Virology Flashcards

Terms Definitions
measles
paramyxo
varicella-zoster
herpes
croup
parainfluenza
CD21
B-Cells
SV40
Polyoma
hepatitis A
picorna
rota virus
reo
hepatitis B
hepadna
CD16
NK cells
PolyomaPapilloma
dsDNAno envelope
condylomata acuminata
genital warts
rift valley fever
bunya
Genome - Papilloma
dsDNAcircular
RNA viruses
Poliovirus.Coxsackie virus.Enterovirus.Rhinovirus.Hepatitis A virus.Norovirus.Rubella virus.Eastern equine encephalitis (EEE)Venezuelan equine encephalitis (VEE)Western equine encephalitis (WEE)Flavivirus.Dengue virus.St. Louis encephalitis virus (SLE)West Nile Fever virus.Yellow Fever virus.Hepatitis C virus.Lassa virus.Lymphocytic choriomeningitis (LCM) virusCoronavirus.SARS Coronavirus.Ebola virus.Influenza A.Parainfluenza virus.Mumps.Measles.RSV.Rotavirus.Colorado Tick Fever virus.HTLV 1.HIV.
examples of dsDNA viruses
adenoviruses
herpesviruses
HSV
VZV
CMV (pneumonia, retinitis)
EBV (mono)
HHV-6, HHV-8 (roseola, Kaposi's)

papovaviruses (tumors of skin, mucosa)
polyomaviruses (neurologic infection)
poxviruses (smallpox)
Epstein-Barr virus disease
Burkitts lymphoma
Mononucleosis
childhood pneumonia
RSV-children, babies, preemies
Genome - ADENO
dsDNAlinearunsegmentedcovalently linked to proteininverted terminal repeats
Vaccine for Hep. B?
Yes.
Treatment of Lassa virus
Ribavirin.
HepA prevention
improve sanitation
avoid raw shellfish
passive immunization- post exposure pooled ISG for clos contacts (mainly for travelers)
85% protection rate

active immunization- formalin inactivated viral particles
protection rate near 100%
recommended if increase risk of acquiring, transmitting HAV, or of developing fulminant hepatitis due to pre-existing liver condition

 
How is the Rotavirus transmitted?
Fecal-oral
Cytomegalovirus symtoms
most are asymptomatic,babies and
immunosuppresed are symtomatic
immunocompromised CMV
AIDs-RETINITIS, viremia, colitisBone marrow-PNEUMONIA, viremia, colotis
Class V - ssRNA (-)
RabiesInfluenza
Genome - INFLUNZA
ssRNA(-)linearsegmentedNO direct terminal repeatsNOT covalently linked to protein
Infectious cycle of Adenovirus
~24 hours.
Diagnosis of Ebola
Serology.Isolation: BSL-4 required.
Treatment of HIV
Antiretroviral drugs.-Nucleoside analog reverse transcriptase inhibitor (NRTI)-Non-nucleoside reverse transcriptase inhibitor (NNRTI)-Protease inhibitor (PI)-Fusion inhibitor-Chemokine co-receptor antagonists-Nucleoside inhibitorsHighly active antiretroviral therapy (HAART)Suppress viral replication.Does not cure HIV infection/AIDS
Clinical complications/tx/prevention of RSV

complications
acute- apnea, increase risk of infant aspiration
chronic- recurrent wheezing, bronchiectasis
immunocompromised- pneumonia


tx
aerosolized ribavarin
bronchodilators, corticosteroids


prevention
strict infection control
for high risk, monthly RSV Ig IV or palivizumab (monoclonal Ab bind to F protein)
clinical characteristics/complications of metapneumovirus
URI's, bronchiolitis, pneumonia
may be coinfection with RSV or influenza
latency location of alpha herpes viruses
neurons
Hep C complications
late complication- hepatocellular carcinoma
usually in patients with cirrhosis

extrahepatic manifestations associated with chronic infection
cryoglobinemia
adenoviruses: pharyngoconjunctival fever characteristics
occurs in small outbreaks

characterized by:
conjunctivitis
pharyngitis
rhinitis
cervical adenopathy
fever

epi- contaminated swimming pools and ponds
kuru: clinical manifestations/symptoms

means "shivering"
initially presents with tremors, ataxia, postural instability
long incuation period
fatal over 2 months-2 yrs


primarily cerebellar involvement
many with amyloid plaques on brain

if had homozygous PRNP on codon 129, associated with earlier age of onset and higher sik of disease
How is the Adenovirus transmitted?
Respiratory
Fecal-oral
Direct contact (eye)
What do the Enteroviruses cause?
Poliomyelitis
Hand-foot-mouth disease
Pleurodynia
Aseptic meningitis
Summer "flu"
progressive multifocal leukoencephalopathy
PML- JC polymavirus, immunocompromised->CNS and white matter damage, memory loss, poor speech, incoordination
class switch to IgA
IL-5 + TGF-beta
antibacterials avoided during pregnancy
FCATSfluoroquinolone, chloramphenicol, aminoglycosides, tetracycline, sulfonamide
Class VII - gapped circular dsDNA
HBV
mRNA synthesis - INFLUENZA
Nuclear processHOST RNApolII
Disease caused by Herpesvirus 5
Cytomegalovirus (CMV)
Treatment of CMV
Acyclovir derivative (Nucleoside analog)
Paramyxo vs. Orthomyxo: Which is larger?
Paramyxo.
Incubation period of RSV
About 3-5 days.
Incubation period of Coxsackie virus
3-9 days.
poxvirus: viroceptors
captured cellular genes which modulate the host immune response

modified versions of receptors for cytokines or chemokines called "viroceptors"
secreted or located in infected cell surface

All homologes to cytokines
management of smalpox

isolation: airborn and contact
communicacable from onset of rash until 7-10 days
isolated untile scabs separate

tx: no known specific therapy (try cidofovir cause it does work in vitro)

smallpox vaccine
live viral vacine (cowpox)
vaccinate pts with early diseas
examples of ambisense RNA viruses
arenaviruses (Lassa fever)
bunyaviruses (encephalitis, hemorrhagic fever)
HepB replication
fuse with host cell membrane
viral capside released into cytoplasm
ds genome completed by enzymes contained within core
capside enters nucleus where there is transcription to genomic and mRNA
RNA enters cytoplasm where there is translation of viral proteins
core assembles around + sense RNA
+ sense RNA is copied to - sense DNA, THEN to + sense DNA
core passes through cytoplasmic membranes (ER, golgi) and becomes enveloped with HBsAg on its surface
fusion of outer membrane with cell membrane leads to viral release (end with virus with partially dsDNA)
Hep B virus: prevention
pre-exposure immunization
vaccine made of HBsAg particles expressed in yeast

post exposure immunization
hep B Ig (HBIG) for babies
prevention of mother to child transmission
papillomavirus: epidemiology

cutaneous warts
common warts occur in school aged children
plantar warts sween frequently in adolescents and young adults
flat warts predominantly in children
other groups at high risk are butchers, meat packers, fish handlers


genital warts
most commonly acquired viral STD
3/4 of US population is infected
respiratory exposure pathogenesis
inhalation of respiratory aerosol dropletes
cough generate many aerosole particles, but the most generated by a sneez
if less than or equal to 5 microns, particles may reach alveoli
more than 5 microns, particles trapped by nasal mucosa

oropharynx and nasopharynx can be a portal of entry
prevention of iCJD
use disposable instruments whenever possible
label specimens carefully, notify lab

effective deconatmination
steam autoclaving at 121-132 C
NaOH
chlorine greater than 10,000 ppm
guanidine thiocyanide
Na hypochlorate (30-60 minutes for inanimate surfaces)
What are the characteristics of established cell lines?
Heteroploid
Indefinite passages
What are the three different classifications of
viruses in regard to Nucleic acid content
1.DNA(ss,ds)
2.RNA(ss,ds,neg strand,pos strand)
3.Retroviruses
What three diseases have Epstein-Barr
been associated with?
a.Nasopharyngeal cancer
b.Chronic fatigue syndrome
c.Hodgkins lymphoma
Koplik's spots
-measles-oral lesions "grain of sand surrounded by an erythema"->leads to rash from ears down-rubella is forehead down
Hepatitis B (HBV)
ds/ssDNAenvelopedretroid DNA step in replication
attachment/entry - POLIO
binds cell surface proteingenome remains in cytoplasm
Symptoms of Vaccinia
- Ocular Vaccinia- Generalized Vaccinia (40% fatality rate)- Encephalitis (40% fatality rate)
Disease caused by Herpesvirus 8
Kaposi's Sarcoma HHV
Incubation period of Hep. A
About 1 month.
Symptoms of Measles
Acute, highly communicable disease with fever, conjunctivitis, coryza, cough, Koplik spots, rash.Rash begins on face.More severe in infants and adults than children.Infectious during prodromal phase.
molluscum contagiousum: clinical signs
discrete smoooth dome shaped lesions
incubation: 14-50 days
skin colored with opalescent caracter
central depresion or umbilication
contain a white, waxy curd like core
size is variable, depending upon stage of development
parainfluenza (clinical consequences/ manifestations)
acute infection of URT/LRT
causes 30-50% of cases of otitis media
characteristic illness
croup (larygeotracheobronchitis)
usually caused by type 1
symptoms- barking cough, hoarse voice, stridor (subglottic narrowing)
steeple sign on X ray- sign of subglottic narrowing

bronchiolitis- inflammation of lower airways
leading cause of bronchiectasis
saccular enlargement of distal airways with wall thickening
destruction and increased mucus production


more severe disease (pneumonia) in immunosuppressed hosts
influenza pathogenesis
enters resp. tract via small particle aerosols produced by talking, coughing, sneezing
typically, infection limited to superficial cell of URT and LRT

penetrates columnar epithelial cell leading to cell death
inhibits protein synthesis
induced apoptosis

loss of ciliated and mucus secreting epithelial cells reduces clearance of bacteria (could lead to super infection)
examples of - strand ssRNA viruses
orthomyxoviruses (ex: influenza)
parmyxoviruses (measles, mumps)
rhabdoviruses (rabies)
filoviruses (ebola)
epidemiology of VZV
childhood illnes (half before school entry)
usually in late winter/early spring
more so in temperate climates
90% of US adults have prior exposure to chicken pox
half of Puerto Rican miliatry recruits have seropositive results

transmission
highly contagious
person to person via respiratory route
may be transmitted 3-5 days before rash

highest mortality with VZV seen in adults
HepB epidemiology
most primary infections in young adult males

important predictors of persistent infection
age at primary infection
the younger you are when you get a primary infection, the higher risk you have of going to chronic HBV

severity of initial disease

Asia, Africa- vertical transmission and chronic hepatitis more common
papillomavirus: general clinical manifestations

cutaneous warts
deep plantar warts
common warts
plane or flat warts

anogenital warts
mechanism of Ab stopping virus
Ab binding
binding of complement
form proteolytic complex
C5b binds and forms MAC to kill virus
Classify Human Papilloma Virus (HPV)
Double stranded DNA
No envelope
Family Papoviridae
What is the season for RSV?
Winter and spring
What type of cells does HIV infect?
a.T-helper cells
b.Macrophages
c.Microglial
d.smooth muscle
e.Dendritic cells
papaine
degrades Ab to Fc + Fab, cannot agglutinate
hantavirus pulmonary syndrome
-sin nombre virus, western states, massive pulmonary edema with sever leg pain-->death
omenn syndrome
missense mutation in the rag genes. disallows recombination of B and T cell (no B and low amount of T)-->Similar to SCID, but less severe (nonsense)
This virus uses fusion to uncoat, then sends the genome to the nucleus.
Herpes
Specimens used for diagnosis of CMV
Throat and urine.
Symptoms of Variola (Smallpox)
High fever, malaise, headache, prostration followed by characteristic centrifugal rash (macular>papular>vesicular>pustular)30% fatality rate.
Pathogenesis of Hep B
Infected hepatocytes. Localized areas of liver necrosis. Damage is reversible with recovery. Chronic hepatitis with HDV co-infection. Hepatocellular carcinoma occurs in ~1% of cases.
Diagnosis of Norovirus
Electron microscopy:- Used in stool specimens.- Requires relatively high numbers of virus.Direct detection:- EIA for Norovirus Ag- PCR
Symptoms of Lymphocytic choriomeningitis (LCM) virus
Many subclinical cases.Acute disease manifested as meningitis.May appear as mild "flu-like" illness with fever, chills, malaise, weakness, headache, sore throat.Rarely will develop into encephalitis.
Epidemiology of Rhinovirus
Worldwide. Adults average 1-2 colds per year. Over 100 serotypes. Transmission is likely to be via contact as through respiratory droplets. Being "chilled" is not a predisposing factor.
Henipa virus characteristics
zoonotic
attach to cell surface via G proteins
HSV: mechanism of replication, transcription, translation
nucleocapsid docks with nuclear membrane and delivers genome into nucleus
transcription by cellular DNA dependent RNA polymerase
viral proteins block cellular DNA and mRNA synthesis
different groups of protein made (SEE OTHER FLASHCARD)

DNA combines with capsid proteins to form nucleocapsid which buds from the nuclear membrane
viral particle is processed in golgi to endocytic vesicle
virus buds by fusion with host cell membrane and is either released as a free virus or may spread from cell to cell
viral glycoprotiens on host cell trigger cell fusion leading to giant cells
during latnecy, viral DNA remain dormant as episomal DNA or replicate
HEV: dx and tx
dx

IgM anti-Hep E Ab
Ab to capsid/ORF2
HEV RNA via PCR


tx- supportive (disease is self limiting in vast majority of cases
parvovirus B19: dx
both IgM and IgG made in immunocompetent pts
viremia detected via DNA hybridization tech

pts with erythema infectiosum are not viremic
Ab production (ELISA) used for dx
IgM present at time of rash
IgG persists throughout life


pts with transient aplastic crisis and those with pure red cell aplasia, B19 DNA assays are used to detect viremia
for the immunocompromised, THEY CANT MAKE AB, SO NO ELISA

pts with transient aplastic crisis also produce Ab
prevention of adenovirus
oral vaccines were developed for use on military recruits contain live virus
virus not attenuated, but took advantage of fact that infection of GI tract of adults doesnt result in illness
efficacy and saftey was well established but lack of availability and demand of vaccine resulted in discontinuation of vaccination in 1999
PrPC genetics/structure
encoded on PNRP gene on chrom 20 (single copy)

highest level of expression in neurons and other CNS cells
also in lymphocytes, skel/cardiac muscle cells


polymorphic at residue 129 (Val to Met)
homozygous for Met assoicated with prion disease

anchored to cell surface by GPI anchor
function unknown (may be involved in cell signaling or neuronal development)
What does the Rotavirus cause?
Gastroenteritis in infants and children 6 months to 2 years
What does the Human herpes virus 8 cause?
Kaposi's sarcoma
How is the Human papiloma virus (HPV) transmitted?
Sexual contact
what does coronaviridae cause
second leding cause of common cold
epidemic keratoconjuncitivitis
adeno, watery pink eye that can be associated with pharyngitis
Only virus to use cell RNA to initiate genome replication.
Retrovirus
Properties of Variola and Vaccinia
Complex structure. DNA, double stranded.Very large and complex DNA virus.Contains >100 polypeptides.Multilayered envelope.Replicates in cytoplasm.Tropic for multiple cell types.
Symptoms of Epstein-Barr virus (EBV)
Infectious mononucleosis - Malaise, fatigue, fever, headache, sore throat, lympadenopathy.Burkitt's lymphoma - Tumor of B cells.Nasopharyngeal carcinoma - Tumor of nasopharyngeal epithelial cells.
Specimens used for diagnosis of Coxsackie virus
Throat swabs.Nasal secretions.Fecal specimens.CSF.(Depends on the disease)
HSV recurrence: prodromal symptoms, when most likely to occur, clinical characteristics
most recurrences happen within first two years of primary genital infection
mostly of HSV-2
prodromal symptoms
pain
burning
tingling
itching

sterotyped lesion at each recurrence (usually at the same spot)
lesions fewer in number, less severe, less systemic symptoms, more rapid healing (8-10 days)
Hep C clinical manifestations in chronic infection
relapsing and remitting symptoms
ALT may be near normal despite biopsy proving advanced disease
parvovirus B19: clinical manifestations of pure red cell aplasia
occurs in pts who are immunodeficient and is a chronic condition
pts may have congenital immunodeficiency, AIDS, lymphoproliferative disorders, or are transplant recipients
presents as persistent anemia
pts lack or have low parvovirus specific Ab response and persistent viremia
Virus can undergo hematogenous spread in what forms
free virus
cell associated (ex: macrophages, lymphocytes)
What separates prions from viruses?
no foreign Ag
no nucleic acid
no immune response to prion

species barrier: most TSE not transmissible between species
except BSE


stable against multiple chemical and physical insults
heat
UV radiation
nucleases
How are the Enteroviruses cultured?
PMK
4 days to isolation
Identify by cell culture neutralization test
What is the most important source
of transmission for hiv
infected cells(wbc)-approximately 5000 infected cells per ml of blood, can be 10000 per ejaculate,can ce
in wbc of vagina
 
what type of hepatitis is very rare in this country?
hep E
Which is the only virus to make a single mRNA?
Polio (picornavirus)
Replicative cycle of Hep. B
Similar to Adenovirus. Final assembly occurs outside of nucleus.
Epidemiology of Lymphocytic choriomeningitis (LCM) virus
Widely seen in Europe and the Americas.Reservoir is house mice.No evidence of human to human spread.
lipid envelope (origin, contents, effect of damage)
lipid bilayer derived from host cell membrane
contains embedded viral proteins involved in host cell recognition/attachment
damage (ex: detergents) block infection
ex: herpesvirus, retrovirus
Relationship between Hepatitis B and D
Hep D envelop contains HBsAg
assembly of intact HDV virons and pathogenicity requires the helper function of HBV
There is no Hep D without Hep B
viral mechanism of evasion of immune response
inhibition of IFN action
decrease cytokine production
suppress MHC expression
reduce B cell activation
antigenic variation
immunologic sanctuaries
latent infection
How is the Respiratory syncytial virus (RSV) cultured?
HEp-2
6-8 days to isolation
Glassy syncytial giant cells
Confirm by immunofluorescence
What are the two types of HIV
HIV 1-reproduces faster,found in europe and US
HIV 2-replicates more slowly found in west africa
Biological properties of Herpesviridae viruses
Growth cycle may be short to long.Cytopathology may be cytolytic or cytomegalic.Cell tropism related to latency may involve: Neuronal cells, lymphoid tissue, specific organ cells (kidney, etc.)Antigenic variability.
What do Herpes simplex virus (HSV) types 1 and 2 cause?
HSV-1: cold sores, fever blisters, whitlow
HSV-2: genital herpes
What is the difference between antigenic drift and antigenic shift?
antigenic drift is slow minor changes in which the HA and NA mutate giving new strains,happens every few years
antigenic shift is a cell with two strains at once and will trade pieces of rna creating an entirely new strain with different HA and NA happens every 10 years
Hep B: dx of self limited primary infection
HBsAg = active infection
first marker to appear
titers fall several weeks after resolution of hepatitis

HBeAg = infectivity
level rises and falls in parallel with HBsAg
marker of active viral replication

HBV DNA (parallels other markers of disease activity)
HBcAb
IgM and IgG appear 3-5 wks after appeaarance of HBsAg
IgG Ab persists

HBsAb
appear several months after disappearance of HBsAg
protects from reinfection

HBeAb
signals less viral replication, leading to better clinical outcome
HHV-6 what does it cause and what disease
has it been associated with
Roseola and it has been associated
with multiple sclerosis
IFN (what activates it and major actions)
active at very low levels to viral infection or dsRNA
actions
induce synthesis of cellular proteins that minimize viral replication
phosphorylation/inactivation of protein synthesis initiation factor and inhibit viral protein synthesis
activation of cellular RNAases that degrade viral mRNA
increase NK cell, cytotoxic T cell, and ADCC activity
rabies
rhabdo
rhino
picorna
echo
picorna
Poxviridae
Variola.Vaccinia.(DNA)
norwalk virus
calici
erythema infectiosum
parvo
CD56
NK cells
CoronavirusesSARS
ssRNA (+)non-segmentedenveloped
Th1
-promotes cell-mediated immunity-activated by IL-12, IFN gamma-produces IFN gamma, IL-2-IFN gamma activates macrophages and shuts down Th2
Hepadnaviridae
Hepatitis B (DNA)
Orthomyxoviridae virus
Influenza A
VZV: complication
hepatitis, pneumonitis, encephalitis

superinfection of cutaneous lesions, especially with S. aureus, group A beta streptococcus

Reye's syndrome: encephalopathy, liver disease
associated with aspirin consumption
30% follow varicella


Guillain Barre syndrome: ascending motor paralysis
Note that skin lesions will not cross the MIDLINE of the body.
Th2
-promote humoral immunity-produce IL-4, IL-5 to promote class switching-IL-5 promotes IgA-produces IL-10 to shutdown Th1
syncytial viruses
herpes, paramyxo, retro
Genome - CORONA/SARS
ssRNA (+)linear
Papillomaviridae.
Human Papilloma Virus (DNA)
name important human poxviruses
smallpox
molluscum contagiosum
Orf
HEV pathogenesis
pseudoglandular rearrangement of hepatocytes and intrahepatic cholestatsis
disease is immune mediated (like HepA)
no progression to chronic hepatitis and no persistent infection (like HepA)
We do not know weither or not it replicates in the GI tract like HepA
How is Hepatitis A transmitted?
Fecal-oral
Adenoviridae, disease, prevention
common cold,conjunctivitis
attenuated vaccine,only used in military
because of associations with cancer
Kaposi's sarcoma
HHV-8 -turns on VEGF->hyperproliferation of vascular-->nasty red/purple rash
Virion - RABIES
envelopedrod shaped/filamentousgenome coated w/VIRAL proteinviral RNA polymerase
Class IV - ssRNA (+)
Polio
Treatment of Vaccinia
Vaccinia immune globulin
Incubation period of Ebola
1-2 weeks.
Diagnosis of HIV
Serology:-Antibody detection: Screening test (EIA) followed by confirmatory test (WB)-Western Blot.-Problem with "window"-Testing used is influenced by prevalence of disease.-PCR now being used more routinely.Cell counts:-CD4 counts.-Viral load:Used to monitor treatment and disease progression.
influenza dx
nasopharyngeal swab

rapid Ag test
distinguish influenza A and B
40-80% sensitivity

PCR (distinguish subtypes)
viral isolation
example of ssDNA viruses
parvoviruses (parvovirus B19)
Structure of herpesvirus
large, enveloped, dsDNA
four structural elements
outer envelope
tegument
amorphus assemblage of virus encoded proteins that help initiate replication cycle

nucleocapsid- icosapentahedral array
inner core- proteins, viral genome
HepA epidemiology
worldwide distribution with highest prevalence in Africa and Asia
related to crowding and poor hygiene

virtually all adults in developing countries are seropositive
in US, most of those with Ab found in west and southwest and among Native Americans

transmission: fecal-oral route, especially in children
person to person in housholds
daycare centers, infected food handler

food and waterborne via raw or partially undercooked shellfish
adenoviruses: pathogenesis

three different interactions
lytic infections- occurs in human epithelial cells, result in human cell death and produce many progeny
latent or chronic infection- involve lymphoid tissue like in tonsilar infection
oncogenic transformation- viral DNA is integrated into host and replicates with cell DNA, but no virons produced
prion pathogenesis theories

interference with ubiquitin proteosome pathway
normally degrades abnormal proteins
protect against against neurodegenerative disease
blockade of pathway leads to loss of critical cellular function (eventually induce apoptosis)

loss of normal PrPC function
toxicity of accumulated PrPSc
Classify Hepatitis E
Single stranded RNA
No envelope
Family Caliciviridae
How is the Herpesvirus 8 transmitted?
Unknown
acute respirtatory disease
adeno, army recruits-->pneumonialive, non attenuated vaccine given to avoid this
IL-1
produced by macrophages to activate T-cells
Type I sensitivity
immediate, IgE->mast cell degranulation-mass cells=tissue, basophils=blood, eosinophils=come in later, elicit damage-primary-already made, histamine, heparin-secondary- arachidonic acid-prostoglandins and luekotriens -allergic rhinitis, food allergies, wheal and flare, ashtma, systemic anaphalactic
Genome - RABIES
ssRNA (-)linearNO direct/inverted repeatsNOT covalently linked to proteins
What 2 viruses have segmented genomes?
InfluenzaReo/Rota
Disease caused by Herpesvirus 3
Varicella-zoster virus
Pathogenesis of CMV
Entrance through epithelial cells.Causes cytomegalic reaction.Spread very slowly in host.Multi-organ involvement: Lung, liver, colon, kidneys, lymphocytes, salivary glands.Can be latent.Viral shedding in oral cavity and urine.
Specimens for Adenovirus diagnosis
Stool. Urine.Throat.Conjunctiva.Rectal swab.Virus excretion may last from days to weeks.
Incubation period for hemorrhagic conjunctivitis (Enterovirus)
1 day.
Pathogenesis of Ebola
Highly virulent.Propism for endothelial cells, macrophages and hepatocytes.High virus titers in all major organs.Mortality rate up to 90%.
genetics/structure/char of poxviruses
infect both vertabrates and invertablrates
enveloped

large brick shaped virus
short surface tubules/filaments


large, complex genome
linear, dsDNA

potential bioterrorism
measles pathogenesis

infects epithelial cells of resp. tract


spread by viremia to RE system, then secondary viremia


replicates in conjunctiva, resp. tract, GI, GU, lymphatic system, bv's, CNS


multinucleated giant cells in skin, mucosa


disease caused by T cell response to virus infected cells lining the capillaries
composition of viruses
protein coat (capsid)
nucleic acid core (genome)
core proteins
lipid envelope (SOME)- lipid bilayer with inserted proteins
hepatitis A: transmission, general incubation period, genetic structure, morphology, stability
picornavirus
+ssRNA
no envelope

transmission- fecal, oral
incubation- 28 days (15-50)
morphology- spherical with icosahedral symmetry
stability
resistant to heat, solvents, acids
destroyed by 5 minutes of boiling
HepB transmission
blood and body fluids
sexual contact
needle sharing

transfusion
blood bank testing for ALT, HBsAg, HBV DNA
do a minipool of a certain amount of specimens for HBV DNA
it positive, do each in that minipool individually



vertical transmission
esp. if mother HBsAg positive and HBeAg positive


percutaneous exposure
esp. w/needlestick where patient HBsAg positive and HBeAg positive
dx: adenovirus
clinical criteria alone (usually dont bother to find out if its something like a cold)

definitive dx involves:
visualization by electron microscopy
tirssue culture
fourfold rise in serum Ab
adenovirus DNA in tissue samples or blood

Ag can be detected in sputum, nasopharyngeal washes or throat swabs by immunofluorescence or ELISA, which serve as rapid dx tests
mechanism of cellular transformation
uncontrolled cell growth
continued growth without senesence
increase rate of cell growth
loss of contact inhibition of cell growth
accumulation of tumorigenic mutation
clinical presentation of vCJD
younger individuals
prsent with psyc/behavioral findings
not as rapid as decline as sCJD
all have Met homozygosity at codon 129 of PRNP
What does the Rubella virus cause?
Rubella 
Congenital rubella
Cytomegalovirus transmission
By repeated exchange of bodily secretions usually sex
Type IV hypersensitivity
delayed->CD4 Th1 activation against self-PPD test, contact dermatitis, multiple sclerosis, type 1 diabetes, Guillian-barre, celiac disease
Capping - CORONA/SARS
Capping/mRNA synthesis via viral polymerase in cytoplasm.Viral protease makes polyproteins.
Genome - HBV
partial dsDNAcovalently linked to proteincircular genome3 direct repeats - 2 near 3' end
Epidemiology of Variola/Vaccinia
Effective variola vaccine (using vaccinia virus)Disease (Smallpox) was declared eradicated in 1980.Vaccinia is used as "vector" vaccine for some animal disease, ex: rabies.Other pox viruses have caused sporadic disease in humans (Monkey pox, Orf virus, Molluscum Contagiosum)
Diagnosis of Enterovirus
Virus isolation in cell culture.
Diagnosis of Lymphocytic choriomeningitis (LCM) virus
Serology.Virus isolation or detection.
Orf: epi/ clinical signs

epidemiology
mostly anima infection of sheep and goats
esp. in Europe, New Zeland

transmitted to humans by contact with infected animals (livestock workers, meat handlers)
lesions on hand
reddish nodules that may form vesicles, pustles, or ulcerate
may self heal in 3-6 weeks
characteristics/genetics of paramyxovirus
enveloped (-) ssRNA
buds from cell surface with embedded surface proteins
attachment to cell surface glycoproteins via hemagglutinin-neuroaminidase (HN), hemaglutinin (H), or G proteins
F protein mediated fusion
subfamilies
paramyxovirinae
respirovirus (parainfluenza)
rubulavirus (parainfluenza, mumps)
morbillivuris (measles)
henipavirus

pneumovirinae
pneumovirus (resp. syncytial virus)
metapneumovirus)
viral capsid: morphology, function
function- protect genome from nucleases
morphology
symmetrical structure with repeating units
repetitive structure minimizes genome size
icosahedral or helical symmetry (allows to be made from repeating, ID subunits aka self assemble)

icosahedral- regular polyhedron with 20 triangular faces and 12 vertices

helical- hollow tube with a helical surface
define primary HSV
first episode HSV
no concurrent HSV Ab's
HepB pathogenesis
acute and chronic hepatitis B are syndrome of hepatocellular necrosis and inflammatory response

cytotoxic T cell response directed at HBsAg/ HBeAg on HBV infected hepatocytes
much of liver damage caused by host inflammatory response
HepA: viral replication
virus enters hepatocyte via unknown cellular receptor
uncoating of viral partical, release of +sense RNA genome
translation of viral polyprotein
polyprotein undergoes proteolytic processing by viral and cellular proteases
RNA dependent RNA polymerase synthesis of - strand copy of viral genome
- strand RNA is used as a template for synthesis of + strand RNA
+ strand RNA is packaged into new viral particles
HAV particles secreted by cell across the apical membrane of the hepatocyte into the biliary canaliculus
from which they are passed into the bile and small intestines
papilloma virus tx

cutaneous warts
OTC salicylic and lactic acid applied after hot warter soak
occlusive bandages increase tx effectiveness
cryotherapy


anogenital warts
podophyllotoxin topical tx (rellapse common)
imiquimode cream (induce production of IFN and other cytokines)
cryotherapy with liquid nitrogen or cryoprobe
CO2 laser therapy
prion disease in humans
familial prion disease
sporadic CJD (most common prion disease)
iatrogenic CJD

acquired CJD
kuru
variant CJD
How is Varicella-zoster transmitted?
Close personal contact especially respiratory
How are the Paramyxoviruses diagnosed?
Direct detection:
Detect by hemadsorption with guinea pig RBCs
Identify by immunofluorescence
What does Hepatitis B cause?
Acute hepatitis with resolution
Fulminant hepatitis
Chronic hepatitis
Hepatovirus disease?
Hepatitis A found in fecal matter,can survive bleach, does not cause cancer
cough, conjunctivitis, coryza, photophobia
measles 3c's and p-->rash-coryza=head cold
Polio 1, 2, 3Human RhinovirusHepatitis A/E
ssRNA (+)non-segmentedno envelope
Which 3 viruses produce equal amounts of viral capsids and polymerase?
Polio (picornavirus)TogavirusRetrovirus
Attachment/entry - RETROVIRUS
Binds cell surface protein.Fusion to plasma membrane.Genome migrates to nucleus.
Symptoms of HSV II
Genital - Vesicular ulcerative lesionsof penis, cervix, vuvla, vagina; may beassociated with fever, dysuria, lympadenopathy;recurrances are common and often asymptomatic in women.Encephalitis - Fever, headache, vomiting,seizures, paralysis; high fatality rate.Neonatal - usually in three forms:Cutaneous, encephalitis, disseminated;mortality rate as high as 80%.
Diagnosis of VZ
Usually made on clinical grounds (symptoms)Culture: Vesicular fluid, fibroblast cultures like MRC 5 used, IF detection more rapid than CPE.Other options: DFA, PCR, EM.
Adenovirus and Hep. B are both found where?
Worldwide.
Properties of Adenovirus
Icosahedral. Double stranded DNA. No envelope. Has protein "fibers". Replicates in nucleus. Narrow host range. ~50 serotypes (
Epidemiology of Rotavirus
Worldwide. Single most important cause of gastroenteritis in children worldwide. Fecal-oral spread. Reservoir likely humans. ~5 billion cases per year; ~5 million deaths per year. Outbreaks more common in winter.
impact of oseltamavir
great reduction in influenza in long term care facilities
effective in household px
effective community px
some efficacy in reduction in hospitalizations
32 hrs faster resolution of symptoms
epidemiology of Herpes Zoster
lifetime risk at least 20%
incidence increase with advancing age or immunosuppression
half of all people living until age 85 will develop zoster
HDV epidemiology
infection only in those who are HBsAg positive
commonly in those with multiple parenteral exposures

three different genotypes
Mechanism of virus inhibiting cellular processes
preferential viral protein synthesis
block cellular DNA, mRNA synthesis
block export of mRNA from nucleus
block cellular protein synthesis
viral mRNA may compete for ribosomal sites
synthesis DNAase to provide substrates for viral genome replication
Name the prion diseases of animals
scrapie (sheep, goats)
BSE (cows)
chronic wasting disease (elk, deer)
transmissible mink encephalopathy
What does the Influenza A virus cause?
Influenza
Primary influenza pneumonia
Brocnhiolitis, croup, otitis media
What are the three ways viruses
are released from a cell?
Budding(viruses with envelope)
Exocytosis
Lysis
common cold
human HMV, echo, but mostly corona and rhino
Which 2 viruses code for a DNA polymerase in the virion?
RetrovirusHepatitis B
What 2 viruses assemble capsids in the cytoplasm?(using a viral protease)
Polio (picornavirus)Togavirus
Treatment for HSV I and HSV II
Acyclovir (Nucleoside analog)Ameliorates symptoms, not curative.
Symptoms of Parainfluenza
Varies by age and type.Infants and children: Croup like illness, bronchitis, bronchiolitis, pneumonia. Fever, rhinitis, pharyngitis, otitis media.Adults: Laryngitis, rhinitis.
Diagnosis of Polio
Virus isolation in human or monkey cell lines.CPE develops within 3-5 days.Identification through neutralization assays.Serology may be used to show 4-fold rise in Ab to poliovirus.
smallpox and chickenpox has what in common
highly contagious
similar incubation period
nosocomial transmission
Clinical characteristics of herpes zoster
latency in dorsal root ganglia (similar to HSV)
recrudescence in a dermatomal distribution
prodromal pain (severe, can be persistent and if it is, it is called post-herpetic neuralgia)
unilateral, involving 1-3 dermatomes (50% thoracic)
HepB: clinical manifestations of acute infection
infection may be subclinical, mild/anicteric, or severe
prodromal symptoms- flu like
anorexia, nausea/vomitting, abdominal pain, may be followed by jaundice

physical exam: enlarged, tender liver
lab finding- elevated transaminases and bilirubin
rare to have fulminant hepatitis with encephalopathy, seizures, and ascities
extrahepatic manifestations- related to circulating HBsAg-HBsAb complexes
polyarteritis nodosa
glomerulonephritis
adenovirus: hemorrhagic cystitis characteristics
25-50% of all cases of hemorrhagic cystitis in kids due to adenovirus
more common in boys
present with hematuria, dysuria, and urinary frequency
dx of TSE: histopathology
florid plaques consist of amyloid core surrouned by ring of vacuoles
spongiform degeneration and reactive astrocytes
immunostaining of pathological prion protien: pretreated to denature normal PrP and staining with Prp Ab reveals plaques staining for PrPSc
What does the Varicella-zoster virus cause?
Varicella - chickenpox
Zoster - shingles
what does Hepatits C do to you?
develope chronic liver disease,developes into cancer
what are the three types of warts?
a.seed warts-fingers and toes
b.planter warts-soles of the feets
c.genital warts
This is the only virus to inhibit host translation.
Polio (picornavirus)
Virus replication of Herpesviridae viruses
Virus envelope fuses with host cell.Nucleocapsid transported into nucleus.Uncoating occurs.Viral DNA is transcribed, replicated.Large number of viral specific proteins generated, some are enzymes.Replicative cycle ranges from 18 hours (HSV) to >70 hours (CMV)
Diagnosis of Coxsackie virus
Virus isolation in cell culture or newborn mice.CPE develops within 6-12 days (slower than Polio)
Function of core viral proteins
carry out functions needed for viral replication
nonstructural proteins
function in assembly and replication
virus encoded enzymes involved in replication (ex: reverse transcriptase)
histones for genome packing
tethering proteins linking core to capsid
HepB dx of chronic infection
HBsAg
if positive after 20 wks, its likely positive indefinitely

HBeAg
some w/persistent HBeAg, highly contagious
highest risk for hepatocellular carcinoma

HBcAg persists
HBsAb- no seroconversion to HBsAb (if you been immunized, you have this Ab)

HBV DNA- level depedent on disease activity, can be measured quantitatiely
Char. of chronic wasting disease
deer, elk
present in heards of at least 14 states and 2 canadian provinces

spread within deer heards
possible blood or salivary transmission

no evidence of transmission in nondeer/elk
How are the Herpesviruses 6 and 7 transmitted?
Contact via respiratory route
how do you get Enteroviruses-poliomyelitis?
oral fecal route,from lakes and pools, goes from intestines to brain,
Diagnosis of Coronavirus
Serology - Ab or Ag detection with EIA or HIIsolation - Challenging, rarely used.
What does the Human papiloma virus (HPV) cause?
Skin, genital and anal warts
Benign head and neck tumors
Cervical and penile cancer
What are the three ways a virus can enter a cell?
1.Direct penetration(shoots genome in)
2.Membrane fusion(envelope fuses)
3.Phagocytosis
NK cells mechanism of action
if cell lacks MHC I, it will kill it
what are the two major antigens on orthomyxoviridae? what do they do?
1.HA-attach to pulmonary cells and cause phag
2.NA-hydrolisis your mucus
When is the best time to collect a specimen for viral culture?
As early as possible, preferably during the vesicle stage
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