Viral diseases (4) Flashcards
What are the characteristics of a virus?
Can only replicate inside the living cells of the other organism
Genetic material is either DNA or RNA
A protein coat that protects
(Some cases) Envelope of lipids that surrounds
the protein coat when they are outside of a cell
How does a virus work?
High jacks host cell metabolism
Builds own genetic material in the genome of host cell
After an infection leave the host cell intact, or transform the host cell, or kill the host cell
What are the fases of an infection?
- Attachment and adsorption
- Penetration
- Uncoating
- Replication
- Release
How does a virus change?
Mutation
Genetic drift
Genetic shift
What is genetic drift?
the change in frequency of an existing gene variant in the population due to random chance
What is genetic shift?
an abrupt change in a genetically determined trait due to mutation
What are interferons (IFN)?
The second line of defence → proteins made and released by host cells
Antiviral agents
Ability to interfere with viral replication within host cells
Active natural killer cells and macrophages
Not virus-specific, but species-specific
Not easy to produce industrially
Virus resistance to interferons
What are the symptoms of equine influenza?
High fever
coughing
weakness
lack of appetite
How is equine influenza transmissioned?
Spreads through aerosol dispersion
Highest risk in a situation where unrelated horses come together (competitions)
Risk of secondary bacterial infection
Antibiotics do not help for influence → given as prevention for secondary bacterial disease
How to vaccinate against equine influenza?
Vaccination → inactivated dead vaccine → short duration of immunity
First vaccination -> 3-8 weeks → second vaccination → every 3-6 months → booster
What types of EHV are there?
EHV 1 -> Abortion, airway infections, neurological problems
EHV 4 → airway infections
How is EHV transmissioned?
Excretion → abortion materials, nasal secretion by carrier
Infection → inhaling
Transmission → direct (other horses) or indirect (materials and humans)
Outbreak control for EHV?
Confirmation of diagnosis
Closure for 4 weeks
Quarantine for infected animals
Temperature animals at risk
Care for infected animals last
Stable hygiene and disinfection
How to prevent EHV?
Horses when transported
Isolate risk groups
Temperature them
Vaccinate all horses twice a year
*Prevent abortion (vaccine every 2 months)
*Prevent severe airway problems
*Prevent the spread of virus particles
