Coronaviruses are:
-enveloped viruses
-single stranded positive sense RNA-RNA size ranges from 28Kb to 32Kb in length
-Thermolabile (inactivated at 56C, 15 min)
-80 to 100 nm in diameter
-Stable at pH6
-Ether labile
-Sensitive to most disinfectants
-Density= 1.24g/cm3
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EM micrograph of negatively stained Infectious Bronchitis Virus showing the pleomorphic nature of the enveloped virus with clearly discernable spikes around the outside of the virus particles.
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Coronaviruses are currently divided into 4 antigenic groups:
(note: recently other groupings have been proposed)
Group I coronaviruses
TGEV, FIPV, CCV, PRCV, HCoV-229E, RbCoV, FECoV
Spike not cleaved
M is N-glycosylated
No HE protein
No ORF 2
Group II coronaviruses
MHV, BCV, HCoV-OC43, HEV, SDAV, SARS-CoV
Cleaved spike
M is O-glycosylated
HE protein
ORF 2 present
Group III coronaviruses (Avian group)
IBV, TCoV
Cleaved Spike
M is N-glycosylated
No HE protein
No ORF 2
Group IV coronaviruses (similar to Group II)
SARS-CoV
-In group III coronaviruses spike forms the basis for different serotypes
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