A multiplex RT-PCR for simultaneous differentiation of three viral pathogens of penaeid shrimp.

A multiplex reverse transcription polymerase chain reaction (mRT-PCR) was developed and optimized to simultaneously detect 3 viral pathogens of shrimp. Three sets of specific oligonucleotide primers for Taura syndrome virus (TSV), white spot syndrome virus (WSSV) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) were used in the assay. The mRT-PCR DNA products were visualized by gel electrophoresis and consisted of fragments of 231 bp for TSV, 593 bp for WSSV and 356 bp for IHHNV. No specific bands of the same size were amplified from other penaeid shrimp pathogenic viruses or bacteria. As little as 10 pg of TSV RNA and 100 pg of WSSV DNA and IHHNV DNA could be detected using gel electrophoresis. Studies are in progress to further test the specificity and sensitivity of this mRT-PCR method on viral isolates, as well as on clinical samples.