Influenza Flashcards
what do viruses need for replication
Host cell
Types of influenza AND is it serious?
Why doesnt type B cause pandemics?
Type A: Serious - epidemics and pandemics (multiple types)
Type B: Serious illness, epidemics
Type C: minor illness
Only one type of B so only cause epidemics
Influenza vs common cold
Influ:
Abrupt onset
high fever
Unwell
Chills
Fatigue
Malaise
cough
sore throat
chest problems
unwell 1-2 weeks
severe complications (pneumonia)
winter seasons
Common cold:
Local: nose and throat
Gradual
Adults uncommonly can get fever (mild)
Sneezing
Sore throat
nose congestion
rapid recovery
Mild
All year around
Antigenic shift vs drift
Frequent mutate surface proteins (antigens) change - drift
New strain arises (out of nowhere) = shift
Describe the process of antigenic drift
using influenza as an example
Lecture Slide (GRADUAL)
- Haemagglutinin on virus binds to sialic acid on epithelial cell membrane
- during infection, the IS reacts with the virus and as the infection resolves, antibodies are formed
- Antibody binds to HA and prevents infection (and future infection)
3.However, overtime the virus mutates and HA changes its shape causing the antibody (which was made to bind to the shape of previous ag) cant bind
- no longer immune
Antigenic shift:
Example
Influenza A has 18 different HA types (eg H1, H3, H5)
treatment of influenza
- when to use them
Neuraminidase inhibitors (prevent interaction between HA and sialic acid receptor)
as new virus is made they are stuck by HA and sialic acid receptor and needs Neuraminidase to cleave it to remove the new particle. So this drug blocks this cleaving and prevents this virus infecting other cells
- oseltamivir
-only useful at very early stage of illness - useful to prevent spread - zanaamivir)
- Vaccination
- trivalent (contains proteins of H1N1, H3N2, B)
what causes of symptoms
IFN-a causes influenza symtpoms
IL-6 causes fever
features of influenza virus particle
haemagglutinin
Neuraminidase
Envelope
Priotein capsid
RNA
Viral proteins
