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SARS Cases Worldwide Reported to WHO as of June 6, 2003
China (5329)
Singapore (206)
Hong Kong (1750)
Vietnam (63)
Canada (219)
U.S. (68)
Europe:8 countries (38)
Thailand (8)
Taiwan (676)
Total: 8404 cases; 779 deaths (~10%case fatality)
Australia&NZ (6)
SA (2)
Masked shop owner in Amoy Gardens complex
photo by Christian Keenan
Coronaviruses
Single Strand RNA, nonsegmented, enveloped, ~31,000 bps
Order: Nidovirales Family: Coronaviridae
• Torovirus and Coronavirus :Grp I, Grp II, Grp III
• 229E and OC43 in humans cause ~1/3 of common colds, reinfections common
• May remain viable for several hours after drying on surfaces
Relative Size of Coronaviruses Compared to Other Microbes
NY Times 4/27/03
Holmes, NEJM 2003;348: 1948
-
Structure of Coronavirus Virion
The spike glycoproteins create corona, bind and fuse with host cell membranes
nucleus
attachmentattachment
maturation assembly
translation
replicationmRNA synthesis
releaserelease
entry
M Denison,Vanderbilt
CDC
X1
X2
X3
X4 X5
NME
20,001 30,00025,000
S
RNA 6
RNA 5
RNA 4
RNA 3
RNA 28.3 kb4.5 kb
3.4 kb
2.5 kb1.7 kb
S1b
1a
NM
EA
B
1 5,000 10,000 15,000 20,000 25,000 30,000
29,727 nt
Genome Organization
- Replicases (1a/1b) & structural genes (S,E,M,N)
- Multiple small genes (X1-X5)-these vary in number, location, and sequence in different coronaviruses
SARS-CoV is similar in general genome organization to other coronaviruses SARS-CoV is genetically distinct from other known coronaviruses
–Structural proteins are < 40% identical –Replicase proteins are < 70% identical –SARS-CoV nsps are not homologous to known proteins
Specific RT-PCR assays will allow the rapid and sensitive detection of the virus, aiding in control
CDC Enterovirus Reference Laboratory
- Distinct from other known coronaviruses
- Neither a mutant nor recombinant
- Previously unknown, probably from a nonhuman host, has acquired the ability to infect humans.
Evidence that Urbani Coronavirus is the Etiology of SARS
• Culture of novel coronavirus from SARS patients in multiple sites worldwide
• Identical Sequence• EM’s from BAL and lung showing coronavirus • PCR finding novel coronavirus nucleic acid• Antibody response specific to novel coronavirus,
sera from other human coronaviruses show no reaction
• Infection re-produced in primate animal model
CIVET CAT
Nocturnal Animal
Related To Mongoose
Delicacy in Southern China
NY Times 4/27/03
Probable SARS cases by reported source of infection,* --- Singapore
February 25--April 30, 2003 MMWR 2003;52:405
MMWR 2003;52:405