Topic 33 - Swine vesicular disease and vesicular exanthema of swine Flashcards
What type of virus is the calicivirus?
RNA virus
What is so special with RNA viruses?
The mutation rate is very high. RNA viruses can change their antigenic properties, change their antigen proteins by mutation.
There are several variants of a RNA virus
They need specific immunity for 100% protection
Is the calicivirus enveloped or non-enveloped?
Non-enveloped
How is the resistance in the environment of calicivirus?
HIGH
Resistant to heat, detergents, disinfectants
Is calicivirus stenoxen or eyroxen?
Stenoxen. (Narrow)
Infect one or two species
Diseases caused by caliciviruses:
- Vesicular exanthema of swine virus
- Feline calicivirus
- Rabbit heamorrhaigc disease
- european brown hare virus
Are calicivirus good or bad antigens?
Good.
After infection of vaccination we see a long lasting immunity
Causative agent of Vesicular exanthema of swine:
Vesivirus genus under the calicivirus family
What is the natural/original host of Vesicular exanthema of swine?
How was it spread to swine?
Sea lion
After feeding pigs with sea food, they was infected
After the 1st outbreak it can spread from swine to swine
Is Vesicular exanthema of swine zoonotic?
YES
but not very contagious, because we use hygienic rules
How is Vesicular exanthema of swine shed?
By saliva and excretes
Incubation time of Vesicular exanthema of swine:
1-4 days
Symptoms of Vesicular exanthema of swine:
- Fever
- Anorexia
- Depression
- Vesicles on mouth, snouts, limbs (causing lameness)
Mortality rate in Vesicular exanthema of swine:
Usually low. The animals who die are weak piglets
Is Vesicular exanthema of swine a dangerous disease?
not really.
But it is impossible to differentiate from Foot and Mouth disease, other than with laboratory tests
How to diagnose Vesicular exanthema of swine:
- Clinical signs raise the suspicion of the disease or FMD
- Laboratry tests
FMD and Vesicular exanthema of swine are clinically IDENTICAL, so need laboratory test to differentiate
Which laboraty test would you do for Vesicular exanthema of swine?
PCR! it is the best method, because it is quick .
Time is very essential, since it also could be FMD
How long can Vesicular exanthema virus survive in the environment?
At least 2 weeks
Differential diagnosis of Vesicular exanthema of swine:
- Foot and mouth disease
- Swine vesicular
- Vesicular stomatitis
How is the vesicular exanthema of swine spread?
- Raw sea food
- Raw pork side-products
- From pig to pig
How to control Vesicular exanthema of swine if there is an outbreak:
- Restriction zone
- Eradication
- Heat treatment of meat
How to prevent Vesicular exanthema of swine:
- Heat treatment of seafood before feeding
Is the swine vesicular disease notifiable or not?
It is!
Are there resent reported cases of swine vesicular disease?
Not between 2015 and 2023
Causative agent of swine vesicular disease (SVD):
Enterovirus genus
Susceptible species in case of swine vesicular disease:
Pigs only
What did swine vesicular disease originate from?
It came from humans, there is a large groups of enteroviruses in humans. The coxsackie somehow adapted to swine, and after adapting it cannot be adapted back
swine vesicular disease, good or bad resistance?
How long will the virus survive?
Good!
Will remain in faeces for several months
Transmission route of swine vesicular disease:
Direct contact of swine
Shedding of swine vesicular disease, how early does it start and for how long does it last?
As it is a RNA virus (fast replication), it can shed even before appearance of clinical signs - 48 hours
Lasts for 4 months
Can asymptomatic pigs shed the virus in case of swine vesicular disease?
yes
Can indirect infection happen in case of swine vesicular disease?
Yes, because the virus have high resistance. Vehicles with faeces attached to the tires can spread the virus
Pathogenesis of swine vesicular disease:
Infection - replication in epithelium of GI tract + throat - shed + reach elementary tract - viraemia - other parts of the body
Infection per os. The virus will reach the gut and will replicate in the epithelium of the throat and gut. It will replicate to a higher number, be shed and from the elementary tract it will enter the blood stream, causing viraemia - reaching different parts of the body
After viraemia in case of swine vesicular disease, what will happen?
Vesicles will be formed. They will rupture, the content will be released and is a source of the virus. The animals do not die, they will recover
Can swine vesicular disease cause abortions?
If the virus reaches the foetus, it can cause abortion, but this is very rare
mortality rate of swine vesicular disease:
0%
Immune reaction of swine vesicular disease
The animals will be seropositive, meaning they will be immune after infection
Incubation time of swine vesicular disease
2-7 days
Clinical signs of swine vesicular disease:
- Fever - showing there is a viraemia
- vesicles - can be seen after viraemia
- Lack of appetite (due to the vesicles in the mouth)
Preselction site of the vesicles in case of swine vesicular disease
- Nose (very typical)
- Legs
- Oral mucous membrane
Pathological lesions in case of swine vesicular disease:
No lesions
How many days before vesicles are ruptured in case of swine vesicular disease?
1-2 days
Based on what, can we diagnose swine vesicular disease?
- Epidemiological rules
- Clinical signs
There are no pathological lesions
- Laboratory examinations
Which method to detect the virus in case of swine vesicular disease?
RT-PCR
Why do we detect antibodies in case of swine vesicular disease?
To recognise asymptomatic carries, but they can be seropositive
Differential diagnosis in case of swine vesicular disease, name some diseases:
- FMD !!
- Vesicular exanthema of swine
- Vesicular stomatitis
- Vesicular disease caused by Senecavirus A
Prevention measures in case of already introduced swine vesicular disease:
- Stamping out of infected herds
- Movement restrictions
Prevention measures in case of non-introduced swine vesicular disease (no infection):
- Control of traffic of pigs and pork
- Ban of swill feeding
- Disposal of food waste
Is there a vaccine of swine vesicular disease?
no commercial vaccine, so we try to prevent the disease
There is another swine vesicular disease, but have another causative agent, what is it?
Vesicular disease caused by Senecavirus A
Transmission route in case of Vesicular disease caused by Senecavirus A:
with discharges, with indirect infection
Clinical signs in case of Vesicular disease caused by Senecavirus A:
Very similar to SVD, but the age affected can be differentiated
Age affected by Vesicular disease caused by Senecavirus A:
Piglets below 1 week of age = show more severe clinical signs
Grower, fattening pigs
Clinical signs in piglets in case of Vesicular disease caused by Senecavirus A:
- Fever
- Depression
- Salivation
- Diarrhoea
- CNS signs
- Spasms
- Vesicles
Clinical signs in growers/fattening pigs in case of Vesicular disease caused by Senecavirus A:
Vesicles
Pathological lesions of piglets in case of Vesicular disease caused by Senecavirus A:
- inflammation of the oral mucosa
- interstitial pneumonia
- encephalitis
Pathological lesions of adults in case of Vesicular disease caused by Senecavirus A:
they dont die
How to diagnose Vesicular disease caused by Senecavirus A
- epidemiological rules
- clinicals signs
What do we use to detect the virus in case of Vesicular disease caused by Senecavirus A
PCR
How to prevent Vesicular disease caused by Senecavirus A
- General epidemiological measures
- Movement restrictions in order to prevent the spread