Pathology and Molecular Diagnosis of White Spot Syndrome Virus (WSSV) among Vannamei Shrimp in Egypt

Abstract

White spot syndrome virus (WSSV) is poorly understood as no available information regarding its possible spread among shrimp cultured in Egypt. Therefore, this work aimed to diagnose WSSV in cultured shrimp by pathological examination and molecular based methods (PCR). A total of 20 shrimp samples were collected from shrimp farms in Egypt. Diseased shrimps exhibited sudden mass mortalities and showed loose cuticle with numerous scattered melanised visible white spots on external surface. Histopathological examination revealed nuclear hypertrophy with eosinophilic (Cowdry A inclusion) to basophilic inclusions in the internal organs (connective tissues). Spheroids were observed in the lymphoid tissues. Cell encapsulation was accompanied by pyknosis and karyorrhexis. PCR results with primers specific for WSSV gave a predicted amplified product at 414 bp fragments using agarose gel electrophoresis. The present findings request more investigations for White spot syndrome virus disease among shrimp in Egyptian farms and recommend the establishment of preventive measures against this virus in Egypt.