Influenza and Corona Viruses Flashcards
Non-human animal surveillance
surveillance for viruses that could threaten wildlife, livestock & domesticated animals
In silico prediction developmet
development of computational methods for predicting emergence risk of zoonotic viruses identified from animal surveillance
Guided surveillance of samples from human illness
surveillance systems for early detection of spillover and emergence of novel human infections
Where does COVID-19 fall interms of transmission & mortality?
less of fatality rate but the transmissibility rate is higher
Overview of Influenza viruses
family Orthomyxoviridae
- (-)-sense, segmented, single stranded RNA viruses
- 4 genera: A, B, C, D
Which influenzavirus genera are associated as seasonal influenza viruses?
A, B and C
Influenza A and B can be associated with…
pigs
Influenzavirus A hosts:
wild aquatic birds, mammals, humans
Influenzavirus B hosts:
humans, seals, ferrets
Influenzavirus C hosts:
humans, dogs, pigs
Influenzavirus D hosts:
cattle
What is the relationship like for influenza (i.e. the pathway)?
NOT a direct linear relationship like ebola is
- most start with wild birds & then can take diff areas
What is the virology of Influenza A?
- cirnodal
- (-) RNA
- enveloped
- influenza virus genome is segmented (8 diff.) –> allow for influenza viruses to mix/match their segments, which increase complexity of influenza viruses (can increase virulence/pathogenicity)
- viral RNA-dependent RNA polymerase - have to carry their own RNA polymerase
- HA and NA proteins (guide the cells that the virus can attach too & also guide the antigens that we have to produce vaccines against)
Where do influenza A viruses circulate in?
humans, domestic animals, pigs, horses, poultry & migratory birds
What is the virology of influenza a?
- 16 diff HA subtypes identified
- 9 NA subtypes
- HA & NA are most antigenically variable (able to swap out & change)
- bat influenza A-like viruses increase this to 18 & 11, but cannot reassort with IAVs (monitor what they can do but haven’t seen it yet)
Influenza __ viruses are NOT divided into diff subtypes
B
Which viruses were seen to show reassortment?
1918 “Spanish influenza”
1857 “Asian influenza”
1968 “Hong Kong influenza”
Antigenic drift…
results in progressive changes of HA & NA antigenicity through mutations (re: seasonal flue)
- RNA can mutate (inability to proof read)
Antigenic shift…
results from genetic reassortment through RNA segment changes b/t different strains (re: pandemic flu)
- can produce drastic changes
What is the main take-away from the timeline of influenza pandemics?
everytime we have a pandemic virus that emerges, that pandemic virus becomes the new seasonal virus until it itself is replaces (either through another pandemic or through another large scale transmission event)
What happens when we get infected by influenza virus?
- binding & entry mediated by HA - sialic acids
- mediated by HA & MA (pH-dependent steps)
- pH shift (& virulent opens up)
Purpose of HA?
helps guide interaction b/t virus & host cell for uptake
Purpose of NA?
helps facilitate the release of new virulent copies
What is the influenza virus epidemiology?
- seasonal influenza outbreaks typ. occur in winter months
- symptoms: onset ~1-4 d post-exposure (quick)
- ~3-5 million cases of severe ILI globally each year
- transmission: presymp. phase (-1 d) to 5-7 d post-symp. onset
- transmission primarily in children
- droplets, aerosols & fomites
What are influenza virus therapeutics?
- M2 inhibitors (adamantanes) eliminated as clinical therapy due to resistance
- best clinical results of NA inhibitors found within 2 days of symptom onset
Influenza vaccines include:
live-attenuated, recombinant, & inactivated vaccine
Live-attenuated:
- recommended for ppl 2-49 years of age
- contraindicated for ppl w/ weakened immune system, pregnant women, or certain chronic diseases
Recombinant:
- eliminates antigenic mutations from cell or egg-based replication
- > 18 years of age
Inactivated:
- comprised of killed influenza viruses
- > 6 months & older, including pregnant women & people with chronic medical conditions
Coronaviruses:
- family: Coronaviridae
- RNA viruses with large genomes ((+)-sense, single-stranded RNA genome
- 4 genera: alpha, beta, gamma & delta
____coronaviruses & ____coronaviruses ONLY infect mammals
alpha
beta
- usually cause respiratory illness in humans & gastroenteritis in animals
- can have large impacts on livestock
What is a difference b/t influenza & coronavirus?
influenza is (-)-sense & coronavirus is (+)-sense
What does coronaviruses look like?
- enveloped
- non-segmented
- spikes!
Spike proteins:
dictates which types of cells it can interact with
(coronavirus is ACE-2)
4 ________ usually cause mild upper respiratory disease in humans
human coronaviruses (HCoVs)
3 _________ cause severe respiratory disease
highly pathogenic HCoVs
Does coronaviruses all originate from same animals?
NO - bats or rodents usually
What is the SARS-COV-2 emergence?
atypical pneumonia cases in Hubei Province, China
- initial reports of a “SARS-like” illness in China - late December
- potential link to Huanan Seafood Wholesale Market
How does COVID-19 pathogenesis differ from influenza with the onset?
5 days onset where they can transmit to community (greater than the 1 day in influenza)
What is the COVID-19 therapeutic development?
drugs that attack 2 primarily points in replication cycle:
- Paxlovid
- inhibit proteolysis step (which converts polyproteins –> dependent RNA transcriptase complex) - Molnupiravir & Remdesivir
- inhibit RNA replication
Emerging infections diseases have disportionate effects on vulnerable communities, for ex:
2009 Influenza Pandemic
- First Nations members:
- were 6.5X higher likelihood of ICU admission
- 8X higher for hospitalizations
- ~7-10% of all hospitalization, ICU admissions & deaths
Traditional development vs. SARS-COV-2 vaccine development
15 years or longer vs. 10 months to 1.5 years total
What is unique about SARS-COV-2 opposed to SARS-COV?
zoonoses
- NOT unique to humans (can move from humans –> animals & then back to humans)
