22 - Positive Strand RNA Viruses (Stapleton) Flashcards
+ strand RNA naked viruses
picornavirus
calicivirus
+ strand RNA enveloped virus
flavivirus
togavirus
retrovirus
coronavirus
picornavirus subgroups
rhinovirus-common cold
hep a-GI
enterovirus- GI (poliovirus, coxsackievirus)
lifecycle of picornavirus
attachment genome released into cytoplasm cell ribosomes bind genome and make polyprotein polyprotein is cleaved by viral protease RDRP creates - strand RNA RDRP copies - strand to make + strand caspid assembles particle released
picornavirus transmission
rhinovirus-respiratory droplets, secretions
enterovirus- fecal oral
respiratory
most common cause of URI
rhinovirus
rhinovirus
picornavirus replicate in URT does no t cause cytopathic effect weak and short lived immune response no antiviral or vaccine
poliovirus life cycle
mucosal surface lymph nodes viremia extraneural tissue retrograde to spinal cord
poliovirus causes
poliomyelitis
faccid paralysis
poliovirus treatment/prevention
no antiviral agents vaccination-3 doses inactivated (salk) attenuated (sabin)-not used in u.s. inactivated doesn't protects against GI infections
non polio enterovirus symptoms
GI pancreatitis fever rash hand-foot-mouth disease meningitis paralysis URI
hep a virus characteristics
picornavirus
highly stable
highly infectious
hep a treatment
no treatment but good vaccine
hep a symptoms
fecal oral spread, food borne
symptoms start 4 weeks after infection
fever, nausea, diarrhea, vomiting, jaundice
jaundice is common in who that have hep a
more common in adults
uncommon in
test for hep a
high ALT-liver damage
IgM antibodies-acute disease
calicivirus and hep e characteristics
naked icosahedral non segmented very stable fecal oral person to person food borne
norwalk/norwalk like/norovirus
world wide
gastroenteritis
difficult to control because of stability
difficult to decontaminate
hep e virus
acute
fecal oral transmission
fatal in pregnant women
no treatment, no vaccines
flavivididae characteristics
icosahedral
+ RNA
enveloped
nonsegmental RNA
genera of flaviviridae
flavivirus
hepacivirus
pegivirus
pestivirus
flavivirus transmission
west nile example
amplifying host (insect, mammal)
vector (mosquito)
dead end host (human, horse)
dead end host
insufficient viremia generated for productive maintenance of virus in population
flavivirus causes what
hemorrhagic fevers
dengue virus
flavivirus
dengue fever-break bone disease
dengue hemorrhagic fever/shock syndrome-lethal, following prior dengue infection
Arthropod borne
arbo
flavivirus
alphavirus
hepacivirus
flavivirus
Hep C
chronic, slowly progressing
hepatocellular carcinoma
testing for hepacivirus
serology (antibodies)
if ELISA positive-PCR
hepacivirus transmission
blood borne
IVDU
exposure to body fluids
sex with IVDU
togavirus types
rubella
alphavirus
togavirus characteristics
enveloped
icosahedral
non segmented RNA
alphavirus
arbovirus
mild-slight fever/headache
severe-encephalitis: headache, fever, coma, tremors, convulsion, death
no antiviral or vaccine
rubella
togavirus
rubella spread
respiratory or intrauterine
rubella symptoms
fever, rash, arthralgia
congenital leads to fetal damage (deafness, blindness, mental retardation, heart disease)
rubella treatment
no antiviral
MMR vaccine-live attenuated
Corona virus characteristics
enveloped non segmental helical \+ strand RNA no treatment or vaccine
coronavirus strains
5 human strains
3 are common cold
2 are SARS and MERS
SARS origin
Guangdong, China
SARS symptoms
high mortality
viral pneumonia
fever, cough, SOB, HA, death from lung damage
SARS transmission
from chinese horseshoe bats
civet cat as intermediate hose
MERS transmission
from camels
acute infections
IgM
what + RNA have treatments
HCV
what + RNA have vaccines
polio, YFV, HAV_
