Download Dia 1 - UGent

Aquaculture activities at the Laboratory of Virology
Faculty of Veterinary Medicine, UGent
<2002
≥2002
White spot syndrome in shrimp
- Aggressive and devastating disease, characterized by
lethargy, lack of appetite and reddish to pink body
discoloration, presence of white spots on exoskeleton
- Infects many crustaceans, including most cultured shrimp species
- Mortalities of up to 100% within 3-10 days
- Cause of huge losses (billions of US$ per year)
Etiology: White spot syndrome virus (WSSV)
- Family of the Nimaviridae, genus whispovirus
- Rod-shaped double stranded DNA virus
- Virion has envelope with a tail-like appendage
and measures 275 nm X 120 nm
Realisations (2002-2011)
a) production & titration of WSSV in shrimp
a) standardized IM inoculation model
• pathogenesis
• virulence/pathogenicity of ≠ strains
• susceptibility (≠ species; ≠ genetic lines; ≠ ages)
• treatments (antivirals, T°, immunomodulating molecules)
• effect of moulting/cuticula damage
c) defence
-> haemocytes
• culture in attachment
• culture in suspension
• particle uptake
• particle destruction
-> haemolymph
Haemocyte culture in attachement
P. vannamei
M.
rosenbergii
T0’
T120’
T24h
T48h
T72h
Haemocyte culture in suspension
P. vannamei
M. rosenbergii
T0’
T10’
T30’
T60’
T120’
T24h
T48h
Particle uptake and inactivation
Beads 200nm
16
Beads 200nm
nº of beads/bacteria per cell
14
12
10
8
Bacteria
6
Bacteri
a
4
Beads 1µm
2
0
0
1
5
10
30
Minutes post inoculation (mpi)
• WSSV? SOP virus purification!
• Vibrio ?
• Co-infections?
60
120
Beads 1µm
Future work (> 2011)
a) standardized PO/PR inoculation model
• pathogenesis
• virulence/pathogenicity of ≠ strains
• susceptibility (≠ species; ≠ genetic lines; ≠ ages)
• treatments (antivirals, T°, immunomodulating molecules)
• effect of moulting/cuticula damage
• role of peritrophic membrane
• how to strengthen barrières (feed, water quality, flora)
b) new defence mechanisms
-> haemocytes
• uptake/inactivation ≠ viruses/bacteria/…
• aggregation/coagulation
• particle catching/isolation system outside haemocyte
• activation
-> haemolymph ?
genetic determinants?