PQS - Orthomyxovirus Flashcards
Influenzaviruses have segmented genome
T
HPAI and LPAI strains differ in the number of basal amino acids in the HA protein
T
HA protein of influenza viruses is responsible for the attachment to the cell
T
attachment to the host cell sialic acid
The M2 protein of influenza viruses serves as an ion channel important in the decapsidation
T
Antigenic drift means serials of point mutations in the HA and NA genes
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The NA protein in the influenza virus is responsible for the release from the infected cells
T
Enzymatic cleavage of the HA protein is needed for the influenza virus penetration into the cell T
T
Genetic reassortment of human and animal influenza viruses result in the occurrence of new human influenza strains
T
Bats have an important role in the epidemiology of influenza
F
Antigenic shift is behind the influenza pandemics
T
Influenza viruses are classified into genera by their HA and NA proteins
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Influenza causes persistent infection in donkey
F
long-term persistence is not known/ not significant
The serotype of influenza viruses is determined by their HA and NA proteins
T
The influenza viruses cause respiratory signs in sea mammals
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- seals, whales
- horse
- swine
- avan
The host range of influenza virus is determined by the NA protein
F
Determined by HA protein
The bird to human host switch of influenza virus is mediated by swine
T
The main host of influenza is the swine
F
Natural host = wild birds !!
in humans inactivated vaccines are used for the immunisation against influenza
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- attenuated
- inactivated
Antigenic drift is behind the seasonal influenza epidemics
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Antigenic shift means the reassortment of the influenzavirus genome segments
T
Influenzaviruses are sensitive to drying out
T
For the in vitro propagation of influenza viruses embryonated eggs is used
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virus isolation – embryonated eggs, cell cultures
In horse and van influelnza !
The high virulence of some influenza A viruses is the result of mutations in the HA gene
T
» serial point mutations = antigenic drift → seasonal influenzas
Dogs are susceptible to horse origin influenza strains
T
The HPAI strains can cause CNS Signs
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- CNS signs (convulsions, torticollis, paralysis)
- catarrhal
- bloody diarrhoea
- mass morbidity and mortality
- skin haemorrhage
- respiratory signs
HPAI causes blood vessel damages and generalised infections
T
- CNS signs (convulsions, torticollis, paralysis)
- catarrhal
- bloody diarrhoea
- mass morbidity and mortality
- skin haemorrhage
- respiratory signs
The HPAI strains are usually developed from the H5 and H7 influenza viruses
T
H5, H7 LPAI can mutate to HPAI!
The LPAI causes immunosuppression
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- immunosuppression
- enteric and respiratory signs
Cat is susceptible to human seasonal influenza
F
HPAI strains are mutations of LPAI strains
F
HAI strains: multiple basic amino acids at the cleavage site of the hemagglutinin (HA) protein
LPAI strains: only one or a few basic amino acids at the cleavage site of the HA protein
HPAI strains belong into a certain haemagglutinin types
T
Anti-neuraminidase drugs inhibit the decapsidation of influenza viruses
F
inhibit the activity of the neuraminidase (NA) protein of influenza viruses
Influenzas Causes enteric symptoms in human
F
respiratory symptoms
Swine recovered from influenza should not be kept for breeding
T
recovered gilts / boars should not be kept for breeding
Influenza causes high morbidity but low mortality in swine
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The HPAI causes skin haemorrhages in swine
F
blood vessel damages, generalised infections
Swine influenza outbreaks occur usually during summer
F
more frequent in autumn and winter, but sporadic
The mortality of swine influenza is high
F
Swine influenza causes high morbidity rate
T
To prevent complications of swine influenza penicillin injections are given to sick pigs
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Swine influenza is easily transmitted to people
T
To prevent complications of swine influenza, antibiotics used
T
In swine all influenza variants can be detected
F
In a horse influenza outbreak all infected horses must be killed
F
The generalized symptoms of horse influenza are result of the interferon response
T
Racehorses should be vaccinated before the influenza season
F
immunisation before the racing season
Breeding mares should be vaccinated before the influenza season
F
immunisation 4-6 weeks before parturition
Influenza causes persistent infection in horses
F
The eggs produced in LPAI infected flock can be hatched
T
= because there is no germinative infection !!
The HPAI infection can be unambiguously differentiated from Newcastle disease by the clinical signs
F
The HPAI strains can cause clinical signs in waterfowl
T
waterfowl mostly asymptomatic carrier, rarely HPAIV causes clinical signs
In poultry farms LPAI may be endemic without clinical signs
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Waterfowl can carry the influenza viruses for long time
T
Influenza viruses are shed by birds exclusively in the nasal discharge
F
Shedding with excretes, faeces
Avian influenza is zoonotic
T
The virulence of avian influenza is determined by the i.v. pathogeny index and mortality
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Avian influenza can switch directly to human and cause epidemics with high case numbers as result of human to human transmission
F
human-to-human transmission is rare
In birds all influenza variants can be detected
F
Avian influenza of high economic impact is caused by HPAI strains
T
Avian influenza virus is primarily spread through bronchial discharge and aerogenic route
F
oronasal infection, shedding with faeces
Avian influenza spread by bronchial discharge
T
