White spot disease (WSD) is one of the most important viral disease for marine shrimp culture, characterised by high and rapid mortality accompanied by gross signs in moribund shrimp of white, initially circular, inclusions or spots in the cuticle, sometimes accompanied by overall red body coloration.
Disease progression is characterised by cessation of shrimp feeding followed within a few days by the appearance of moribund shrimp swimming near the surface at the edge of rearing ponds. Rapid and severe pond mortality follows shortly after the first appearance of gross signs. The causative agent of WSD is white spot syndrome virus (WSSV) or white spot virus (WSV), a double stranded DNA (dsDNA) virus which shows a wide host range among crustaceans and is potentially lethal to most of the commercially cultivated penaeid shrimp species.
For definitive diagnosis and certification of WSSV infection status of broodstock and fry, polymerase chain reaction (PCR) technology is recommended.