White spot syndrome virus WSSV  in Shrimp

White Spot Disease (WSD) casts a shadow over shrimp farming operations worldwide, posing significant challenges to productivity and profitability. This disease, caused by the White Spot Syndrome Virus (WSSV), threatens shrimp production at all life stages and can lead to devastating mortality rates if left unchecked. In this comprehensive guide, we delve into the intricacies of WSD, exploring its causative agent, modes of transmission, clinical symptoms, and actionable prevention strategies.

Understanding White Spot Disease (WSD)

WSD is a formidable adversary in the realm of shrimp farming, affecting a wide range of crustaceans, including popular species such as Pacific white leg shrimp (vannamei). Afflicted shrimp exhibit an array of clinical symptoms, including anorexia, lethargy, reddish discolouration, and the hallmark circular white spots on the carapace and other exoskeletal parts. Mortality rates can skyrocket to 80-90% within a matter of days, necessitating emergency harvests to mitigate losses.

White Spot Syndrome Virus (WSSV)

White Spot Syndrome Virus (WSSV), is a rod-shaped double-stranded DNA virus notorious for its devastating impact on shrimp populations. WSSV is transmitted both horizontally and vertically, spreading through oral ingestion, waterborne transmission, and carrier organisms. Crustaceans, including crabs, copepods, and squilla, serve as hosts or carriers, facilitating the spread of WSSV in aquatic environments.

Modes of Transmission

Horizontal transmission of WSSV occurs primarily through ingestion of infected organisms or contact with carrier animals, with the virus capable of surviving in water and soil for extended periods. Poor pond management practices, inadequate drying periods between culture cycles, and stocking of infected larvae contribute to the likelihood of WSSV infection. Vertical transmission from infected brooders to larvae further perpetuates the cycle of disease.

Prevention Strategies

Mitigating the risk of WSD requires a multifaceted approach encompassing stringent biosecurity measures, proper pond preparation, and adoption of best management practices (BMP). Key prevention strategies include:

  1. Thorough pond preparation ensures the proper drying and application of lime, to eliminate WSSV reservoirs in wet soil.
  2. Stocking of post larvae (PL) of at least PL15 stage, selected through stress tests and PCR testing to ensure WSSV negativity.
  3. Implementation of strict biosecurity measures, including reservoir ponds, bird and crab fencing, and sanitation protocols.
  4. Best Management Practices for maintaining optimal water quality, feed usage, and shrimp health through regular monitoring.
  5. Consideration of probiotics and immunostimulants as adjunctive measures, while exercising caution against the indiscriminate use of chemicals.
Conclusion

In the battle against White Spot Disease, knowledge is power. By understanding the causes, symptoms, and prevention strategies outlined in this guide, shrimp farmers can fortify their defenses against WSD and safeguard the health and productivity of their shrimp stocks. Through proactive measures and diligent adherence to best practices, we can mitigate the impact of WSD and pave the way for a sustainable future in shrimp farming.

Armis ensure the prevention of EHP entry or re-entry into farms by implementing stringent biosecurity measures: Conduct thorough PL and broodstock inspections, enforce quarantine measures, and ensure disinfection of incoming water and pond bottoms between crop cycles.

Armis as a solution for functional feed. Given that EHP infects the gut, addressing it effectively can be achieved by integrating Armis into the feed regimen.