The effect of stress on Atlantic salmon's congenital immunity to IPN

Jan 02, 2013

Stress affects the congenital immune defence system. New doctoral research has revealed how stress can lower the immunity of salmon and increase its susceptibility to viral infection.

Furthermore, stress can increase the propagation of viruses in the fish's and can cause "benign" viruses to turn "pernicious".

Koestan Gadan has studied the consequences of stress on the innate immune defence system of the salmon and how it makes the fish more susceptible to disease. She chose the IPN virus (infectious ) as a model virus for her research. IPN is the cause of considerable losses in Norwegian and has for many years been the most frequently diagnosed disease for this fish.

Up until now, there has been little documentation of how different affect salmon's immune defence system. Changes in temperature and salinity, too much or too little oxygen in the water, pollution and physical handling are all sources of stress for these fish. The same applies to normal physiological changes such as for example smoltification, i.e. the way the fish prepares itself for the transition from fresh to seawater.

Gadan discovered that these stress factors lead to increased production of the in the fish. This increase in the level of cortisol affects the immune system of the fish and weaker immunity makes them more susceptible to infections. The fact that stress can trigger an outbreak of IPN is corroborated by the experiences of many in the field. Gadan's research shows that various environmental factors are stressful to the fish, in turn triggering an increase in the level of cortisol in the blood and causing harm to their congenital system, which is essential to their capacity to ward off .

Gadan also demonstrated that leads to a high level of cortisol over time, which results in increased mortality, a high propagation of viruses and chronic infections. For the first time, she was able to prove that when infected salmon fry were exposed to stress, otherwise benign variants of the IPN virus changed into pathogenic viruses. In other words, stress lowers resistance, increases the "production" of IPN virus in the fish's internal organs and can lead to benign viruses changing into pernicious variants of the virus.

Cand.Scient. Koestan Gadan defended her doctoral research at the Norwegian School of Veterinary Science on 17th December with a thesis entitled: "Studies on stress and innate immunity in relation to infectious pancreatic necrosis virus in Atlantic salmon (Salmo salar L.)"

Explore further: Half-tonne of smuggled ivory seized in Saudi

add to favorites email to friend print save as pdf

Related Stories

Mapping immune genes in salmon

Oct 03, 2011

Morten F. Lukacs' doctoral research at The Norwegian School of Veterinary Science has identified and mapped a group of immune genes that are the key to warding off infectious agents such as viruses and bacteria ...

The secretive immune system of the salmon

Jan 27, 2009

During his doctoral thesis, Erlend Haugarvoll discovered new aspects of the salmon immune system. His research looked at the immune cells in the gills of salmon and at immune responses to vaccination. A special ...

VHS virus infects fish via their gills

May 13, 2009

Viral haemorrhagic septicaemia (VHS) is a highly contagious disease of rainbow trout in fresh water, causing great economic loss in the European trout farming industry. In his doctorate, Bjørn Erik ...

Recommended for you

UN biodiversity meet commits to double funding

Oct 17, 2014

A UN conference on preserving the earth's dwindling resources wrapped up Friday with governments making a firm commitment to double biodiversity aid to developing countries by 2015.

Climate change alters cast of winter birds

Oct 17, 2014

Over the past two decades, the resident communities of birds that attend eastern North America's backyard bird feeders in winter have quietly been remade, most likely as a result of a warming climate.

New data about marsh harrier distribution in Europe

Oct 17, 2014

The use of ringing recoveries —a conventional method used to study bird migration— in combination with more modern techniques such as species distribution modelling and stable isotope analysis helps to ...

User comments : 0