Mhr Topic 33: Enveloped Rna Viruses 2 And 3

Front 1

Togaviruses (genome and types)

Back 1

Enveloped, SS+ unsegmented RNA. Have Rubiviruses and Alphaviruses (discussed in arboviruses).

Front 2

Rubella Virus (infection, disease)

Back 2

1) Respiratory droplets. Goes from respiratory to lymph and blood (can be transmitted to fetus).
2) Child - fever and rash which starts on face and goes down body. Also get occipital lymphadenopathy.
Adults - May also get joint pain and arthritis but may be asymptomatic which can cause vertical transmission.
Fetus - If first tri. can lead to death, miscarrage, or congenital rubella: Cardiac problems, deafness, cataracs/blindness, retardation.

Front 3

Rubella Virus (diagnosis, treatment)

Back 3

Diagnoses via rubella Ab titers.
MMR vaccine for children. Live attenuated and therefore cant be given to pregnant women.

Front 4

Coronaviruses (genome, types)

Back 4

Enveloped, + helical unsegmented RNA.
Common cold strains and SARS-coronavirus

Front 5

SARS (infection, disease)

Back 5

1) Respiratory droplets. Highly infectious.
2) Different from other coronaviruses b/c goes into lower respiratory tract. Severe, often fatal pneumonia with respiratory failure in addition to fever cough. Also can get gastroenteritis and diarrhea.

Front 6

SARS (Diagnosis, treatment)

Back 6

1) Strain was diagnosed during outbreak via PCR.
2) Only therapy was quarantine after diagnosis.

Front 7

Paramyxoviruses (genome, types)

Back 7

1) enveloped, SS - nonsegmented RNA.
2) Parainfluenza, mumps, measles, RSV

Front 8

Paramyxoviruses important proteins

Back 8

N = Neuraminidase.
H = Hemagglutinin
F = Fusion
N and H mediate attachment to cells, F mediates fusion.

Front 9

Every virus in this section is transmitted how?

Back 9

Through respiratory droplets which can stay infectious on objects for awhile.

Front 10

Parainfluenza virus (infection, disease)

Back 10

1) Respiratory droplets
2) Common cause of croup - inflamation of larynx/trachea causing blockage of the airway leading to a barking cough. Also causes ear infections, flu like, pneumonia, bronchitis, and common cold.

Front 11

Rubulavirus (infection, disease)

Back 11

Mumps
1) Respiratory droplets
2) Key is Swelling of Parotid Glands. Get flu-like illness. Virus gets into blood can cause encephalitis, meningitis, and painful swelling of testes (orchitis) which can lead to infertility.

Front 12

Rubulavirus treatment

Back 12

MMR vaccine. Live attenuated.

Front 13

Morbillivirus receptor

Back 13

Use CD46 receptor to infect cells. Widely distributed receptor giving virus many different host cells.

Front 14

Pneumovirus (treatment)

Back 14

Might need to give kids respiratory support. High risk kids can be given antibodies. Immune response is weak and re infections do occur.

Front 15

Morbillivirus (infection, disease)

Back 15

Measles
1) Respiratory droplets. Highly infectious. Virions are inhaled, replicate in respiratory epithelium, and spread into blood stream.
2) Fever, cough, runny nose, red eyes, rash (which starts in the mouth (koplick spots), then face, then down body). Can also cause pneumonia and encephalitis.

Front 16

Morbilivirus (diagnosis, treatment)

Back 16

1) Mouth rash (koplick spots) differentiates from other rashes.
2) MMR live atenuated vaccine.

Front 17

Pneumovirus proteins

Back 17

Lack N.
H and F are present.

Front 18

Morbillivirus proteins

Back 18

Measles
Lack N.
H and F are present.
F causes Syncytia - Large multinucleated aggregates formed by fusion of many cells.

Front 19

Pneumovirus (infection, disease)

Back 19

Respiratory Syncytial virus (RSV)
1) Respiratory droplets. Highly infectious
2) Main cause of bronchitis and pneumonia in young children. Worse in kids with CF or immunocompromised. Can cause pneumonia in elderly. Adults get common cold.

Front 20

Orthomyoxovirus (genome, types)

Back 20

Influenza
Enveloped -SS segmented RNA.

Front 21

Influenza proteins

Back 21

No F. Have N and H but they act independently. H facilitates initial binding, N facilitates viral release.

Front 22

Influenza transmission

Back 22

Respiratory droplets. Highly infectious. Also highly seasonal. Winter is peak season b/c people are packed together and the low temp low humidity facilitate droplets to spread infection.

Front 23

Influenza replication

Back 23

Replicates in respiratory epithelial cells. Other than retroviruses, only RNA virus which replicates in the nucleus:
-H bind to sialic acid receptors, get endocytosed
-Gets uncoated
-Goes into nucleus
-P protein takes a cap from host cell and puts it on RNA making it look like host.
-Viral RNA dependent RNA polymerase (present in virion) transcribe -RNA to +mRNA which either get translated by host, producing virion poteins or stay in nucleus for -RNA strand production.
-Virions released via N, no cytolytic but cell dies from viral stress.

Front 24

Antigenic drift

Back 24

Single AA mutations happen constantly due to low fidelity polymerase. If these mutations change H and N proteins, will alter viral angitgenicity. This is why you need a new flu vaccine every year.

Front 25

Antigenic Shift

Back 25

Occurs when 2 different strains of a segmented virus infect the same cell. If recocmbination occurs, and entirely new virus can be formed, and if it involves H and N, is called antigenic shift. Ability of Influenza A to infect multiple species allows it to shift with other species of influenza causing the 15 year epidemics.

Front 26

Influenza type A (disease, treatment)

Back 26

1) Responsible for most human disease and animal influenza. Only typre reported to cause pandemics via antigenic shift (b/c can infect multiple species.)
2) Can treat with amantidine and neuraminidase inhibitors between 24-48 hours of symptoms. There is also annual flu virus.

Front 27

Influenza type B (disease, treatment)

Back 27

1) Responsible for intense local influenza outbreaks in nursing homes/schools. Can undergo antigenic drift but not shift b/c only a human virus.
2) Only neuraminidase inhibitors work. Also have annual vaccine.

Front 28

Influenza vaccine.

Back 28

2 types: Injection is killed virus, Mist is live atenuated. The vaccines contain multiple strains including at least 1 A and 1 B. Predict the antigen of the virus by checking the breakouts in spring in SE asia. Prep the vaccine before it hits us in fall/winter.

Front 29

Influenza Diagnosis

Back 29

Clinical symptoms in flu season, repid flu test detecting antigens in respiratory secretions, or a culture which takes longer.

Front 30

Which 2 Paramyxoviruses have neuraminidase (N) and which 2 dont?

Back 30

Do = Parainfluenza, Mumps
Dont = Measles, Pneumovirus

Front 31

Job of neuraminidase and hemagglutinin in influenza

Back 31

Hemagglutin mediates viral attachment and entry into cell via sialic acid receptors. Neuraminidase facilitates viral release by cleaving sialic acid sugars off infected cell to prevent re-entrance.

Front 32

What do amantadine, zanamivir, and oseltamivir do to inhibit influenza

Back 32

Amantadine blocks uncoating, zanamivir and oseltamivir inhibit release of virions by inhibiting neuraminidase.