Detection of Taura Syndrome Virus in cultured Litopenaeus vannamei in Iran by histopathology and polymerase chain reaction

Objective: The reason behind the importation of Litopenaeus vannamei to Iran was disease susceptibility of indigenous species such as Penaeus indicus to WSSV. The first experimental movement of L. vannamei to Iran began in the late 2004 for research purpose by Iranian Fisheries Research Organization. During two years (2004-2006) research conducted by IFRO on their potential for aquaculture, the government approved to use this species instead of P. indicus. The purpose of this paper is to describe the occurrence of TSV in farmed L. vannamei in Iran. Method & Materials: Suspected shrimps were procured from farms culturing L. vannamei in Boushehr Province in the south of Iran. The sample were collected and examined for clinical signs and then fixed in Davidson fixative for histopathology. Many samples were also preserved in 95% ethyl alcohol for PCR method. To study TSV infection by PCR, we used two commercial PCR kits, called IQ2000TM WIT Multivir System and IQ2000TM TSV Detection and Prevention System from Farming IntelliGene Tech. Corp., Taiwan. Results & Conclusion: The gross sign of moribund shrimp was red discoloration in body surface as well as in tail and appendage. The gut of shrimp was empty and in the close observation many necrotic areas were seen in the tail and appendage. The histopathological examination showed characteristic acute form of TSV such as multifocal necrosis in the cuticular epithelium and often in the subcuticular connective tissue and at time in the underlying striated muscles. Multiple spheroid inclusion bodies were scattered the affected area of cuticle tissue. These spherical inclusion bodies in H&E staining gave eosinophilic to basophilic color as well as in hind gut and stomach. The samples also examined by PCR kits for TSV infection with the respective RNA extracts. The PCR results showed the samples were positive to infection with TSV.

کلیدواژه ها:

Taura syndrome virus ، Litopenaeus vannamei ، Detection ، Shrimp ، Iran