What is the latest discovered reason for the massive die-off of the shellfish mu

Scientists are investigating a massive die-off of the shellfish mussels in the Clinch River in southeastern United States. Scientists blame this on pollution, habitat loss and climate change. But they suspect the most recent decreases have another cause. Richard, a biologist, and his team believe an infectious disease could be responsible. The team is comparing healthy mussels with dying ones in an attempt to narrow down a list of possible diseases.