Environmental Risks of Plastisphere Viruses: Carrier Effects, Virus–Host Interactions, and Mechanisms of Resistance Dissemination

Once microplastics enter environmental systems, they rapidly develop plastisphere biofilms that provide a distinct interface for viral attachment, enrichment, and transport. Compared with bacterial communities in the plastisphere, the occurrence and ecological roles of viruses have received much less systematic attention. This review therefore examines the basis of viral enrichment in the plastisphere, the characteristics of plastisphere viral communities, and their major environmental risks. Current evidence suggests that plastisphere viruses may contribute to pathogen transmission, resistance dissemination, and ecological functional disturbance through a progression from surface retention to virus-host interaction within biofilms. However, most available evidence still relies on metagenomic association analyses, whereas direct validation through infection assays, host tracking, and functional experiments remains limited.