37 - Rhabdoviruses - Rabies and other enveloped RNA viruses

Question 1

do Rhabdoviruses have (+) sense ssRNA or (-) sense ssRNA genome

Answer 1

(-) sense ssRNA genome

Question 2

what are the primary reservoirs for rhabdoviruses?

Answer 2

wild mammals

Question 3

T/F Rhabdoviruses have segmented RNA expression

Answer 3

False, non-segmented

Question 4

how is Rhabdoviruses spread?

Answer 4

bites, scratches, and inhalation of droplets

Question 5

T/F Rabies is almost always fatal once clinical signs/symptoms appear

Answer 5

true

Question 6

where will the rhabdoviruses replicate

Answer 6

local replication at bite site and replication in peripheral nerves

Question 7

where are the highest levels of rhabdoviruses found?

Answer 7

salivary glands and sensory nerves in oral mucosa

Question 8

what is the incubation period for rhabdoviruses?

Answer 8

variable (1 day to years; 75% w/n 90 days)

Question 9

what happens during the prodromal phase of a rhabdovirus infection?

Answer 9

fever, headache, malaise (general systemic viral signs)

Question 10

what symptoms are present in the furious form of rhabdovirus infection?

Answer 10

encephalitis, hydrophobia, delirium, agitation, seizures

Question 11

average time for pt to die of rabies

Answer 11

18 days after onset of clinical symptoms

Question 12

what treatment can reduce risk of rabies infection?

Answer 12

wound cleaning/care

Question 13

which virus is depicted as relatively large RN viruses with distinctively spaced spikes on their envelopes

Answer 13

Coronaviruses

Question 14

what are the 3 major types of human coronaviruses

Answer 14

cold
enteric viruses
pandemic coronaviruses (e.g. SARS, MERS, CoVID-19)

Question 15

what happens with coronavirus during early phase of replication?

Answer 15

genome is translated and polymerase is synthesized, which makes (-) sense copy of RNA

Question 16

what happens with coronavirus during late phase of replication?

Answer 16

(-) sense RNA is used to replicate new genomes and produce 5-7 nested mRNA’s

Question 17

up to _______% of adults are seropositive to common respiratory strains with the coronavirus epidemiology

Answer 17

90

Question 18

what season is coronavirus more prevalent in?

Answer 18

winter and early spring

Question 19

229E and NL63 are what type of coronavirus?

Answer 19

alpha

Question 20

OC43, HKU1, SARS-CoV, SARS-CoV-2, and MERS-CoV are what type of coronavirus?

Answer 20

Beta

Question 21

what cells are the primary infection with coronavirus?

Answer 21

epithelial cellswh

Question 22

at is the incubation period for coronavirus?

Answer 22

~3 days (range 2-5); slightly longer for SARS (4; 2-10), & MERS (5, 2-14)

Question 23

SARS virus infects and leads to destruction of the _________ epithelium

Answer 23

alveolar

Question 24

what are the disease manifestations of Coronaviruses?

Answer 24

respiratory infection with common cold-like symptoms

Question 25

What is the disease manifestation of SARS/MERS

Answer 25

atypical pneumonia with high fever, chills, rigors, headache, dizziness, malaise, myalgia, cough, or breathing difficulty

Question 26

what is recommended for prevention of coronaviruses?

Answer 26

good hygiene

Question 27

what is the mean incubation period for SARS-CoV-2

Answer 27

4-5 days (up to 14)

Question 28

_________% of identified pt's experienced fever, cough, or shortness of breath, _______% had muscle aches, and ________% reported headaches with SARS-CoV-2

Answer 28

70, 36, 34

Question 29

what are example tx's of COVID-19

Answer 29

itonavir-boosted nirmatrelvir [Paxlovid] (protease inhibitor) Remdesivir (nucleoside analog) Molnupiravir (nucleoside analog) Corticosteroids (Dexamethasone) immune modulators monoclononal antibody therapies (EUAs)

Question 30

T/F Rubella is a ssRNA with a loose envelope

Answer 30

true

Question 31

how is rubella transmitted?

Answer 31

respiratory secretions

Question 32

when was rubella eliminated in the U.S.?

Answer 32

1966 (usually < 10 cases/year)

Question 33

what are the two clinical forms of rubella?

Answer 33

postnatal rubella (age 5-9) (generally mild, lasting only 3 days) congenital (intrauterine) rubella (infection during the 1st trimester; likely will cause miscarriage or multiple defects)

Question 34

T/F no specific tx available for highly contagious rubella

Answer 34

True

Question 35

is Flavivirus (-) sense or (+) sense virus?

Answer 35

(+) sense, ssRNA

Question 36

is flavivirus enveloped or non-enveloped?

Answer 36

enveloped

Question 37

flavivirus will enter via ____________ mediated endocytosis

Answer 37

receptor

Question 38

where will flaviviruses replicate?

Answer 38

in membranous ER structures

Question 39

how many polyproteins are in flavivirus genome

Answer 39

single polyprotein

Question 40

what important genes are within the flavivirus genome

Answer 40

NS3 (serine protease) NS5a (replication complex protein) NS5b (polymerase) These are major drug targets!

Question 41

how is hepatitis C virus primarily acquired?

Answer 41

blood contact (blood transfusions, needle sharing by drug abusers)

Question 42

what percentage of pt's will remain infected indefinitely with hep C?

Answer 42

75-85%

Question 43

__________ can also result from chronic hep c infection

Answer 43

cancer

Question 44

what were the cons of the initial tx of hep c with pegylated interferon and ribavirin?

Answer 44

horrible side effects for a 50-50 chance of helping

Question 45

what are the cons of the new tx for hep c that target polymerase complex and protease

Answer 45

incredibly expensive ($63k-$189k)

Question 46

how are arboviruses spread?

Answer 46

arthropod vectors (e.g. mosquitoes, fleas, ticks, gnats)

Question 47

a majority of illnesses caused by arboviruses are [mild, moderate, severe] fevers?

Answer 47

mild, some may cause sever encephalitis, and life-threatening hemorrhagic fever

Question 48

what does acute arbovirus infection result in?

Answer 48

undifferentiated mild fever with rash

Question 49

what is a common complication of arbovirus infections?

Answer 49

viral encephalitis

Question 50

T/F typical arbovirus infection resolve with no long-term effects

Answer 50

True (rare complication arise with secondary infection and invasion of a target organ)

Question 51

where do vectors and viruses tend to be clustered?

Answer 51

tropics and subtropics

Question 52

____________ life cycles are closely tied to the ecology of the vectors

Answer 52

arbovirus

Question 53

what can dengue virus, west nile virus, and zika virus be grouped into?

Answer 53

flaviviruses

Question 54

example of alphavirus

Answer 54

chikungunya virus

Question 55

what will be caused by a flavivirus carried by Aedes aegypti and Aedes albopictus?

Answer 55

Dengue

Question 56

what is a complication to dengue?

Answer 56

dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS)

Question 57

prevention for dengue?

Answer 57

dengvaxia vaccine (questionable efficacy due to possible risk of hospitalization 2 years after vaccine)

Question 58

an estimated 70-80% of human ____________ infections are subclinical or asymptomatic

Answer 58

West Nile Virus Disease

Question 59

why is there no specific tx or vaccine for west nile virus disease?

Answer 59

companies aren't super interested as it doesn't cause much disease

Question 60

what are the complications of zika virus?

Answer 60

assoc. with congenital microcephaly, other congenital neurological defects, and possible assoc with guillain-barre syndrome (most are asymptomatic)

Question 61

what is the common sign/symptom for chikungunya virus?

Answer 61

fever & joint pain (polyarthralgia)

Question 62

what are the hallmarks of retroviruses?

Answer 62

reverse transcription integration into host genome

Question 63

major drug targets for general retrovirus replication

Answer 63

reverse transcription integration maturation (protease)

Question 64

what mediates reverse transcription?

Answer 64

RNA-dependent DNA polymerase (reverse transcriptase)

Question 65

T/F Reverse transcriptase is highly accurate

Answer 65

False. it is highly error-prone which allows for rapid evolution of the virus

Question 66

what are the two major types of error generated by reverse transcriptase?

Answer 66

nucleotide misincorporation strand transfers

Question 67

what mediates the integration process of retroviruses?

Answer 67

integrase enzyme

Question 68

when does HIV-1 maturation occur?

Answer 68

during/after budding

Question 69

viral ______ cleaves polyproteins for HIV-1 maturation

Answer 69

protease

Question 70

T/F HIV transmission occurs by direct and specific routes

Answer 70

true

Question 71

Can HIV survive long outside the body?

Answer 71

No

Question 72

where is the major site of replication for HIV

Answer 72

lymph nodes in the gut