The affected animals show presence of brown to black eroded areas on the body surface and appendages.  

CAUSES  

Bacteria such as Vibrio spp., Aeromonas spp., and Flavobacterium spp., with chitinolytic activity. 
 

Based on gross signs and symptoms and confirmed by isolation and identification of bacteria from the site of infection by standard microbiological methods.  

PREVENTION  

Reduce organic load in water by increased water exchange. Avoid unnecessary handling and overcrowding to minimise chances of injury and infection.  

CONTROL  

Induce moulting by applying 5-10 ppm teaseed cake. Improve water quality by increasing water exchange. If there is no improvement, shrimps may be fed with antibiotic (after ascertaining in-vitro sensitivity of the pathogen) fortified feeds (e.g., 1.5g oxytetracycline /Kg of feed) at 2-10% of the biomass for 10-14 days.