What is White Spot Disease?

About White Spot Disease:

• What is it? It is a highly contagious viral infection that affects crustaceans such as prawns, yabbies and crabs.
• When found in high-intensity production areas, such as prawn farms, white spot disease results in the rapid mortality of prawns.
• It has the potential to cause a significant financial impact on the farmed prawn industry.
• Causative Agent:
  • White spot syndrome virus, a large DNA virus assigned as the only member of the genus Whispovirus (family Nimaviridae).
  • The virus is known to occur in fresh, brackish and marine water.
  • All life stages are potentially susceptible, from eggs to broodstock.
  • The virus does not pose a risk to food safety or human health.
• When infected with White Spot Disease, the prawns may,
  • have loose shells;
  • show numerous white spots (0.5–2.0mm in diameter) on the inside surface of the shell;
  • be discoloured pink-to-red;
  • have unusual mortality;
  • come to the edge or water surface;
  • demonstrate unusual swimming patterns;
• How it is spread:
  • It is primarily spread through the movement of infected animals or contaminated water.
  • Birds that feed on and move infected animals can spread the disease. 
  • Marine worms have been implicated as potential carriers of the disease.
• Control:
  • Not moving crustaceans out of the white spot disease-restricted area.
  • Destruction, disposal and decontamination procedures for infected prawn premises.

 

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Q1) What are crustaceans? 

Crustaceans are invertebrate animals in the phylum Arthropoda, subphylum Crustacea, and include the barnacle, crab, crayfish, lobster, shrimp, water flea, and pill bug. Although largely aquatic, a few crustaceans are found in terrestrial habitats. Of the nearly 40,000 aquatic species of crustaceans, only about 10% occur in freshwater habitats.

Source: 100 acres of shrimp farms hit by white spot disease in Nagapattinam, loss estimated in crores