Complete and in-depth Term Test 2 Summary Notes for CSB351 for EXAM prep. Kevin has combined notes from his peers and his own work to provide the most complete and comprehensive study guide for all types of students. He has achieved an overall cumulative GPA of 3.95 during his undergrad at the Univ...
Lecture 21 – Enteroviruses: Poliovirus, Rhinovirus
So polio used to be a thing
o Ubiquitous vaccinaton has mostly eradicated it from the world
But not completely, stll fares up in the Middle East/South Asia
o Been around forever
FDR and Tutankhamun could get it
Polio as a template: enteroviruses
o Specifc type of picornavirus
o Polio rapidly mutates in the gut, but is stable outside
Hence, we can use polio vaccines from the 1950s and they’d stll work
And we don’t need boosters
o Polio is paralytc because it moves to the brain
Others move to skin, muscle or liver (foot and mouth, myocardits, hepatts A)
o Transmission of polio
Oral-fecal-oral, and nasopharyngeal
Infecton can create viremia, but most growth is in gut
GALT
o Gut associated lymph tssue
o Polio grows in GALT for fve weeks
Also grows in intestne, CCS, lymph tssues
Mostly affects unvaccinated children
Herd immunity
o Enough immunizatons mean polio dies out before it can fnd a
host
Sanitaton
o Clean out the feces, that would help
Some people are asymptomatc carriers
o Clinical features of infecton/pathology
Types of infecton
Asymptomatc (90%)
o Virus only in mouth, throat, gut
Abortve poliomyelits
o Flu-like
Fever, sore throat, headache, constpaton, vomitng
Invasion of CCS (1-2%)
o Meningits, back pain, muscle spasm
o Stll no paralysis
Paralytc poliomyelits (0.1-2%)
o 1-4 weeks afer infecton
o 10% mortality rate, 80% paralysis rate
, o Flaccid paralysis
Weak, asymmetrical, no loss of sensaton
o 1/200 cases lead to irreversible paralysis
Virus enters bloodstream, invades CCS, usually near
legs
Virus destroys nerve cells, muscles atrophy and lose
total functon
Acute faccis paralysis (ALP)
o Cranial (bulbar) paralysis
Trunk, thorax muscles get infected and atrophy
Worst case, polio gets to brain stem, atrophying
swallowing, speaking and breathing
The iron lung is supposed to breathe for them
Infecton route
Virus enters orally, multplies in tonsils, lymph nodes, gut
CCS infecton requires either viremia or infecton directly from intestne
Preventon
Salk vaccine
o Killed virus
o Inject formaldehyde-treated virus into patent
Sabin vaccine
o Live, atenuated
o Drip atenuated virus onto tongue
Eradicaton
o Cot totally eradicated like smallpox or rinderpest, but we’re
getting there
o Only endemic to Afghanistan, India, Pakistan, Cigeria
Postpolio syndrome
Cew-onset muscle atrophy and weakness, plus pain, 30-40 years afer
inital infecton with poliovirus
VAPP
Vaccine-associated paralytc poliomyelits
Oral polio vaccine virus gets into unvaccinated individuals and causes
disease
o Oral vaccine partcles have probably reverted to virulence
Rhinovirus
o The common cold
o Structure
Icosahedral, non-enveloped
o Genome
+ssRCA, like the other picornaviruses
Over 100 serotypes
Polyproteinous
, Cleaved into individual proteins
o Replicaton
Entry
ICAM-1 receptor on cell matches with rhinovirus capsid with
capsomeres
10% of rhinoviruses use some other receptor
Uncoatng, transcripton of polyprotein mRCA (in cytosol), replicaton of
genome through –ssRCA intermediate, translaton and processing of
polyprotein, packaging
o Transmission
Aerosol, airborne or direct contact
Tropism for nasal mucosa
o Symptoms
Sniffling, sneezing, aching, coughing, stuffy-head, etc.
o Cure for the common cold?
Zinc, maybe?
Zinc compettvely inhibits ICAM-1 before the cold shows up
So it’s bad if you have a cold already
Does not work orally, either
o Must stck zinc up your nose
Lecture 22 – Picornavirus: Hepatitis A, Coxsackie,
Aphthoviruses
Con-polio enteroviruses
o Coxsackie A/B, echovirus, enterovirus D68; let’s look at coxsackie
Coxsackie A
Hand, foot and mouth virus
Coxsackie B
Pericardits/myocardits, Bornholm disease
o Distributon
Global
o Host range
Humans, maybe chimpanzees and monkeys
o Epidemiology
Same as other enteroviruses
Found in water, soil, vegetables, shellfsh
o Transmission/tropism
Fecal-oral route
Aerosol transmission if pulmonary symptoms are present, if there is
conjunctvits, or if subjects have it in their throat
o Pathogenicity
Virus replicates in throat and small intestne, and lymph nodes around those
, Via blood or lymph, virus reaches target organs
o Symptoms
Many different clinical symptoms, hard to tell
Enteroviruses usually have featureless diseases
Fever, rash, fu-like syndrome
o Tissue-level effects
Skin/mucosa
Herpangina (mouth blisters)
Stomatts (oral mucosa infammaton)
Hand, fooy mouth disease
o Vesicles on palms, soles, mouth
Striated muscle
Pleurodynia (Bornholm disease)
o Sudden chest pain due to diaphragm
o General malaise
Heart
Myocardits, pericardits, myopericardits
o Infammaton of heart and/or heart sheath
Ofen fatal in infants
Gut, liver
Abdominal pain, hepatts (rare)
COT diarrhea
Pancreas
Strong implicatons of type I diabetes, which is the one where the
pancreas islet cells get destroyed
o Autoimmune reacton
Respiratory
Pneumonia, cold, respiratory tract infectons
Eye
Conjunctvits (pinkeye)
o Immune response
Antbodies are lifelong, although it does depend on the circulaton of a virus in a
community
o Preventon/control
Co vaccine
Don’t poop where you eat
Hepatoviruses
o Formerly enteroviruses, now classifed as their own thing
o Hepatts A
o Characteristc features
Liver cell tropism
Small/absent VP4 protein
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