B&B RNA Viruses Flashcards
All (-) RNA viruses have
helical capsid
Which (+) RNA virus does not have an icosahedral capsid?
Corona (helical)
All helical RNA viruses are
enveloped
RNA viruses that are icosahedral can be
enveloped or naked
Which RNA virus is not ss?
Reovirus (ds)
Which RNA viruses do not replicate in cytoplasm?
Influenza and Retroviruses
Which RNA viruses are not linear?
BAD: Bunya, Arena and Delta (HDV)
Which RNA viruses have a segmented genome?
BOAR: Bunya, Orthomyxo, Arena, Reo
Caliciviruses
Non-enveloped, (+) ssRNA, linear, icosahedral
Norovirus (Norwalk Virus)
Viral gastroenteritis
2-3 days
Not inflammatory: no blood, mucus or fecal leukocytes
Hepeviruses
Non-enveloped, (+) ssRNA, linear, icosahedral
Hep E
Reoviruses
REO: Respiratory Enteric Orphan viruses
Non-enveloped, dsRNA, icosahedral
11 segments, linear
Contain RNA-dependent RNA polymerase
Coltivirus
Reovirus
Colorado Tick Fever
Fever, chills, myalgias, HA
Self-limited
Rotavirus
Reovirus
Gastroenteritis in kids
No blood, mucus, few/no fecal leukocytes
Live, attenuated vaccine given prior 6mo
Picornaviruses
PERCH: Poliovirus Echovirus Rhinovirus Coxsackie Virus Hep A
Picornaviruses
Non-enveloped, (+) ssRNA, linear, icosahedral
Synthesize large polyprotein that is cleaved to viral proteins
Which Picornavirus is not an enterovirus (fecal-oral transmission)?
Rhinovirus (Common Cold)
- Cannot survive in stomach (acid-labile)
- Transmitted directly via respiratory droplets
Inactivated Polio Vaccine
Salk
Injected so generates systemic antibody response (mostly IgG)
Live Polio Vaccine
Sabin
Local IgA antibody response
Echovirus
Picornavirus
Aseptic (viral) meningitis
90% of viral meningitis is caused by
Coxackie and Echoviruses
Hep A
Picornavirus
Non-enveloped
Which Coxsackie causes aseptic meningitis?
Both A & B
Hand, foot and mouth syndrome
Coxsackie A
Kids
Sore throat, oral vesicles
Rash: small lesions on hands, feet, buttocks
Herpangina
Coxsackie A Kids High fever, seizures Mouth blisters No rash Summer
Myocarditis, Pericarditis
Coxsackie B
Naked RNA Viruses
Calici (Norwalk)
Hepe (HEV)
Reo (Rota, Colti)
Picorna (PERCH)
Coronavirus
Enveloped, linear
only (+)ssRNA with helical capsid
Corona virus is a cause of
common cold
most common is rhinovirus
Which virus causes SARS?
Corona virus SARS: Up to one week prodome Fever, malaise, HA, Myalgias Cough, dyspnea Sometimes progressing to respiratory failure
Retroviruses
Enveloped, ssRNA, linear
Reverse Transcriptase
DNA replicates in nucleus
How is Human T-lymphotropic virus (HTLV) similar to HIV?
2 identical strands of (+) RNA
Enters CD4 T cells
Reverse transcribed to DNA
DNA product integrated into host cell genome
How is HTLV different from HIV?
T-cells proliferate and transform (rather than dying)
T-cell leukemia-lymphoma (Non-Hodgkins lymphoma)
Flaviviruses
Enveloped, (+) ssRNA, linear, icosahedral
Which Flavivirus is not a mosquito-borne illness?
Hep C
What four mosquito illnesses are caused by Flavivirus?
Yellow Fever
Dengue Fever
St. Louis Encephalitis
West Nile Virus
Viruses that are transmitted by a mosquito or tick bite are called
Arboviruses
Yellow Fever
Virus can live in monkeys Arbovirus Infects liver (jaundice) High fever, HA, jaundice, high bilirubin AST>ALT Hemorrhage (black vomit) No specific tx Vaccine available
Yellow Fever Histo
Councilman Bodies in liver
Dengue Fever
Arbovirus "Break Bone Fever" Fever, HA, Retro-orbital pain SEVERE muscle/joint pain Maculopapular rash No specific therapy
How are St. Louis and West Nile viruses similar?
Arboviruses Birds Encephalitis: fever, AMS Sometimes meningitis sx Most people asymptomatic
Togaviruses
Enveloped (wear a toga), (+) ssRNA, linear, icosahedral
Which family is Rubella in?
Togavirus
Which family are Western and Eastern Equine Encephalitis in?
Togavirus
Rubella
German measles, 3-day measles Exanthem/Rash in kids Inhalation of respiratory droplets Mild fever, lymphadenopathy Maculopapular rash 1-5 days after fever Life-long immunity No specific Tx
Lymphadenopathy in Rubella occurs
Posterior cervical and posterior auricular areas
Rubella Vaccine
MMR (live-attenuated)
Congenital Rubella Syndrome
TORCH
Mom gets fever, rash, lymphadenopathy
Fetus gets deafness, cataracts, cardiac disease
PDA, Pulmonary Artery Stenosis, Blueberry Muffin Baby
Congenital Rubella Syndrome
How are congenital CMV and Rubella similar
Deafness, Blueberry Muffin Baby
How are congenital CMV and Rubella different
CMV: Seizures, Hepatosplenomegaly
Rubella: Cataracts, congeintal heart malformations
Equine Encephalitis
Resides in birds and transmitted by mosquitos
Most infections asymptomatic but can cause encephalitis
Which encephalitis due to Arbovirus is the worst?
Eastern Equine Syndrome
(+) Enveloped RNA Viruses
Corona
Retro
Flavi
Toga
All (-) RNA viruses are
helical and enveloped
Bunyavirus
(-) ssRNA virus
helical, enveloped
Segmented (BOAR)
Circular genome (BAD)
Which family is California encephalitis virus in?
Bunya virus
Arbovirus
Resevoir is rodents instead of birds
Rift Valley, Crimean-Congo, and Hantavirus infections are part of which family and can cause what?
Bunyaviruses
Hemorrhagic fever
All RNA-viruses that can cause encephalitis are
Arboviruses (mosquito-borne)
What RNA-viruses can cause encephalitis?
Flaviviruses (birds) -St. Louis, West Nile Togaviruses (birds) -Eastern and Western Equine Bunyaviruses (rodents) -California
Hemorrhagic fever is a viral infection always caused by
enveloped RNA viruses
Hantavirus often progresses to
renal or respiratory failure
Filoviruses
Ebola and Marburg
Enveloped, (-)ssRNA, linear, helical
Spread by body fluid contact
Hemorrhagic fever
Arenaviruses
Enveloped, (-)ssRNA, helical Segmented (BOAR) Circular Genome (BAD) Lassa Fever Lymphocytic Choriomeningitis Virus (LCMV)
Lassa Fever
Arenaviruses
Hemorrhagic fever
Spread by urine from rats
Close contact with infected people
Lymphocytic Choriomeningitis Virus (LCMV)
Arenavirus
Rare cause of viral meningitis
Rats and mice
Bunyavirus
Rift Valley (mosquito)
Crimean-Congo (tick)
Hanta (rodents)
Filoviruses
Ebola/Marburg
Arenavirus that can cause hemorrhagic fever
Lassa Fever (rats)
Flaviviruses that can cause hemorrhagic fever
Yellow Fever, Dengue
Rhabdoviruses
Enveloped, (-)ssRNA, linear, helical
Rabies
Rabies incubation period
1-3 months
Rhabdoviruses like to bind to
Ach receptors on peripheral nerves before migrating to CNS
Rabies vaccine
Inactivated Vaccine
Administer with rabies immunoglobin
Orthomyxoviruses
Enveloped, (-)ssRNA, linear, helical Segmented genome (BOAR)
Influenza A
Most common
Pandemics
2 Key envelope proteins
-Hemagluttinin: binds to cells and assists virus entry
-Neuraminidase: removes sialic acid from glycoproteins so viral progeny can exit
Replicates in nucleus
Antigenic Drift
Minor changes in hemagluttinin and neuraminidase
Due to random mutations in glycoproteins
Epidemics
Antigenic Shift
Major structural change in hemagluttinin or neuraminidase proteins Segmented Virus: Recombination Animal/Human infect same cell Pandemics BOAR: Bunya, Orthomyxo, Arena, Reo
Paramyxovirus
Enveloped, (-)ssRNA, helical
Kids
All contain F (fusion) proteins
F (fusion) protein
Helps Paramyxovirus fuse with respiratory epithelial cells
RSV Tx
Palivizumab monoclonal antibody against F protein (Paramyxovirus)
Paramyxovirus
Parainfluenza, RSV, Measles, Mumps
Parainfluenza causes
Croup in kids
Treat respiratory distress with steroids
O/w self-limiting
RSV Tx
Infants
Ribavirin
Palivizumab
