Download Diseases are naturally occurring in all animals, including

FACTS
Development in the health situation of farmed
salmonids since 1990
Diseases are naturally occurring in all animals, including aquaculture animals.
Although Norwegian aquaculture of salmonids is still to be considered a young and
continuously evolving industry, there is a positive trend with regard to infectious
diseases.
Since 1990 the production of salmonids (salmon and trout) has increased
more than fivefold (tons slaughtered fish), while the number of disease
outbreaks has declined by 25%. This was despite the fact that 2009
figures include new diseases that were unknown in 1990.
The fish farmers are focusing on good fish health in collaboration with the fish health
personnel. Due to the close and fruitful collaboration between the authorities,
scientists and the industry, new diseases have been identified, effective vaccines
have been developed and general hygienic principles for disease prevention have
been implemented.
The most important contagious loss-making diseases
Infectious Salmon Anaemia (ISA): Decline in ISA from 98 outbreaks in 1990 to 10
outbreaks in 2007. There were fewer outbreaks than in 2008, in line with the
estimated annual rate of 10 -15 outbreaks. ISA is a disease that is considered to be
under control, although there is some fluctuation in the number of outbreaks from
one year to the next. This is mainly due to the development of diagnostic tools and
very strict preventive hygiene measures that where applied at the end of the 1980s.
In certain areas vaccines against ISA are used. ISA is considered to be a low level
endemic disease in Norway.
Bacterial Kidney Disease (BKD): Decline in BKD from 77 outbreaks in 1990 to 3
outbreaks in 2009. Strict control of the broodfish has resulted in a dramatic reduction
of incidents. Norway has an approved surveillance programme for BKD.
References
The health situation in farmed
fish in Norway 2007, 2008 and
2009 (National Veterinary
Institute)
Surveillance and control
programs for terrestrial and
aquatic animals in Norway,
Annual report 2006
(National Veterinary Institute)
Annual report 2003
(National Veterinary Institute)
The Animal Health and Disease
Status in Norway 2003
(Norwegian Food Safety
Authority)
Fish Health and Fish diseases;
(Universitetsforlaget AS 1999,
ISBN 82-00-12718-4)
Animal Health Standards in
Norway (Royal Ministry of
Agriculture Norway, 1994)
Fish Health and Fish diseases
(Special issue, Norsk
Veterinærtidsskrift nr 6, 1989)
July 2010 - Norwegian Seafood Federation | www.fhl.no/english | [email protected]
Pancreas Disease (PD): Increase in PD from 5 outbreaks in 1995 to 75 outbreaks in
2009. This represents a 25 % reduction from 2008. PD is a serious viral disease
causing severe losses. PD was diagnosed back in the 1980s, with the majority of
outbreaks along the coast of Western Norway. The fish farmers and authorities have
carried through extensive action plans, reducing the number of outbreaks. Vaccines
have been on the market since autumn 2008, but the availability is still limited.
Heart and Skeleton Muscle Inflammation (HSMI): Increase in HSMI from 54 outbreaks
in 2004 to 139 outbreaks in 2009. HSMI was diagnosed for the first time in 1999 in
Trøndelag and Mid-Norway is still the focal point, but the disease occurs now along
the whole coastline. I 2009 a virus was identified suspected to be causing HSMI. It
appears that all farmed salmon carries the virus. The disease develops over a long
time and occurs often in combination with other diseases.
Furunculosis, Cold-Water Vibriosis and Vibriosis: Decline in furunculosis from 255
outbreaks in 1990 to 0 outbreaks in 2009; cold-water vibriosis from 24 outbreaks in
1990 to 0 outbreaks in 2009; vibriosis from 42 outbreaks in 1990 to 9 outbreaks in
2009.Theses well-known bacterial diseases were considered to be endemic in Norway
at the beginning of the 1990s and are now being controlled by effective vaccines.
Outbreaks of vibriosis in farmed cod were included in the numbers around 2002,this
explains the apparent increase in salmonids.
Infectious Pancreatic Necrosis (IPN): An increase in the number of IPN outbreaks in
from 168 outbreaks in 1990 to 223 outbreaks in 2009 (158 in 2008). IPN is a disease
causing significant losses and farming conditions seem to have an impact. Although
there has been a lot of research, effective preventive measures are still lacking.
Status of other contagious diseases
EHN: Never recorded.
IHN: Never recorded. Norway is a disease-free zone except for a buffer zone along
the border with Russia.
VHS: Outbreaks reported in 1974 and 2007, succeeded by cases within the disease
control zone in both 2008 and 2009. Norway has the status of a disease free zone
except for a buffer zone along the border with Russia and the control zone around
the outbreak in 2007.
Winter ulcer: For many years, winter ulcer has caused severe losses in salmon and
rainbow trout aquaculture. In 2009 the number of reported outbreaks was 36, a
decline from 58 in 2009. The cause is still not fully understood, but Moritella viscosa
is considered to be the most important agent. Vaccines are now available, reducing
the severe losses in infected farms.
Infection with Flavobacterium psychrofilum: A raise from 3 outbreaks in 2004 to 16
in 2009. This systemic infection was diagnosed in salmon, rainbow trout and char.
CMS: 76 outbreaks were reported in 2009, approximately the same as in previous
years (85 in 2007, 75 in 2009).The disease occurs mainly in large salmon ready to be
slaughtered, causing severe losses. The most probable cause is a virus.
Increased knowledge –
new methods
There has been a rapid
development in knowledge and
competence since the start of
modern farming of salmonids.
In the beginning, the
infectious agent for ISA was
still not identified. Diseases
like PD and HSMI were not
diagnosed and the cause was
of course unknown.
•
Today there are effective
vaccines for ISA and PD.
•
Vaccines have reduced
significant health
problems due to winter
ulcer and other bacterial
infections in aquaculture
of salmonids.
•
With regard to HSMI, CMS
and other new diseases,
intensive research is in
progress to identify risk
factors, identify and
characterize the disease
agent, develop diagnostic
tools and vaccines.
There will be a great demand
for research and development
also in the future. One of the
biggest challenges will be
identifying and investigating
new emerging diseases.
Diseases are an important
factor accounting for major
losses in aquaculture. The aim
is to minimise the extent.
None of the diseases
mentioned in the fact sheet
represent a risk for human
health. Diseased fish is
never placed on the market
for human consumption.
“Autumn disease”: Along the coast of Western Norway 25 outbreaks of a new disease
were diagnosed in 2008. There were fewer outbreaks of “autumn disease” in 2009.
The disease is characterized by a prolonged development and high mortality. A
microsporidium is suspected to be the causative agent.
Sea lice: Separate factsheet www.fhl.no/papers
________________________________________________________________________
Examples of general preventive hygiene measures
- Minimum distance between aquaculture farms and to establishments slaughtering
aquaculture animals
- Mandatory health surveillance scheme and daily uptake and recording of dead fish
- Minimum time for fallowing before new smolt is put into the sea
- Health requirements for transport and the placing on the market of live aquaculture
animals
- Disinfection of effluents from slaughterhouses and processing facilities
- Disinfection of intake water in hatcheries
Department
Health and Quality
Gunn Harriet Knutsen
[email protected]
Tlf. 951 47 831
July 2010 - Norwegian Seafood Federation | www.fhl.no/english | [email protected]
July 2010 - Norwegian Seafood Federation | www.fhl.no/english | [email protected]