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9.23 RNA viruses part 2
10am by Dr. Amedee
188
Microbiology
Professional
09/25/2011

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Cards

Term
What family of viruses is influenza a part of?
Definition
orthomyxovirus
Term
What's the significance of the name orthomyxovirus?
Definition
ortho= straight, myxo= mucus
Term
Describe the genome and protein covering of the influenza virus.
Definition
enveloped helical (pleomorphic) virus with RNA SS - with multiple genomic segments
Term
What are the three major types of influenza virus?
Definition
A, B, and C
Term
Is influenza prone to zoonoses?
Definition
influenza naturally infects a variety of species particularly type A
Term
How many gene segments do influenzas A, B and C have?
Definition
A- 8, B- 8, C-7
Term
Which species do each influenza type infect?
Definition
A= humans, swine, avian, equine, marine mammals
B= humans only
C= humans, swine
Term
List the different major influenza types from most to least severe.
Definition
A (often severe)> B (occasionally severe) > C (usually mild)
Term
Describe the epidemic potential of influenza A.
Definition
extensive; epidemics and pandemics (antigenic drift and shift)
Term
Describe the epidemic potential of influenza B.
Definition
outbreaks; occasional epidemics (antigenic drift only)
Term
Describe the epidemic potential of influenza C.
Definition
antigenic drift only
Term
What is the purpose of hemagglutinin?
Definition
binds sialic acid for entry of the virus
Term
Describe the structure and different types of hemagglutinin.
Definition
trimer; highly variable; H1-9 with 16 HA subtypes
Term
How are the HA subtypes of Hemagglutinin important in the function of the virus?
Definition
HAO cleaved into HA1 (used for attachement) and HA2 (used for fusion)
Term
What is the purpose of neuraminidase?
Definition
cleaves sialic acid during release
Term
How many different neuraminidase types are there?
Definition
N1-N2 in humans (9 NA subtypes in birds)
Term
Neuraminidase is used as a target for which drugs?
Definition
tamiFlu and Relenza
Term
Which viral flu protein accumulates mutations in each infection such that the virus out is not the same as the virus in/
Definition
HA protein
Term
T/F Genetic reassortment is easier for flu than other viruses.
Definition
true
Term
How does the influenza virus endter the cell?
Definition
receptor mediated endocytosis, then acidic environment in endosome allows release of viral particles which go to the nucleus
Term
What is the function of RNA segment 1 for influenza A?
Definition
PB2- RNA synthesis ?virulence
Term
What is the function of RNA segment 2 for influenza A?
Definition
PB1- RNA synthesis
Term
What is the function of RNA segment 3 for influenza A?
Definition
PA- RNA synthesis
Term
What is the function of RNA segment 4 for influenza A?
Definition
HA- Attachment
Term
What is the function of RNA segment 5 for influenza A?
Definition
NP: RNA synthesis
Term
What is the function of RNA segment 6 for influenza A?
Definition
NA- virus released from cell
Term
What is the function of RNA segment 7 for influenza A?
Definition
M1, M2- Matrix
Term
What is the function of RNA segment 8 for influenza A?
Definition
NS1, NS2- nonstructural (NS1, INF antagonist)
Term
Describe antigenic shift.
Definition
Sudden. Emergence of "new" H or N subtype in the human population. Occurs every 10-40 years. Little or no herd immunity to new flu and probably emergence from domestic animals
Term
Describe antigenic drift.
Definition
1) incremental 2) emergence of varient H subtype in humans 3) occurs every 2-3 years 4) accumulation of mutations evades herd immunity 5) probably emergence within humans
Term
Describe influenza nomenclature.
Definition
virus type/geographic origin/strain number/year of isolation (virus subtype)
Term
What is the only infectious disease capable in a pandemic year of increasing the world death rate?
Definition
influenza via antigenic shift
Term
Name the major flu pandemics in the past century.
Definition
1918 Spanish flu, 1957 Asian Flu, 1968 Hong Kong flu (1977 Russian Flu, and 2009 Swine-origin H1N1)
Term
What modifications must be made to the viral RNA before it is able to be transcribed by host ribosomes?
Definition
"cap snatching"- PB1 protein takes 5' cap and about 10 nucleotides from host mRNA and puts it on viral RNA
Term
Which protein is responsible for making + ssRNA from influenza genomic - ssRNA?
Definition
RNA polymerase activity of PB1 protein
Term
Which enzyme is responsible for making new copies of influenza viral genome from +ssRNA?
Definition
PB1 protein
Term
How do influenza progeny leave the host cell?
Definition
budding from the host cell
Term
In a hemagglutination Inhibition Assay, what happens to RBCs not bound by the influenza virus?
Definition
they sink to the bottom of the well to form a button
Term
Where/when was the first case 2009 novel H1N1? When was it pandemic and when did the pandemic officially end?
Definition
April 2009 in Veracruz Mexico. Pandemic peaked in Nov 2009 and officially ended in August 2010
Term
How many deaths, hospitilizations, and infected people were there in the 2009 H1N1 pandemic in the US? What population had the highest number of cases?
Definition
20,000 deaths, 270,000 hospitlizations, 43-89 million infected people, highest number of cases in 18-65 year olds
Term
What is swine origin influenza H3N2?
Definition
virus resulting from genetic re-assortment of 2009 H1N1. 4 cases in children in Indiana and Pennsylvania (3 had contact with swine). All recovered and no person to person transmission noted
Term
T/F Influenza is limited to the respiratory tract.
Definition
true! tracheitis!
Term
How does influenza damage the host?
Definition
multiplies in ciliated respiratory epithelium cells which causes cell damage which elicits an acute inflammatory response and impairs mechanical and cellular host responses. This damage renders the host highly suceptible to invasive bacterial superinfection
Term
How does influenza pave the way for secondary bacterial infection?
Definition
damages host cells/defenses and bacteria actually adhere more redily to the surfaces of influenza virus infected cells
Term
Production of what cytokine begins recovery from influenza infection?
Definition
interferon
Term
A rare complication can occur in young children with influenza who are treated with salicylates that is called....
Definition
Reye's syndrome
Term
What percent of the US population gets the flu each year?
Definition
5-20% (more than 200,000 people hospitalized)
Term
How many people die of the flu each year?
Definition
annual flu associtaed deaths range from 3,000 to 49,000
Term
Why was the 1918 flu so devastating?
Definition
rapid dissemination from the URT to the LRT inducing a cytokine storm that causes inflammation and increased mortality
Term
What is the "high dose" flu vaccine?
Definition
for people 65 and older, IM, has 4x antigen, first available last year
Term
What is the intradermal flu vaccine?
Definition
inactivated flu vaccine for people between 18 and 64 that is injected into the dermis
Term
Describe the live attenuated flu vaccine.
Definition
a nasal spray recommended for "healthy" people aged 2 through 49 years of age who are not pregnant
Term
What's in this years flu vaccine?
Definition
A/California/7/2009 (H1N1)
A/Perth/16/2009 (H3N2)
B/Brisbane/60/2008
Term
Describe the drug Amantidine/Rimanditine.
Definition
antiviral for influenza A that targets the M2 ion channel and blocks fusion. It is adminstered orally and resistant strains are emerging
Term
How does Relinza/Zanamivir work?
Definition
its a influenza A and B antiviral that targets virus release by inhibiting NA. It is inhaled and resistent strains are emerging
Term
Describe Tamiflu/Oseltamivir.
Definition
influenza A and B antiviral that targets virus release by inhibiting NA. It is administered orally and resistant strains are emerging
Term
What is the mortality rate of bird flu?
Definition
58%
Term
How is avian flu transmitted?
Definition
bird to human transfer (which is rare) with limited human to human transmission
Term
What will cause Bird Flu to become a human pandemic virus?
Definition
better binding to human configuration of receptor neuraminic acid by HA, better replication and enhanced production of progeny virus in humans (diverse genes), better processing of viral RNAs and proteins (diverse genes ), Can be achieved either by mutation or recombination with current cirvulating human strains of H1N1 or H3N2
Term
Contrast human alpha 2,6 tropism and alpha 2,3 tropism.
Definition
2,6= high transmission, low virulence
2,3= low transmission and high virulence
Term
Describe the genome and protein covering of arena viruses.
Definition
enveloped helical (pleomorphic) with segmented RNA genome (1 large negative RNA segment, one small ambisense strand), Two seperate nucleocapsids surrounding the L and S RNA.
Term
WHat gives arena viruses a "sandy" appearance?
Definition
virion contains host cell ribosomes
Term
Arenaviruses are transfered to humans zoonotically from...
Definition
rodents
Term
What are some examples of Arena viruses?
Definition
lymphocytic choriomeningitis virus, hemorrhagic fevers (lass fever virus, Junin, machupo)
Term
Where from the host are arena viruses shed?
Definition
urine or droppings
Term
How do humans get arena viruses?
Definition
contact with excretions of an infected rodent (ingestion, direct contact of abraded skin, aerosol transmission from rodent urine or saliva
Term
Which arena viruses are associated with secondary person-to-person and nosocomial transmission? How does this occur?
Definition
lassa and Machupo; direct contact with blood or other excretions containing virus particles, airborne transmission from contaiminated material (medical equipment)
Term
How does lymphocytic choriomenigitis present?
Definition
most are asymptomatic or mild febrile illness. biphasic febrile illness: 1)fever malaise, lack of appetite, muscle aches, headache, nausea for a week; 2) meningitis or encephalitis
Term
What congenital issues occur with transplacental infection of LCM?
Definition
hydrocephalus, chorioretinitis, and mental retardation
Term
How long after exposure do symptoms of LCM occur?
Definition
8-13 days
Term
What is the primary host of LCM?
Definition
mus musculus (common house mouse) 5% of mice in US infected without sings of illness.
Term
Can you get LCM from your pet hamster?
Definition
possibly but rodents other than the mice are not natural reservoirs for the disease. However other rodents can be infected via breeding colonies like in a pet store
Term
Are humans more likely to get LCMV from their pets or from a house mouse?
Definition
house mouse but infectious from pet rodents have also been reported
Term
Can LCM be transmitted from person to person?
Definition
only "vertically" (through placenta)
possible transmission via organ transplantation
Term
What is the prognosis of LCM?
Definition
most recover completely, mortality is less than 1%
Term
What is the tx for LCM?
Definition
hospitilization and supportive tx (corticosteroids and other anti-inflammatory drugs) for those with meningitis or encephalitis
Term
What disease does Lassa virus cause?
Definition
lassa fever (African hemorrhagic fever)
Term
What diseaes does Junin virus cause?
Definition
Argentine hemorrhagic fever
Term
What disease does machupovirus cause?
Definition
bolivian hemorrhagic fever
Term
What disease does guanarito virus cause?
Definition
venezuelan hemorrhagic fever
Term
What disease does Sabia cause?
Definition
brazilian hemorrhagic fever
Term
What are the symptoms of arenavirus hemorrhagic fevers?
Definition
fever, hemorrhagic manifestations, shock, neurologic manifestations, hepatitis, acute deafness
Term
How long does viremia and viral shedding occur in arenavirus hemorhhagic fevers?
Definition
viremia for > 1 month, viral shedding in urine for > 2 months
Term
What is the prognosis of patients with Lassa fever?
Definition
15-20% of patients hospitalized for Lassa fever die from it. Only 1% of infections result in death
Term
Death rates from Lassa fever/arenavirus hemorrhagic fevers are particularly high for what population?
Definition
women in the third trimester of pregnancy--approx 95% of fetuses die in utero
Term
How do you treat arena virus hemorrhagic fevers?
Definition
supportive care, IV rabavirin may be helpful
Term
How do you diagnose arenavirus hemorrhagic fever?
Definition
travel history, serology (ELISA) for IgM or IgG
Term
Describe the genome and capsid of rabdovirus.
Definition
enveloped RNA ss- with helical capsid that is bullet shaped. RNA polymerase and genome are enclosed in matrix protein
Term
Surface glycoproteins of rhabdoviruses are important because...
Definition
they allow the virus to attach to host cells and are also the targets of neutralizing antibodies
Term
Give two examples of rhabdoviruses.
Definition
rabies and vesicular stomatitis virus
Term
What are the three phases of rabies virus?
Definition
prodome, neurologic and comatose
Term
Describe the prodom phase of rabies virus.
Definition
2-7 days: headache malaise
Term
Describe the neurologic phase of rabies virus.
Definition
few days: difficulty swallowing, CNS effects
Term
Describe the comatose phase of rabies virus.
Definition
upt to 2 months, fatal convulsions
Term
What is the rabies vaccine called?
Definition
HDCV (human diploid cell vaccine)
Term
How is rabies infection treated?
Definition
passive and active immunization.
Term
T/F Post-exposure vaccination for Rabies virus is possible.
Definition
true
Term
How does rabies spread throughout your body?
Definition
1)replicates in muscle, 2)enters periphearl nervous system, 3) passive ascent via sensory fibers, 4)replication in dorsal ganglion, 5) rapid ascent in spinal cord, 6)infection of spinal cord, brainstem, cerebellum etc 7) descending infection via nervous system to eye, salivary glands, skin and other organs
Term
What is happening during the incubation period of rabies and how long does it last?
Definition
virus is traveling to the brain within nerves; may last weeks to months
Term
How long does it take after virus has multiplied in the brain for an animal to show signs of rabies?
Definition
3-5 days signs are evident
Term
T/F Besides being bitten by an infected animal, Rabies is also often spread via other routes such as contamination of mucous membranes, aerosol transmission, and corneal and organ transplanatation.
Definition
false, although documented, spread of infection in those ways is very rare
Term
Which animal is responsible for most transmission of rabies to humans in the US?
Definition
bats
Term
What histological finding is diagnostic for rabies infection?
Definition
negri bodies in the brain
Term
How do you diagnose Rabies in a live humna patient?
Definition
several tests needed 1) viral isolation or RT-PCR in saliva 2) antibodies to rabies virus in serum or spinal fluid 3) detection of rabies antigen in cutaneous nerves at the base of hair follicles from nape of neck
Term
Who came up with the first rabies vaccine?
Definition
pasteur
Term
How do you treat rabies post exposure?
Definition
regimen of one dose of immune globulin and four doses of rabies vaccine over a 14 day period (3,7,14)
Term
How is HDCV made?
Definition
in tissue culture usuing hormal WI-38 fibroblasts. The rabies virus is then inactivated
Term
Describe the rabies virus used for animals.
Definition
live attenuated vaccine (flury strain) grown in chick embryos
Term
What is VRG or Raboral?
Definition
recombinant anti-rabies vaccine made by inserting the gene for the surface glycoprotein of rabies into vaccinia virus (used for treating wild animals since it can give herd immunity because its a live virus)
Term
What are the different types of Bunyaviruses?
Definition
arboviruses and hantaviruses
Term
Name 3 different arboviruses.
Definition
California and LaCrosse encephalitis virus, Rift valley fever
Term
Name two hantaviruses.
Definition
Hemorrhagic fever with renal syndrome (HFRS), and Hantavirus pulmonary syndrome (HPS)
Term
Describe the genome and capsid of a hantavirus.
Definition
ss RNA - with 3 segments
envelope with glycoproteins G1 and G2
Term
Where is HFRS?
Definition
observed in Hantaan, Korea; china Japan, Russia, first described in the 1950s in the Korean War
Term
What do you call the mild version of HFRS?
Definition
nephropathia epidemica (NE) (puumala hantavirus)
Term
Which hantavirus is old world? new world?
Definition
old: HFRS, new: HPS
Term
What're different types of HPS?
Definition
sin nombre virus "four corners virus" or "navajo flu"
Term
Where do you find HPS?
Definition
first identified in humans in the US in 1993, western US. Bayou virus in Monroe. BLack Creek Canal VIrus in FL.
Term
HOw do you get hantaviruses?
Definition
found in urine and feces of infected rodents but it does not make the animal sick. Transmitted thru aeorsolized rodent excreta.
Term
What population has the majority of HPS mortalities?
Definition
10-60 years old
Term
What is the rodent reservoir of Sin nombre virus?
Definition
deer mouse. Has an epizootic cycle
Term
What is the major target organ, first phase, second phase and mortality of HFRS?
Definition
Kidney, febrile, shock, 1-15%
Term
What is the major targe organ, first phase, second phase and mortality of HPS?
Definition
lung, febrile "prodrome"; shock/pulmonary edema, 50% mortality
Term
Name two filoviruses.
Definition
ebola virus and marburg virus
Term
Describe the filoviruses.
Definition
cause african hemorrhagic fever, enveloped, helical (filamentous/pleomorphic), SS RNA -, viral GP surface protein mediates entry
Term
Where do you get African hemorrhagic fever (ebola, marburg) from?
Definition
zoonoses from bats
Term
What is the disease process of african hemorrhagic fever (ebola, marburg)?
Definition
infect endothelial cells with cytopathic effects, blood loss
Term
How do you die of African hemorrhagic fever? What percent of patients die?
Definition
hypovolemic shock, > 65% mortality
Term
Name the subtypes of Ebola.
Definition
Zaire, Sudan, Reston
Term
Describe the paramyxoviruses.
Definition
ss RNA - genome, enveloped, helical capsid
Term
Name the different paramyxoviruses.
Definition
respiratory disease (RSV, parainfluenza, metapnuemovirus)
mumps and exanthems (measles, mumps)
zoonoses (nipah and hendra)
Term
What populations are affected by ReSV?
Definition
infants and the elderly
Term
What disease do parainfluenza viruses cause?
Definition
croup or acute respiratory disease in young children, 4 serotypes
Term
Describe the envelope of parainfluenza virus.
Definition
hemagglutinin and neuraminidase on the same spike
Term
Which parainfluenza serotypes particularly can cause serious disease in infants and young children?
Definition
1 and 3
Term
What is the course of illness of infection with parainfluenza virus?
Definition
mild URI with variable progression over 1-3 days to involvement of middle or lower respiratory tract. Duration of acute illness varies from 4 to 21 days
Term
How do you diagnose parainfluenza viruses?
Definition
isolation or antigen detection
Term
How do you treat croup?
Definition
no specific treatment
Term
Describe the virion structure of RSV.
Definition
similar to parainfluenza virus except that the envelope glycoproteins are an attachment (G) protein and a fusion (F) protein
Term
What are the glycoprotiens on the RSV virus used for?
Definition
G glycoprotein mediates attachment; F or fusion glycoprotein induces fusion of viral envelope with host cell surface
Term
What are the different types of RSV?
Definition
there are two antigenic subgroups (A and B). Dimorphism is due primarily to differences in the G glycoprotein
Term
What is the major cause of bronchiolitis and pneumonia among infants under 1 year of age?
Definition
RSV
Term
How do you detect RSV?
Definition
virus isolation, PCR, immunoflouresence, and immunoassays
Term
What parts of the respiratory tract does RSV infect?
Definition
bronchi, bronchioles, alveoli (clinically categorized as croup, bronchitis, bronchiolitis or pneumonia)
*confined to respiratory epithelium
Term
Who is at risk for contracting RSV besides infants?
Definition
elderly and immunocompromised
Term
What is the rate of pts with secondary infection of pts with RSV?
Definition
50%
Term
How long is the RSV virus shed?
Definition
5-7 days; young infants may shed virus for 9 to 20 days
Term
Why is RSV so severe?
Definition
TH2 stimulated cytokines cause injury
Term
What are the pathological findings of RSV?
Definition
necrosis of epithelial cells; interstitial mononuclear inflammatory infiltrates
Term
What drug is used in severe cases of RSV?
Definition
ribavirin
Term
Describe the RSV vaccine.
Definition
there isn't one
Term
What is the second leading cause of bronchiolitis in infants and young children?
Definition
human metapneumovirus
Term
T/F Reoviruses are ubiquitous and have been found in humans, simians, rodents, cattle and a variety of other hosts.
Definition
true
Term
What nucleic acid is found in adenoviruses/bocavirus?
Definition
DNA
Term
What type of virus is rubella?
Definition
togavirus + ssRNA
Term
How is mumps, measles and rubella spread?
Definition
aerosol
Term
Describe the disease caused by the measles virus?
Definition
"rubeola" 7 day measles, maculopapular, erythematous rash, Koplik spots, buccal mucosa; largely disappeared in the US
Term
Describe the disease caused by the mumps virus?
Definition
epidemic parotitis; once the principle cause of aseptic meningitis; largely disappeared in the US
Term
What populations were susceptible to measles?
Definition
5-10 year old children in old world; unknown to new world and caused death of native adults
Term
Where is the virus located in measles?
Definition
initial replication in the URT, proceeding to the respiratory mucosal epithelium, followed by dissemination to distant sites; and T and B cells (resulting in transient immunosuppression).
Term
T/F Measles is highly contagious.
Definition
true
Term
How long is the incubation and acute phase of measles?
Definition
1-2 weeks incubation; acute phase < 1 week
Term
What are the symptoms of the measles?
Definition
fever, cough, Koplik's spots on the buccal mucosa
Term
What are complications of the measles?
Definition
bacterial superinfection, encephalitis, keratitis, orchitis, oophoritis; VERY RARELY will have subacute sclerosing panencephalitis (progressiv neurological and intellectual deterioration)
Term
Where in the body is the Mumps virus located?
Definition
initial replication in the respiratory tract and local lymph nodes followed by dissemination to the salivary glands and CNS. Secondary viremia may cause spread to other organs
Term
How long is the incubation period and acute phase of mumps?
Definition
incubation: 2-4 weeks
acute: 1 week
Term
What are the symptoms of Mumps?
Definition
fever, parotitis
Term
What are the complications of mumps?
Definition
meningitis and encephalitis, pancreatitis, orchitis, and oophoritis
Term
What virus causes the german measles?
Definition
rubella
Term
Where in the body is the rubella virus?
Definition
replication in the URT, followed by dissemination to lymphoid tissue, skin and organs
Term
Why is it important to vaccinate against rubella?
Definition
can cause fetal damage (cardiac defects, CNS defects, eye defects, deafness, hyperplasia of the liver and spleen)
Term
T/F There is no treatment mumps, measles, or rubella.
Definition
true
Term
What is the MMRV vaccine?
Definition
measles, mumps, rubella, varicella virus vaccine
Term
What types of viruses are the henipavirus (nipah/hendra)?
Definition
zoonotic paramyxoviruses
Term
Where do zoonotic paramyxoviruses come from?
Definition
from bats to domesticated animals (pigs and horses)
Term
What are the symptoms of henipavirus (nipah/hendra)?
Definition
fever, respiratory distress with pulmonary edema, severe abdominal pain, difficulty swallowing that rapidly progresses to meningitis. >50% of patients become comatose. >60% mortality rate
Term
Describe the coronavirus genome and virion.
Definition
enveloped SS + RNA virus. Spike-like glycoprotein projections are petal shaped; give "crown or solar corona" appearance
Term
What virus replicates via "nested" RNAs?
Definition
coronaviruses
Term
Neutralizing antibodies and cell-mediated responses for coronaviruses are directed against...
Definition
spike-like glycoprotein projections
Term
What kind of diseae do coronaviruses cuase?
Definition
URI in humans; very common; usually mild with no severe infection except in pulmonary compromise
Term
How many serotypes of coronaviruses are there?
Definition
we don't know
Term
What percent of colds are caused by coronaviruses?
Definition
5-10% of common cold overall
35% in an outbreak epidemics in winter and springtime
Term
Where did SARS began/spread?
Definition
Nov 2002 in Guangdong PRC; officially discovered in Feb/mar 2003, exported to Hong Kong and Toronto in major outbreaks. Resolved by quarantine methods
Term
How many cases of SARS have there been worldwide?
Definition
>8,000
Term
What is the mortality rate of SARS?
Definition
10%
Term
T/F SARS-causing corona virus evolved from avirulent human coronaviruses that cause the common cold.
Definition
FALSE!!! probs from a very closely related coronavirus found in civet cats
Term
Pathogenicity of RNA viruses is frequently associated with ....
Definition
cross species jump
Term
T/F Mumps and exanthem viruses' sole reservoir is humans
Definition
true
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