Shell disease is primarily caused by various bacteria that erode the shells of crustaceans.
Many different bacteria are associated with shell disease. Common isolates include species from several Gram-negative genera such as Achromobacter, Acinetobacter, Aeromonas, Plesiomonas, Pseudomonas, and Vibrio. These bacteria are commonly found on the shell surfaces of healthy animals, suggesting that the disease may arise when the crustacean's defenses are compromised or when environmental conditions favor bacterial proliferation.
In essence, while these bacteria are typically present, shell disease develops when there's an imbalance that allows these microorganisms to aggressively attack and degrade the shell.
