ISOLATION OF WHITE SPOT SYNDROME VIRUS (WSSV) IN EGYPTIAN SHRIMP USING CONVENTIONAL PCR AND REAL TIME PCR (QPCR) TECHNIQUES

Abstract

Shrimp aquaculture industry threated by high mortality rates and severe economic losses as a result of white spot syndrome virus (WSSV) infection. Early-screening and diagnosis of WSSV are great strategies to decrease the economic losses of the disease on shrimp aquaculture. Therefore, this study was carried out to detect of white WSSV infected shrimp under using two molecular based methods, conventional PCR and qPCR. A total number of 90 samples of red (Aristeus antennatus) and gray (Penaeus latisclcatus) shrimp were collected from Kafr El-Sheikh and Alexandria governorates. External examination of shrimps collected from Kafr El-Sheikh Governorate revealed typical WSSV clinical signs (including loose and easily detached cuticle with appearance of small white spots (3 mm in diameter) and /or larger patches in the external surface of carapace and cephalothorax. The internal examination showed yellowish white, fragile and swollen hepatopancreas and swollen or shrunken lymphoid tissue. Red shrimp showed slightly obvious white spots without any internal lesions. PCR results confirmed the clinical investigation and postmortem (PM) examination and revealed presence of WSSV partial sequences with a size of 190 bp in shrimp samples from Kafr El-Sheikh Governorate. In contrast, samples collected from Alexandria (Borg El-Arab) gave negative results. The result of qPCR confirmed that obtained by conventional PCR and showed that all positive results of WSSV by conventional PCR gave cycle threshold (Ct) values ranged from 34.81 to 40.06. Our results concluded that, WSSV Diseases of shrimp attack shrimp markets of Kafr El-Sheikh Governorate. The conventional PCR and qPCR based methods for isolation and identification of shrimp WSSV, provided accurate results.Key words: WSSV; PCR; qPCR; shrimp