Diagnosis of white spot syndrome virus (wssv)‎ among shrimp for the first time in egypt

Abstract EN

A total of 120 shrimps (Penaeus japonicus, penaeus semisulcatus, penaeaus Penaeus Kerathurus, Parapen-aeus Longirostris, Metapenaeus Monoceros and Irachy Penaeus) were colle-cted seasonally (from August, 2006 to August, 2007) from Mediterranean Sea and Red Sea from different geographical areas (Alexandria, Dommiat, Port Said, and Suez).

The visual examination revealed that specimens had a white spot covering the carapace of the shrimp and the cuticles.

The clinical examinations revealed white spot covered the inner aspect of the carapace (subcuticlar tissues).

While the histopathological examination showed intranuclear inclusion bodies with hypertrophy of the nucleus of gills, stomach and subcuticlar tissues.

Polymerase chain reaction (PCR) primers were used to detect naturally infected shrimp.

In addition to high specificity, the one-step and two-steps PCR protocols were found to have sensitivities of 10-100 pg and 100 femtograms, respectively.

These primers (LMT1, LMT2) which gave amplified products of the one step (211bp) and two step (211 bp).

Primer is so sensitive so it helps us in studding the presence of white spot syndrome at area that virus were not previously diagnosed and detection of asymptomatic carrier shrimp with (WSSV), as it helps for detection of very low concentration of the viral DNA.

The two-steps PCR protocol is recommended as a very sensitive and specific alternative protocol to Western blot assay for the detection of WSSV, moreover these primers could be used for survey and diagnosis of the presence of WSSV as it was used to diagnosis of various four geographical isolates.

Anyhow this primer considered the primer of our choice for detection and diagnosis of (WSSV) for the first time in Egypt by using of polymerase chain reaction, while the primer 146F1 / 146R1 and 146F2 / 146R2 were recommended for the heavily infected shrimp samples with the virus and it gave positive result 0.83 % only of the examined samples.

While the primer (LMT1, LMT2) gave 10.8 % positive result with the same shrimp samples in two steps protocol while one step protocol using the same primer gave 5 % positive result.

The positive results were higher in winter and autumn than summer and spring (the positive results in the winter were 23.3 %, autumn was 16.6 % while summer 3.3 %).

The results also were higher in Suez and Damietta than Port Said and Alexandria.