Lecture 4: Pandemics and emerging diseases Flashcards
Why are viral infections more common now than bacterial
Hygiene decreased bacteria
What does H and N mean in H1N1
H and N proteins
What infection has H and N
Influenza
Define HA
Hemagglutinin, allows the virus to bind to host cells.
What are different HA proteins able to do
They have different specificities for molecules thus some infect upper airway and some lower airway
What are NA proteins
Neuraminidase, allows for the release of viruses from the cell surface
Why is NA important
Important for entry into the cells and the spread of progeny viruses
What do HA and NA together make
Viral capsid
What parts of the virus are “seen” by the immune system
HA and NA
What causes the virus to be invisible to your immune system?
Changing the amount of H and N
What is the influenza genome made up of
7-8 individual single stranded RNA molecules
Why does RNA help the influenza
Highly prone to mutation
Why does being single stranded help the influenza
Prone to mutation
Does the influenza strain have proof reading abilities
No
What is antigenic drift
Mechanism for variation in viruses that involves the accumulation of mutations within the genes that code for antibody binding sites
Describe the steps of viral infection
- Virus infects target cells
- Inserts RNA genome into cell
- RNA is replicated
- Viral protein synthesis
- New virus is made and removes from the cell free to infect more cells
What happens if two different influenza viruses infect the same cell
The process of reassignment can occur which is when gene segments are swapped between influenza viruses
What can result from reassortment
Completely novel pathogens, antigenic shift
What does reassortment allow for different species
Allows influenza viruses to jump from species
What bad thing can happen do to reassortment
A novel influenza that could kill thousands
What contribute to reassortment of the influenza virus
- his density farming practices with mixed species
- travel
- reluctance to report newly detected pathogens
What did the 2009 H1N1 cause
- pandemic
- fire drill
- scientists are crying wolf
