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57 Cards in this Set

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What are the two subgroups of the Togaviridae family?
Alphavirus (arbovirus)
Rubivirus
What is an arbovirus?
transmitted by arthropod
What is the structure of the Togaviridae?
positive stranded ssRNA
icosahedral capsid
enveloped from host cell plasma membrane and displays 2 peplomers
E1 & E2 peplomers serve as attachment and fusion proteins
How does rubella virus (rubivirus) present clinically?
febrile fever
rash
lymphadenopathy (usually auricular)
not contagious
50% asymptomatic
What is CRS Congenital Rubella Syndrome?
caused by seronegative pregnant women exposed to rubivirus and causes blindness, heart defects, mental retardation, death in fetus/neonate
What is post-natal Rubella?
rubella virus caused disease after natal period more common in adolescent and adult
What is the pathogenesis of rubivirus (rubella)?
1. adolescent and adult respiratory transmission
2. virus can be found in throat, blood, urine, feces
3. 7 day incubation -> viremia
4. prodrome occurs
5. Ab is formed and disease starts to resolve
What coincides with maximum lymphadenopathy in rubella?
rash begins to appear starting on face and spreading downward over the trunk and extremities. rash fades over time, so it looks like rash is running down and "out of the feet."
How long after rash will virus shed from respiratory tract?
up to 2 weeks
What is rubella tx?
supportive,
self-limiting
What types of cells are common in rubella complications?
synovial cells -> polyarthritis/polyarthralgia that is usually self-limiting
What three findings should be indicative of rubella complication encephalitis?
fever, stiff neck, lethargy
can see lymphocytes in CSF
What is Progressive Rubella Panencephalitis (PRPE)?
happen years after rubella infection recovery, there is neurologic deterioration which eventually leads to death and it most commonly associated with congenital rubella infection
What can you do clinically determine rubella infection? This is usually only done in pregnant women and congenital rubella cases.
antibody id for rubella Ab in serum samples, check rising titers in preggos
What type of vaccine is used for a rubella virus prevention?
live attenuated, NOT for pregnant women since it's live
What month of fetal age is the cut off for most probable of getting MAJOR abnormalities or stillbirth?
4 months, but most die in the 1st year and if do not die, then will shed virus for over 1 year. Abnormalities occur with pretty much all rubella babies.
What is a nickname for a rubella infected neonate?
blueberry muffin baby caused by Thrombocytopenia purpura
What is german measles?
rubella!
What is the transmission vector for Alphavirus?
mosquito
What three diseases are caused by Alphavirus?
EEE - eastern equine encelphalitis
WEE - western equine encelphalitis
VEE - venezuelan equine encelphalitis
What is the pathogenesis of Alphavirus?
1. mosquito infects
2. primary infection occurs at location of inoculation
3. primary viremia occurs with febrile response manifesting
4. secondary viremia occurs with classical clinical signs: myositis, arthritis, rash, encephalitis
What two clinical symptoms go along with Alphavirus crossing the BBB?
nausea, vomiting
What is significant about EEE infection?
mortality rate is 80% with treatment, which makes it most deadly mosquito borne infection in the US
How to dx Alphavirus?
check rising IgM titers
Tx for Alphavirus?
supportive, NO vaccine, avoid mosquitos
Coronaviridae name refers to what physical property?
very large peplomers that make the virus look crowned under electron microscope
What two genera are a part of the Coronaviridae family and what do they cause?
1. Coronavirus - lesser [than rhinovirus] causative agent of common cold
2. Torovirus - GI distress
Regarding pathogenesis of coronoviridae, what is significant?
they do NOT cause viremia.
What is the structure of a Coronaviridae?
positive ssRNA
helical capsid
enveloped w/ peplomers for attachment and penetration
What age demographic is most commonly infected with Coronaviridae?
all ages
What massive outbreak in 2002 was caused by Coronaviridae?
SARS
What is the treatment of Coronaviridae?
supportive, self-limiting
What is significant about multiple sclerosis and Coronaviridae?
RNA sequences in brain tissue of MS pts are similar to Coronaviridae RNA
What family of virus causes flu?
Orthomyxoviridae
What two genera of Orthomyxoviridae will be of most concern?
A, B.

C is self-limiting and doesn't cause major problems
What is the significance of Type A flu?
it can infected people AND animals
What is the structure of Orthomyxoviridae?
negative ssRNA
helical capsid
enveloped w/ HA, NA, M2 from plasma membrane
can undergo reassortment
What is reassortment?
phenomenon that flu virus undergoes in which pieces of one segmented ssRNA can interchange with other viral strains and reassemble to produce unique, new strains
What is the significance of HA, NA, M2?
HA - hemagglutinin for binding
NA - neuraminidase for degredation of mucus
M2 - ion channel to regulate pH inside the virion
How can you distinguish types of flu based on standard nomenclature?
A/USSR/90/77
type/location/strain number/year of isolation
What causes differences in subtypes of type A flu?
antigenic shift per changes in HA molecules and NA molecules, hence the nomenclature H1N1 refers to the HA subtype 1 and NA subtype 1
What is the chronological pattern of antigenic shift refer to?
there is an antigenic shift cycle that occurs every few years which causes a new pandemic where H2N2 -> H3N2 -> H1N1 -> H2N2 -> H3N2 -> H1N1 and so on.
What portion of the flu virion always changes with antigenic shift?
HA does always change, historically
NA does not always change
What is Antigenic drift?
slow change in hypervariable region based on RNA mutations in both type A and type B.
Why do a lot of A type strains come from SE Asia and China?
people live in closer proximity to animals
What demographic of people are most susceptible to flu infection?
elderly - will die
kids - will get infected, but not die
What is a clinical hallmark of flu infection?
abrupt onset of fever, headache, sore throat, non-productive cough, rails
What clinical hallmark is NOT indicative of flu?
coryza - head cold stuffiness
When in the pathogenesis of the flu does it go systemic?
it doesn't. flu stays in the respiratory tract.
What is ZstatFlu?
it's it's blue it's flu rapid flu test. takes 30 minutes
What is the tx for flu?
supportive.
no aspirin for kids because of Reye's syndrome.
extreme cases may warrant Neurominidase inhibitors antivirus which binds to neurominidase on the virus
What are the two neurominidase inhibitors on the market and when is it proper to use them?
only to pts who have had symptoms for less than 2 days:
1. Relenza
2. Tamiflu
What is the significance of Amantadine and Rimantadine?
teratogens only effective for type A viruses, these drugs block the M2 ion channel of the virion and are no longer used because of abuse related resistance.

DO NOT GIVE TO PREGNANT WOMEN.
What 2 seasonal vaccines are available?
1. TIV - trivalent inactivated vaccine
2. LAIV - live attenuated vaccine

both type A and B are used in each vaccine
What is special about the LAIV vaccine?
reassorted live-attenuated strains with cold-adapted strain which produce a mild flu state, but is trivial and provides better support. adminstered via intranasal spray
What is Avian Flu?
H5N1, person to person spread rare, must have direct contact with bird carrier
What is Swine flu?
"novel H1N1" that endured antigenic drift and spread throughout the world within 1 mo of being identified. symptoms are identical to H1N1, but population of highest incident was 5 - 24 y/o. LAIV and TIV different for novel than regular, but can be given simultaneously.