What’s killing mussels across Scandinavia?

A series of mass mortality events (MMEs) are currently wiping out freshwater mussels across Norway and Sweden. These events appear to be caused by an infectious disease. In brief, this is because the mortality appears downstream of locations in rivers where mussels have been transplanted for restoration programmes, indicating the potential transmission of some etiological agent during restoration attempts. To address these MMEs, I have bought together a team of interdisciplinary scientists with experience in a diverse range of fields, from histology to computer science.

The general sampling design we have undertaken is to sample both sick and healthy mussels from the impacted area and healthy mussels from a non-impacted area. We also sample water from both impacted and non-impacted areas. We have been searching these samples for any signals of potential pathogens. So far, we have completed several studies, including metagenomics, histology, hemocytology, experimental infections, and bacteriology. This work has revealed several potential pathogens which require further investigation. Next steps involve electron microscopy and viral metagenomics to gain a better understanding of the identity of potential drivers. Watch this space!