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MOHD4: Exam 2 > RNA viruses > Flashcards

RNA viruses Flashcards

1
Q

this family of viruses produces both full length and subgenomic length RNA, the latter from which structural proteins are translated

A

togaviruses

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2
Q

all subgroups of this “naked”, 12-pentamer family cause acute infections including the common cold and GI tract infections

A

picornovirus

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3
Q

this illness presents with characteristic swelling of cheeks, parotid gland and under the jaw, and may lead to male sterility due to viral replication in the testis

A

mumps

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4
Q

Name that virus:

A

coronavirus

*note the halo of glycoprotein spikes emanating from their envelope

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5
Q

1 cause of upper respiratory tract infections

A

rhinovirus

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6
Q

what major property of influenza virus accounts for its strain variability?

A

segmented genome that reassorts

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7
Q

family of viruses that includes EEV, WEV and Chikungunya virus

A

togavirus

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8
Q

most common cause of arbovirus-related encephalitis in the US, with more than 3/4 of those infected being asymptomatic (iceberg effect)

A

West Nile Virus

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9
Q

bullet shaped viral family that causes rabies

A

rhabdovirus

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10
Q

subgroup of the bunyavirus family that:

  • is found in the “Four Corners” and recently in Yosemite
  • has a segmented genome and causes hemorrhagic fever
  • is spread by aerosolizatoin of high levels of virus in rodent excreta
A

hantavirus

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11
Q

What does Anti-Hep A IgG tell you about a person’s infection status?

A

only that a person is immune to re-infection. does not tell you about the time of the infection (IgM identifies “acute infection”).

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12
Q

calicivirus subgroup that causes “cruise ship diarrhea”

A

norovirus

*caliciviruses are very stable and are spread via fecal-oral route, from food and person to person

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13
Q

bunyavirus subgroup that is endemic in the midwest and mid-Atlantic in heavily wooded areas and is a leading cause of encephalitis

A

la crosse virus

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14
Q

naked, icosahedral, dsRNA viral family that causes rotavirus

A

reovirus

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15
Q

viruses responsible for ~90% of non-bacterial meningitis

A

enteroviruses (A-D)

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16
Q

Which of the following statements about Paramyxoviruses is FALSE?

A. They enter via the respiratory tract and are phagocytosed by lung macrophages

B. Some subgroups spread to many cell types, causing viremia

C. They are transmitted to the basal side of tracheal epithelia and released on the apical side

D. An inactivated virus vaccine is usually given in combination with rubella (MMR)

E. The vaccine for paramyxoviruses is grown in chicken eggs.

A

D. The vaccine is a live attenuated virus vaccine.

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17
Q

the minor differences in influenza strains each year are due to antigenic shift or drift, which arises as a result of what mechanism?

A

antigenic drift; arise from point mutations in the RNA due to error prone repair

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18
Q

how is WNV best diagnosed?

A

IgM antibodies in the blood

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19
Q

leading cause of viral encaphalitis in the US

A

HSV

20
Q

+strand RNA viral family that has a helical capsid structure and causes SARS and MERS, as well as the common cold

A

coronavirus

21
Q

virus that binds to ICAM-1, a receptor that is distributed widely in the body whose expression is decreased by alcohol consumption

A

rhinovirus

22
Q

viral illness for which there is a live attenuated vaccine given to those traveling to endemic areas (South America and Africa)

A

yellow fever virus

23
Q

this virus:

  • is stable to heat and pH and survives in the environment a long time
  • is highly infectious and food bourne
  • is spread via fecal-oral route from person to person
  • causes fever, nausea, diarrhea and vomiting ~4 weeks after infection, but before jaundice
A

HAV

24
Q

Which of the following statements regarding Calicivirus and HEV epidemiology is FALSE?

A. There are no antivirals or vacccines available for either.

B. Calicivirus is the #1 cause of adult, non-bacterial gastroenteritis.

C. Because of their inherent stability, Caliciviruses exhibit good replication in cell culture

D. HEV is associated with poor sanitation in developing countries..

E. HEV is not associated with chronic infections.

A

C. These viruses grow poorly in cell culture.

25
Q

Which of the following is NOT one of the top causes of URIs as mentioned in class?

A. Coronavirus

B. Rhinovirus

C. Strep pneumoniae

D. Adenovirus

E. Parainfluenzavirus

A

C.

Other top causes include RSV, influenza, and Group A strep.

26
Q

similar to west nile virus, these viruses are arboviruses with a mosquito vector (rare in the US) that infect dead end mamalian hosts

A

EEE and WEE viruses

27
Q

virus that causes a flaccid paralysis through motor end plate disruption, leading to death of motor neurons

A

poliovirus

28
Q

influenza A or B undergoes major strain differences year to year, and this is due to antigenic shift or drift.

A

A; shift

29
Q

this viral family:

  • causes infections transmited by saliva and respiratory secretions
  • causes measles, mumps and RSV
  • replicates in the cytoplasm but does not steal cellular 5’ cap
A

paramyxoviruses

30
Q

what are the components of the seasonal flu vaccine?

A

HA from two “A” strains and from one “B” strain to make trivalent inactivated vaccine or attenuated FluMist

31
Q

Which of the following statements about Dengue Fever is FALSE?

A. It is known as “break bone” disease and is painful but rarely lethal

B. Over 40% of world’s population is at risk for contracting it

C. Symptoms include rash, fever and intense muscle pain

D. It has 5 serotypes, each of which confers immunity to those who have had a previous infection

E. Dengue hemorrhagic fever or shock syndrome is frequently lethal.

A

D.

Dengue hemorrhagic fever or shock syndrome (DHS/DSS) is frequently lethal and is thought to result from an enhanced illness due to memory immune cells from a previous infection.

32
Q

highest risk factor for this viral illness is IV drug use; chronic infection leads to clinical liver disease in 20%

A

HCV

33
Q

this viral family is similar to the picornavirus family, except that its members are enveloped, employ a complex cell entry via multiple receptors, and exit a host cell by budding into internal cellular membranes (ie, ER)

A

flavivirus

34
Q

influenza pandemics tend to have what type of reservoirs?

A

avian and swine

35
Q

an infection of the lower respiratory tract that causes syncytia formation in lung epithelia

A

RSV

*It is the leading cause of bronchiolitis, and like other Paramyxoviruses, no immunity can be formed because it only replicates in the respiratory tract.

NOT TRUE for measles and mumps - these two illnesses elicit long term protection because they are systemic infections.

36
Q

what are the 3 features of rhinovirus that result in a weak and short lived immune response?

A
  1. it only replicates in the respiratory tract
  2. it does not cause a cytopathic infection of nasopharyngeal mucosal cells
  3. immunity to one strain does not protect against others, and there are more than 140
37
Q

virus responsible for hand foot and mouth disease

A

coxsackie A (and Enterovirus 71)

38
Q

this togavirus:

  • is one of 6 childhood exanthems
  • is transmitted via respiratory or intrauterine route
  • causes fever, rash, arthralgia
  • congenital illness leads to fetal damage
A

Rubella

39
Q

togavirus subgroup that cuases arthritic symptoms and joint pain - currently spreading in Europe and central Asia from Africa

A

Chikungunya virus

40
Q

illness that:

  • is one of 6 childhood exhanthems
  • presents with high fevers and Koplik spots
  • is a major killer of infants and toddlers in Africa
A

Rubeola (measles)

41
Q

Infection with subtypes 1-3 of this virus causes croup

A

parainfluenza

*type 4 causes mild URI. no treatment or vaccine.

42
Q

two subgroups of flavivirus that replicate in insect and mamalian hosts, and cause encephalitis (not spread person to person)

A

West Nile Virus (WNV)

St. Louis Encephalitis Virus (SLEV)

*horse ranchers!

43
Q

Describe how orthomyxoviruses get into, replicate, and get out of host cells.

A
  1. HA precursor gets proteolytically cleaved by serine proteases in the lung
  2. HA1 binds to sialic acid on host surface epithelial cells
  3. Virus particle enters into endosome, begins pumping protons in to lower pH so it can release its capsid
  4. Genome expression: occurs in nucleus, where virus steals 5’ cap and uses it as primer for RDRP to transcribe mRNA
  5. Genome replication: occurs in nucleus. RDRP uses -strand RNA to make +strand
  6. Viral neuroaminidase cleaves sialic acid on host cell membrane allowing virus to bud as a virion
44
Q

family whose members contain viral protein VPg in their genome that acts as a primer for RNA synthesis by the host cell ribosomes

A

picornavirus

45
Q

characteristic pathology of this disease are Negri bodies - inclusion bodies found in the cytoplasm of infected nerves

A

rabies

46
Q

Which of the following statements regarding Poliovirus is FALSE?

A. It is the only enterovirus for which there is a vaccine available

B. The inactivated polio vaccine also protects against GI infection as well as polio

C. The live attenuated polio vaccine is no longer given in the US

D. There are no antiviral treatments for polio

E. Widespread vaccine success reduced the research and development funding available for polio treatment

A

B.

The inactivated vaccine is what is given in the US, as it does not cause vaccine-related polio like the live attenuated can; however, it does NOT protect against GI infection.

MOHD4: Exam 2 (7 decks)

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