Isolation ofVibrio parahaemolyticus andVibrio cholerae (Non-O1 and O139) from moribund shrimp (Penaeus monodon) and experimental challenge study against post larvae and juveniles

Outbreak of Vibrio infection was reported from a shrimp farm near Chennai, south India. Both green and yellow Vibrio were isolated from disease outbreak of Penaeus monodon (Milne Edwards) culture farm and biochemically confirmed as Vibrio parahaemolyticus and Vibrio cholerae . Randomly selected V. parahaemolyticus (VP1) and V. cholerae (VC1) were reconfirmed by partial 16S rRNA gene analysis. Both were tested against post larvae and juveniles of P. monodon by bath challenge test and intramuscular injection respectively. The study revealed that VP1 is more virulent than VC1 isolated from same source against P. monodon post larvae and juveniles. Phylogenetic tree based on comparison of partial 16S rRNA gene analysis revealed close relationship of VP1 with other shrimp pathogens like Vibrio harveyi and Vibrio alginolyticus . There might be some close relationship for disease development among all these strains.