Dynamics of infection in selected tissues of White Spot Syndrome Virus-infected Litopenaeus vannamei

Abstract

White spot syndrome virus (WSSV) remains as the most dreaded pathogen of shrimp aquaculture since its first incidence in China in 1991. WSSV is a double stranded DNA virus belonging to the genus Whispovirus of family Nimaviridae. It has a wide host range and because of its high virulence it can cause 100% mortality in a period of 3-10 days. The target tissues of WSSV are of ectodermal and mesodermal origin, including gills, cuticular epithelium etc. In the present study, tissue level dynamics of white spot syndrome virus infection in P. vannamei was investigated. For this healthy shrimps were challenged with the virus and a time course quantification of virus load in subcuticular epithelium, gills and pleopods was carried out by Real Time PCR against the generated standard curve, which could detect as minimum as 10 copies of virus in tissue samples. In the examined tissues, the viral load increased as time progressed, however, at different degrees. Compared with gill, viral load was higher in the sub-cuticular epithelium followed by the pleopods. The study provides knowledge regarding the infectivity within the early time periods following infection. This baseline information could potentially contribute in the sensitivity determination during development of diagnostic techniques with enhanced sensitivity which can help to manage the disease to a greater extent.