DAO 47:235-239 (2001)  -  doi:10.3354/dao047235

A non-stop, single-tube, semi-nested PCR technique for grading the severity of white spot syndrome virus infections in Penaeus monodon

Wansika Kiatpathomchai1, Vichai Boonsaeng2,*, Anchalee Tassanakajon3, Chainarong Wongteerasupaya4, Sarawut Jitrapakdee2, Sakol Panyim2

1National Center for Genetic Engineering and Biotechnology, Bangkok 10400, Thailand
2Department of Biochemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
3Department of Biochemistry, Faculty of Science, Chulalongkorn University, Phyathai Road, Bangkok 10330, Thailand
4Department of Biochemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Bangkok 10110, Thailand
*Corresponding author. E-mail:

ABSTRACT: A single-tube, non-stop, semi-nested polymerase chain reaction (PCR) technique was developed for simultaneous detection and severity grading of white spot syndrome virus (WSSV) infections in the black tiger shrimp Penaeus monodon. The test uses 1 sense primer and 3 anti-sense primers that produce up to 3 PCR products (1100, 526 and 250 base pairs [bp]) depending upon the severity of infection. Specifically, heavy infections (≥2 × 104 viral particles) of WSSV produce all 3 fragments, while moderate infections (around 2 × 103 viral particles) produce 2 (526 and 250 bp) and light infections (20 to 200 viral particles) produce 1 (250 bp). In addition, the technique uses internal control primers that yield a shrimp characteristic fragment for non-infected samples and samples with a low quantity of viral target in order to assure integrity and reproducibility of the PCR assays. The non-stop, single-tube, semi-nested PCR technique is simple and convenient and can detect as little as 5 fg WSSV DNA (20 viral particles) in crude extracts of postlarval samples or extracts of pleopods and haemolymph from larger shrimp.


KEY WORDS: White spot syndrome virus · WSSV · Single-tube nested PCR · Penaeus monodon


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