Mucosal immunity and microbial homeostasis in healthy and diseased oysters

Oyster populations worldwide suffer severe losses each year due to a number of pathogenic infections. Among the most damaging are two protozoan parasites, Haplosporidium nelsoni (the causative agent of MSX) and Perkinsus marinus (responsible for Dermo disease), both of which have been strongly linked to mass mortality events in the eastern oyster (Crassostrea virginica) along the US coast. These parasites are known to affect the microbial ecology of their hosts, but little is known about how they interact with the mucosal microbiota of oysters. In this study, we investigated the microbial communities present in the pallial mucus of healthy and diseased oysters collected from Oyster Bay, New York.