Infectious Challenges - virus Flashcards
(24 cards)
Define virus
Small infectious agent which replicates only inside the living cell of another organism
what is avian influenza
Infectious viral disease of birds caused by influenza A virus
Name the 6 features of flu virus anatomy
- nucleoprotein (RNA)
- lipid envelope
- capsid
- hemagglutinin
- neuraminidase (sialidase)
What are the 2 types of avian influenza
- highly pathogenic avian influenza (HPAI)
- low pathogenic avian influenza (LPAI)
-> LPAI subtypes = H5 + H7 able to mutate to HPAI
What is the natural hosts of avian influenza
Wild birds
How does avian influenza spread
Colonises in the gut and is spread via faeces + salivation
How is avian influenza spread within + between farms
- direct contact (equipment, vehicles, people)
- infected faeces
- air transmission over short distances
- live bird markets
What are the symptoms of avian influenza
- swollen head
- dullness
- low egg production
- loss of appetite
- respiratory signs
- sudden death
What are mild symptoms of avian influenza in humans
- fever
- sore throat
- cough
- headache
- muscle aches
What are severe symptoms of avian influenza in humans
- high fever
- chest infection
- respiratory failure
- Multi organ failure
- death
How does avian influenza attack
- virus enters + replicates
- travels to lungs + triggers immune system
- cytokines sento to attack virus but cause deadly inflammation - blood + fluid leak into air sacs
- host drowns in its own blood
What is a highly pathogenic strain of avain influenza
H5N1
What are the methods of control for avian flu
- animals must be slaughtered accordance to animals health act 1981
- quarantine measures
Strict sanitary measures used - vaccination programmes
What are the advantages of vaccination in bird flu
- stops unethical measures = destruction of large numbers of animals
- greater stock densities
- protection against infectious disease
- economic benefits
What are the disadvantages of vaccinating against bird flu
- difficult to distinguish between infected + non infected animals
- vaccinated animals cannot be exported
- loss of disease free status
- vaccinated animals are still carriers
What are the antiviral drugs used for treatment of humans with bird flu
-Tamiflu
- relenza
what is foot and mouth disease
Picornavirus - affects all cloven-hooved animals
What are signs of foot + mouth disease
- fever
- dullness
-Shivering
-Slavering - anxiety
- loss of appetite
- loss of condition
- reduced milk yield
- tenderness / lameness of feet
- unusual mouth movements
How is foot and mouth disease spread
- directly by contact with infected animals
- indirectly via carriers (vehicles, feed, water)
In what animal was foot and mouth disease first identified in
Pigs
what were the problems with the attempt to stop the spread of infection of FMD
- few expertise for identification
- difficult to identify in sheep
- not enough man power
- difficulty in disposing of carcasses
What policies are implemented to avoid another epidemic of FMD
- improve livestock health + hygiene
- forbid swill feeding
- strict border controls for imports (quarantine)
What is hte legal requirement if FMD discovered
- duty to report a suspected case to APHA/DEFRA/LA
- nominated staff inspect
- restriction + culling if confirmed
- failure to do so = prosecution
Who was most affected by swine flu
Young adults / teenagers
