Viral Pathogenesis Flashcards
3 ways for viruses to be maintained in nature?
- shed into environment
- vector: insect, needle
- congenitally
a systemic viral infection is worse than a local ? T/F?
False. Not correlated with severity
Explain tropism
anatomical localization of infection (initially determined by receptor specificity
What’s parenteral inoculation?
via mosquito or bite
What determines initial site of virus deposition in the airways? Explain
droplet size.
>10um= nose
5-10um = airways
<5um = alveoli
What the body temp in nose vs. lung bases?
33 degrees nose
37 degrees lung bases
Rhinovirus spreads from initial site?
Nope. localised
3 viruses that spread from infection site?
MMR baby. and varicella
3 viruses that stay localised?
rhino
influenza
resp syncytial virus (RSV)
What kind of cytopathic effect could RSV have on lungs?
presence of giant cells
How does measles infect you?
breath it in
replicate in epithelials of URT
infects Macros, lymphos, DCs into lymphnodes
circulate and amplify and go back to lungs and mouth
How are HIV and measles similar?
both cause immunosuppression
What are koplick spots?
measles initial replication causes aggregations of lymphocytes
T/F? Viruses that infect GI have an envelope for more protection?
FALSE YO! are acid and bile resistant, no envelope
What does rotavirus cause?
diarrhea
two viruses that infect GI but spread
Hep A
polio
HIV and Hep B don’t have receptors for epithelial cells, how would they enter?
abrasions/breach via rectal route
What’s an M cell?
kinda like a DC cell but in the GI, they’re the sentinels in the GI sampling and presenting to underlying lyphoid tissue
how many shells does rotavirus have? why?
triple shelled to withstand the GI environment
What does rotavirus do to you?
infects GI, destroys M cells, epithelial cells, inflammation, gastroenteritis
Rota virus causes diarrhea, how is it amplified or dangerous to children?
dehydration
NSP4 protein increases fluid secretion
What’s the difference between primary and secondary viremia?
primary: in circulation amplifying
secondary: reaches target tissues
Name a systemic virus that infects meninges
enteroviruses
Name a systemic virus that infects CNS
polio
coxsackie
Name a systemic virus that infects skin
group A coxsackie (hand/foot/mouth)
echovirus
Name a systemic virus that infects muscle
Group B coxsackieviruses
What virus enters transcutaneously?
papillomavirus
HepB,C,HIV
What viruses from insect/animal bites?
dengue virus - fever, rash, poly arthritis
conjunctiva route is rare, what viruses can enter this way?
adenovirus
enterovirus 70
HSV
What’s the mechnism of spread of a virus?
epithelium lymph capillary vein lymph node circulation
in primary viremia, where is the virus
free in plasma
in secondary viremia, it infects vascular endothelium or release in large amount from what two organs?
liver
spleen
How is viremia managed by the immune system? how long?
macrophages to the rescue! take 1-2 weeks
What is cell-associated viremia?
spread via the immune system
HIV - CD4
measles/dengue: monocytes
what does smallpox do to a fetus?
it’s cytocidal, death and abortion
what do non cytocidal viruses do to foetuses? 2 examples?
developmental abnormalities: rubella, cytomegalovirus