Exploring the association between viruses, microplastics and biofilms, and the impact of exposure to an in vitro digestion model

Abstract

Human ingestion of and exposure to microplastics (MPs) are increasing due to the vast spread of MPs in various ecosystems and plastic particles existing all around us. MPs are easily colonized by both human pathogenic and apathogenic microorganisms in the environment, creating small microbial communities called plastispheres. The body of knowledge regarding food poisoning with ingestion of different planktonic bacteria, viruses etc. is large. However, there is lacking knowledge on what happens with the microorganisms in plastispheres when humans ingest them, and whether this provides a pathway for food- and waterborne infection and thereby disease. Therefore, the importance to investigate the consequences ingestion of plastispheres might have on human health is significant. My project focused on how Tulane virus (TV) and bovine coronavirus (BCoV) would attach to plastic pieces both with and without biofilm, and if they were incorporated in biofilms created by environmental microorganisms found in river water on plastic pieces. In addition, we have investigated the viral stability in the plastispheres when being sent through an in vitro digestion model, by executing RT-qPCR and RT-ddPCR. Results show that both viruses attach to plastic, become a part of the plastisphere, and have been found throughout the digestion model and in biofilm sediments after finished digestion. Finally, because of the many challenges faced underway during this work, this thesis provides valuable information for others who might want to carry out experiments with viruses, plastispheres, and the in vitro digestion model.