Micro Week 1 Introduction to Viruses

Created by drcjsnell 

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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

Yes

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

diarrhea

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

Measles-paramyxovirus.
rubella-togavirus -> german measles
Roseola-HSV 6/7
Varicella
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?

Yes

All +RNA are enveloped except Picorna and caliciviruses

True

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?

Yes

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

hantavirus

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

EBV

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

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