White spot syndrome (WSS) is a viral infection of penaeid shrimp. The disease is highly lethal and contagious, killing shrimp quickly. Outbreaks of this disease have wiped out the entire populations of many shrimp farms within a few days, in places throughout the world. White spot syndrome virus (WSSV) is the lone virus of the genus Whispovirus (white spot), which is the only genus in the family Nimaviridae. It is responsible for causing white spot syndrome in a wide range of crustacean hosts.