117 terms

Micro Week 1 Introduction to Viruses

These are mostly notes by Feldman includes herpesviruses, arboviruses, flu, paraflu, hantavirus and a couple more
Naked Viruses
reoviruses (rotavirus), enterovirus, rhinovirus, polio, coxsackie, papillomas, parvo b19, norwalk, and hep E, adenoviruses Families: caliciviruses, picornaviruses, and reoviruses. Picornas being rhino, polio, coxsackie.
Enveloped viruses
Togas, flaviviruses, influenza, paramyxos, rabies, bunyaviruses (hantavirus), coronas, filos (Ebola). This includes ebola, marburg, RSV, yellow fever, hep c, MMR, Hep B, Herpesviruses, poxviruses.
What are the 2 important things that HSV codes?
HSV 1 is a dsDNA virus that codes a DNA polymerase and a viral thymidine kinase.
When HSV1 hides in the trigeminal nerves and HSV2 hides in the DRG what protein product are they making?
They don't make a protein product just latency associated transcript which is an intron. LAT
How does HSV spread?
Usually by mucosal surfaces, and body fluids. Little kids sharing cups.
HSV 2 on a childs face/mouth indicates?
Child abuse even tho it is possible but rare for HSV2 to get on the face/mouth
What are some conditions of HSV?
Gingivostomatis, keratitis ulcers on the cornea, eczema makes it worse, whitlow on finger, possible encephalitis
Tx for herpes
acyclovir, which is a nt analog w/no OH at the 3 position. vThyme Kinase Pis the analog but the vDNA polymerase can't use it.
HSV 1/2 gives fever blisters, what does 6,7,8 give?
6/7 gives a Roseola rash. 8 gives Kaposi sarcoma (a huge bump). The bumps from 1/2 are called fever blisters.
Varicella is spread thru the air? Y/N
What are some differences between the infection of HSV and VZV?
VZV initially causes a viremia where HSV doesn't. HSV spread is limited by the nerve it infects. Both viruses can't be caught from fomites
Who gets varicella pneumonia?
Adults get it more because they have a stronger immune rxn to varicella.
What is the other name for shingles?
Varicella zoster is chicken pox and herpes zoster is shingles, even tho it is the same virus.
What virus do you get a unilateral rash? and what syndrome can it cause
shingles, and it does not cross the midline. Post herpetic neuralgia
What kind of vaccine do you usually give for viruses?
U give a live attenuated so that it can go in and make proteins ->cd8 response. I think only flu viruses use Ig for neutralization blocking hemaglutinin.
Which is better an immunization? or getting the infection for protection against a virus?
Immunization is always worse because it a shot to a muscle. Where the infection will produce immunity at cells where you are most likely to pick up the disease like nasal and oral cavity.
What virus family does CMV belong to?
Herpes viruses
How is CMV spread?
fluids, and contact. It does cause a viremia which is how it gets to babies in pregnant mothers.
What are the sx of CMV?
either asymp or mild mono which does not produce heterophile Ig.
Can you spread CMV asx?
Yes there are shedders. CMV is also tx w/the cyclovirs
Where does CMV hide?
in lymphocytes. In lab you see cells with a basophilic nuclear inclusion called an OWL'S EYE (BOARDS)
What's a quick test for mono?
Heterophile antibody which indicates EBV.
What is the disease process of EBV?
It actively replicate in the throat but then lis latent once it hits the blood stream. It hides in B cells and makes 10 proteins called EBNAs-epstein barr nuclear antigens.
What are some sx/syndromes you can get from EBV?
Burkitt's lymphoma (jaw cancer), nasopharynx cancer
What does EBV do to B cells?
They induce them to proliferate. EBV latency = mono. The rxn of t cells to these b cells is what causes mono, NOT THE RXN TO THE VIRUS.
Where does heterophile Ig come from?
It comes from one of the genes in the B cell that EBV induces
Sx of mono
Fever, malaise, sore throat, adenoids. The huge increase in B and T cells -> splenomegaly and possible rupture so no tackle football.
Difference betw EBV and HSV latency
EBV creates 10 EBNAs while HSV creates LAT.
Markers associated with the immune response to extracellular bacteria
TH2, MHC2, CD4, Humoral immunity
Markers associated with intracellular bacteria
TH1, CD4, MHC2, Cell mediated. The bacteria use their own machinery (ribosomes). For this answer just think of bacteria that invade macrophages.
Markers associated with viruses
TH1, CD8, MHC1, Cell mediated
How do infected cells signal for help?
Interferon alpha and beta -> TH1 response. alpha and beta-> upreg of MHC1 on infected cells.
What does interferon gamma do?
It upreg NK cells. Interferon gamma is made by TH1 cells. interferon alpha, beta, and gamma upreg NK cells
What does IL12 do?
It is a cytokine that signals TH0 cells to turn into TH1 cells.
What signals do infected cells send out?
interferons alpha and beta -> upreg MHC1s and they send out IL12 which makes TH0->TH1. They also send out IL2 which calls out to T killer cells.
Which IL makes TH0->TH2?
IL 4 and 5. Which is inhibited by interferon gamma which is secreted by TH1 cells.
What cells have MHC1
All cells, even platelets, except RBCs
What 3 genes make up MHC1
HLA A/B/C. 3 from mom and 3 from dad -> 6 total variations of the MHC1 protein.
Pathogens that grow inside cells that don't use their own machinery are presented on MHC1 or 2?
2. Pathogens that use human machinery are presented on MHC1.
TH1 does what? TH2 does what?
TH1 helps upreg phagocytosis of macrophages and neutrophils. TH2 ->Ig production
When T cells arrive at the thymus what receptors do they have?
They have none. They are CD4-,CD8-,TCR-. At the cortex they become double positive. Positive selection = picking cd4 or 8. negative selection is getting rid of the autoimmune ones. In + selection the cell is picking 1 of 6 MHC1s or MHC2.
Name 3 families of RNA+ viruses
Picornaviruses, arboviruses, corona viruses
Name 2 kinds of arboviruses
Flavivirus, togavirus.
Name a corona virus
Hep D
Name some picornaviruses
polio, rhinoviruses, enteroviruses, heparnavirus (hep A)
Name 2 enteroviruses
Cocksackie and rhinoviruses
Name which are naked and which are enveloped: picornas, rhinos, and corona viruses
Picornakeds, rhinos and coronas are enveloped (colds are passed p2p). So this means picornas are passed fecal oral/ fomites. One unique corona virus is SARs
Boards: is this virus infectious? RNA + vs RNA-
RNA + if dumped into cytosol = mRNA and ready to be translated
What is a Reovirus and what is unique about them?
dsRNA viruss but they act like minus RNA viruses. Ex rotavirus-infant diarrhea.
Name 2 kinds of enteroviruses and how they're transmitted
Polio and cocksackie viruses. Fecal oral transmission, naked viruses. Enteroviruses cause "generalized newborn disease". Enteros cause 90% of aseptic meningitis.
What does Cocksackie A cause?
If a kid has oral lesions it usually is Cocksackie A: hand foot mouth or HSV1. The bumps from Cocksackie A are called herpangina. Cocksackie B: pericarditis
Enteroviruses are RNA +/-
Which Hepatitis viruses are naked and enveloped
A&E naked, C&D envelope. Hep C is an STD. Hep D only coinf B. A & E are fecal oral
What sx come from Norwalk and Caliciviviruses
Which virus has to carry its own polyermase? +/-
Minus has to carry their own. When the minus and the + line up and becomes a dsRNA this is what tickles the TLR.
Where do rhino viruses like to replicate?
upper respiratory tract. They are sensitive to pH so no stomach. (no such thing as stomach flu)
What kind of genome do retroviruses have and name two families
ss+RNA viruses. oncoviruses and lentiviruses. They have long terminal repeats which is why they have to integrate.
Name some arboviruses
west nile virus, dengue fever, yellow fever
In HIV what does tat and rev do
Tat upregs the promoter on the cDNA. Rev drags the ssRNA genome out of the nuke so that introns aren't cut out of genome.
What do PR and GAG in HIV do
They code for assembly proteins and budding
What is the M and T tropic forms of HIV?
The early infection of HIV only hits macrophages primarily (M tropic). The late infection only hits T cells (t tropic). M tropic uses CCR5 receptor. late uses CXCR4.
Drugs for rev transcriptase in HIV
There's NNRTI-allosterically inhib like 3TC. NRTI-directly inhib like AZT.
What does the HIV antibody test for
P24 capsid protein.
Describe the influenza genome
A/B/C versions. A/B have 8 different RNA segments. Only Flu A can mix up its RNA. H1-3 and neuramidase 1-2
What is the reservoir for flu A
Humans, chicken, birds. Flu B and C can't jump animals to humans.
Flu sx
sudden onset, high fever, myalgia. Spreads by sneezing cuz it only really infects the lungs. H1N1
If a person has an immunity to neuramidase but not a specific hemaglutinin are they immune?
Yes, to that strain.
How do you create a pandemic flu virus?
Flu A. When an animal and human virus coinfect. ->Hx Nx.
What is antigenic drift
when the genes that code HA mutate and Igs won't recognize over time. Flu season occurs each year cuz of antigenic drift
What is reassortment
When viruses coinfect and mix up their hemaglutinin and neuramidase genes.
What is H5N1? Why is it more invasive than a regular flu?
It is bird flu. Normal flu hits only the lungs where hemaglutinin can bind. But H5 can bind anywhere and infect called pantropic. It rarely makes the jump to humans because it binds to sialic acid 2,3 where humans are 2,6.
What are orthomyxoviruses and paramyxoviruses?
both are RNA minus but paramyxos are 1RNA segment and can get to lower respiratory tracts.
Types of paraflu viruses
paraflu, measles, mumps, respiratory syncytial.
Differences between flu and paraflu
flu 8 RNA segments, drifts, shifts. paraflu is paramyx so 1 RNA segment. It does not drift or shift, spreads by fomites where flu is p2p. flu has a vaccine paraflu doesn't. paraflu is a pediatric virus. Parainfluenza hits lower respiratory and influenza hits upper.
What is the main complication of parainfluenza?
Croup = inflammed sublottis->dyspnea, stridor, barking.
Difference between parainfluenza and RSV?
Parainfluenza (barking) have trouble breathing in. RSV trouble breathing out. Both are lower resp infections
What kind of infection does RSV cause?
Bronchiolitis. naked, fomites. Trouble expiring. No vaccine. sx are like asthma. 1 RNA segment, no drift no shift cuz its paramyxovirus. RSV is the #1 cause of pneumonia in kids and flu in adults
What kind of virus is Mumps
Paramyxovirus. 1 RNA segment, no drift, no shift, ez to vaccinate. Infects upper respiratory. Parotid gland swelling
What kind of virus is measles
Paramyxovirus-1 RNA segment, thus ez to vaccinate. Head to toe rash, upper resp infection. 3 C's coryza, conjunctivitis, cough. Gives Koplik spots in mouth
What is the rhabdovirus?
Rabies, vaccinate animals. BOARDS: see a Negri inclusion body in effected cells. Can be asx for a year.
What is a bunyavirus. What is the main one
Arbovirus. Arbos do not do p2p transmission. Main bunyavirus is the hantavirus from rodent feces and urine. -> ARDS. No vaccine
Sx of hantavirus
Fever, myalgia, abd pain, shock. Capillary leak syndrome (drowning in lungs).
What is a filovirus. Name 2
Marburg and Ebola. fomites and fluids-fecal oral. Sx nausea, sore throat. Hallmark sx is petechiae. Capillary leak syndrome is a sx
Flu vs cold sx
Flu: fever, dry cough, myalgia
Colds don't have these sx.
Name some families of dsDNA viruses
papovaviruses, adenoviruses, herpesviruses, poxviruses
What is the only ssDNA virus
parvoviruses like B19
Name some poxviruses
smallpox, vaccinia, molluscum contagiosum
How can HPV cause cancer
Naked virus. E6 gene codes a protein that can bind p53. When virus integrates E2 gene turns down. E2 turns down E6 and E7. E7 binds Rb. Rb usually binds to E2F and acts as a tumor suppressor. Sx of reg HPV warts on hands and feet.
What is a prion
an enzyme that acts like a virus. It turns proteins in the scrapie form -> creutzfeld-Jakob disease which is a neurological disease.
B19 is what kind of virus
a ssDNA and a parvovirus. Naked. Replicates in RBC precursors. sx erythema infectiosum and arthrits. Eryhema infectiosum is called fifth disease. trans:fluid and fomites
Sx of B19
Biphasic: 1. fever malaise. 2 lowered Hb and rash caused by immuno complexes. no vaccine, no therapy available. The arthritus it causes is symmetrical.
The 5 childhood rashes
rubella-togavirus -> german measles
Roseola-HSV 6/7
Fifth Disease-b19
Name the viruses that can cause human cancer
HPV, EBV, HepB, HTLV. In HPV pap smears look for koilocytes
Name some poxviruses
Variola, vaccinia, molluscum contagiosum (multiple skin lesions). All are dsDNA and enveloped but they REPLICATE IN CYTOPLASM*
2 Most important things about poxviruses
replicate in cytoplasm cuz the viruses are fat as **** and small pox is off the earth. they spread by respiratory.
What is vaccinia, sx
a mix of cowpox and variola->crazy eczema. Enveloped
Molluscum contagiosum sx
small warts on genitals of children
Describe Adenoviruses
dsDNA. Naked. Can be GI or respiratory. almost pantropic. Transmit by dirty water. sx tonsillitis, pneumonia, croup (upper respiratory barking)
DNA viruses
Adeno, papilloma, parvo, herpes, pox, hepB. These include: EBV, CMV, vaccinia, smallpox. All of these are naked except the herpes viruses and Hep B.
RNA viruses
Reo, picorna, calicivirus, toga, flavi, orthomyxo, paramyxo, bunya (hanta), rhabdo, filo, corona. This includes Ebola, marburg, influ, hep C, the arbos like yellow fever, measles, mumps, RSV, coxsackie, norwalk, Hep E, Polio, rhinos, enteros.
All minus strand RNA are enveloped?
All +RNA are enveloped except Picorna and caliciviruses
Corona,influenza, and rhinoviruses are all different from one another
Corona and influenza are enveloped while rhino is naked
Corona and rhino are +RNA while influenza is -RNA
If you vaccinate Hep B are you vaccinated against hep D?
What causes Croup
Influ and parainflu, and adenoviruses
sx of flu: nonprod cough, otitis media
What does oseltamir do
blocks neuramidase so HA can't be cleaved so virus can't bud out
What causes capillary leak syndrome
Flu vs cold
flu: myalgia, fever, dry cough
Adenoviruses infect what?
GI, respiratory, and oropharynx
Parvo virus causes?
Slap cheek rash, kills RBC precursors (aplastic crisis) and causes 5th disease
only lupus and parvo b19 get slap cheek
HSV 6/7/8 do what
6&7 causes roseola rash
8-an STD and its Kaposi sarcoma
Burkitts lymphoma, c-myc
How does polio -> paralysis
attacks anterior horn cells
also meningitis
Cox A causes....Cox B causes?
Cox A-herpangina ie hand foot mouth disease
Cox B- endocarditis
Why is rubella an exception togavirus
It it not transmitted by an insect vector like other togaviruses. It is p2p.
What kind of viruses are all the Heps
Hep A-picorna
Hep B-HepaDNA
Hep C-Flaviviruses

Hep E-Caliciviruses
Hep G-Flavivirus
Why is the tx for CMV different?
no TK gene
have to tx w/gangcyclovir

note variola = small pox
vaccinia-cow pox