Lecture 7 Flashcards
What sort of virus are Orbiviruses
non-enveloped viruses
What is the structure of Orbiviruses (2)
- Triple capsid
2. 10 segmented dsRNA
What transmits Orbiviruses
Intectes predominantly biting midges
List some Orbiviruses (5)
- African horse sickness virus
- Blue tongue virus
- Epizootic haemorrhage disease virus
- Equine encephaosis virus
- Palyam virus
What opportunity is created with segmented genome
Mutations
What is blue tongue and AHSV transmitted by
Culicoides midges
How many serotypes of AHSV are there
9
How many serotypes of BTV are there
27
What are the hosts of AHSV
horses, donkeys, zebras and mules
What is the heart form of AHSV signs
- fever followed by swelling of head and eyes
What is the heart form of AHSV terminal
bleeding in membrane of mouth and eyes
What is the lung/pulmonary form from of AHSV signs
Difficulty in breathing
Frothy discharge may pour from nose
What is the mixed form of AHSV signs
Symptoms from both the heart and lung forms
What are the three forms of ASHV
- Heart form
- Lung/pulmonary form
- Mixed form
How to control AHSV (4)
- Vaccine
- Control the vector
- Movement of animals
- Good management
Where is Equine encephalitis virus prevalent
SA, Kenya and Botswana
What has a higher transmission rate, AHSV or EEV
EEV
How was BTV brought into Australia
windburn dispersal fron indonesia
How many segments does BTV involve
10
Clinical signs in a sheep of BTV (2)
- Fever, excessive salivation, swelling of the face and tongue and cyanosis of the blue tongue
- Hyperaemia of muzzle nose and coronet
Clinical signs in a cow of BTV
- Conjunctivitis, rhinitis with nasal exudate and ulceration of the nares
Clinical presentation of BTV varies between different host species and individuals based on (3)
- Host, vector, environmental factors
- Virulence of the infecting strain
- Expression of inflammatory and vasoactive mediators by host endothelial cells and other cells such as macrophages and dendritic cells
Where does BTV replicate
Draining lymph node before being disseminated by the blood and lymph to sites of secondary replication throughout the body
Where does virus replication principally occur with BTV
Lungs and spleen
In BTV, what does the cell membrane invaginate
Erythrocytes and platelets during viraemia
Characteristic clinical signs of BT (2)
- Damage which is caused by the virus to endothelial cells in the walls of blood vessels
- leads to vascular thrombosis, tissue infraction/necrosis, vascular leakage, oedema and haemorrhage
What can foetal infection with BTV result in (5)
- Abortion
- Growth retardation
- Teratogenesos
- Birth of viraemic offspring
- No obvious abnormality
What are the side effects of animals that recover from BTV
Muscle degeneration that manifests as weakness, prostration and torticollis, slipper formation of the hooves, a characteristic break in the wool in sheep and a transient decrease in fertility of breeding
How to control BTV (3)
- Vaccination
- Illegal movement of animals
- Vector control
How many stereotypes of epizootic haemorrhage disease are there
7
What is EHDV similar to
BTV
How many RNA segments does Rotavirus have
11
What does rotavirus cause in young mammals
Diarrhoea
The 7 stereotypes and what the effect
- Group A: humans
- Group B: Humans and animals
- Group C: humans and animals
- Group D-F: animals
How can you get infected with Rotavirus
Fecal-oral route
What makes rotavirus resistant to acidic pH
tripple protein coat
What does Rotavirus produce
Virus-encoded enterotoxin which leads to gastroenteritis and severe diarrhoea
What can Rotavirus destroy
mature enterocytes
What is NSP4
Non-structural protein
In an infected cell what is NSP4 associated with
Assembly of the vision
What can secreted NSP4 attach to
Receptors on healthy enterocytes
(Rotavirus) From the infected cell where do water and electrolytes leak
Into the lumen of the intestine
How many segments is Avian orthoreovirus
10
What does Avian orthoreovirus infect
Birds
How can Avian orthoreovirus infect birds
- Transovarial transmission
- Fecal-oral route
- The respiratory tract
- Infection may also enter through the exposure of broken skin of the feet or legs of chickens
What is the most commonly observed problem with Avian orthoreovirus
infection of tendons with resultant rupture of the tendons and haemorrhage
How many segments are there with infectious bursa disease (Gumboro)
two segments of dsRNA
Where does infectious bursa disease (Gumboro) replicate
Immature B cels
What does replication in immature B cells cause in infectious bursa disease (Gumboro)
Massive necrosis of the bursa
What is the result of infectious bursa disease (Gumboro)
Immunosuppression
What is ELSIA used to monitor
Antibody titres in samples from breeders and broilers
How can the gnome of infectious bursa disease (Gumboro) be detected
By real-time PCR with different probes being used to differentiate the hyper virulent strains
How to control infectious bursa disease (Gumboro)
- Vaccination
- Good management - biosecurity
- When hyper virulent strains are present broilers are vaccinated once maternal antibody has been metabolised
How many BTV are there in Australia
10
How was AHSV transported to Spain
From a zebra from Namibia
What does MLV stand for
Modified live vaccine
What can avian orthroreovirus cause
- Reovirus tenosynosis
- Stunting and runting
- Helicopter syndrome