Pancreatic Disease (PD)

Pancreatic Disease (PD) is a viral disease that affects farmed Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and other salmonids. It is caused by the Salmonid alphavirus (SAV), specifically the Salmon pancreas disease virus (SPDV), resulting in severe economic losses in aquaculture due to high mortality rates and reduced growth performance 1. PD was first identified in Scotland in 1976 and later reported in Norway in 1989, and has since been observed in several other countries 1.

Etiology

• Causative Agent: Salmonid alphavirus (SAV), specifically Salmon pancreas disease virus (SPDV) 1.

• Transmission Methods:

  • Seawater currents
  • Human activities
  • Lack of preventive measures between sites 1

Risk Factors

• Environmental factors and farm management practices can influence the spread and impact of PD 2.

Diagnostic Methods

• Clinical Examination: Observation of physical and behavioral symptoms 1 2.

• Laboratory Tests:

  • PCR (Polymerase Chain Reaction)
  • Virus isolation
  • Histopathology 25

Differential Diagnosis

• It is crucial to differentiate PD from diseases with similar symptoms, such as infectious pancreatic necrosis (IPN) and heart and skeletal muscle inflammation (HSMI) 2.

Treatment Options

• Current Treatments: No effective antiviral treatments are available for PD. Management focuses on preventing the spread and mitigating the impact through culling and containment measures 4 6.

• Experimental Treatments: Chemotherapeutics such as povidone-iodine for IPN and benzipyrene for IHN show promise in controlling mortalities, but their practicality in eliminating carrier fish has not been fully evaluated 8.

Preventive Measures

• Biosecurity Protocols:

  • Strict quarantine measures for new stock to prevent the introduction of SAV 1.
  • Regular disinfection of equipment and facilities to minimize the risk of contamination 8.
  • Eradication and avoidance strategies have been successfully applied in Brittany and parts of Denmark and Italy 6.
• Vaccination Strategies:

  • Vaccines against PD are available and have shown effectiveness in reducing infection levels, mortality rates, and viral shedding 1 7.
  • A monovalent vaccine was made commercially available in 2007, and a multivalent vaccine capable of immunizing fish against multiple SPDV strains was introduced in 2015 1.
• Farm Management Practices:

  • Reduced stocking densities to decrease the risk of virus transmission 1.
  • Regular health monitoring and early detection programs to identify and manage outbreaks promptly 1.
  • Implementing all-in/all-out stocking practices to reduce the risk of spreading infections 1.
  • Environmental manipulation, such as elevated water temperature, has been successfully used to control IHN 8.

Real-World Examples

• Notable Outbreaks:

  • Norway (2010): Economic losses were estimated to be 0.72 € per kg in Norwegian salmon production due to high mortality rates, reduced growth, and reduced quality of the finished product 1.
• Response Strategies and Outcomes:

  • Norway: Implementation of a combination of vaccination, improved biosecurity measures, depopulation, closure of poorly managed fish farms, and geographical separation of sites has proven to reduce PD outbreaks 1.
  • In 2008, Norway divided its coastline into two administrative zones separated by a production-free zone of 10 nautical miles and introduced a vaccination program 1.

• Lessons Learned: The importance of early detection, robust biosecurity, and coordinated response efforts in controlling PD outbreaks. However, the effectiveness of some measures, such as the administrative zoning in Norway, has been questioned as the number of PD outbreaks has not significantly reduced 1.

Recent studies on Pancreatic Disease (PD) in salmonids have focused on various aspects of the disease, including its prevention, control, and economic impact. Here are some notable recent research findings:

1. "Effect of vaccines against pancreas disease in farmed Atlantic salmon"
   Authors: Røsæg, M. V., et al.
   Reference: Røsæg, M. V., et al. (2021). Effect of vaccines against pancreas disease in farmed Atlantic salmon. Journal of Fish Diseases, 44(11), 1695-1707.
   Link to study
2. "Prevention and control of viral diseases of salmonids"
   Authors: Wolf, K.
   Reference: Wolf, K. (1976). Prevention and control of viral diseases of salmonids. Journal of the Fisheries Research Board of Canada, 33(4), 1059-1066.
   Link to study

These studies represent advancements in understanding the prevention, control, and economic impact of Pancreatic Disease in various regions, particularly in Norway and other European countries with significant salmon farming industries.

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Last Modified: 2024-07-26

Tags: #PancreaticDisease, #AtlanticSalmon, #RainbowTrout, #Trout, #Salmonoids #Salmon, #Norway, #Chile, #ViralDisease, #Virus