L33_RNA Viruses 2 Flashcards
What type of virus is rotavirus, what type of genome, is it segmented, is it enveloped, what shape capsid?
Reovirus, dsRNA, segmented, naked, icosehedron
What type of virus is the influenza virus, what type of genome, is it segmented, is it enveloped, what shape capsid?
Orthomyxovirus, - ssRNA, segmented, enveloped
What type of virus is HIV, what type of genome, is it segmented, is it enveloped, what shape capsid?
Retrovirus, + ssRNA (2copies), enveloped
What does rotavirus cause, and what are the main symptoms?
Causes severe gastroenteritis, profuse watery diarrhea, dehydration, maladsoption
What demographic does rotavirus generally infect and what is the peak season?
Affects infants and children, peak incidence during the winter.
What is unique about rotavirus uncoating?
It never fully uncoats, it just loosens and allows necessary particles to enter and leave, so it protects it mRNA
How does rotavirus egress?
Either through cell lysis, or it buds into the RER and uses the secretory pathway (when doing this it acquires a temporary lipid envelope)
When does a rotavirus virion become infectious?
After processing in the gut lumen
What prevention and treatment methods are used for rotavirus?
Prevention: Two live attenuated vaccines
Treatment: Oral rehydration
What are the common symptoms of the flu?
Headache, Fever, Muscle weakness, joint aches, limited runny or stuffed nose, sore throat, coughing, nausea and vomiting
How many segments are in an influenza genome?
8
Where does flu virus transcription and replication take place?
In the nucleus, each segment of DNA has a nuclear localization signal. Each segment has RDRP on its end.
How do new flu virions assemble and egress?
They assemble at the plasma membrane and bud outwards.
What is the last step required to release a new flu virion?
The haemaglutinin is stuck to all sialic acid on surface of cell, so you need Neuraminidase to cleave these bonds and release the new virion into the extracellular space.
How is the flu virus transmitted from person to person?
respiratory droplets
What is a major target of flu drugs?
Inhibiting neuraminidases from cleaving hemaglutinin-sialic acid link
What type of treatments are available for people with the flu?
Antiviral drugs
Is the flu shot a live vaccine?
No it is inactivated
Is the flu mist a live vaccine?
Yes but it is attenuated given that it can only replicate in the cool parts of your respiratory tract.
How many strains are covered by a typical flu vaccination?
3 different strains, that change depending on the predicted circulation for that season.
What is the difference between Antigenic shift and drift?
Shift= genetic shuffling Drift= random mutation
how often do flu pandemics happen?
every 10-12 years
List some symptoms of acute HIV infection
Fever, weight loss, mouth sores and thrush, myalgias, liver and spleen enlargement, systemic lymphadenopathy, nausea and vomiting, headache, possible rash
What does the HIV virus bid to?
CD4 and chemokine receptors on T cells and macrophages
Have antibodies shown any effectiveness agains AIDS?
No
How does an HIV virus enter a cell?
It binds to CD4 and co-receptor and fuses with the cell
Describe the un-coating of HIV virus
similar to rotavirus, HIV does not completely un-coat
Describe the life cycle of HIV once in the cell
Reverse transcriptase produces a compliment strand to the two copies of the + ssRNA genome. These copies migrate into the nucleus and are inserted into the host genome. The host RNA poly 2 transcribes the viral genome, this transcript can be used for protein synthesis or as a genome of a new virion.
describe the translation and modification to produce final HIV proteins.
The initial translation creates a poly protein which then needs to be cleaved by a protease into individual protein. Protease inhibitors are a major drug target.
Describe the maturation and egression of the HIV virus.
2 copies of the ssRNA genome and viral proteins egress from the cell by budding. Final maturation happens outside of the cell where proteases help rearrange capsid proteins into the final trapezoidal shape. This final maturation process is another target for HIV drugs
What metrics are used to diagnose HIV?
Serological assay for antibodies (GP120)
Nucleic Acid assays for viral load
CD4 T cell count
What are some prevention measures used for HIV?
Risk avoidance, community awareness, Public health measures, Antiviral Drugs (Chemoprophylaxis)
How many different Antiretroviral Therapies are used on a person to treat AIDS
Multiple to avoid resistance.
What are some of the types of HIV drugs?
Nucleoside inhibitors, non-nucleoside inhibitors, protease inhibitors, integrase strand trasnfer inhibitors, CCR5 antagonists
What do the H and N stand for in typing a flu?
Hemagluttinin and Neuraminidase
What two RNA virus virions undergo final maturation outside of the cell?
HIV and Rotavirus.
Name a few differences between the flu and primary HIV infection symptoms
In primary HIV you dont have the cough and nasopharynx symptoms. you also see mouth sores and hepto and splenomegaly, systemic lymphadenopathy
