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ENVB 437 Study Guide - Winter 2018, Comprehensive Midterm Notes - Virus, Dna, Protein


Department
Environmental Biology
Course Code
ENVB 437
Professor
Gordon Hickey
Study Guide
Midterm

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ENVB 437
MIDTERM EXAM
STUDY GUIDE
Fall 2018

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Eukaryotic cells and viruses - Lecture 1 (January 8th 2018)
Slide 1 Influenza
- flu season peaks in February
Slide 2 - Why is influenza interesting?
- sin curve for the peaks in winter where flu is prevalent
- 6th cause of death in Canada
o usually due to a secondary pneumonia
o similar to HIV (opportunistic pathogen)
- this is epidemic flue
- in pandemic flu, there is a greater propensity for the virus to cause destruction of the alveoli
Slide 6 - Influenza
- seasonal influenza
o globally associated with 250,000 to .5m per year or less
o in the USA (per year)
35,000 deaths (about 200 in Canada)
>200,000 hospitalizations
$37.5billion in economic cost (influenza and pneumonia
o intervention may be required to treat secondary infection
o ex: ventilation to help breathing by lungs
- pandemic influenza
o an ever present threat
o the last pandemic was in 2009
Slide 7 - Pneumonia and influenza mortality by age
- usually very young people and very old people are more susceptible
- young people's immune system is not fully established
- older people tend to die of influenza (vaccination is important)
- in a pandemic flu, it is more common that the opposite age group (mid 20s - 35ish) die from influenza-
related reasons
Slide 9 - modes of transmission
- Droplet transmission (coughing)
- Air-borne transmission
- Contact
Sneeze:
- material from a sneeze travels 2-3m at a velocity of 150km/h
- a single sneeze releases up to 40,000 droplets
Slide 10 - Airborne tmission
o airborne transmission occurs when viruses travel on dust particles of small respiratory droplets that
may become aerosolized when people sneeze, cough, laugh, or exhale
o they can be suspended in the air much like invisible smoke
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o they can travel on air currents over considerable distances
o with airborne tmission, direct contact with someone who is infected is not necessary to become ill
ex: air dryers in public washrooms
Slide 11 - contact transmission
- two types
o direct: involves body-to-body surface contact
o indirect: occurs via contact with contaminated hands, or inanimate objects. i.e countertops, door
knobs, telephones, towels, money, clothing, dishes, books, needles, etc.
Slide 12 - definitions
- epidemic
o a located cluster of cases
- pandemic
o worldwide epidemic
- antigenic drift
o changes in proteins by genetic point mutations and selection
o ongoing and basis for change in vaccine each year
if your immune system could previously recognize that virus, you will not recognize it as
efficiently due to the change in protein structure
why we have vaccinations every year
- antigenic shift
o changes in proteins through genetic reassortment
o produces different viruses not covered by annual vaccine
dramatic change in structure
the virus cannot at all be recognized by the immune system, as if it were the first time we
were exposed
o Pandemics are due to this
the more novel the virus evolved, the worse the pandemic
Slide 14 - pathogenesis
- because it is spread in aerosols, it is very easy for it to get around
o very efficient
o difficult to avoid
- 1° infection:
o necrosis of ciliated cells of the upper respiratory tract (URT) results in fever, chills, muscle aches,
headaches, prostration, anorexia, extreme anger at whoever infected you
o usually infection for 3-7 days
death very rare from epidemic influenza - normally respiratory damage predisposes 2°
infections e.g. pneumonia to cause death
Slide 16 - clinical manifestation
- within about 4 hours you start to feel nasal congestion
- these feelings tend to dissipate after 3 days
- infectivity:
o before you start producing any symptoms - you are infectious without knowing
o you can become infective and start shedding the particles
o you are not producing the maximum load of the particles but you have the potential to infect
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