Summary
Summary Study Unit 2 Viruses Part 2
- Course
- Genetics 344
- Institution
- Stellenbosch University (SUN)
Part 2 of the study unit on viruses.
[Show more]
Seller
Follow
Content preview
GENETICS 344: ADVANCED TOPICS IN GENETICSSTUDY UNIT 2: VIRUSES
LECTURE 5
8. TOPICAL VIRUS EXAMPLES
8.1 EBOLA VIRUS DISEAS (EVD)
• Symptoms usually begin with influenza-like stage
o Fatigue, Fever, Headaches, Joint&muscle&adominal pain
• Incubation period = 2 – 21 dys
• Bleeding phase
o 5 – 7 dys after 1st symptoms
o Internal & subcutaneous bleeding – Reddening of eyes & bloody vomit
• Death within 7 – 16 dys after 1st symptoms
• EVD outbreaks can have case fatality rate of up to 90%
• History:
o Named after Ebola river in Central African Republic
o 1976 – 2013 – WHO: 1 716 cases
o 2014 – 11 300 deaths
• Outbreak in 2018 – started in Congo
o Infected 2 620 people
o Killed 1 762 – mortality = 67%
o Confirmed case in big city with airports, etc – easy spread via transit
o Ebola doesn’t spread very rapidly
• Spread is dependent on:
o Size of particle
o Droplet spread
o Host receptors
o Onset of symptoms
o Stability of virion
• EVD occurs after ebola virus is transmitted to initial human via contact with infected
animal’s body fluids
o Zoonotic disease
• Human-to-human transmission via:
o Direct contact with blood/bodily fluids from infected person
o Contact with contaminated medical equipment
• Potential for widespread EVD infections is considered low
o Disease is only spread by direct contact with secretions from infected person
• Quick onset of symptoms
o Easier to ID sick individuals
o Limits person’s ability to spread disease by traveling
• Airborne transmission hasn’t been documented during EVD outbreaks
• Are infectious as breathable 0.8 – 1.2 μm droplets
• Fruit bats = Natural reservoir of virus – not affected by virus
,8.1 EBOLA VIRUS DISEAS (EVD)
• Etiology:
o EVD is caused by 4 of 5 viruses in genus Ebolavirus / family Filoviridae/ order
Monogevirales:
o 4 disease-causing viruses:
▪ Bundibugyo virus (BDBV)
▪ Sudan virus (SUDV)
▪ Taï Forest virus (TAFV)
▪ Ebola virus (EBOV, ZEBOV, Zaire virus)
o Ebola virus is most dangerous – responsible for largest number of outbreaks
o 5th virus = Reston virus (RESTV) Not thought to be disease-causing in humans
• Ebola Virus Structure:
o Filamentous particles
o May appear in shape of shepherd’s crook / in shape of U or 6
o May be coiled / branched
o 80 nm in width – ranges from 974 – 1086 nm in length
• Ebola Virions:
o Linear
o Non-segmented
o ss(-)RNA
o Non-infectious
o Possess inverse-complementary 3’ & 5’ end
o Don’t possess 5’-cap
o Are not polyadenylated
o Not covalently linked to protein
o 19 kb long & contain 7 genes
o Carries polymerase with it to start process before replication
, 8.1 EBOLA VIRUS DISEAS (EVD)
• Replication
o Ebola virus binds to cells with anchor protein (GP) on surface of virus
o Attachment to host receptors through GP glycoprotein like DC sign & DC-SIGNR
o Cellular receptor like HAVCR1 (TIM1) binds phosphatidyl serine on virion membrane
▪ Signal is transduced into cell that trigger micropinocytosis program allowing
virion entrance
o Macropinocytosis
▪ Mechanism for cell to ingest extracellular liquid & dissolved molecules
▪ Exploited by viruses to get in cells
o GP1 interacts with host NPC1 in late macropinosome
▪ Promotes fusion of virus membrane with vesicle membrane
o Ribonucleocapsid is then released into cytoplasm
o Sequential transcription
▪ Viral mRNAs are capped & polyadenylated by polymerase stuttering in
cytoplasm
o Replication presumably starts when enough nucleoprotein is present to encapsidate
neo-synthetized antigenomes & genomes
o Ribonucleocapsid interacts with matrix protein
▪ Buds via host ESCRT complexes from plasma membrane
▪ Releasing virion
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller joeyolivier. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R50,00. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
72042 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy summaries for 14 years now