Term
What enzyme must a negative RNA virus have? |
|
Definition
|
|
Term
Name the naked RNA viruses. |
|
Definition
picornaviridae, caliciviridae, astroviridae, reoviridae |
|
|
Term
T/F Astrovirus contains ds RNA. |
|
Definition
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|
Term
What are the only two examples of diseases in humans caused by reoviruses? |
|
Definition
colorado tick fever and rotavirus |
|
|
Term
Enteroviruses, hepatoviruses, and rhinoviruses are all types of ____ viruses. |
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Definition
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|
Term
Name the different types of enteroviruses. |
|
Definition
poliovirus (3), coxsackie A (1-22 & 24), coxsackie B (1-6), echovirus (1-9, 11-27, 29-34), parechovirus (1-4), kobuvirus (aichi prototype), enterovirus (68-71) |
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|
Term
Name the picornovirus that is also a hepatovirus. |
|
Definition
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|
Term
How many different types of rhinoviruses are there? |
|
Definition
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|
Term
Describe picornavirus virions. |
|
Definition
small icosahedral, naked virions with + ss RNA. Capsid formed from 60 copies of nonglycosylated proteins |
|
|
Term
How long does it take for one cycle of replication of a picornavirus? |
|
Definition
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|
Term
How do picornaviruses leave the host cell? |
|
Definition
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|
Term
How do picornaviruses enter the host cell? |
|
Definition
attachment then entry via receptor-mediated endocytosis. Receptors are members of the immunoglobulin superfamily |
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|
Term
What receptor does polio use? |
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Definition
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|
Term
Of the picornaviruses, most rhinoviruses and several coxsackie viruses use which receptor? |
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Definition
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|
Term
Describe the translation of picornoviruses. |
|
Definition
proteins translated at one polyprotein and initated at internal ribosome entry site. Polyprotein cleaved by a viral protease. Viral RNA synthesis through "-" strand intermediate with VPg at 5' end. Terminal cleavage of VPO into VP2 and 4 matures particle |
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Term
Describe the poliovirus polyprotein. |
|
Definition
first capsid (P1) then noncapsid genes (p2 and 3) |
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Term
Describe the characteristics of enteroviruses and Hep A relevant to transmission. |
|
Definition
resistant to pH between 3-9, detergents, heat, mild sewage tx |
|
|
Term
Describe the characteristics of a rhinovirus (picornovirus) relevant to transmission. |
|
Definition
labile at acidic pH; optimum gorwth at 33 degrees C |
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|
Term
About how many symptomatic infections do enteroviruses cause each year? |
|
Definition
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|
Term
How do enteroviruses get from where they entered the body to where they cause the disease? |
|
Definition
intestines-> lymhphoid -> target tissue |
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|
Term
There have been no cases of wild poliovirus in the US since ___. |
|
Definition
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|
Term
IPV (instead of OPV) has been used in the US since ____. |
|
Definition
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|
Term
What is bulbar paralysis caused by paralytic polio? |
|
Definition
when CNs and respiratory center in teh medulla are affected leading to paralysis of neck and respiratory muscles |
|
|
Term
What are the symptoms of a mild case of polio? |
|
Definition
|
|
Term
T/F Most polio infections are asymptomatic. |
|
Definition
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|
Term
In what percent of patients is poliovirus replication limited to the GI tract? |
|
Definition
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|
Term
T/F Polio can cause an aseptic meningitis. |
|
Definition
true, occurs in about 2% of patients |
|
|
Term
What parts of the CNS are infected by polio? |
|
Definition
anterior horn cells of the spinal cord and motor cortex of the brain |
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|
Term
Nuerons can continue to recover from polio infections for how long? |
|
Definition
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|
Term
What are the target tissues of coxsackie A? |
|
Definition
herpangina and hand, foot and mouth disease, aseptic meningitis |
|
|
Term
What are the target tissues of coxsackie B? |
|
Definition
myocardial and pericardial infections, pleurodynia, and aseptic meningitis |
|
|
Term
What are the target tissues of parechovirus? |
|
Definition
respiratory and GI, rare encephalitis and myocarditis |
|
|
Term
What is the target tissue of kobuvirus? |
|
Definition
|
|
Term
What is the target tissue of echovirus? |
|
Definition
aseptic meningitis, usually during the summer |
|
|
Term
Which enterovirus infect the meninges? |
|
Definition
|
|
Term
Which enteroviruses infect muscle? |
|
Definition
|
|
Term
Which enteroviruses go on to infect the skin and cause hand, foot, and mouth disease as well as rash herpangina? |
|
Definition
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|
Term
How do you diagnose and treat enteroviruses? |
|
Definition
RT-PCR or viral isolation and culture. However, viremia may be undetectable at time of symptoms. CSF specimens during acute phase are positive in 10-85% of samples treatment is supportive care |
|
|
Term
What is the principle agent of the common cold? |
|
Definition
rhinovirus (restricted to upper respiratory tract, causes mild URI in all age groups) |
|
|
Term
What is the time course of rhinoviruses? |
|
Definition
1-2 day incubation period; acute symptoms last 3-7 days |
|
|
Term
How do you treat rhinovirus infection? |
|
Definition
no specific tx or vaccine (possible block of receptor attachment) |
|
|
Term
What type of virus is a norovirus? |
|
Definition
|
|
Term
What are the characteristics of gastroenteritis caused by calciviruses? |
|
Definition
|
|
Term
WHat are the characteristics of gastroenteritis caused by astrovirus? |
|
Definition
mild, self-limiting, in children |
|
|
Term
What two factors contribute to a high transmission risk in viruses that cause gastroenteritis? |
|
Definition
large quantities of virus in the stool and the virus is resistant to the environment |
|
|
Term
Describe the calcivirus virion. |
|
Definition
naked, icosahedral, positive ssRNA. Contain a single large capsid protein. Viral surface has 32 cup-shaped depressions (calici) |
|
|
Term
What are the caliciviruses are medical importance? |
|
Definition
norwalk and "norwalk like" viruses (NLV) "sapporo-like" viruses (SLV) |
|
|
Term
What is the primary agent responsible for most acute diarrheal diseasein adults and children? |
|
Definition
norovirus (90% of all viral diarrheal disease) |
|
|
Term
T/F Norovirus is considered ubiquitous. |
|
Definition
true, 70% of people have had it by age 7 |
|
|
Term
What are the different genogroups of norovirus? |
|
Definition
GI-V, which are each divided into at least 31 genetic clusters |
|
|
Term
Which is the most dominant type of norovirus over the last several years? |
|
Definition
|
|
Term
How many particles of norovirus are needed to cause infection? |
|
Definition
|
|
Term
Name the norwalk and norwalk like viruses. |
|
Definition
norwalk, hawaii, snow mountain, montgomery county, taunton (england) |
|
|
Term
What is the time frame of norovirus? |
|
Definition
incubation period of 24-48 hours. abrupt onset with watery diarrhea, N/V, lasting 24-60 hours |
|
|
Term
T/F Most norovirus infections are asymptomatic. |
|
Definition
false, around 30% of norovirus infections are asymptomatic |
|
|
Term
What percent of diarrheal cases in infants does astrovirus account for? |
|
Definition
|
|
Term
T/F Astrovirus cannot be grown in cell culture. |
|
Definition
|
|
Term
Astrovirus particles are resistant to... |
|
Definition
acid stable and heat resistant |
|
|
Term
Describe Reovirus genome and virion. |
|
Definition
ds RNA, segmented genome, icosahedral capsid, naked |
|
|
Term
What is the leading cause of severe acute gastroenteritis among children worldwide? |
|
Definition
|
|
Term
Describe the viral nucleocapsid of rotavirus? |
|
Definition
composed of three concentric shells that enclose 11 segments of ds RNA |
|
|
Term
How many serotypes are there of rotavirus? |
|
Definition
5. the outermost layer contains two structural proteins: VP4 (protease cleaved protein, P protein) and glycloprotein (G protein) which dfined the serotype of the virus. Also targets for neutralizing antibodies |
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|
Term
T/F Rotavirus is highly contagious. |
|
Definition
|
|
Term
When does rotavirus infection usually occur? |
|
Definition
late fall, winter and early spring |
|
|
Term
What is the disease course of rotavirus? |
|
Definition
1-3 day incubation, followed by abrupt onset of vomiting, abdominal cramps, low-grade fever with frequent copious watery stools |
|
|
Term
T/F Most children are seropositive for rotavirus by age 3 |
|
Definition
|
|
Term
How do you diagnose rotavirus? |
|
Definition
detection of virus particles or viral antigens in the stool |
|
|
Term
T/F Both rotavirus vaccines are orally administered, non-living virus vaccines. |
|
Definition
false they are live virus vaccines |
|
|
Term
How was Rotateq developed? |
|
Definition
contains 5 reassortant rotaviruses developed from human and bovine parent rotavirus strains |
|
|
Term
RotaTeq contians which antigen? |
|
Definition
RV5 pentavalent human-bovine reassortant rotavirus vaccine |
|
|
Term
What are the doses of rotarix? |
|
Definition
2 doses at 2,4 months of age |
|
|
Term
What is the antigen used in rotarix? |
|
Definition
RV1 (monovalent human rotavirus vaccine) |
|
|
Term
When were the two rotavirus vaccines liscensed? |
|
Definition
rotateq in 2006, rotarix in 2008 |
|
|
Term
How was rotarix vaccine created? |
|
Definition
contains a human rotavirus strain isolated from a child; was first attenuated by passaging 33 times in African green monkey kidney cells, then cloned and further passaged in vero cells |
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|
Term
T/F The second infection with rotavirus tends to be less severe than the first infection. |
|
Definition
true however niether vaccine nor natural infection will provide full immunity from future infections |
|
|
Term
What is a possible complication of RotaShield? |
|
Definition
intussusception, taken off the market in 1999 |
|
|
Term
What are the symptoms of colorodo tick fever? |
|
Definition
acute disease with fever headache and severe myalgia |
|
|
Term
Characterize the genome of the virus that causes colorado tick fever. |
|
Definition
12 double stranded RNA genomic segments |
|
|
Term
Where is reovirus that causes colorado tick fever found? |
|
Definition
western and northwestern US, western canada; host is the dermacentor andersoni wood tick; natural host are mammals (squirrel, rabbits and deer) |
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|
Term
What are the most prevalent and/or significant enveloped RNA viruses? |
|
Definition
influenza, paramyxo, and retroviruses |
|
|
Term
Name the enveloped RNA viruses that cause CNS disease and hemorrhagic fevers? |
|
Definition
togaviruses (alpha viruses), flavivirus, and bunyaviruses |
|
|
Term
|
Definition
equine encephalitis viruses (EEE, VEE, WEE) chickungunya fever (asia) and rubella (rubi viruses) |
|
|
Term
|
Definition
yellow fever, dengue, st louis encephalitis, west nile, and hep C |
|
|
Term
|
Definition
california encephalitis, LaCrosse encephalitis, Rift valley fever, hantavirus |
|
|
Term
Where are california and laCrosse encephalitis found and what are they transmitted by? |
|
Definition
found in US, transmitted by mosquitoes and chipmunk is a reservoir host |
|
|
Term
Where is rift valley fever found and what transmits it? |
|
Definition
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|
Term
What are the symptoms of hantavirus infection. |
|
Definition
hemorrhagic fever and pulmonary syndrome |
|
|
Term
What population does california encephalitis affect most? |
|
Definition
highest rates of disease in children |
|
|
Term
What time of year is california encephalitis at its peak? |
|
Definition
|
|
Term
Does california encephalitis predominantly affect suburban or rural environments? |
|
Definition
vector is found in both places (aedes triseriatus) |
|
|
Term
Describe the virion of a togavirus. |
|
Definition
SS RNA + enveloped with icosahedral symmetry |
|
|
Term
How does a togavirus enter a cell? |
|
Definition
via receptor-mediated endocytosis |
|
|
Term
|
Definition
insect borne encephalitis |
|
|
Term
|
Definition
|
|
Term
T/F Rubella is insect borne. |
|
Definition
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|
Term
What is the natural host of an alphavirus and how is it transmitted? |
|
Definition
mammal or bird with no apparent disease; transmitted by mosquitoes |
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|
Term
Why is is alphavirus only trandmitted by mosquitoes? |
|
Definition
viral replication in gut of vector is essential |
|
|
Term
Describe the pathogenesis of alpha virus. |
|
Definition
infected arthropod bites and injects virus from salivary glands to capillary bed. Then the virus replicates in the reticuloendothelial system. The systemic phase with symptoms of viremia and fever. Then there is active infection of target tissue (CNS or skin and blood vessels, or viscera and muscle) |
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|
Term
What organisms are infected by alphaviral encephalitides? |
|
Definition
found principally in horses (and humans) as accidental dead-end hosts from enzootic transmission from birds or rodents |
|
|
Term
What are the different types of alphaviral encephalitides? |
|
Definition
EEE (eastern equine encephalitis), WEE (western), VEE (Venezuelan) |
|
|
Term
Which is the most severe of the alphaviral encephalitides? What's the mortality? |
|
Definition
EEE, 33% mortality with severe neurological sequelae |
|
|
Term
|
Definition
EE is very rare but it is found in atlantic and southern coastal states |
|
|
Term
Where does EEE come from? |
|
Definition
reservoir in birds, possibly pheasants, bird-bird transmission |
|
|
Term
T/F Most people recover completely from WEE. |
|
Definition
true, there is a 2-3% mortality |
|
|
Term
What are the symptoms of WEE? |
|
Definition
more frequently symptomatic in children and range from mild flu-like to encephalitis |
|
|
Term
|
Definition
|
|
Term
|
Definition
mostly in western and mid-western states but range of bird and vector rules, so not restricted there |
|
|
Term
What is the mortality rate of VEE? |
|
Definition
very low (0.5%) in humans but devastating for horses |
|
|
Term
|
Definition
reservoirs in rodents rather than birds |
|
|
Term
|
Definition
chiefly south america and southern US |
|
|
Term
Where is chickungunya fever found? |
|
Definition
asia, thailand, maylasia, india |
|
|
Term
What are the symptoms of chickungunya fever? |
|
Definition
debilitating illness with fever, h/a, fatigue, N/V, muscle pain and joint pain |
|
|
Term
What is the treatment for Chickungunya fever? |
|
Definition
there is no tx or vaccine |
|
|
Term
What is the viral vector of chickungunya fever virus? |
|
Definition
|
|
Term
What are the flaviviruses? |
|
Definition
yellow fever, denque, st. louis encephalitis, west nile and hepatitis C |
|
|
Term
Describe the virion of flaviviruses. |
|
Definition
SSRNA +, enveloped, and icosahedral |
|
|
Term
What type of virus is yellow fever? |
|
Definition
|
|
Term
Which virus type cause encephalitis and hemorrhagic fever? |
|
Definition
encephalitis hemorrhagic fevers |
|
|
Term
What are the encephalitides of the flavivirus? |
|
Definition
st. louis encephalitis (US-Canada), Japanese B encephalitis (Asia, pigs, and birds) murray valley fever (australia), west nile fever (widespread), powassan virus (North America-tickborne) |
|
|
Term
Which flaviviruses cause hemorrhagic fevers? |
|
Definition
|
|
Term
What are the symptoms of flaviviral encephalitis? |
|
Definition
fever, h/a, chills, vomiting; drowsiness and nuchal rigidity 1-2 days later. May progress to confusion, convulsion, coma and death |
|
|
Term
What are the symptoms of yellow fever? |
|
Definition
chills and fever followed by visceral infection of liver and/or kidneys. GI hemorrhage and characteristic black vomit |
|
|
Term
What is the mortality of yellow fever? |
|
Definition
|
|
Term
How can you prevent yellow fever? |
|
Definition
live, attenuated 17D vaccine |
|
|
Term
What are the natural host of yellow fever? |
|
Definition
|
|
Term
How is yellow fever transmitted? |
|
Definition
sylvatic cycle and urban cycle (human-mosquito-human) cycle; man not necessarily dead-end |
|
|
Term
Where is Yellow Fever found? |
|
Definition
sporadically in the forested areas of south america and in afra during the rainy season |
|
|
Term
What is the most widespread arbovirus in the world? |
|
Definition
|
|
Term
How many cases of dengue fever are there per year? |
|
Definition
|
|
Term
Where in the US is Dengue fever found? |
|
Definition
|
|
Term
Can you be infected with Dengue fever multiple times? |
|
Definition
yes, there are 4 serotypes |
|
|
Term
How is Dengue fever transmitted? |
|
Definition
between mosquitoes and humans (aedes aegypti). Transmission occurs when mosquito feeds on a person during a 5 day period when large amounts of virus are in the blood |
|
|
Term
What has caused Dengue to disseminate around the world? |
|
Definition
transport of aedes mosquitoes around the world (WWII) |
|
|
Term
Where is denque fever found? |
|
Definition
endemic in asia, the pacific, the americas, africa, and the caribbean |
|
|
Term
What is the time course of the symptoms of Dengue fever? |
|
Definition
begin 4-7 days after the mosquito bite and typically last 3-10 days. Causes severe headache and severe pains in muscle and joints ("breakbone fever") rapidly fading maculopapular rash; hematuria, leukopenia, thrombocytopenia. Convalescence slow but certain |
|
|
Term
What is Dengue hemorrhagic fever? |
|
Definition
aka dengue shock syndrome. Occurs upon re-infection with another serotype, immune complex type of disease, circulatory shock and hemorrhage, high mortality, esp in children |
|
|
Term
What is the time course/symptoms of dengue hemorrhagic fever/dengue shock syndrome? |
|
Definition
fever lasts from 2 to 7 days. As fever declines symptoms including persistent vomiting, severe abdominal pain, and difficulty breathing may develop. Capillaries become permeable causing ascites and pleural effusions, leading to shock and death |
|
|
Term
Dengue epidemics require.. |
|
Definition
large number of vector, large numbers of people with no immunity to dengue, the opportunity for contact between the two |
|
|
Term
|
Definition
treat symptoms 1) blood/platelet transfusion 2) IV fluids/electrolytes 3) oxygen therapy |
|
|
Term
What is the prognosis for dengue HF? |
|
Definition
most pts recover with early and aggressive care. Half of untreated pts who go into shock don't survive |
|
|
Term
Where/when was west nile fever virus found in the US? |
|
Definition
|
|
Term
T/F Most humans develop no clinical signs of disease when infected with west nile. |
|
Definition
true (only 20% develop disease of west nile fever) |
|
|
Term
Which populations have the most severe cases of west nile? |
|
Definition
|
|
Term
How do you prevent west nile fever? |
|
Definition
aggressive mosquito control (birds are now uniformly infected) |
|
|
Term
What test is used by blood banks to determine that donated blood does not contain west nile virus? |
|
Definition
nucleic acid amplification test (NAAT) |
|
|
Term
When are levels of WN virus highest? when are IG levels highest? |
|
Definition
about 3 days before symptom onset 2-3 days post onset |
|
|