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“African Swine Fever: Prevention
is better than cure”
Win
terb
otha
mD
arby
Ani
mal
H
ealt
h &
Wel
fare
day
7t
h M
arch
201
9
CReSA and CReSA activities
Adapted from De la Torre, A and Arias , M. INIA-CISA
ASF: an African neglected disease
African Swine Fever
External membrane
NucleoidCapsid
Internal
membrane
Internal
membrane
Matrix
There is no vaccine available
In P
ola
nd
,Lit
huan
iaan
d L
atvia
export
atio
ns
dro
pby
50%
(1,0
00 m
illi
on
dola
rs)
2019: ASFV outbreaks
• 1 million pigs sacrificed• 26 Provinces in China
• ASFV found in processed meat Vietnam is infected• Taiwan (ASFV positive carcases in the beach)
• China produced 639.82 million pigs in 2018
Map courtesy of Pig Progress
IMAGEN: Sánchez Cordón et al. 2018. Vet. J.
The current European scenario
The good news: ASFVs is transmitted by direct contact
HUMANS ARE NOT SUSCEPTIBLE TO ASF
ASF is not a human health concern, neither a social alarm
ASFV
But… humans are the main risk factor for ASFV
reintroduction
PREVENTION is the KEY!
ASFV
Do not underestimate the enemy!
Australia: ASFV in processd meet found at the airport
Same issue in Taiwan, South Coreaand Thailand
Taiwan: Carcasses found by the beach
ASFV
Complexity = success200 nm
Highly resistant in the environment
o days in fecesoYears in frozen carcasseso >140d in processed meatoUp to 18 months in blood (4˚C)!!!!
ASFV
Disinfectants:
2% sodium hydroxide, detergents and phenol substitutes, sodium or calcium hypochlorite (2-3% available chlorine), and iodine compounds
RB
C
RBC
V
VV
ASFV infected macrophage
ASFV-mediated hemadsorption ASFV hemagglutination
EVADING THE IMMUNE RESPONSE
Courtesy Sharon Brookes VLA
1 ml of blood might contain
100 million ASFV
particles!!!!!
ASFV
YX
• Early diagnosis and massive culling
Disease expansion!
- Endemic
poor countries No economic compensation
African swine fever Control
•There is no vaccine availableA
SFV
can
be
era
dic
ate
d
wit
ho
ut
a va
ccin
e
Vaccines and ASFV
• Inactivated viruses (chemical or heat) don’t work or rendered controversial results.
•Proteins: partial protection or no protection.
•Long-term choice
•Attenuated viruses normally confer SOLID HOMOLOGOUS protection BUT safety issues
have hampered field implementation.
MECHANISMS OF PROTECTION
- Specific antibodies CAN INDUCE PARTIAL PROTECTION (passive transfer). Onisk et al,
1994.
-Specific CD8 T-cells CAN INDUCE PARTIAL PROTECTION (in vivo depletion). Oura et al,
2005.
Genetically attenuated viruses: a vaccine alternative for ASF?
ß-gusp72
L R
vF2
ß-gusp72
L R
vF1
ß-gusp72
L R
BA71TK
ß-gusp72
L R
BA71∆CD2CD2
Summary
1.Deletion of CD2 attenuates BA71 in vivo
2.BA71ΔCD2 protects in vivo in dose-dependent manner against lethalchallenges with:
a) BA71 homologous strain
b) E75 heterologous strain
3.BA71ΔCD2 induces CD8+ T-cells that specifically recognize homologousand heterologous ASFV strains in vitro
4.BA71ΔCD2 protects in vivo against Georgia07 heterologous lethalchallenge
Summary (II)BA71ΔCD2 protects in vivo against intranasal challenge
Full protection
BA71ΔCD2 protects in vivo against tick-bite infection (genotypes different than I and II)
Lack of CD2 difficult the tick transmission of BA71ΔCD2
BA71ΔCD2 can be grown in tissue culture cells (manufacturing)
BA71ΔCD2 protects in vivo
Further work is needed to optimize the vaccine:Safety DIVA
SFS-12-2019: A vaccine against African swine fever
• Developing safe and efficient DIVA vaccines against ASF
• Domestic pig and wild boar
• Collaborative project with third parties affected by ASFV• Stakeholders are essential• Participation of the Pharmaceutical industry is crucial
EU innovation project