Coronavirsues Flashcards
Are coronaviruses + or - strain RNA or DNA viruses?
+ strand RNA viruses
Are coronaviruses enveloped?
Yes
_____ is the agent of COVID-19
- cause of up to 30% of common colds
SARS-CoV-2
______ is agent of severe acute respiratory syndrome (SARS)
SARS-CoV
_____ = atypical pneumonia
- jumped from animals to humans
§SARS
_____ is a viral respiratory illness; 30-40% mortality rate
MERS
______ can be asymptomatic or presymptomatic; mild, moderate, severe, and critical:
SARS-CoV-2
______ is a viral respiratory illness that has a 30-40% mortality rate.
Middle East Respiratory Syndrome (MERS-CoV)
Coronavirus has a (+) grna which allows it to udnergo transcription ______.
immediately.
individuals who have SpO2 <94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) <300 mmHg, respiratory frequency >30 breaths per minute or lung infiltrates >50%.
Severe illness caused by SARS-CoV-2
Individuals who have respiratory failure, septic shock, and or multiple organ dysfunction
critical illness caused bu SARS-CoV-2`
Severe acute respiratory syndrome in severe/critical illness
SARS
SARS-CoV-2 enters host cells through a _____ receptor.
ACE2
- Direct Cytotoxic effect
- Dysregulation of the RAAS
- Endothelial cell damage and thromboinflammation
- Dysregulated immune response
Mechanism of SARS-CoV-2
angiotensin converting enzyme (cleaves angiotensin II (vasoconstrictor) to angiotensin 1-7 (vasodialator) ACE2 activity lowers blood pressure
ACE2
transmembrane protease, serine 2 (cleaves (“primes”) Spike protein)
TMPRSS2
renin angiotensin aldosterone system (blood pressure regulation)
RAAS
T/F: COVID 19 is associated with deterious effects on many other oragn systems.
true
+ stranded RNA viruses
do not have envelope
Picornaviruses
habitat = gastrointestinal tract include: poliovirus and coxsackievirus
echoviruses - enteric cytopathic human orphan viruses
enteroviruses
a category of Picornaviruses
habitat = respiratory epithelium
rhinoviruses
a category of Picornaviruses
very stable in food and water also stable at pH 3 (stomach)
Enteroviruses:
t/f: Organ involvement for enteroviruses:
only occurs if viremia persists
usually does not; <5% typically
true
Sensitive to acidic pH Replicate poorly above 33 C
Rhinoviruses
3 antigenic types PV 1, PV2, PV3 Capsid differences between types
Icosahedral capsid (30 nm - small!)
plus strand RNA genome 7500 nt in length
poliovirus
poliovirus receptor (PVR)
CD155
RNA alone can cause infection!
-shown by researchers
POLIOVIRUS
destruction of host cells
virus is shed into stool
up to 10,000 virus per infected cell) even weeks to months after symptoms
gone
lytic virus
Transmission of polio virus
fecal-oral
Internal Ribosome Entry Site
Poliovirus IRES
T/F: IRES serves as the “cap” of the viral RNA, promoting translation of viral RNA into viral proteins
true
Because of____, translation starts far from the 5 end of poliovirus RNA (normal mRNA translation starts near 5’ end)
IRES
results from destruction of anterior horn cells in spinal cord
Flaccid Paralysis (poliovirus)
most severe form
respiratory muscle paralysis (medulla oblongata)
~25% mortality
Bulbar poliomyelitis
Live oral vaccine (Sabin) mimics the normal infection process of poliovirus
Killed parenteral vaccine (Salk) only generates serum antibodies
Poliovirus vaccines
aseptic meningitis
herpangina- sudden onset of fever vesicles/ulcers on tonsils and palate
group A coxsackieviruses
hand, foot, and mouth disease blisters on hand, feet, and palate
coxsackievirus type A16
heart (myocarditis)
respiratory tract (pleurodynia)
mucous membranes of eye (hemorrhagic conjunctivitis)
group B coxsackieviruses
~ 100 serotypes
account for ~1/2 the cases of the common cold bind to respiratory epithelial cells
ICAM-1 (most) or VLDL receptor (some) replication details very similar to poliovirus
Acid sensitive and 33oC optimum for replication
no tissue destruction
Rhinoviruses
Vaccine prospects for Rhinoviruses are______ due to too many variants
poor
viruses transmitted by arthropods
multiply in tissues of vector, often without producing disease
For many arboviruses humans are dead-end hosts:
viremia of short duration
virus levels in blood are low
Arboviruses (arthropod-borne viruses)
plus stranded RNA (single linear molecule)
enveloped
Togaviruses
2 phases of translation -first produce early proteins and then late proteins -like coronavirus
Togavirus replication
Member of Togavirus family
Rubivirus genus but not arthropod-borne
Rubella = German measles
one of the 5 childhood exanthems (along with measles, roseola, chickenpox, and fifth disease)
Rubella virus
plus stranded RNA (single linear molecule)
enveloped
Flaviviruses
mostly mild illness (Zika fever) except for congenital infection of fetus, which leads to microcephaly and other birth defects transmitted by mosquitos from person to person (most common)
Aedes aegypti mosquito (worldwide distribution of A. aegypti below)
Zika virus (a Flavivirus)
T/f: Zika virus is also transmitted sexually
true
most prevalent disease caused by arboviruses
does not cause significant mortality
Dengue fever
generally not a zoonosis: transmitted by mosquitos from person to person
Dengue fever
when partial immunity exists due to prior infection dengue hemorrhagic shock (DHS) dengue shock syndrome (DSS)
due to immune enhancement. virus forms immune complex/readily enter macrophages increases viral load
Dengue fever
historical importance
– first human disease found to be caused by a virus
– first viral disease confirmed to be spread by insect vector
– Mosquito: Aedes aegypti • spread by two methods (via mosquito)
– human to human
– monkey to human
yellow fever
– severe cases of ____ ____ results in
• jaundice • lesions and hemorrhaging of infected organs
yellow fever
____ ____ is treated via attenuated live vaccine and insect control measures
yellow fever
