RNA Viruses

Question 1

Influenza viruses (Orthomyxo)

Answer 1

“Envelope: Yes
RNA Structure: SS- linear, 8 segments
Capsid Symmetry: Helical
Antigenic shift-drift. HA (hemagglutinin - promotes viral entry), NA (neuaminidase - promotes progeny virion release)
-Replicates in nucleus
-A: Avian, pandemic, shift/drift, NA/HA, 8 segments; H1, H2
-B: Human, epidemic, drift, NA/HA, 8 segments, Reyes syndrome
-C: Human, sporadic, drift, HA, 7 segments”

Fever-myalgias-cough. Increases risk bacterial pneumonia. Major epidemics due to changes in hemaglutinin. Reyes syndrome (ASA).

Question 2

Measles virus (Paramyxo)

Answer 2

"Envelope: Yes
RNA Structure: SS - linear, nonsegmented
Capsid Symmetry: Helical
Maculopapular rash (Morbiliform)
-all paramyxo contain a surface fusion protein, which causes respiratory epithelial cells to fuse and form multinucleated cells"

“Rubeola. Koplick spots (Red spots with blue/white center). MMR (live attenuated). Encephalitis is complication. Winter epidemics. Rare SSPE (subacute sclerosing panencephalitis)
3 C’s: cough, coryza, conjunctivitis
Rare giant cell pneumonia
Rash presents last and spreads from head to toe; includes hands and feet: discreet rash that becomes confluent”

Question 3

Mumps virus (Paramyxo)

Answer 3

“MMR, Parotitis, testicular involvement post puberty can cause sterility
Symptoms: parotitis, orchitis, aseptic meningitis”

Question 4

RSV (Paramyxo)

Answer 4

“No NA or HA
Has fusion protein”

bronchilitis, pneumonia

Question 5

Parainfluenza (Paramyxo)

Answer 5

multinucleated giant cells

Croup: seal-like barking cough

Question 6

Rubella (Togavirus)

Answer 6

“Envelope: Yes
RNA Structure: SS + linear
Capsid Symmetry: Icosahedral”

“Congenital infection (IgM). MMR
Rubella: aka German ““3 day”” measles
Fever, postauricular adenopathy, lymphadenopathy, arthralgias, fine truncal rash that starts at head and moves down”

Question 7

EEE, WEE, VEE (Togavirus)

Answer 7

EEE: highest mortality

Asymptomatic>symptomatic infection.

Question 8

Hantavirus (Bunyaviridae)

Answer 8

"Envelope: Yes
RNA Structure: SS - circular, 3 segments
Capsid Symmetry: Helical
Transmitted by aerosols
S, M, L segments
HFRS: old word
HPS: new world

“Diffuse pulmonary infiltrates. (pulmonary edema) Rodent (deer mouse) droppings/urine. SW US
Hemorrhagic fever, pneumonia”

Question 9

Yellow fever virus (Flavi)

Answer 9

"Envelope: Yes
RNA Structure: SS + linear 
Capsid Symmetry:  Icosahedral
Transmitted by Aedes mosquito
Has a monkey or human reservoir"

“Mosquito. Human reservoir.
Symptoms: high fever, black vomitus, and jaundice”

Question 10

Dengue (Flavi)

Answer 10

“Mosquito, Human reservoir. Rash. Thrombocytopenia (decreased platelets), petechial hemmorhages. Bone pain = break bone fever.
Enlarged lymph nodes
Maculopapular rash”

Question 11

Hepatitis C (Flavi)

Answer 11

“Transmission: Blood, IVDU (intraveneous drug use), post-transfusion.
Chronic infection/inflammation - HCC risk.
4 C’s: Chronic, Cirrhosis, Carcinoma, Carrier”

Question 12

Arenavirus

Answer 12

“Envelope: Yes
RNA Structure: SS - circular, 2 segments
Capsid Symmetry: Helical
Lassa fever virus: spread by mice. Lymphocytic choriomeningitis virus.”

Question 13

Coronavirus

Answer 13

“Envelope: Yes
RNA Structure: SS + linear
Capsid Symmetry: Helical
Club like projections on virus.”

“Common colds to SARS. Asia.
Pneumonia”

Question 14

Ebola (Filo)

Answer 14

"Envelope: Yes
RNA Structure: SS - linear 
Capsid Symmetry:  Helical
Filaments. SSRNA – polarity
Wormy-looking virus"

Question 15

HIV (Retrovirus)

Answer 15

“Envelope: Yes
RNA Structure: SS + linear
Capsid Symmetry: Icosahedral (HTLV) complex and conical (HIV)
Integrates into chromosome”

Infects CD4 lymphs. Acute retroviral syndrome. Clinical latency is not virologic latency.

Question 16

Rabies (Rhabdovirus)

Answer 16

“Envelope: Yes
RNA Structure: SS - linear
Capsid Symmetry: Helical
-Bullet shaped.
-Retrograde spread up sensory nerves to CNS. Inhibits release of inhibitory neurotransmitters
-Negri bodies are characteristic cytoplasmic inclusions in neurons infected by rabies virus; commonly found in Purkinje cells in cerebellum
Rabies has a long incubation period (weeks to months) before symptm onset”

“encephalitis
Postexposure treatment is wound cleansing and vaccination +/- rabies immune globulin
Travels to CNS by migrating in a retrograde fashion up nerve axons
Progression of disease: fever, malaise, agitation, photophobia, hydrophobia, paralysis, coma, death
Transmission: more commonly from bat, raccoon, and skunk bites than from dog bites in the U.S. “

Question 17

Hepatitis D (Deltavirus)

Answer 17

“Envelope: Yes
RNA Structure: SS - circular
Capsid Symmetry: uncertain
Defective virus”

"Fulminant hepatitis 
Parenteral, sexual, maternal-fetal
Superinfection: short
Co-infection: long
Defective virus, dependent on HBV; superinfection: negative prognosis"