Choices available for controlling infectious disease present and future

1
Choices available for controlling infectious
disease present and future

• Professor Patrick Smith
• Schering Plough Animal Health
• (Aquaculture)
• European Aquaculture Technology
  Working Lunch
• 
  Brussels
• 9th
  October 2007

2
Species farmed

• Over 30 species worldwide
• Many new / emerging species
• 16 species farmed in Europe with at least half
  being new / emerging species

3
Fish disease

• Caused by pathogenic bacteria, viruses,
• Parasites and fungi
• Disease is the single most important limiting
  factor in the continuing growth of the
  aquaculture industry.

4
Industry needs

• Chemotherapeutants
• - antimicrobials
• - antiparasiticides
• Vaccines
• - technologies
• - new - oral vaccines
• - improved knowledge of the immune
• response (with special emphasis on the
  development of potency tests)
• Anaesthetics
• Ectoparasiticides
• Biosecurity and disinfectants

5
Industry needs contd/

• Immunostimulants / Immunomodulators
• Alternative treatments
• - other chemotherapeutants
• - prebiotics
• - probiotics
• - biological control
• - phage therapy
• Diagnostic kits
• - monitoring and surveillance

6
Cost of bringing a product to market

• Financial
• Man hours
• Time

7
Prescribing Cascade

• Article 10, Directive 2001/82/EC
• Where no authorised medical product ..
  exceptionally .. to avoid causing unacceptable
  suffering to the animals .. a veterinarian .. a
  small number of animals.
• Food animals only substances authorised for
  such animals in the Member States

8
Prescribing Cascade

• Problems for minor / new species
• Vets have to use the prescribing cascade on a
  regular basis.
• Animals on a single holding facility.
• Needs prior approval by Veterinary Authorities.
• Actives must be in Annex I, II or III of
  Directive 2377/90.
• If imported from another Member State must be
  authorised in food-producing animals.
• Unsuitability of products authorised for other
  food-animals (e.g. premix, soluble or low
  concentration of active ingredient).
• 500C day withdrawal period.
• Record keeping.

9
Solution?

• Authorised products should be licensed for
  salmonids or fin-fish rather than one species
  (generic licence for fish).
• Recognition that cascade is having to be used on
  a routine basis.
• Small number of animals not practical for
  farmed fish.
• IP protection extended to 15 years.
• Involvement of Trade Organisations.

10
Vaccines

• Since the first commercial vaccines for fish
  became commercially available in the late 1970s
  they have proved to have had profound
• Economic benefits
• Environmental benefits
• Animal welfare benefits
• The credibility of fish vaccination has become
  firmly established.

11
Fish Vaccines

• 1982
  2007
• 2 vaccines 26
  vaccines

12
Vaccine delivery methods

• Immersion
• First to be developed
• Catalyst to develop other fish vaccines
• Only method for small fish
• Limited range and protection
• Injection
• High stress
• Size limit
• Adjuvants
• Automation
• Oral
• Low stress
• New technologies
• Catalyst to develop oral fish vaccines
• Allows booster vaccination strategies to be
  developed

13
New Species Problems
Vaccines

• New Diseases
• e.g. Vibrio anguillarum 02B in cod,
• Francisella sp. in cod.
• Edwardsiella tarda in turbot
• Tenanacibaculum maritimus in sole
• IPN in marine species
• Small numbers
• - Licensing not justified
• - ATC vaccine numbers too small
• ? Autogenous route for larger numbers
  (interpretation of
• autogenous route hatchery vs on growing
  site)
• - Limited information on metabolism and
  epidemiology

14
Vaccines

• Solutions
• Increase numbers allowed on ATC
• Autologous route
• Greater acceptance of new technologies
• Simplify licensing of pure recombinant proteins
• Review risk of live attenuated vaccines

15
Vaccine Technologies
Simple inactivated
Recombinant
VLP vaccines
DNA vaccines
Live modified vaccines
Gene silencing
16
Immunostimulants

• Chemical, drug, stressor, on action that
  elevates the non-specific defence mechanism of
  the specific immune response (Anderson 1992
• Over 30 product types tested with various
  results extensive research
• Few available to fish farmers
• Cost benefit?
• Regulatory issues

17
Disinfectants

• Iodophors
• Formalin
• Gluteraldehyde
• Virkon
• Biotrol

18
Biosecurity and Disinfectants for Aquaculture

• Uses are varied (wellboats and other transport,
  farm equipment, clothing, )
• Many products available
• Not licensed?
• Testing guidelines?
• Environmental impact?
• Efficacy in specific conditions?
• Undervalued (and underused?) tool
• Would benefit from EU registration process

19
Alternative treatments in Aquaculture

• Alternative control measures
• Other chemotherapeutants
• Immunostimulants / immunomodulators/ prebiotics /
  probiotics /phage therapy
• Biological control measures
• Avoidance and Prevention
• Good husbandry
• Biosecurity measures
• Monitoring and surveillance

20
Alternative treatments

• Making a medicinal claim
• - The product is a medicine and needs to be
  licensed before it
• can be used in the EU Dir.2001/82/EC
  
• Complex nature of some products preclude
  licensing
• A feed additive with a physiological claim?
• - The product needs to be licensed before it
  can be used in the EU Reg. 1831/2003
• And the others residues, biocide directives . .
  . .
• The end of any alternative treatment?

21
Diagnostic Kits

• 6 Manufacturers worldwide
• Latex agglutination tests
• Monoclonal antibody based test ELISA format
• DNA Dot Blot hybridization technique
• Polymerase chain reaction (PCR) kits
• Immuno chromatography kits