RNA viruses Flashcards
reoviruses
rotavirus
coltivirus
non-enveloped, icosahedral, dsRNA virus
Reovirus- Rotavirus
non-enveloped, icosahedral, dsRNA reovirus
primary cause of fatal diarrhea in children worldwide (6% of child deaths under age 5)
deadly due to severe diarrhea, vomiting, dehydration, electrolyte abnormalities
Reo-virus Coltivirus
non-enveloped, icosahedral, dsRNA reovirus
Colorado tick fever
found in mountainous regions of western US and Canada
spread by woodtick to hikers, hunters, and the like
Picornavirus- enterovirus
non-enveloped, ss+ linear, icosahedral
enteroviruses include poliovirus, coxsackivirus, and echovirus
primary spread via feco-oral route, alternatively resp secretions
polio
this is a picornavirus, icosahedral, non-enveloped, ss+linear RNA
it affects the anterior horns of the spinal horn, and motor neurons of the pons and medulla leading to paralysis
- salk vaccine- killed and injected
- sabin vaccine- live and eaten
Echovirus
picornavirus, enterovirus
ss+linear RNA
non-enveloped
icosahedral
summer outbreaks of
viral meningitis
URI
myocarditis
detection is possible via PCR of CSF, which enables outpatient care and conservation of healthcare resources (not much treatment needed for viral meningitis)
Coxsackivirus
picornavirus, enterovirus, ss+ linear RNA, icosahedral, non-enveloped
hand-foot-mouth disease viral myocarditis, pericarditis aseptic meningitis herpangina febrile pharyngitis
HAV
picornavirus, ss+linear RNA, icosahedral, non-enveloped
feco-oral spread
Rhinovirus
picornavirus, ss+linear RNA, icosahedral, non-enveloped. common cold. >100 serologic types.
Acid labile, destroyed by stomach acid, and does not infect the GI tract (unlike other picornaviruses)
Calicivirus- Norwalk virus
nonenveloped, icosahedral, ss+linear
viral gastroenteritis
vomiting, diarrhea, point- source outbreaks
cruise ship
nursing home
Flavivirus
Enveloped, SS+linear, icosahedral
includes arboviruses (arthropod-borne)
includes yellow fever and hep C, which turn the skin yellow
Flavivirus- Arbovirus- Yellow fever virus
a flavivirus
enveloped
ss+linear
icosahedral
yellow fever-
Aedes mosquito
reservoir- humans and monkeys
Sub-Saharan Africa and South America
hemorrhagic disease (epistaxis, petecheal, purpuric gum lesions, black vomitus, Councilman bodies on liver biopsy)
high fever
jaundice
Flavivirus- Arbovirus- Dengue virus
ss+RNA linear, enveloped, icosahedral
most common mosquito-born disease worldwide
classic breakbone fever-
retroorbital pain
joint pain
HA
complication- dengue hemmorhagic fever= thrombocytopenia and increased capillary wall fragility
Flavivirus- arbovirus- WNV
ss+linear, enveloped, icosahedral
endemic in USA since 1999
flu-like sx are common: HA, malaise, back pain, myalgia, anorexia 3-6 days
severe sx in 1/150: meningitis/encephalitis, flaccid paralysis (anterior horn involvement), alterations in consciousness, death
Dx with serology for WNV IgM abs, serum or CSF
Arboviruses that cause encephalitis
St. Louis encephalitis virus
Eastern equine encephalitis virus
Western equine encephalitis virus
California encephalitis virus
flavivirus- arbovirus-st. louis encephalitis
ss+RNA linear, enveloped, icosahedral
arbovirus (mosquito- born)
can cause encephalitis
Togavirus- Rubella
ss+linear RNA, enveloped, icosahedral
congenital disease leads to cataracts deafness heart defects -PDA -pulmonic stenosis
blueberry muffin
Coronavirus
enveloped, ss+linear, helical
“common cold” and SARS
common cold
rhinovirus
coronavirus
Retrovirus- Human T cell leukemia virus
enveloped, SS+linear RNA, 2 copies, icosahedral
uses reverse transcriptase
infects motor neurons of the anterior horn
poliovirus
WNV
Orthomyxovirus- influenza
enveloped, helical, ss (-)RNA
hemagglutinin promotes viral attachment to host cell
neuraminidase promotes release of progeny virions
rapid genetic change
-reassortment= shift, which leads to pandemics
rearrangement= drift, which leads to seasonal epidemics
patients are susceptible to viral PNA and serious bacterial infections with s. aureus, s. pneumoniae while they are infected with influenza
mechanism of action for zanamivir, oseltamavir
inhibit neuraminidase
virion not released from host cell
use only in severe influenza, must be administered within 24 hrs of symptom onset
Paramyxovirus- parainfluenza
ss-RNA linear, nonsegmented
enveloped
helical
parainfluenza virus- croup
seal- like barking cough, inspiratory stridor that mimics asthma
steeple sign on xray
pulsus paradoxus secondary to upper airway obstruction
paramyxovirus- respiratory syncytial virus
ss-RNA linear, nonsegmental, enveloped, helical
bronchiolitis +/- PNA in the small bronchioli of babies
winter
brassy cough, wheezing, respiratory distress
passive immunization with palivizumab (monoclonal RSV immunoglobulin), monthly during the winter months in premature infants, or infants who have chronic lung disease
treatment: supportive
NOT ribavirin
winter viruses
influenza
rotavirus
RSV
summer viruses
enteroviruses
-poliovirus, echovirus, coxsackivirus
arbovirus- WNV
Ribavirin
guanosine analog
approved for RSV, hepatitis C
no longer recommended for RSV
side effects:
teratogenicity, hemolytic anemia
Rubeola- paramyxovirus
ss-RNA linear, nonsegmental, enveloped, helical
cough
coryza (runny nose)
conjunctivitis
maculopapular rash descending from head to toe
Koplik spots early on (blue grey spots on buccal mucosa, surrounded by a base of red
complications- years later there may be subacute sclerosing panencephalitis (SSPE), or giant cell PNA (immunocompromised host)
Mumps- paramyxovirus
ss(-)RNA linear, nonsegmented, enveloped, helical
parotitis, orchitis (possible future sterility), meningitis
Viral meningitis
coxsackievirus
echovirus
enterovirus
mumps virus
Rhabdovirus- rabies
ss(-) linear RNA, enveloped, helical
transmission from bat, raccoon, skunk, dog to human
infection is retrigrade vie neurons and ACHR to hippocampus and purkinke cells of cerebellum
Negri bodies are eosinophilic cytoplasmic inclusions
symptoms manifest months to years later
fever/malaise/n/v progresses
to hydrophobia, photophobia, agitation, hypersalivation
progresses to coma and death
Bunyavirus- hantavirus
ss(-) 3 segments of RNA, enveloped, helical
hemorrhagic fever pulmonary syndrome -fever -progressive pulmonary edema -respiratory failure
spread by aerosolized deer mouse urine
segmented viruses
Bunyaviruses
Orthomyxoviruses
Arenaviruses
Reoviruses
mouse urine
lassa virus (Arenavirus)
LCMV (arenavirus)
hantavirus
Filoviruses
ss-RNA, linear, enveloped, helical
Ebola and Marburg viruses
Ebola spread through fluids
fever, HA, myalgia
leading to vomiting, diarrhea, fluid loss, electrolyte imbalance, multiorgan failure, shock, death
treatment: supportive
prevention is key (contact and droplet isolation to prevent transmission of someone has been exposed)
characteristic “barking seal” cough
croup
childhood diarrhea in winter months
rotavirus
asthma- sounding infection in infants (esp preemies)
paramyxovirus
RSV
