Vibrio alginolytigus causing shell disease in the mud crab Scylla serrata (Forskal 1775)

Scylla serrata is one of the most cultured mud crab species in the aquaculture which is also susceptible to shell disease. In the present study, Vibrio alginolyticus MF680287.1 caused by shell disease and isolated from infected mud crab S. serrata grow out pond located at Mahendrapalli, Nagapattinam District, Tamil Nadu, India. Further, gross observation of infected mud crab showed shell lesion on the dorsal carapace. The histological examination of normal and diseased mud crab S. serrata carapace and gills was conducted. The shell lesion affected in the S. serrata carapace layers showed loss of membrenous layer and epithilium. The bacterial colonies were abundant in the cuticle. The gill lamellae showed cuticlar damage in the formation of haemocyte nodules and eosinophilic granular cells.