The document discusses the role of DNA vaccines in addressing fish diseases within the aquaculture industry. It highlights the necessity for disease prevention in fish farming due to the economic losses caused by outbreaks and underscores the potential advantages of DNA vaccination, including cost-effectiveness and dual immune response activation. Future prospects include developing species-specific vaccines and improving mass vaccination strategies while addressing regulatory and environmental safety concerns.

1. DNA Vaccines for Fish Diseases
Hakim Mudasir Maqsood
Ph.D. (Animal Biotechnology)
Div. of Biotechnology, FVSc and AH
SKUAST-K

2. Outline
o Aquaculture for affordable animal protein
o Hurdles in intensive farming
o Vaccinology in Aquaculture industry
o DNA vaccines (current status & future prospects)

3. Overview of Aquaculture production
• Global fish production = 158 million tonnes*
• Global Aquaculture production (food fish) = 70.5
mt*
• Per capita consumption
9.9Kg in 1960s 19.2kg in 2015*
• India (total culture production is 4.2 mt) = 0.4
mt (mariculture); 3.8 mt (inland aquaculture)**
• J & K = 20.03K tonnes (Trout 262 tonnes) ***
Seed: carp = 440 lac; trout = 90 lac ***
*SOWFA, FAO, 2015
**FAO Year Book, 2012
***State Fisheries Department, 2016

5. World aquaculture production continues to grow

6. Global fish utilization and supply
Growth 3.2%
1.6%

7. Conti…
• ~ 870 million people were chronically undernourished in
2010-12 (FAO, 2014)
• In order to produce more we have to shift from Extensive to
industrial scale INTENSIVE FARMING.
• But with Intensification comes problems!!!
Fish: affordable source of animal protein
• 16.7% of global population intake of animal protein
• 6.5% of all protein consumed
• 150g of fish = 60% daily protein requirement
FAO, 2015

8. Problem in Intensive Culture: Diseases
• Intensive culture = More animals per Unit area
• Increase in Horizontal Transfer of diseases
• Disease outbreaks affects:
 production,
 trade and
 economy

9. • Annual losses in 16 Asian countries >USD 3 billion.
(OIE, 2012)
• World’s shrimp industry suffered losses of ~US$10
billion since 1990 due to WSSV and IMV
• Vietnam alone reports loss of US$1 billion per year
on average.
• Chilean salmon farming industry suffered from
Infectious Salmon Anaemia in 2007 350-400 K
tonnes of fish, US$2 billion of revenue and 30,000
jobs.
• Cost of IHNV disease in 2001 to 2003 ~ CAD $200
million
Addressing fish disease issues is a necessary condition for
securing new private investment in aquaculture.

10. OIE listed disease, 2016 (Fish)
• Epizootic haematopoietic necrosis disease
• Infection with Aphanomyces invadans (EUS)
• Infection with Gyrodactylus salaris
• Infectious Salmon Anaemia Virus (ISA)
• Infection with Salmonid Alphavirus
• Infectious Haematopoietic Necrosis (IHN)
• Koi Herpesvirus Disease
• Spring Viraemia of Carp (SVC)
• Red sea bream Iridoviral Disease
• Viral Haemorrhagic Septicaemia (VHS)

11. Profitable Aqua Farming
Minimal use of
Antibiotics
More Fish
Less Disease
Use of
Antibiotics,
Chemotherapy
Immunoprophylaxis
Sustainable Aquaculture
Disease prevention and control are crucial to maintain a sustainable
aquaculture
Vaccinology in Aquaculture Industry

12. Vaccinology in Aquaculture Industry
• First report of disease prevention in carp using
vaccine is by Sniezko et al.,1938 = A. punctata
• Duff (1942) = A. salmonicida (Trout)
• First commercial vaccine against ERM, 1976
• First commercial vaccine against SVC, 1982
• First report of DNA vaccination against IHNV.*
• In 2005, Apex-IHN® (Novartis Animal Health) the
first DNA vaccine ever to be cleared for
marketing.*
* Anderson et al., 1996
*Canadian Food inspection Agency

13. During the 1980s, salmon farming in Norway experienced huge losses due to bacterial diseases
(mostly Vibrio spp.) and a total crash in the industry was only prevented by the use of vast
amounts of antibiotics
Case Study: Grave et al., 1990, 2003

14. The use of vaccine resulted an immediate and permanent reduction in
the use of antibiotics, concurrent with a three fold increase in fish
production
Conti…Case Study: Grave et al., 1990, 2003

15. Types of Fish Vaccine Formulation!
• Bacterins
• Live attenuated vaccines
• Multivalent vaccines
• rDNA vaccines
Administration

16. Brudeseth et al., 2013
Green = vaccination is commonly used
Yellow = vaccination is used but not fully implemented
Red = fish vaccination is under development
Current status of fish vaccines

17. Brudeseth et al., 2013
Major producers of licensed fish vaccines

18. Major bacterial fish diseases in relation to vaccine availability
Bacterial disease/pathogen Major fish species affected Primary region(s)/country (s)
Vibriosis (Listonella anguillarum and V.
spp.)
Salmonids/Cod/Halibut/Sea
bass/bream
Amberjack/yellowtail
Globally
Coldwater vibriosis (V. salmonicida) Salmonids Northern Europe,
Furunculosis (A. salmonicida) Salmonids Northern Europe,
Canada/USA
ERM/Yersiniosis (Yersinia rukeri) Salmonids (FW) Europe, Chile, Canada/USA
BGD (Flavobacterium branchiophilum) Salmonids and Carp Europe, Chile, Canada/USA
Rainbow trout fry syndrome (F.
psychrophilum)
Salmoinds Europe, Chile, Canada/USA
BKD (R. salmoninarum) Salmoinds Europe, Chile, Canada/USA,
Japan
Streptococciosis (S. iniae) Tilapia Asia

19. Major viral fish diseases in relation to vaccine availability
Viral disease/pathogen Major fish species affected Primary
region(s)/country(s)
IPN/IPNV Salmonids Globally
Pancreases disease /PDV Salmonids UK, Ireland, Norway
Infectious salmon
anemia/ISAV
Salmonids Canada/USA (East),
Norway, UK
IHN/IHNV Salmonids Canada/USA (West)
VHS/VHSV Rainbow trout, brown trout,
Japanese flounder
Europe and USA
Channel cat fish virus CCV Channel cat fish USA
SVC Carp species Europe
Grass carp hemorrhagic
disease / GCHDV
Grass carp China

20. DNA Vaccination
• DNA vaccination is defined as the intentional
transfer of genetic material (DNA/RNA) to
somatic cells for the purposes of influencing
the immune system.*
• For DNA vaccination, a short-term expression
is sufficient for evoking an immune response.
• It is different from Gene therapy!
*The Norwegian Biotechnology Advisory Board

21. DNA vaccine in Fish!
Promoter = pCMV or pIRF1A in case of IHNV

22. Distribution of pDNA in Fish
Jensen et al., 2008

24. Tonheim and Dalmo, 2008
Immune response against DNA vaccine
Exogenous PathwayEndogenous Pathway

25. Endogenous Exogenous
Antigen (Viral for example) entry in host cells

26. DNA Vaccine against IHNV
Plasmid DNA
CMV promoter-enhancer,
bovine growth hormone
polyA signal,
Kanamycin
viral G protein gene

27. Factors influencing transfection and gene
expression
• pDNA vector design (super coiled DNA, choice of promoter, polyA signals)
• pDNA concentration
• Dosage (ng)
• Age and size of fish
• Water temperature
• Route of administration

28. Structure (A)Mechanism of action (B)of suicidal DNA vaccine for IHNV
Alanso et al., 2014
Suicidal DNA vaccines: Improved safety
Gene construct Action

29. Overview of studies performed with DNA vaccines
encoding viral or bacterial antigens in fish

30. Tonheim and Dalmo, 2014
Conti…

31. Advantages of DNA vaccines
demonstrated in Fish
• Activation of both humoral and cellular immunity
• Intrinsic immunostimulatory property due to CpG
motifs
• Multivalent vaccination possible by simply mixing
of DNA vaccines
• More effective when given at the early life stage
• Effective cross-protection
• Temperature-independent protection (Poikilothermic)
• Inexpensive and easy to produce
• Stable as dry powder or in solution (no storage
problems)
Lorenzen and LaPatra, 2010

32. Disadvantages/current concerns
• Difficulty/cost of delivery is high!
• Development of myosists (myocytes
becoming targets of CTLs)
• A relatively high antigenic mass needed in
most fish vaccines compared with similar
vaccines used in higher vertebrates.
• Environmental release of pDNA!!!
• Regulatory Issues*
Antibiotic resistance genes may then spread to
various bacterial populations in intestine of fish or
soil and water.
*Norwegian Gene Technology Act

33. 1. Leakage of DNA from administration site
2. By consumption of pDNA residues in the meat of
vaccinated animals
3. By spills or waste of DNA vaccine from production
process
4. pDNA may find its way to intestine where bacteria
may be taken up and released with faeces

34. Future prospects of DNA vaccinology
in Aquaculture Industry
• Out of 35000 fish species known, 600 species are
cultured as food fishes and this number will
increase
• More number of Species specific DNA vaccines
need to be developed
• Better understanding of fish immune system will
help to design more efficient DNA vaccines
• Use of multiple epitopes in a single vaccine

35. Future prospects of DNA vaccinology in Aquaculture Industry
Conti…
• Immunoprophylaxis against fish
parasites at industrial scale needs
attention.
• Need for new strategies for mass
vaccination of small fish
• Recombinant live feed!!!
Environmental safety concerns currently hinder the
development and use of DNA vaccines in fish.

36. @ Mudasir