CSB351Y1 Study Guide - Final Guide: Hepatocyte, Nipple, Semliki River
8 Jun 2018
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!Viruses with positive-sense RNA genomes (non-enveloped):
!! 1. Picornaviridae: The following viruses will be covered with some details:
•General genome features:
•+ssRNA
•Vpg, IRES, encoded Poly A
•T=1, 4 subunit capsid proteins forming canyon
•polyprotein translation, cleaved by viral protease.
•replication: VPg on both new and old strand (polyUUU priming)
•Entry: endocytosed.
Polioviruses
serotype: 3
host: humans and chimpanzee
Receptor: CD155
replication: GALT, intestine and CNS
transmission: oral fecal and Nasopharyngeal
who and where: afghanistan, india, pakistan, nigeria (endemic)Any age but
mostly under 5.
Disease: 90% asymptomatic. Abortive poliomyelitis (flu like),1-2% Invasion of
the CNS (neuronal signs, but no paralysis). Paralytic poliomyelitis (0.1-2%; 10%
fatal, 80% residual paralysis=acute flaccid paralysis); bulbar paralysis
(a"ecting breathing muscles;-10% die)
tx or vaccine: 2 vaccines: SALK (IPV)=dead virus, SABIN=weak but alive(VAPP
risk).
DRUG: WIN
complications: postpolio syndrome (30-40 years post infection)
Rhinoviruses
serotype: more than a 100
host: humans only
Receptor: ICAM1
replication: nasal airway, best at 33º.
transmission: airbone and direct contact
who and where: Anyone, anywhere.
disease: cold
tx or vaccine: tough luck!! Atleast it gets easier with consequent infections
Coxsackie viruses
serotype: 2 types A (23 serotypes) and B( 6 serotypes). Antigenically unrelated
host: humans and primates (CA17 causes paralysis in monkeys
replication: Mainly in the oral pharynx, GI and lymph N. then viremia=many
possible tissues:
who and where: anyone , worldwide
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disease: many disease, CA: hand foot and mouth +stomatitis; B: myocarditis,
pericarditis and bornholm disease. (skin and mucosa (stomatitis and hand foot
mouth disease), respiratory track=pneumonia, bronchitis, summer colds),
striated muscles (pleurodynia or Bornholm Disease= diaphragm sudden
extreme pain), CNS, myocardium, pancreas (type 1 diabetes implication) and GI
symptoms. and conjunctivitis)
transmission: oral fecal and aerosol if respiratory symptoms
tx or vaccine: none. wash up!
Hepatitis A virus. (stable in high temp and adverse envirnoment)
serotype: 1, (side note: VP4 may be missing in this virus)
host: only humans
replication: likes the liver
transmission: oral fecal route and contaminated food
who and where: anyone, anywhere; more in poor sanitation.
disease: mostly gastro and flu like symptoms. rarely fulminant hepatitis
requiring transplant. (symptoms: flu like, coca cola pee, high liver enzymes)
tx or vaccine: TWINRIX
Echoviruses (entero cytopathogenic human orphan)
serotype: ?
host: primates, Humans are the only reservoir known.
replication: human oral pharynx then transit to stomach and lower GI
transmission: oral fecal route. (other route possible)
who and where: ?
disease: subclinical, can cause a wide range of disease as well.
Tx or vaccine: ?
Cardioviruses
serotype: Mengo, ECMV, Theiler (mice virus)
host: a"ects many species.
replication
transmission: oral fecal (ingested)
who and where
disease: theiler causes (TMEV) and MS in mice. in humans symptoms can
progress to acute myocarditis. Mengo: can cause acute fever in humans.
tx or vaccine
special: L protein (leader sequence), a"ects interferon.
Aphtoviruses (Foot and mouth disease).
serotype: ? (highly contagious and sensitive to acidity= dies in human
stomach)
host: cloven hoofed species who and where: animals, many parts of the world
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disease: foot and mouth disease (animals)
*like picos but di!erent
Caliciviruses: small group of non enveloped viruses (Norwalk/Norovirus virus)
Special how: look like a cup; T=3. polyprotein and Subgenomic; makes empty
shells! No IRES (has VPg and poly A) 3 ORF (1=NS protein, 2=subgenomic
structural; 3=?)
serotype= 3 distinct.
host: humans
replication: cytoplasmic
transmission: oral fecal
who and where: anyone who eats crap. mostly in confined places where
humans aggregate.
disease: GI symptoms (food poisoning)
tx or vaccine: none, Hydrate.
Viruses with positive-sense RNA genomes (enveloped): Toga, Flavi,
Nido(corona virus)
1. Togaviruses: (Alphas and Rubivirus)
General genome info: Icosahedral (T=4+ lipid envelope from cell.
- positive ssRNA
-envelopped (trimer of heterodimer glycoprotein (80 of 3XE1/E2)
-Cap (polymerase has methyl transferase activity) and Poly A
-polyprotein (short and long with polymerase: UGA stop codon leaks
10-20% and subgenomic (CP: autocleaves; glycoprotein: E1 (fusogenic)/
E2(receptor binding): need processing first: palmitoylation and
glycosylation) (calici-like)
-regulation: blocking polymerase site with uncleaved polyprotein
-4 NS and 5 Structural proteins.
-entry: endocytosis
Alpha:sindbis(egypt) Semliki (uganda)= mosquito transmission urban+forest
serotype: ?
host: caninfect birds, horses and humans
replication: BUDS FROM CM.
transmission: mosquitoes
who and where: Tropical regions. NOT highly pathogenic for humans
disease: usually not serious, can lead to fever, rash and arthralgia and
encephalitis.
tx or vaccine: none
Rubella (little red) virus.
serotype: 1 (susceptible to envirnoment and chemical agents)
host: ONLY HUMANS
Document Summary
Receptor: cd155 replication: galt, intestine and cns transmission: oral fecal and nasopharyngeal who and where: afghanistan, india, pakistan, nigeria (endemic)any age but mostly under 5. Abortive poliomyelitis ( u like),1-2% invasion of the cns (neuronal signs, but no paralysis). Paralytic poliomyelitis (0. 1-2%; 10% fatal, 80% residual paralysis=acute accid paralysis); bulbar paralysis (afecting breathing muscles;-10% die) tx or vaccine: 2 vaccines: salk (ipv)=dead virus, sabin=weak but alive(vapp risk). Drug: win complications: postpolio syndrome (30-40 years post infection) Rhinoviruses serotype: more than a 100 host: humans only. Receptor: icam1 replication: nasal airway, best at 33 . transmission: airbone and direct contact who and where: anyone, anywhere. disease: cold tx or vaccine: tough luck!! Coxsackie viruses serotype: 2 types a (23 serotypes) and b( 6 serotypes). Antigenically unrelated host: humans and primates (ca17 causes paralysis in monkeys replication: mainly in the oral pharynx, gi and lymph n. then viremia=many possible tissues: who and where: anyone , worldwide.
