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Sequential method for rapid early diagnosis of white spot syndrome virus in crayfish

Renyu Xue
Qin Zhang
Yuhong Wei
Yuexiong Zhu
Xiaoyan Zhou
Guangli Cao
Chengliang Gong


We developed a practical method to rapidly detect and diagnose latent white spot syndrome virus (WSSV) in infected crayfish that were non-symptomatic for WSSV. This method included a simplified extraction of DNA template, optimized loop-mediated isothermal amplification (LAMP), and final visualization of the product by means of staining with SYBR green I. Using this method, WSSV was detected in crayfish that had been artificially infected in two ways: at 5 h after injection, and 24 h after feeding with tissue from WSSV-infected crayfish (at a stage when such infected crayfish were non-symptomatic), and a thousand times or more dilution can omit fluorescent background when SYBR green I was used. Results indicate that this was a rapid, convenient, and highly sensitive method for the early diagnosis and detection of WSSV. The whole detection procedure took less than one hour to complete.

Key words: White spot syndrome virus, loop-mediated isothermal amplification, SYBR green I, Procambarus clarkii, early diagnosis.