COST OF DISEASE TO UK TROUT FARMERS

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COST OF DISEASE TO UK TROUT FARMERS
Robert Hughes, Trout Technical Sales
Manager Skretting (U.K.)

• The Carp Society, Lechlade
• Tuesday, 19th February 2008

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COSTS WHATS INCLUDED

• Mortalities
• Rejections at point of sale e.g. R.M.S.
• Loss of performance F.C.R. and S.G.R.
• Treatments
• Vaccination and other preventative potions
• Exposure programmes i.e. P.K.D.
• Legislative losses e.g. B.K.D.
• Fallowing/disinfection costs
• Mortality / rejection disposal costs
• Consequential loss

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COST REPORTING - DIFFICULTIES

• No farm communication
• Over reporting
• Under reporting
• Diagnosis
• Mortality valuation actual or potential?
• Multiple disease incidences proportioning blame
• Unexplained (black) losses blame?

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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WHITE SPOT

• Potential huge mortalities
• Reduced severity on most farms 2007(environmental
  conditions)
• Becoming a problem on cage farms now.
• Incidence and severity increased since malachite
  green withdrawal
• Farms using multiple treatments of formalin
  and/or salt (often ineffective).
• We need a more effective treatment.
• 2008 likely to be very different. No. 1 in 2006
  (1.5million cost to industry)

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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PROLIFERATIVE KIDNEY DISEASE (P.K.D.)

• Major problem July Sept
• Historically south of England but now in all
  areas of UK
• 2 new sites 2007
• Exposure programmes successful but expensive.
• No licensed treatments
• Some exciting trials on going with P.K.D.
  resistant strains.

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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ENTERIC REDMOUTH (E.R.M.)

• Viirtually endemic on grower farms
• Many isolates are proving to be the EX5 strain
• However , new Relera vaccine now being used, so
  we can expect improved protection.
• Sulfatrim not available now, so Branzil is being
  used under a Special Import Certificate as the
  only treatment.

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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RAINBOW TROUT FRY SYNDROME(R.T.F.S.)

• Virtually endemic.
• Slightly increased incidence 2007
• Still becoming more prevalent in larger fish.
• No apparent resistance to Florfenicol yet, but it
  could happen.
• No new antibiotics in the pipeline
• Work on vaccines ongoing
• Still affecting immersion vaccination efficacy
  e.g. ERM

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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Red Mark Syndrome (R.M.S.)

• First reported UK 2004
• Increased incidence and severity on some farms
  this year. Some huge rejections just recently
  (40 ).
• 49 farms now affected representing nearly 70 of
  the industry, based on tonnage.
• Becoming a major problem in the rainbow trout
  restocking sector and some brown trout in
  Scotland
• Now in salt water
• Antibiotic treatments difficult due to withdrawal
  periods (often prevalent in near market size
  fish).
• Skretting / Industry funded research ongoing at
  University of Stirling.
• Transmission trial work carried out at
  C.E.F.A.S., Weymouth.
• Other work carried out at Aberdeen and Heriot Watt

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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RAINBOW TROUT GASTRO ENTERITIS (R.T.G.E.)

• First reported UK 200
• Probably affecting 30-40 of the industry (based
  on tonnes produced)
• 2007 not quite as bad as 2006 (environmental
  conditions), but outbreaks a month earlier than
  2006 in Scotland
• Farmers taking preventative measures to control
  the problem
• Salt and Alterna diets effective but sometimes
  only suppress and not eliminate the condition.
• Antibiotic treatments difficult due to the
  withdrawal periods on often near market size fish.

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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BACTERIAL KIDNEY DISEASE (B.K.D)

• Potentially catastrophic for live fish producers
• Financial losses are mostly for legislative
  reasons
• Clinical symptoms very rarely seen in England and
  Wales
• Some losses on cage sites in Scotland
• Causative organism probably widespread
• Current legislative position is stifling the
  industry

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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VIRAL HAEMORRHAGIC SEPTICAEMIA (V.H.S.)

• Yorkshire outbreak 2006
• Large financial losses to farm owner and farms
  with movement restrictions in catchment area
• Original source still not clear
• UK regained VHS-free status by slaughter,
  disinfection , fallowing and setting up
  designated zone

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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SLEEPING DISEASE

• First reported UK 2002
• 2 new sites in England in 2007 and still proving
  to be a serious problem in Scotland.
• 8 sites with clinical disease, 2 others showing
  AB positives.
• Only improved biosecurity will stop this disease
  spreading further.
• As it is a viral disease there are no treatments.
• Trials using P.D. vaccine have not been
  successful, so far.

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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FURUNCULOSIS 2007

• Now becoming a major problem in the U.K. trout
  farming industry.
• Affecting new sites every year. Now Scotland.
• Now not just an issue in warm water conditions
  e.g. 2007 has been a bad year.
• Antibiotic sensitivity patterns many and various
• Vaccines (immersion and i.p.) can be successful,
  but no licensed oral boost vaccine, yet.

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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OTHER SIGNIFICANT DISEASES

• BACTERIAL DISEASES
  TREND
• Lactococcosis
  -
• Post swim up loss syndrome (enteritis)
• VIRAL DISEASES
• Infectious Pancreatic Necrosis (I.P.N.)

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OTHER SIGNIFICANT DISEASES (CONT.)

• ENVIRONMENTAL DISEASE
  TREND
• AND PARASITES
• 
  
• Bacterial Gill Disease
• Gas bubble disease / gas supersaturation
• CO2 related issues
• Costia (now in larger fish)
• Other external parasites
• Eye fluke
  
• Fungal problems
• OTHER DISEASES
• Strawberry disease
• Puffy skin condition

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ESTIMATED COSTS TO UK TROUT INDUSTRY ()
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TROUT DISEASE RANKING AND TRENDS (3 YEAR AVE.)
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ARGULUS

• Becoming widespread on recreational still water
  fisheries in UK. Moving further north.
• Estimated 5 million loss caused to this
  industry.
• Has caused closure of several businesses over
  last 2 years.
• Slice works but withdrawal period restrictive.
  
• Not a serious problem on actual fish farms, yet.
  

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Production trend UK trout farming (tonnes)
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CONCLUSIONS

• Industry gross sales value about 34,000,000
• 3 year average financial loss attributable to
  fish health / disease 6,070,000 (excluding
  Argulus).
• Equals 17.9
• 2006 - 7,200,000 (22.5)
• General trends of most current diseases are
  upwards.
• New disease/conditions are appearing all the time
• Climatic conditions cause big differences.
• Fewer treatments are available

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THOUGHTS FOR THE FUTURE

• WE NEED
• TO PROVIDE MORE ACCURATE INFORMATION ON FINANCIAL
  IMPACT OF SPECIFIC DISEASE
• T0 CONSIDER WELFARE ISSUES RELATING TO FISH
  DISEASES
• TO KEEP THE THE REAL NASTIES OUT e.g. V.H.S.,
  LACTOCOCCUS
• CHANGES TO B.K.D. LEGISLATION
• FURTHER COLLABORATION/COMMUNICATION BETWEEN THE
  INDUSTRY AND D.E.F.R.A./C.E.F.A.S./F.R.S.
• FURTHER TRAINING FOR THE INDUSTRY e.g. FISH
  HEALTH COURSES
• CONTINUATION OF RESEARCH WORK ON DISEASES OF
  MAJOR ECONOMIC IMPORTANCE e.g. RMS

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THOUGHTS FOR THE FUTURE cont.

• WE NEED
• TO PROTECT THE CONTINUED USE OF EXISTING
  THERAPEUTANTS AND EXPLORE POSSIBILITIES OF NEW
  ONES (SHORTER WITHDRAWAL PERIODS?)
• A MORE EFFECTIVE WHITE SPOT TREATMENT
• LICENSE FOR SLICE TO CONTROL ARGULUS WITH
  SHORTER WITHDRAWAL PERIOD.
• MORE PREVENTATIVE STRATEGIES (E.G. VACCINES,
  IMMUNOSTIMULATORS, PROBIOTICS ETC.)
• TO IMPROVE BIOSECURITY REGIMES
• CONTINUE WORK ON STRAIN SELECTION FOR DISEASE
  RESISTANCE