Preliminary Study of Vibrio parahaemolyticus Infection in Shrimp

The present study investigated Vibrio parahaemolyticus infection in shrimp. A total of 150 freshly moribund whiteleg shrimp (Penaeus vannamei) were collected randomly from various fishermen and various locations in Ismailia Governorate, Egypt, and subjected to clinical, postmortem and bacteriological examinations. Following bacteriological analysis, about 22 Vibrio parahaemolyticus isolates were recovered from the examined samples. The infected shrimp exhibited observable clinical signs such as eroded cuticle, brownish to black patches scattered all over the body surface, sloughing of the abdominal appendages, dark and reddish discoloration on pleopods, periopods, carapace and tail area. The most common postmortem findings were whitish musculature, and the hepatopancreas in most cases was either congested or atrophied. On TCBS agar media, V. parahaemolyticus exhibited green or bluish green centered colonies. Microscopically, the recovered isolates were Gram-negative, straight or slightly curved short rods and arranged singly or in chains. All the retrieved isolates were negative for the ONPG test and citrate utilization test, while, positive for oxidase, catalase, lysine decarboxylase, ornithine decarboxylase with alkaline slant, acidic butt for TSI test. Our research emphasizes the critical shrimp health threats posed by V. parahaemolyticus.