Análise quantitativa da carga viral do vírus da Mionecrose infecciosa (IMNV) em diferentes tecidos do camarão marinho Litopenaeus vannamei naturalmente infectado

Abstract

The Pacific white shrimp Litopenaeus vannamei is the most important shrimp species in volume in world aquaculture. However, in recent decades, outbreaks of several diseases, especially viral diseases, were responsible for significant economic losses, threatening the sustainability of shrimp farming worldwide. In 2004, Brazilian shrimp farming was seriously affected by a new disease, caused by the Infectious myonecrosis virus (IMNV). Thus, disease control based on rapid and sensitive pathogen detection methods has become a priority worldwide. In this study, specific quantification method for IMNV was developed using real-time PCR with SYBR Green dye and viral load of the principal target tissues was quantified. A recombinant plasmid that contains the target IMNV sequence was constructed and a linear relationship between plasmid DNA and Ct values (R² = 0.992) was obtained for a range from 108 to 10² copies of IMNV. Viral load of IMNV was different for various tissues, being higher in haemolymph and muscle, followed by pleopods and gill.