Influenza
What is the structure of influenza
RNA genome
capsid is spherical but variable in shape (pleomorphic) has a viral envelope with 2 spike proteins
the seasonal flu are what types of influenza
type a and b
what is pneumonia
inflammation of the lungs
What are the most common causes of viral pneumonia hospitalizations
1.COVID caused by SARS
2. Serious complications of influenza type a
3. RSV or respiratory syncytial virus
What type of vaccines do we have for bacterial pneumonia
Subunit vaccines based on the capsule antigens
What are the two spike proteins and what are there roles
H-protein: binds to receptor for viral attachment and entry
N-protein: cuts the virus free from the cell during budding
What is type b associated with and who does it typically infect
relatively mild infection and usually affects children and immunosuppressed
What is Pneumonitis
Non-infectious Pneumonia
What is the structure of RSV
enveloped virus with RNA genome, its spike protein is G-protein which it uses for attachment, binds to ciliated cells, capsid shape is variable
Why are people allergic to the flu vaccine
because the virus is grown using chicken eggs and some people can have a reaction to the trace amounts of egg proteins in the vaccine
What is the primary natural reservoir for type a
wild aquatic birds
What viral reproduction of type A causes
Cytopathic effects in the tissues they infect
What is the most common gram-positive and gram-neg types of pneumonia
Gram-Positive: Strepococcus pneumoniae also reffered to a pneumococcus/ pneumococcal pneumonia (primary)
Gram-Negative: Haemophilus influenza also reffered to as H-flu or Hib (hib is the most serious form of the disease it is type B) (opportunistic)
Summary of RSV mode to pathogenesis
replication kills cells of air passages, inflammation causes fluid build up and bronchiolitis
Why is RSV a threat
Because of its transmissibility, it is highly contagious, and 99% of children will have RSV at least once by the age of 2.
Why is type a able to be passed to multiple host species
Because of the H-protein, which receptor is sialic acid and can be found in the lung cells of most mammals
what causes the symptoms of influenza type a
respiratory symptoms: caused by viral replication in the respiratory tract
common symptoms: caused by an inflammatory response to infection
Pneumolysin
only on S.pneumoniae it is a type 2 toxin that destroys neutrophils and macrophages leads to inflammation
What is the structure of covid (SARS-CoV2)
enveloped RNA virus with helical capsid, contains a S-Protein that binds to ACE2.
Why does covid effect the blood vessels and heart too not just the lungs
Because they have large numbers of ACE2 receptors
define genetic reassortment, antigenic shift, and antigenic drift
Genetic reassortment: mixing of genome segments when two flu subtypes co-infect the same host (usually pigs)
Antigenic drift: small changes in viral antigens caused by rapid mutations due to error-prone RNA polymerase
Antigenic shift: a major change in viral antigens due to genetic reassortment that produces an entirely new subtype
Describe the flu vaccine
it is either inactivated or a subunit(acellular) and trivalent, meaning it contains three different antigens: two type A strains (H1N1 and H3N2) and one type B strand
What does H-flu release to cause inflammation and what does it do
LPS
leads to an inflammatory response that damages lung cells causing fluid leaking in the alveoli and then adds more fluid by increasing mucous production
Summary of Covids mode of pathogenesis
Waves of replication progress through respiratory tract, blood vessels, and heart
Is there a treatment for RSV
not really treatment is limited to oxygen supplementation, CPAP, and ventilation