Infectious Pancreatic Necrosis (IPN)

• Abdominal Swelling: Distended abdomen due to fluid accumulation 14.
• Pale Gills: Typically pale gills in affected fish 4.
• Hemorrhages: Bleeding in internal organs, including ventral areas and fins 4.
• Darkening of the Skin: Affected fish may exhibit darkened coloration 14.

• Lethargy: Fish lying still on the bottom of tanks or ponds 4.
• Loss of Appetite: Anorexia and significant weight loss 2.
• Abnormal Swimming Patterns: Fish may swim in a corkscrew or spiral motion 14.

Early Stages: Sudden and progressive increase in mortality at first feeding of fry, particularly in faster-growing individuals 4.

Advanced Stages: Pronounced physical symptoms such as abdominal swelling, hemorrhages, and darkened skin, leading to high mortality rates of 10% to 90% 14.

Impact on Fish Health: IPN severely compromises immune function and overall vitality, making fish susceptible to secondary infections 3.

Causative Agent: Infectious Pancreatic Necrosis Virus (IPNV), an Aquabirnavirus 12.

Transmission Methods:

• Horizontal Transmission: Spread through infected water and equipment 1.
• Vertical Transmission: From parent to progeny through infected eggs 1.

Environmental Factors: Outbreaks can occur at water temperatures between 4°C and 18°C, with stress factors such as high stocking densities and fluctuations in water temperature and salinity increasing susceptibility 4.

Farm Management Practices: Movement of equipment from infected sites and improper handling of mortalities and wastes can facilitate the spread of the virus 1.

Clinical Examination: Observation of physical and behavioral symptoms 12.

Laboratory Tests:

• PCR (Polymerase Chain Reaction): Detects IPNV genetic material in fish tissues 3.
• Virus Isolation: Culturing the virus in tissue culture 1.
• ELISA and Antibody Neutralization: For identification of the virus 1.

Biosecurity Protocols:

• Testing of broodstock and destruction of eggs from infected parents 1.
• Avoiding movement of equipment from infected sites 1.

Vaccination Strategies: A provisional marketing authorization has been granted for a vaccine against IPN 1.

Farm Management Practices:

• Maintaining high water quality and low stocking density 2.
• Implementing strict protocols regarding movement, water sources, and stock replacement 2.

• Scotland: High prevalence of IPNV infection in farmed Atlantic salmon in seawater, with increasing incidence in freshwater salmon farms in recent years 1.
• Norway: Considerable mortalities from IPN in Atlantic salmon post-smolts 1.

• IPN is considered one of the major fish disease problems in Canada 6.

IPN Incidence in Norway:

• IPN has been a significant problem in Norwegian salmon farming, particularly affecting post-smolts after transfer to sea water 35.
• In recent years, the prevalence of IPNV infection has been very high in farmed Atlantic salmon in sea water 3.

Geographical Spread:

• IPN is widespread in Norwegian salmon farms, affecting both freshwater and seawater environments 35.

Economic Impact:

• IPN has caused considerable mortalities in Atlantic salmon post-smolts, leading to significant economic losses for the Norwegian salmon industry 35.

Treatment & Management:

• A provisional marketing authorization has been granted for a vaccine against IPN in Norway 3
• Strict biosecurity measures are implemented to prevent the spread of the virus between farms 3

IPN Incidence in Scotland:

• The prevalence of IPNV infection is very high in farmed Atlantic salmon in sea water 3
• In freshwater salmon farms, the prevalence of infection and incidence of disease is lower but has increased in recent years 3

Geographical Spread:

• IPN affects salmon farms across Scotland, in both freshwater and marine environments 3