Analysis of viral load between different tissues and rate of progression of white spot syndrome virus (WSSV) inPenaeus monodon

Abstract

At present the most common and most devastating disease of shrimp is caused by the white spot syndrome virus (WSSV), which has spread throughout the world mainly by different species of crustaceans carrying the virus. After experimental injection of Penaeus monodon with a known copy number of WSSV in the abdominal muscle, the rate of viral progression in different tissues at 12, 24, 36 and 48 hpi (hours post infection) was assessed using quantitative real-time PCR. At 12 hpi the viral load was highest in haemocytes followed by pleopod, muscle and gills whereas at 48 hpi, the gills, the main target of WSSV, showed the highest viral load followed by pleopod, muscle and haemocytes. Viral copy number in the haemocytes was the lowest beyond 12 hpi indicating a remarkable reduction in the rate of viral replication in haemocytes compared with other tissues. The viral load in haemocytes, though increased again beyond 36 hpi, never surpassed the load in the other tissues. The real-time PCR assay with its high sensitivity and wide dynamic range make it ideal for detecting low-level WSSV infections that can occur in apparently healthy P. monodon.

Temporal and spatial dynamics of white spot syndrome virus in the Chinese mitten crab, Eriocheir sinensis

“…White spot syndrome virus amount among crabs, crayfish, freshwater prawns, spiny lobster and clawed lobsters was also highly variable suggesting that relative susceptibility varies between crustacean taxa (Jeswin et al . ). It is important to point out that data on WSSV load in traded commodities (e.g.…”

“…; Jang, Meng, Seo, Cho, Kim, Ayyaru & Kim ; Jeswin et al . ; Sun et al . ); although, to date, there was no related report about the economic Chinese mitten crab E. sinensis , which have been proven to be highly susceptible to WSSV infection (Bateman et al .…”

“…As to moribund P. stylirostris , Litopenaeus vannamei and P. monodon juveniles, the viral load showed an average of 3.0 × 10 7 , 1.6 × 10 6 and 2.1 × 10 3 copies ng −1 DNA in the pleopods respectively (Durand & Lightner ; Jeswin et al . ; Sun et al . ), whereas in E. sinensis , WSSV amount achieved 1.23 × 10 8 copies ng −1 DNA at 144 hpi.…”

“…Because of the lack of continuous cell cultures for crustaceans, the quantification of WSSV particles has not been possible. Quantitative real‐time PCR (qPCR) allows the determination of the number of copies of a DNA segment in a particular tissue sample and has been applied in WSSV quantitative detection (Durand & Lightner ; Sritunyalucksana, Srisala, McColl, Nielsen & Flegel ; Jeswin, Anju, Chacko Thomas, Porinchu Paulton & Kizhakedath ; Mendoza‐Cano & Sánchez‐Paz ; Sun, Li & Xiang ). However, so far there has been no report to apply this robust assay in WSSV detection from the crab E. sinensis and systematically study the temporal and spatial dynamics of WSSV amount in this commercially important crab.…”

Development of In situ hybridization and real‐time PCR assays for the detection of Hepatospora eriocheir, a microsporidian pathogen in the Chinese mitten crab Eriocheir sinensis

“…In addition, increased pathogen replication is affected by stressors including high stocking density and environmental parameters (Jeswin et al . ; Ding et al . ).…”