DISEASE SITUATION IN EUROPEAN RAINBOW TROUT AQUACULTURE

1
DISEASE SITUATION IN EUROPEAN RAINBOW TROUT
AQUACULTURE
Dr. Chris Gould Manager Global Technical
Services (Salmonids)
2
Contents

• Rainbow Trout Production in Europe trends
• Major Freshwater Diseases of Rainbow Trout in
  Europe What where? Up or
  Down? Ranking?
• Conclusions?

3
Rainbow Trout Freshwater Production
Eastern Europe expanding rapidly 250 000
tonnes (1 billion fish)
4
Rainbow Trout Seawater Production
80 000 tonnes
5
Main Diseases - Trout

• Bacterial
• ERM all countries except Norway (Finland ?
  recently)
• (EX5) UK, Eire, France, Norway, Finland,
  (other?)
• Furunculosis all countries
• Vibriosis Italy (fw) Norway,
  Finland, Denmark, Spain, UK (sw)
• Lactococcosis warm-water countries (Italy,
  Spain, France, Portugal, Turkey, Bulgaria,
  (UK))
• RTFS all countries (except Norway?)
  now regularly affecting bigger fish
• RTGE Spain, France, UK, (Italy?)
• Strawberry Disease all countries? (not Dk or
  De)
• RMS UK, (France, Spain, Finland) Switzerland?

6
Main Diseases - Trout

• Parasitic
• Whitespot all countries
• PKD UK southern Europe
• Costia all countries
• Trichodina all countries
• Gyrodactylus/Dactylogyrus all countries
• Argulus sp. all countries

7
Main Diseases - Trout

• Viral
• Sleeping Disease (SD) Spain, France,
  Germany, Italy, UK
• Viral Haemorrhagic Septicaemia (VHS) all
  countries (?) (UK)
• Infectious Pancreatic Necrosis (IPN) all
  countries
• Infectious Haematopoietic Necrosis (IHN)
  Italy, France, Germany, Belgium, Spain,
  others?

8
Main Diseases (Trout) Up or Down?

• Parasitic Whitespot ??? PKD Costia Tric
  h Gyros Argulus ??

• Bacterial ERM EX5 ? Furunc ? Vibrio Lac
  to ??? RTFS ? RTGE ?? Strawberry ? RMS ?

• Viral SD ? IPN VHS ?? IHN (?)

9
Main Diseases (Trout) - Ranking

• Vibrio
• IPN
• RMS
• Strawberry
• SD
• VHS
• IHN
• (Argulus)

• ERM (EX5)
• Whitespot
• Lacto
• RTFS
• PKD
• RTGE
• Furunc

Ranking- based on a combination of factors
10
EX5

• a new biogroup of Yersinia ruckeri
• 1993 first isolation (Exmoor)1993-2001 only
  11 isolates (from 5 farms)2003 outbreak on 1
  farm in early spring (Feb) with
  farm-wide mortality2004 11 farms
  (geographically diverse) from February
  September2005 16 farms2006 20 farms
  (representing over 50 of UK table trout
  production)2007 24 farms2008 already a
  new site being tested.

11
EX5 Isolates
12
EX5

• appears EX5 is more prevalent (or pathogenic?) at
  lower water temps than Hagerman Type I (outbreaks
  seen earlier in the year)
• affects all sizes of fish
• External Symptoms same as Hagerman Type I (but
  fewer black hangers before morts start)
• Internal Symptoms same as Hagerman Type I
• same gross colony morphology on plate,
  agglutinates with Mono-Yr kits, same antibiotic
  sensitivity profiles

13
EX5

• Differential diagnosis API 20E identification
  profile 5107100 positive for gelatin
  Voges-Proskauer tests (this is differential for
  EX5) non-motile (Y. ruckeri usually motile)
• commercial vaccines seen to give a level of
  protection against EX5 but insufficient in
  some/most cases to avoid clinical symptoms and
  need for chemotherapy
• this has led to development of bivalent immersion
  vaccine AquaVacTM RELERA
• N.B. Appears that injection vaccination with
  standard ERM vaccine affords 100 protection

14
EX5

• Sampling program underway in other European
  countries..
• So far positive isolates confirmed from Eire
  (2005 1 site) France (2006 onwards 19
  isolates geographically diverse) Norway
  (2006/7 1 salmon site motile) Finland (1
  isolate confirmed late 2007) Spain (under
  suspicion)
• What about other countries?

15
Spread of Lactococcosis throughout Europe
UK - 2000
?
Brittany - 1999
Pays Basque - 1998
Italy - 1991
Spain - 1995
16
Conclusions

• Trout
• LOTS of disease problems!
• Lactococcosis continues to be a HUGE problem in
  Italy Spain
• RTFS continues to spread and is affecting bigger
  fish (and will get worse..)
• Whitespot problems have increased and control is
  much more difficult
• Furunculosis is becoming more common
• Vaccination against traditional bacterial
  diseases is effective (where done properly!)

17
Conclusions

• Trout
• New disease problems are occurring and are
  rapidly becoming a serious issue in a number of
  countries RTGE (BIG impact in
  Spain) Sleeping Disease RMS Strawberry
  Disease EX5 (on the ascendancy?)
• Will these new trout problems move into salmon?

18
The end