lecture 2 part 2 Flashcards
name the 4 most common viral diseases
common cold
influenza
flulike syndromes
gastroenteritis (stomach bug – diarrhea and vomiting)
name six DETERMINANTS of viral disease (affect how virulent a virus is)
-exposure/ entry – very virulent if enters through respiratory
-viral dose: higher = greater chance of infection
-target tissue/tissue tropism – if it has to move to a secondary site, there’s more time to deal with it
-permissiveness of cells
-host status (age, immunity, health)
-viral structure - naked vs enveloped. in gut, naked virus has a better chance of surviving
explain the pathway of the POLIO VIRUS
virus is ingested and goes through GALT. the virus invades via M cells and replicates in monocytes.
the virus then gets to a regional lymph node and replicates there.
from the lymph node, it goes into the blood (viremia) and crosses the endothelium of the BLOOD BRAIN BARRIER.
it goes into the spinal cord and replicates there, causing cell destruction and paralysis
then the virus is excreted in the feces through the gut
what is the primary site of infection for the polio virus
the gut
what are the 3 classes of viral vaccines?
- killed
- live attenuated
- subunit
differentiate between the 3 types of viral viruses
killed – killed virus
attenuated – have mutations (has to be more than one). they are whole viruses that look normal from the outside but are incapable of sustaining an infection
subunit based – subunit of a viral protein is introduced. it is not functional unless it has the other subunits
which is considered the “best” type of viral vaccine and why
attenuated viruses look normal they just have mutations that make it incapable of sustaining an infection
attenuated viruses induce an antibody AND a T cell response
subunit and killed viral vaccines only induce an antibody response
which specific viral vaccines are subunit based?
hepatitis B
COVID
measles, mumps, and rubella are which type of viral vaccine?
live attenuated
besides measles, mumps, and rubella, name more vaccines that are live attenuated
polio, rotavirus, yellow fever, chicken virus, shingles
name 3 specific viral vaccines that are KILLED
hepatitis A, rabies, influenza
explain 5 ways in which viruses attempt to evade the immune system
-produce proteins that inhibit the IFN response
-modify viral antigen to make them look like friendly host proteins
-cell-cell spreading (synctia)
-suppress antigen presentation (interfere with binding of peptide to MHC class 1)
-inhibit lymphocytes(T cells, B cells, NK cells)
what is the BEST viral immunosuppressor
HIV — interferes with the helper T cells
which 2 viruses have a MODERATE degree of immunosuppression
measles and rubella
which 2 viruses have a low degree of immunosuppression
HSV, Vaccinia
explain how HSV and Vaccinia exhibit ___ immunosuppression
LOW immunosuppression
produce proteins that function as viroreceptors or VIROKINES – compete with the cytokines of the host organism
which virus exhibits immunosuppression by causing the overproduction of cytokines?
measles – moderate response
true or false
the immune system itself is a MAJOR contributor to disease or symptoms caused by some viral infection
true:
ex:
-experiencing flu like symptoms is the effect of the PRODROME phase of the immune system – due to the innate response. cytokines cause the hypothalamus to raise the temperature
type IV hypersensitivity reactions –allergic reaction. mediated by effector T cells
Type III hypersensitivity reactions: IgG antibody-antigen deposits form in small vessels and alveoli. aggregate there and clog the vessels
type 3 and type 4 hypersensitivity reactions are caused by….
VIRUSES
Explain how the hepatitis B virus exhibits immunopathologies
causes hypersensitivity response
CD8+ T cell – causes type IV hypersensitivity
Antibody – causes type 3 hypersensitivity
Which TWO viruses induce both type 3 and type 4 hypersensitivity reactions? what is the term for this?
hepatitis B and RSV
called immunopathologies
a “cytokine storm” can cause…
septic shock
ARDS – acute respiratory distress syndrome
name 4 symptoms of ARDS and the cause of it
cause = cytokine storm. too many pathways lead to the production of cytokines which is not good for the cell
symptoms:
necrosis (death of cells due to lack of blood supply)
tissue destruction
influx of leukocytes (white blood cells)
dilation of blood vessels
what will happen in the prodrome phase is very long?
the virus will continually replicate at the primary site. eventually they will accumulate and be released to the secondary site of infection – bad symptoms will be experiencede
explain the disease course of a virus when the prodrome phase is short
prodrome phase lasting ~1 day – symptoms will be experienced at the primary site of infection, and then there will be healing after around 4 days
