GovWire

Contents

1. How to spot white spot disease
2. How white spot disease is spread
3. Preventing and controlling white spot disease
4. Further information on white spot disease
5. Legislation relating to white spot disease
6. Who to contact if you suspect white spot disease

White spot disease (or white spot syndrome virus - WSSV) is a serious viral disease of decapod crustaceans (of the Order Decapoda), all of which are considered susceptible to the virus at all life stages - whether marine, brackish, or freshwater. It is one of the most important diseases affecting shrimp production globally, and in particular can cause high mortality in penaeid shrimp species such as whiteleg shrimp (Penaeus vannamei).

More information on susceptible and vector species can be found here: GB Lists of susceptible and vector species.

In Great Britain the disease status for white spot disease is categorised as undetermined, however, the virus has never been detected in UK populations of crustacea. It is a listed (also referred to as notifiable) disease which you are legally obligated to report immediately to the Fish Health Inspectorate (FHI), Cefas. Fish Health Inspectorate - GOV.UK (www.gov.uk)

It does not affect humans.

How to spot white spot disease

Outbreaks can occur due to environmental stressors such as rapid changes of salinity, the ideal water temperature for White spot disease expression is between 18C and 30C.

Signs of the disease can include:

• shrimp moving towards the pond edge or surface
• reduced appetite
• erratic swimming
• lethargic
• high levels of colour variations
• light white discoloured spots
• high morbidity or mortality

How white spot disease is spread

White spot disease is spread through movements of and contact with infected crustaceans, contaminated water or equipment.

Infected crustaceans can act as carriers and do not have to be sick or diseased to spread the virus.

Preventing and controlling white spot disease

There is no treatment for white spot disease.

Prevention is the best approach to disease control. You can protect your crustacea from serious diseases by being aware of the signs of white spot disease and other serious diseases and checking stock health regularly. Implement good husbandry and biosecurity practices.

Further information on biosecurity measures plans, guidance and templates can be found here: Biosecurity Measure Plans - Information and Templates - GOV.UK (www.gov.uk)

You must be sure any crustaceans introduced are white spot disease free. Do not buy crustacea of unknown origin.

Follow the rules on moving aquatic animals: Aquatic animal health and movements guides - GOV.UK (www.gov.uk)

You must report it to the FHI immediately if you notice or become aware of crustaceans showing any of the signs of white spot disease. The FHI will investigate and apply disease control measures if required.

Further information on white spot disease

World Organisation for Animal Health (WOAH) Aquatic Manual chapter White spot syndrome virus.

Legislation relating to white spot disease

The Aquatic Animal Health (England and Wales) Regulations 2009

The listed diseases are in Regulation 1251/2008 as amended by the Animals, Aquatic Animal Health, Invasive Alien Species, Plant Propagating Material and Seeds (Amendment) (EU Exit) Regulations 2020, at Chapter 2, Annex 1A and Schedule 1 of The Aquatic Animal Health (England and Wales) Regulations 2009.

Who to contact if you suspect white spot disease

If you suspect or know of a listed disease of fish or shellfish in England and Wales, you must report it immediately to the Fish Health Inspectorate (FHI), Cefas. You must also inform the FHI immediately if you know or suspect that increased mortality has occurred.

Under the Aquatic Animal Health (England and Wales) Regulations 2009 it is a legal obligation to report suspicion of white spot disease in any farmed or wild shellfish to the FHI. It is an offence under the Regulations to fail to inform the FHI of suspicion of white spot disease.

• Email:?fhi@cefas.gov.uk
• Telephone: 01305 206700- Monday to Thursday - 9:00 am to 5:00 pm, Friday 9:00 am to 4:30 pm
• For emergencies out of hours telephone: 01305 206630