Ch32-33 Corona- picorna- arbo Flashcards
(49 cards)
describe coronaviruses
- positive strand RNA viruses
- enveloped
what is the agent of COVID 19
SARS-CoV-2
what is MERS and what is the mortality rate
- middle east respiratory syndrome
- viral respiratory illness
- 30-40% mortality rate
what is the coronavirus life cycle
- 1st phase of translation: includes an RNA dependent RNA polymerase
- 2ns phase of translation
- acquire viral envelope by budding of nucleocapsid into the ER
what are the clinical presentations of people with SARS CoV 2
-asymptomatic
- mild illness
- moderate illness
- severe illness: less than 94% O2, PaO2/FiO2 less than 300 mmHg, less than 30 breaths per minute
- critical illness: respiratory failure, septic shock, multiple organ dysfunction
explain the viral entry mechanism of SARS coV 2
RBD of spike protein binds to ACE2
what does ACE2 do
lowers BP
what does TMPRSS2 do
transmembrane protease, serine 2 cleaves spike protein
what are the proposed mechanisms of COVID 19 infection
- direct cytotoxic effect
- dysregulatino of RAAS
- endothelial cell damage and thromboinflammation
- dysregulated immune response
describe picornaviruses
- positive stranded RNA viruses
- do not have envelope
what is the habitat of enteroviruses and what are they types
- GI tract
- poliovirus and coxsackievirus
what are the types of picornaviridae
- enterovirus
- hepatovirus
- parechovirus
- rhinovirus
what are the types of enteroviruses
- coxsackievirus A
- cocksackievirus B
- echovirus
- enterovirus
- poliovirus
what is the habitat for rhinoviruses
respiratory epithelium
describe enteroviruses
- very stable in food and water
- stable at pH3 (stomach)
describe rhinoviruses
- sensitive to acidic pH
- replicate poorly above 33 C
describe organ involvement for enteroviruses
- only occurs if viremia persists
what are the 3 types of polioviruses and what are the differences between the types
- PV1, PV2 and PV3
capsid differences
what is the transmission of poilioviruses
fecal-oral
what is the poliovirus receptor
CD155
what is the poliovirus IRES and what does it stand for
- internal ribosome entry site
- serves as the cap of the viral RNA, promoting translation of viral RNA into viral proteins
because of IRES where does translation start
far from the 5’ end of poliovirus RNA
how does poliovirus affect the CNS
- flaccid paralysis: destruction of anterior horn cells in spinal cord
- bulbar poliomyelitis: respiratory muscle paralysis
what are the factors that increase the severity of poliovirus infections
- physical exertion and trauma
- tonsilectomy
