4. Discussion
Here we demonstrate that genome material from PCV2 could be detected in a high fraction of mussels in Denmark. PCV2 is a pathogen that has only been detected in pigs and is not considered a threat to public health. The presence of a porcine virus in shellfish does, however, document that virus present in pig slurry has the potential to be accumulated in shellfish which is often consumed raw or lightly cooked. Interestingly, the zoonotic viruses RV-A and HEV were not detected in shellfish in the present study despite that these viruses indeed are present in pig slurry in positive herds and the HEV prevalence in Denmark is more than 90% . Even though RV-A and HEV are considered stable in the environment, PCV2 is one of the most resilient viruses known . Nevertheless, RV has previously been detected in shellfish, and experiments with virus-like particles have shown that RV has the potential to persist in shellfish . The persistence of HEV in soil has been compared to that of HAV. HEV survived for nine weeks at outdoor temperatures and for ten weeks at 37°C whereas HAV persisted for 8 and 13 weeks, respectively .