Flu, RSV, Ebola (complete) Flashcards
What is the basic structure of influenza?
- RNA virus w/ a segmented genome
- Genome: 8 pieces of ssRNA
- Lipid envelope
Have A and B types
What are important proteins in influenza?
- Hemagglutinin (surface)
- Neuraminidase (surface)
Matrix protein lines inner lipid envelope
Describe the role influenza plays in pathogenesis
Causes problems in:
- upper/lower respiratory tract
- nasopharynx
- trachea
What is the basic structure of RSV?
- Paramyxoviridae family
- ss, nonsegmented RNA virus
Have A and B types — A causes worse disease
What are important proteins in RSV?
- F protein: fusion of viral envelope w/ host cell
- G protein: initial binding of virus to host cell
Describe the role RSV plays in pathogenesis
- Causes severe damage to epithelium and brochiolar ciliary apparatus
- Causes collection of fluid in bronchioles => obstruction of brochioles and alveoli — maybe collapse of emphysema of airway
- Can constrict smooth muscle of bronchioles
What is the basic structure of ebola?
- Enveloped, negative sense RNA
What are important proteins in ebola?
- Glycoprotein (important for attachment/entry)
- Matrix proteins VP40 (structure, stability) and VP24 (assembly, budding)
Describe the role ebola plays in pathogenesis
- Enters body through mucosal surfaces or cuts in skin
- Only need a few virions for infection
- Travels in immune cells to regional lymph nodes where it replicates and spreads throughout the body
Outline routes of viral entry of influenza virus
- Binds to sialic acid
- Endocytosed
Which cells/organs are infected with influenza infection?
- Upper/lower respiratory tract
- Nasopharynx
- Trachea
Describe the mechanism of infection of influenza
- Binds to sialic acid
- enters cell
- replicates
- releases from cell
Describe the clinical presentation of influenza infection
- Adolescents&adults: fever, chills, myalgias, HA, cough
- Infants/toddlers: GI probs, fever >103, anorexia, resp probs
- Neonates: high fever, lethargy, decreased eating, mottling, apnea
Which cells/organs are infected with RSV infection?
- Nasopharynx
- Lower respiratory tract
Describe the mechanism of infection of RSV
- Invades conjunctiva/nasopharynx
- Replicates in nasopharynx => then in respiratory epithelium
- Spreads to lower resp tract by inhalation or spread
Describe the clinical presentation of RSV infection
- Respiratory distress
- Wheeze/rhonchi
- Hypoxia
- Copious secretions
- Brochiolitis
Which cells/organs are infected with ebola infection?
Infection of vessel wall cells => severe fluid/blood loss
Describe the mechanism of infection of ebola
- Replicates in lymph nodes => very efficiently
- Induces massive cytokine storm => destroy vessel walls and induce DIC, shock
- Causes dysregulated immune response and extensive tissue death
Describe the clinical presentation of ebola infection
- IP: 2-21 days, usually 6-10 — not contagious until symptomatic
- Febrile (fatigue, malaise, body aches)
- GI probs (n/v/d, epigastric pain)
- Shock
- Gastro hemorrhage, secondary infections, meningoencephalitis
Describe the transmission of influenza virus
- Respiratory route (coughing/sneezing)
- Also contact w/ infectious particles on hands or inanimate objects
Describe the effective prevention strategies for influenza
- Vaccination!!!
- Also washing hands
- Sneeze into arm
Just wash your fucking hands!!!
Describe the transmission of RSV
- Large, droplet spread — respiratory spread
Describe the effective prevention strategies for RSV
wash yo handzz
Describe the transmission of ebola
Enters through mucosal surfaces or cuts in skin
Describe the effective prevention strategies for ebola
Avoid body fluids of someone with ebola
What are the different stages of vaccine development for influenza?
Phase 4! Got em out and using em!
What are the different stages of vaccine development for RSV?
- No vxs
- Used to be one in the 60s but causes crazy horribleness (kids who got the vx were more likely to be hospitalized when they got the disease)
What are the different stages of vaccine development for ebola?
- 2 vaccines in phase 2/3 trials
- another vx in phase 1
What are the differences between the types of influenza vaccines?
IIV:
- 3 or 4 strains
- Killed virus
- IM
LAIV:
- 4 strains
- Live
- Intranasal
What are the differences in populations in terms of who can and cannot receive certain types of vaccines?
IIV:
- > /=6 months
- Yes for preggers
- Yes for immunocompromised
LAIV:
- 2-49 years
- No preggers or immunocompromised
- Slightly higher cost
Describe antigenic drift
- Point mutation in neuraminidase
- Does NOT change subtype of the virus — just a minor change
Can result in epidemic b/c Abs that were resistant to previous flu type are now unable to prevent binding of flu to sialic acid
Describe antigenic shift
- reassortment of genome segments
- A major change => new subtype
- Caused by exchange in gene segments
- May result in pandemic
Think Contagion: bat and pig genes combined => pandemic craziness
Describe the origin of pandemic H1N1
- Mexico
- Has gene segments similar to viruses found in pigs
Describe the basic epidemiology and morbidity/mortality of H1N1
- Affected primarily those under 24yo
- Hospitalizing primarily those between 18 and 64
- Pregnant women at crazy high risk
Discuss the newly-emerging influenza viruses including H5N1. What is an outline of its geographic occurrence and its importance to public health?
- Started in China => spread to most of Asia, and parts of ME and Africa
- Infects whole flocks of birds (e.g. wild and domestic, chickens, geese)
- Have to wipe out whole flocks to prevent spread — otherwise horrible public health problems
Also just imagine your whole livelihood, income, family, everything relies on a flock of chickens and then they get this flu… they have to be killed otherwise it will affect other families in the same boat. Plus it might get you sick too!
Describe the necessary qualities in an influenza virus strain to potential cause a pandemic
1) Emergence of new flu virus subtype
2) Virus must infect humans => cause serious illness
3) Sustained transmission and spread (continue w/o interruption) easily among humans
Describe the stages of a pandemic
Efficient and sustained human-to-human transmission
Describe the stages leading up to a pandemic
1) Low risk of human cases
2) Higher risk
3) No or very limited human-to-human transmission
4) Evidence of increased transmission
5) Evidence of significant transmission
6) Efficient and sustained transmission (PANDEMIC)
Describe the naming system of influenza A viruses
Virus type / geographic origin / Strain # / Year of isolation (Virus subtype)
Eg for H1N1:
A/California/7/2009(H1N1)
Describe clinical management of ebola
- No approved therapies
- Supportive: fluid repletion (b/c of leaky vessels)
- Dialysis, ventilation
- Pt isolation
Describe the treatment of ebola
Abs from survivors (convalescent serum) — trial stage
Drugs:
- favipiravir => under development, trial in Guinea
- Brincidovovir => targets DNA viruses (used in tx of US ppl)
