Topic 35 - Duck viral hepatitis disease Flashcards
Is duck viral hepatitis disease worldwide?
yes
Causative agent of duck viral hepatitis disease:
Duck hepatitis A virus under Avihepatovirus family, picornavirus
Which virus causes duck viral hepatitis disease
Picornavirus
How many serotypes belong to Avihepatovirus genus?
3
Serotype 1, 2 and 3
Which serotype of Avihepatovirus genus is pathogenic?
Genotype 1 = highly pathogenic and most widespread
Genotype 2 + 3 = less pathogenic
Which serotype under Avihepatovirus does duck viral hepatitis disease belong to?
Serotype 1
Resistance of duck viral hepatitis disease:
High
How long can duck viral hepatitis disease survive, and where does it survive?
In bedding for 10 weeks
Species susceptible for duck viral hepatitis disease:
All duck species and arts
How is duck viral hepatitis disease shed and for how long?
In faeces, for weeks
Infection route of duck viral hepatitis disease:
Most commonly: per os, via faeces
But also, tracheal discharge
In case of duck viral hepatitis disease, is there a germinative infection?
NO
Midterm Q for sure!!
Mortality rate in ducklings in case of duck viral hepatitis disease:
90%
What can cause the mortality in ducklings to decrease in case of duck viral hepatitis disease, and to what % does it decrease to?
If there is yolk immunity the mortality decreases to 50%
How long will the yolk immunity last in case of duck viral hepatitis disease?
3-6 weeks of age
Which age of ducks will we see clinical signs in case of duck viral hepatitis disease?
1-4 weeks of age
Which age of ducks will we see most severe clinical signs in case of duck viral hepatitis disease?
first week of life
What can cause complications in case of duck viral hepatitis disease?
Secondary bacterial infections
Name examples of secondary infections in case of duck viral hepatitis disease:
Mycotoxins
Salmonella
They will trigger the disease = fast spread within the herd
What is the pathogenesis of duck viral hepatitis disease?
Infection, we have a replication which causes viraemia and the virus will spread to further organs and there is a second replication
What is the replication site in case of duck viral hepatitis disease?
Mucous membrane of the GI tract
What are the organs the virus is spread further to with viraemia, in case of duck viral hepatitis disease?
- Liver (especially!)
- Spleen
- Kidney
Incubation time in case of duck viral hepatitis disease:
2-3 days
Clinical signs in peracute cases of duck viral hepatitis disease:
Rarely see clinical signs, only death within few hours
Which age is mostly affected by the per acute phase of duck viral hepatitis disease?
day-old ducklings
Mortality rate in case of per acute phase of duck viral hepatitis disease?
Close to 100%
From which age can we see acute phase of duck viral hepatitis disease?
From 2nd week of age
Clinical signs in case of acute phase of duck viral hepatitis disease:
- Depression
- Lethargic
- Ataxia
- Spasmodical paddling
Acute phase of duck viral hepatitis disease, death within?
Few days!
In case of duck viral hepatitis disease, what are the spasmodical paddling due to?
Damage to the kidney
In case of duck viral hepatitis disease, in which organ can we see the most important pathological lesions?
Liver!
Pathological lesions in liver, in case of duck viral hepatitis disease:
- Enlarged
- yellow
- Liver dystrophy + necrosis
- Haemorrhages with sharp edge (VERY TYPICAL)
Pathological lesions in spleen, in case of duck viral hepatitis disease:
- Enlarged
- Mottled
Pathological lesions in kidney, in case of duck viral hepatitis disease:
- Swollen
- Nephrosis
Based on what can we diagnose duck viral hepatitis disease
- Epidemiological rules
- Clinical signs
- Post mortem lesions
- Histopathology
+ detection of the virus
Which method do we use to detect virus in case of duck viral hepatitis disease?
PCR
But also, IF
Can we detect antibodies in case of duck viral hepatitis disease?
yes, but it cannot support the diagnosis due to the asymptomatic clinical signs
Differential diagnosis in case of duck viral hepatitis disease:
- Duck plague
- Duck hepatitis caused by astrovirus (lower mortality!!)
- Salmonella complication
Treatment of duck viral hepatitis disease:
There is no treatment!
Only prevention
Prevention measures in case of duck viral hepatitis disease:
- Epidemiological rules
- Vaccine
Which epidemiological rule is especially important in case of duck viral hepatitis disease, and why?
Strict isolation in the first 4 weeks of age
We benefit from the fact that there is no germinative infection
Which type of vaccines can be used for duck viral hepatitis disease, and which is most commonly used?
- Inactivated
- Live, attenuated
- Combination: Live, attenuated + inactivated
The combination vaccine is mostly used today!!
How do we vaccinate with the combination vaccine in case of duck viral hepatitis disease?
First time: vaccinated with live-attenuated vaccine
Second time: inactivated vaccine
At what age do we vaccinate, with combination vaccine, for the first time in case of duck viral hepatitis disease?
7-12 week of age
What will the first jab in case of combination vaccine do in duck viral hepatitis disease?
It will result in high level of immune response
At what age do we vaccinate, with combination vaccine, for the second time in case of duck viral hepatitis disease?
Right before laying, at 18 week old
What will the second jab in case of combination vaccine do in duck viral hepatitis disease?
It will give a uniform immunity
