The affected shrimp larvae show necrosis of appendages, expanded chromatophores, empty gut, absence of faecal strands and poor feeding. Cumulative mortalities may be very high reaching up to 80% within few days.  

CAUSES  

Bacteria skuch as Vibrio alginolyticus, V. parahaemolyticus and V. anguillarum.  

DIAGNOSIS  

Microscopic demonstration of motile bacteria in the body cavity of moribund shrimp larvae, and confirmed by isolation and identification of pathogenic bacteria by standard microbiological methods.  

PREVENTION  

Maintain good water quality and reduce organic load in the water by increased water exchange.  

CONTROL  

10-15 ppm Ethylene diamine trtra acetic acid (EDTA) to the rearing water.