A unique, 50-year dataset collected by researchers at the Virginia Institute of Marine Science shows that Chesapeake Bay oysters are developing resistance to the pair of diseases—MSX and Dermo—that have helped push populations of these iconic shellfish to one percent of historical levels.
This is despite the increasing prevalence in the Bay of the parasites that are responsible for the two diseases. MSX disease results from an infection by the single-celled protozoan Haplosporidium nelsoni. Dermo is caused by the parasite Perkinsus marinus.
Researchers in VIMS' Shellfish Pathology Laboratory began gathering the data in 1960 as part of their "Spring Imports" project. Each May, the researchers collect about 700 oysters from a disease-free area in the Bay. The current collection site is in the upper reaches of the Rappahannock River near Ross Rock, where low-salinity waters inhibit the parasites that cause MSX and Dermo disease.
The researchers then transport these disease-free oysters to the saltier waters of the York River near VIMS, where they are placed in cages and monitored each month through October for signs of disease.
Read the entire study from VIMS