental and metagenomic evidence demonstrates that both enveloped and non-enveloped viruses can adhere to MPs via electrostatic and hydrophobic interactions, often mediated by biofilm and eco-corona formation. These interactions extend viral stability across environmental compartments and can modulate host immune responses, exacerbating infection outcomes. By integrating physicochemical, microbiological, and toxicological perspectives, this review emphasizes that MPs are not inert residues but active ecological interfaces that can reshape viral ecology and increase public-health risks. Future studies combining molecular, environmental, and epidemiological approaches are essential to quantify the real impact of MP-virus interactions on ecosystem balance and infectious-disease dynamics.