Bacterial White Patch Disease caused by Bacillus cereus

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Bacterial White Patch Disease caused by Bacillus cereus

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The Litopenaeus vannamei aquaculture industry in India has faced a severe problem with a new type of bacterial diseases namely White Patch Disease (WPD). In day by day the disease causes gradual mortalities and once the severe disease outbreak comes, the farm faced high mortality of more than 70 % within 3 to 5 days. The major symptoms are white opaque patches in the carapace, necrosis, whitish blue coloration, loss of appetite and pale white muscles. Infected shrimp was subjected Gram staining found that the rod shaped bacteria was the pathogen. Genomic identification also confirmed that the causative pathogen is Bacillus cereus WPD (GenBank No: KF673474.1). Also B. cereus WPD had the ability of higher virulence factors including hemolytic activity, lipase activity and high mortality to the L. vannamei and Artemia when challenging at the rate of 104 to 108 cfu/ml.

–          A new type of bacterial diseases namely White Patch Disease (WPD) was identified in L. vannamei culture

–          The causative pathogen is gram positive Bacillus cereus identified by 16S rRNA sequencing.

–          The farm faced high mortality of approximately 70 % within 3 to 5 days.

Dr. Amerneni Ravi Kumar (raviaqua@rediffmail.com) posted these gram-stained, wet-mounts of Bacillus cereus to the pictures section of The Shrimp List.  They were isolated from shrimp with white tail muscles.

Source: Sciencedirect. S. Velmurugana, 1, P. Palanikumara, 1, P. Velayuthania, M.B.S. Donioa, M. Michael Babua, C. Lelina, S. Sudhakarb, T. Citarasua.

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