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