Lecture 14 Flashcards
Symptoms of Wellfleet Bay Virus (WFBV) (3)
- Diarrhoea 2. Lethargy 3. Recumbency
Clinical signs of WFBV
Lesions on liver
What is WFBV closely related to
Quaranjavirus genus
What type of animal does WFBV infect
Birds (common eiders)
How big are Orthomyxoviruses
80-120nm
What does Cygnet River virus infect
Ducks
How did the ducks get Cygnet River virus
They were fed incorrecly
What are natural host for influenza A
Wild waterbirds
What are the subtypes of influenza A (2)
- Hemaggutinin (HA) 2. Neuraminidase (NA)
Where does avian flu virus usually replicate
Epithelial cells of GIT
Where do birds excrete the virus in large quantities
Droppings
How is avian influenza infection caught
Asymptomatically
In influenza A, which subtypes have caused an endemic (4)
- H1N1 2. H2N1 3. H2N2 4. H3N2
Explain the subtypes and the species they infect
What occurs in reassortment (ANTIGENIC SHIFT)
Occurs when 2 distinct influenza viruses concurrently infect the same person or animal and may result in progeny virus with genetic material from both viruses
What occurs in mutations/adaptations (ANTIGENIC DRIFT)
Occurs when an influenza virus accumulates mutations that enable more efficient infection and spread in a new host
What does viral replication use cells to do? (3)
- Read own RNA 2. Synthesise proteins 3. Assemble the new viruses
Where does RNA synthesis occur
The cells nucleus
Where does protein synthesis occur
Ribosomes in cytoplasm
During viral replication where does Hemagglutinin attach
Sialic acid receptors on the cell
Where does influenza HA bind
to sialylated glycans on cell surface
What are the clinical signs of LPAI (3)
- Respiratory and/or GIT infection 2. Sneezing, coughing, ocular and nasal discharge, and swollen infraorbital sinuse 3. morbidity and mortality low
What are the clinical signs of HPAI (5)
- Severe, systemic disease 2. Cyanosis and edema of the head, comb and wattle 3. Oedema and red discolouration of the shanks and feet due to subcutaneous haemorrhages 4. Blood-tinged oral and nasal discharge 5. Greenish diarrhoea
What are the 3 types AIV and NDV
- Velogenic strains: high mortality 2. Mesogenic strains: respiratory disease in young chickens and decrease egg production 3. Lentogenic strains: mild respiratory infection or no symptoms
Explain the evolution of influenza A/H5N1 virus
What are some problems with A/H5N1
- Large death in birds 2. Many birds have to be killed 3. Huge financial cost
Where did the H7N9 virus occur
China
What type of population does H7N9 effect
older males
What are some strategies in markets to reduce avian viruses (3)
- Market cleaning 2. Destocking overnight 3. Rest days
Clinical signs of swine influenza (6)
- Going off feed 2. High fever 3. Discharge from eyes and nose, sneezing 4. Breathing difficulties 5. Barking cough 6. Huddling and inactivity
Why can pigs get infected with both human and avian viruses
Their tracheal epithelium has both receptors for avian and human viruses
Which type of influenza virus in horses is the only one that still exists
H3N2
Clinical signs of equine influenza (3)
- Increase in temperature 2. Deep, dry, hacking cough 3. Watery nasal discharge which may later become thick and smelly
Which 2 strains of influenza virus have been identified in dogs
- H3N8 2. H3N2
What two swabs are essential when swabbing a bird for influenza
- Oropharyngeal swab 2. Cloacal swabs
