African Swine Fever Flashcards
what is referred to epidemic 1 of ASF
In 60s, endemic in Sardinia- Genotype 1
What is referred as Epidemic 2 of ASF?
07, Caucasus region- genotype 2
ASF found in which animals
wild boars & domestic pigs
ASFV name
Asfaviridae, asfavirus
ASF virus physical aspect
at least 24 genotypes, very big, many genes = many antigens
asfavirus way of infection
- some genes block interferon production & antiviral defense mechanism
- encodes prot of eukaryotic origin (difficult to differentiate from somatic cells)
-multiplication in macrophages (block of the IS) - prot: induction of Ab BUT none neutralizing ones!
what are the main problem the body encounters against ASFV
- interferon are blocked
- hidden from IS
- no neutralizing anitbodies
ASFV genome
Ds linear DNA: cytoplasmic inclusion body despite being DNA virus
ASFV polymerase
its own, can rep in vector AND swine
ASFV resistancy
enveloped BUT high resistance
60° for 30mins
what is the vector of ASFV
tick (biological vector)
Africa: transmission of ASFV
- tick-tick (vertical)
- tick-warthog (dead end host)
- tick-domestic swine
europe & asia, transmission of ASFV
Boar-pig, pig-pig, boar-boar, tick-pig
spreading of ASFV in europe & Asia
inf: saliva, nasal discharge (tick) shedding before CS (48hrs)
spreading: airport, raw meat, transport
lesser importance of tick in europe
mortality in acute ASF
100%
mortality in chronic ASF
<30%
what kind of cycle can be found between warthog- ticks and ticks-ticks?
Sylvatic cycle
both asymptomatic carriers (doesnt do anything)
which genotype does O. moubata caries?
genotype 1
What genotype of ASF does O. erraticus can carrie ?
O: Ornithodorus
Genotype 1
which genotype of ASF Ornithodorus verrucosus can carry
genotype 2
ASFV pathogenesis
PO/Tick
tonsils, regional Ln
Viraemia (macrophages)
Spleen, lymphatic T., endothel
when does the virus of ASF start shedding
even 48hrs before start of CS
Consequence of a persistent viraemia of ASF?
immunosupppression
Abs against ASFV
6-8 days postinfection
non neutralizing
virus wears membrane of macrophage like a raincoat (Abs can’t reach it)
persistent
immune complex formation
Obvious clinical sign of ASF
Abortion
in case of DD for abortion => ASF should be said first
ASF incubation time
4-19 dys (usually 2-7dys)
Peracute CS of AFS
rapid death without rapid fever, CS or patho changes
Acute ASF CS
fever 40-42°
no appetite
dyspnea (bloody serous discharge)
conjunctivitis
diarrhoea (with coagulated blood)
CNS signs
skin haemorrhages, cyanotic ears
lung oedema
Subacute ASF CS
mild symptoms (milder acute form)
longer course (4wks)
more frequent CNS symptoms
death within 14-30dys
chronic ASF CS
recurrent fever, athritis
focal skin necrosis & ulcers in protuding parts
resp signs
death as late as 2-15 mths
T/F
chronic case of ASF easy to diagnose
false
Patho of ASF
acute course: damage of blood vessels
gallbladder and choleductus region show gelatinous inflitration
oedematous lung
muscle necrosis is a patho finding of ASF?
Yes, chronic form
how to differantiate between ASF & CSF
RT-PCR can
diag methods for ASF
RT-PCR
Hemadsorption
DD of ASF
CSF
acute paratypus
PDNS
swine erysipelas
difference between CSF & ASF
- ASF has more serious haemorrhagic appearance
- Higher mortality
- Enlarged spleen
- Oedema in the wall of the gall bladder
Prevention of ASF
no spe prevention (animals WILL die)
preventive zone 3km
Observation zone 10km (can be resolved after 45 dys)
ban on import of live pigs, airports, ports & border station
Treatment of ASF
no vaccine
(2 ASF vaccine dvlped in vietnam but not to WOAH standards)