HEPI40225
SARS Outbreak Development Facts
INITIATION OF
THE OUTBREAK
During 2002-2003,
the world population faced a potential pandemic produced by an no identified causal virulent agent, no diagnostic laboratory
tests available, with unknown symptoms and risk factors for transmission, no known treatment or prevention measures, and no
infection-control practices of proven efficacy for a high infective pathogen.
The severe acute
respiratory syndrome (SARS) is believed to have emerged in China in November 2002 and progressed to a global health threat
by the spring of 2003
o World Health Organization. Acute respiratory syndrome, China. Wkly Epidemiol Rec 2003;78:41–8.
o World Health Organization. Acute respiratory syndrome, China, Hong Kong Special Administrative
Region of China, and Viet Nam. Wkly Epidemiol Rec 2003;78:73–4.
o Centers for Disease Control and Prevention. Outbreak of severe acute respiratory
syndrome—worldwide, 2003. MMWR Morb Mortal Wkly Rep 2003;52:226–8.
After Dr. Carlo Urbani identified
an outbreak of the previously unknown respiratory disease among Vietnam hospital workers in late February 2003, he alerted the global health community to the high transmissibility and lethality
associated with the outbreak. apparently became infected himself, he felt ill, while he was assisting to a conference
in Thailand on March 11.
On March 15, 2003 WHO issued a global travel alert, after
clusters of SARS cases being reported from China, Hong Kong, Vietnam, Singapore, and Canada. Dr Urbani died on March 29th.
On July 5, 4
months after its initial recognition, WHO declared that SARS had been contained.
SARS outbreak experience represents a remarkable achievement
for a truly extraordinary international public health effort. The world’s scientific, clinical, and public health communities
successfully confronted the outbreak, instituting sensitive surveillance systems, isolation and infection-control practices,
intensive contact tracing, community containment, including quarantine, and developing diagnostic assays for detecting the
pathogen.
o
Lingappa JR, McDonald
LC, Simone P, Parashar UD. Wresting SARS from uncertainty. Emerg Infect Dis [serial online] 2004 Feb [date cited].
Available from: URL: http://www.cdc.gov/ncidod/EID/vol10no2/03-1032.htm
IMPACT OF THE OUTBREAK
During 4 months, the outbreak produced a substantial impact
to the countries’ health systems, economical structures, and on the community’ and hospital workers’ health.
This generated a consistent scientific and administrative international response to the outbreak:
HEALTH
o
8,098 cases
o
774 deaths were attributed to SARS
o
World Health Organization. Summary of probable
SARS cases with onset of illness from 1 Nov 2002 to 31 July 2003. (Accessed Dec 6, 2003). Available from: URL: http://www.who.int/csr/sars/country/table2003_09_23/en/
SOCIAL AND ECONOMICAL
The outbreak produced huge social an economical distress,
fear of contagion was rampant, especially among healthcare workers, producing billions of dollars had been lost of renews
and medical expenses for the countries affected.
o
Lingappa JR, McDonald
LC, Simone P, Parashar UD. Wresting SARS from uncertainty. Emerg Infect Dis [serial online] 2004 Feb [date cited].
Available from: URL: http://www.cdc.gov/ncidod/EID/vol10no2/03-1032.htm
SCIENCE
Laboratory test
to detect SARS-CoV infection, nucleic acid assays and serologic tests, were developed early during the SARS outbreak
o Ksiazek TG, Erdman D, Goldsmith CS, Zaki SR, Peret T, Emery S, et al. A novel coronavirus associated with severe acute respiratory syndrome [comment]. N Engl J Med
2003;348:1953–66.
o Peiris JS, Lai ST, Poon LL, Guan Y, Yam LY, Lim W, et
al. Coronavirus as a possible
cause of severe acute respiratory syndrome [comment]. Lancet 2003;361:1319–25.
- Drosten C, Gunther S, Preiser W, van der Werf S, Brodt HR, Becker S,
et al. Identification
of a novel coronavirus in patients with severe acute respiratory syndrome [comment]. N Engl J Med 2003;348:1967–76.
Case definitions were developed and latterly revised by WHO
during the outbreak
o
Health Organization. Severe acute respiratory syndrome (SARS). Wkly Epidemiol Rec 2003;78:81–3.]
o
World Health Organization. Case definitions
for surveillance of severe acute respiratory syndrome (SARS). (Accessed Dec 6, 2003), Available from: URL: http://www.who.int/csr/sars/casedefinition/en/;
SOURCE OF THE PATHOGEN
The origins of the SARS-associated coronavirus (SARS-CoV)
remain unclear
The SARS outbreak may have been preceded by transmission
of SARS-CoV or a related virus from animals to humans. SARS-CoV has now been shown to infect other animals, including:
·
macaques
o
Fouchier RA, Kuiken T, Schutten M, van Amerongen
G, van Doornum GJ, van den Hoogen BG, et al. Aetiology: Koch’s
postulates fulfilled for SARS virus. Nature 2003;423:240.
·
ferrets and cats
o
Martina BE, Haagmans BL, Kuiken T, Fouchier
RA, Rimmelzwaan GF, Van Amerongen G, et al. Virology: SARS virus
infection of cats and ferrets. Nature 2003;425:915.
·
pigs and chickens
o
Weingartl HM, Copps J, Drebot MA, Marszal PS,
Smith G, Gren J, Andonova M, et al. Susceptibility of pigs and chickens to SARS coronavirus. Emerg Infect Dis 2004;10: 179–84.
These animals not necessarily transmit the virus to humans,
and none of these animals are known to act as natural amplifying hosts for the virus.
Serologic studies in Hong Kong suggest that SARS-like viruses
may have circulated in human populations before the 2002–2003 outbreak
·
Zheng BJ, Guan Y, Wong KH, Zhou J, Wong KL,
Young BWF, et al. SARS-related virus predating SARS outbreak, Hong Kong. Emerg Infect Dis 2004;10: 176–8.
Antibodies to SARS-CoV have been identified in animal handlers
·
Centers for Disease Control and Prevention.
Prevalence of IgG antibody to SARS-associated coronavirus in animal
traders—Guangdong Province, China, 2003. MMWR Morb Mortal Wkly Rep 2003;52:986–7.and a
In Guangdong Province, where the outbreak was probably originated,
SARS-like coronavirus was identified in palm civets and other animals indigenous
o
Guan Y, Zheng BJ, He YQ, Liu XL, Zhuang ZX,
Cheung CL, et al. Isolation and characterization of viruses related
to the SARS coronavirus from animals in southern China. Science 2003;302:276–8.
TRANSMISSION OF THE PATHOGEN
HIGH RISK GROUPS
SARS outbreak spread from Asia (Vietnam, Singapore, and Hong
Kong) to America through ill travelers, and from community to hospitals, where hospital workers became critical high-risk
group.
o
Centers for Disease Control and Prevention.
Update: outbreak of severe acute respiratory syndrome—worldwide,
2003. MMWR Morb Mortal Wkly Rep 2003;52:241–8..
The United States
had eight cases were laboratory-confirmed.
o Schrag J, Brooks JT, Van Beneden C, Parashar UD, Griffin PM, Anderson LF, et al. SARS surveillance during emergency
public health response, United States, March–July, 2003. Emerg Infect Dis 2004;10:185–95.
o Centers for Disease Control and Prevention. Update: severe
acute respiratory syndrome—worldwide and United States, 2003. MMWR Morb Mortal Wkly Rep 2003;52:664–5.
o Centers for Disease Control and Prevention. Updated interim surveillance case definition
for severe acute respiratory syndrome (SARS)—United States, April 29, 2003. MMWR Morb Mortal Wkly Rep 2003;52:391–3.
In the United States the disease remained a travel-associated
illness only, with no hospital or community transmission.
o Schrag J, Brooks JT, Van Beneden C, Parashar UD, Griffin PM, Anderson
LF, et al. SARS surveillance during emergency public health response, United States, March–July, 2003. Emerg Infect
Dis 2004;10: 185–95.
o Park BJ, Peck AJ, Kuehnert M, Newbern C, Smelsey, McDonald LC. Lack
of SARS transmission among healthcare workers, United States. Emerg Infect Dis 2004;10: 244–8.
o
Peck AJ, Newbern EC, Feikin DR, Isakbaeva ET,
Park BJ, Fehr JT, et al. Lack of SARS transmission and U.S. SARS case-patient. Emerg Infect Dis 2004: 217–24.
Healthcare settings played a key role in amplifying disease
outbreaks. In Singapore, Canada, and Vietnam, disease was transmitted to many hospital workers by ill travelers or contacts
of ill travelers. The nosocomial spread of the disease was successfully contained within hospitals using infection control
directions.
o
Wong RSM, Hui DS. Index patient and SARS outbreak
in Hong Kong. Emerg Infect Dis 2004;10: 339–41.
In China, Taiwan, and Hong Kong the disease was not quickly controlled in the hospitals, and the virus spread into the community resulting in extensive disease transmission.
o Wu J, Xu F, Zhou W, Feikin DR, Lin C-Y, He X, et al.
Risk factors for SARS among persons without known contact with SARS patients, Beijing, China. Emerg Infect Dis 2004;10: 210–6.
o Liang W, Zhu Z, Guo J, Liu Z, He X, Zhou W, et al. Severe
acute respiratory syndrome, Beijing, 2003. Emerg Infect Dis [serial online] 2004 Jan . URL: http://www.cdc.gov/ncidod/EID/vol10no1/03-0553.htm
The epi-link (previous exposure to a suspect, affected area,
fever clinic) was present in most SARS patients, inclusive in places with extensive community transmission.
o
Wu J, Xu F, Zhou W, Feikin DR, Lin C-Y, He
X, et al. Risk factors for SARS among persons without known contact with SARS patients, Beijing, China. Emerg Infect Dis 2004;10:
210–6.
Age was an important
risk for the disease. Persons older than sixty years had fatality rates of nearly
50% . The disease was mild in children, habin low infectibility and lower morbidity and mortality
o Bitnun A, Allen U, Heurter H, King SM, Opavsky MA, Ford-Jones EL, et al. Children hospitalized with severe acute respiratory syndrome-related illness in Toronto. Pediatrics
2003;112:e261.
o Hon KL, Leung CW, Cheng WT, Chan PK, Chu WC, Kwan YW, et al. Clinical
presentations and outcome of severe acute respiratory syndrome in children [comment]. Lancet 2003;361:1701–3.
o Yang G-G, Lin S-Z, Liao K-W, Lee J-J, Wang L-S. SARS-associated coronavirus infection in teenagers. Emerg Infect Dis
2004;10: 382–3.
MODE OF TRANSMISSION
The primary mode of transmission is by large droplets, data
about clusters suggests aerosol transmission also.
o Wong RSM, Hui DS. Index patient and SARS outbreak in Hong Kong. Emerg
Infect Dis 2004;10: 339–41.
o Christian MD, Loutfy M, McDonald LC, Martinez KF, Ofner M,Wong T,
et al. al. Possible SARS coronavirus transmission during cardiopulmonary resuscitation. Emerg Infect Dis 2004;10: 287–93.
o
Wong T-W, Lee C-K, Tam W, Lau JT-F, Yu T-S,
Lui S-F, et al. Cluster of SARS among medical students exposed to single patient, Hong Kong. Emerg Infect Dis 2004;10: 269–76.
Appropriate infection-control practices are associated with
low transmission of SARS.
o
Centers for Disease Control and Prevention.
Severe acute respiratory syndrome—Singapore, 2003.
MMWR Morb Mortal Wkly Rep 2003;52:405–11.
Individual variability was often observed. Low exposure has been usually associated with probable cases, and no transmission has been documented despite of abundance of exposure opportunities.
o Park BJ, Peck AJ, Kuehnert M, Newbern C, Smelsey, McDonald LC. Lack of SARS transmission among healthcare workers,
United States. Emerg Infect Dis 2004;10: 244–8.
o Peck AJ, Newbern EC, Feikin DR, Isakbaeva ET, Park BJ, Fehr JT, et al. Lack of SARS transmission and U.S. SARS case-patient.
Emerg Infect Dis 2004: 217–24. 28. Ha LD, Bloom S, Nguyen QH, Maloney
SA, Le MQ, Leitmeyer KC, et al. Lack of SARS transmission among public hospital workers, Vietnam. Emerg Infect Dis 2004;10:
265–8.
o Isakbaeva ET, Khetsuriani N, Beard RS, Peck A, Erdman
D, Monroe SS, et al. SARS-associated coronavirus transmission, United States. Emerg Infect Dis 2004;10: 225–31.
o Goh DL-M, Lee BW, Chia KS, Heng BH, Chen M, Ma S, et
al. Secondary household transmission of SARS, Singapore. Emerg Infect Dis 2004;10: 232–4.
Transmission in hospital settings has been clearly documented.
o Christian MD, Loutfy
M, McDonald LC, Martinez KF, Ofner M,Wong T, et al. al. Possible SARS coronavirus transmission during cardiopulmonary resuscitation.
Emerg Infect Dis 2004;10: 287–93.
o Seto WH, Tsang D, Yung RW, Ching TY, Ng TK, Ho M, et al. Effectiveness
of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome
(SARS) [comment]. Lancet 2003;361:1519–20.
o Ofner M, Lem M, Sarwal S, Vearncombe M, Simor A. Cluster of severe acute respiratory
syndrome cases among protected health care workers—Toronto, April 2003. Can Commun Dis Rep 2003;29:93–7.
- Loeb M, McGeer A, Henry B, Ofner M, Rose D, Hlywka T, et al. SARS among
critical care nurses, Toronto. Emerg Infect Dis 2004;10: 251–5.
Super-spreading events ( transmission from one case to many
secondary cases), although sporadic, and nosocomial transmission were significant in the evolution of the outbreak.
o
Wong RSM, Hui DS. Index patient and SARS outbreak
in Hong Kong. Emerg Infect Dis 2004;10: 339–41. 25. Christian MD, Loutfy M, McDonald LC, Martinez KF, Ofner M,Wong T, et al. al. Possible SARS coronavirus
transmission during cardiopulmonary resuscitation. Emerg Infect Dis 2004;10: 287–93.
o
Wong T-W, Lee C-K, Tam W, Lau JT-F, Yu T-S,
Lui S-F, et al. Cluster of SARS among medical students exposed to single patient, Hong Kong. Emerg Infect Dis 2004;10: 269–76.
o
Shen Z, Ning F, Zhou W, He X, Lin C, Chin DP,
et al. Superspreading SARS events, Beijing. Emerg Infect Dis 2004;10: 256–60.
Severe illness, delay in the diagnosis, older age (mean 54
versus 44), and an increased number of close contacts have been identified to risk factors for super-spreading events.
o
Shen Z, Ning F, Zhou W, He X, Lin C, Chin DP,
et al. Superspreading SARS events, Beijing. Emerg Infect Dis 2004;10: 256–60.
INFECTION CONTROL
SARS-CoV transmission
can be effectively contained by strict adherence to infection-control practices.
The use of N95
respirators or surgical masks effectively reduce transmission in hospitals
o Seto WH, Tsang D, Yung RW, Ching TY, Ng TK, Ho M, et al. Effectiveness
of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome
(SARS) [comment]. Lancet 2003;361:1519–20.
o Ofner M, Lem M, Sarwal S, Vearncombe M, Simor A. Cluster of severe acute respiratory
syndrome cases among protected health care workers—Toronto, April 2003. Can Commun Dis Rep 2003;29:93–7.
- Loeb M, McGeer A, Henry B, Ofner M, Rose D, Hlywka T, et al. SARS among
critical care nurses, Toronto. Emerg Infect Dis 2004;10: 251–5.
Respirators. The use of N95 respirators or surgical masks
have been also effective in reducing community transmission.
o
Wu J, Xu F, Zhou W, Feikin DR, Lin C-Y, He
X, et al. Risk factors for SARS among persons without known contact with SARS patients, Beijing, China. Emerg Infect Dis 2004;10:
210–6.
Monitor compliance. Premature relaxation of infection-control
measures in some SARS-affected areas had profound implications.
o
Centers for Disease Control and Prevention.
Update: severe acute respiratory syndrome—Toronto, Canada,
2003. MMWR Morb Mortal Wkly Rep 2003;52:547–50.
Education. Training of preexposure infection-control and
consistent use of masks, gowns, gloves, and eye protection are import to control
the outbreak.
o
Lau JTF, Fung KS, Wong TW, Kim JH, Wong E,
Chung S, et al. SARS transmission among hospital workers, Hong Kong. Emerg Infect Dis 2004;10: 280–6
LABORATORY RELIABILITY
SARS clinical
case definition is nonspecific, capturing respiratory illness caused by other pathogens (e.g., Mycoplasma pneumoniae
and influenza)
o Schrag J, Brooks JT, Van Beneden C, Parashar UD, Griffin PM, Anderson LF, et al. SARS surveillance during emergency
public health response, United States, March–July, 2003. Emerg Infect Dis 2004;10: 185–95.
Laboratory assays, although sensitive for detecting antibody
and viral RNA, they can not identify SARS-CoV early in the course of disease. However, laboratory confirmation of the infection
is particularly important in targeting infection control measures during the outbreak.
- Centers for Disease Control and Prevention. Update: severe acute respiratory syndrome—worldwide and United States, 2003. MMWR Morb Mortal Wkly Rep 2003;52:664–5.
- Centers for Disease Control and Prevention. Updated interim surveillance case definition for severe acute respiratory syndrome
(SARS)—United States, April 29, 2003. MMWR Morb Mortal
Wkly Rep 2003;52:391–3.
- Peiris JS, Chu CM, Cheng VC, Chan KS, Hung IF, Poon LL, et al. Clinical progression and viral load in a community outbreak
of coronavirus-associated SARS pneumonia: a prospective study.
Lancet 2003;361:1767–72.
- Booth CM, Matukas LM, Tomlinson GA, Rachlis AR, Rose DB, Dwosh HA, et al. Clinical features and short-term outcomes of 144 patients with
SARS in the greater Toronto area. JAMA 2003;289:2801–9;
erratum appears in JAMA 2003;290:334.
Abnormal findings on chest radiographs are universal for
SARS patients, but radiographic changes may not be seen until 7-10 days of the onset.
o
Choi KW, Chau TN, Tsang O, Tso E, Chiu MC,
Tong WL, et al. Outcomes and prognostic factors in 267 patients with
severe acute respiratory syndrome in Hong Kong. Ann Intern Med 2003;139:715–23.
o
Vu HT, Leitmeyer KC, Le DH, Miller MJ, Nguyen
QH, Uyeki TM, et al. SARS in Vietnam, February–May, 2003. Emerg Infect Dis 2004;10: 334–8.
In research activities, the diagnostic assays have shown
importance in following the natural history of SARS infection and the associated immune response.
o
Isakbaeva ET, Khetsuriani N, Beard RS, Peck
A, Erdman D, Monroe SS, et al. SARS-associated coronavirus transmission, United States. Emerg Infect Dis 2004;10: 225–31.
o
Peiris JS, Chu CM, Cheng VC, Chan KS, Hung
IF, Poon LL, et al. Clinical progression and viral load in a community
outbreak of coronavirus-associated SARS pneumonia: a prospective study. Lancet 2003;361:1767–72.
o
Chan KH, Poon LLLM, Cheng VCC, Guan Y, Hung
IFN, Kong J, et al. Detection of SARS coronavirus in patients with suspected SARS. Emerg Infect Dis 2004;10: 294–9.
The seroconversion of probable SARS cases is:
o
92% to 100% within 28 days after the onset
RT-PCR detects the virus in respiratory secretions in:
o
<50% during the first 4 days of illness
o
Peak levels in both respiratory and stool specimens
are found by day 11–12 of illness
o
Virus can persist in stool for weeks thereafter
o
Isakbaeva ET, Khetsuriani N, Beard RS, Peck
A, Erdman D, Monroe SS, et al. SARS-associated coronavirus transmission, United States. Emerg Infect Dis 2004;10: 225–31.
o
Zhai J, Briese T, Dai E, Wang X, Pang X, Du
Z, et al. Real-time polymerase chain reaction for detecting SARS coronavirus, Beijing, 2003. Emerg Infect Dis 2004;10: 300–3.
o
Peiris JS, Chu CM, Cheng VC, Chan KS, Hung
IF, Poon LL, et al. Clinical progression and viral load in a community
outbreak of coronavirus-associated SARS pneumonia: a prospective study. Lancet 2003;361:1767–72.
o
Chan KH, Poon LLLM, Cheng VCC, Guan Y, Hung
IFN, Kong J, et al. Detection of SARS coronavirus in patients with suspected SARS. Emerg Infect Dis 2004;10: 294–9.
The sensitivity and specificity of ELISA and RT-PCR was confirmed
by comparative studies, although at the beginning of the outbreak they reliability was uncertain.
o Enzyme-linked immunosorbent assays for detecting SARS antibodies.
o Wu H-S, Chiu S-C, Tseng T-C, Lin S-F, Lin J-H, Hsu Y-F, et al. Serologic
and molecular biologic methods for SARS-associated coronavirus infection, Taiwan. Emerg Infect Dis 2004;10: 304–10.
o Real-time reverse transcription–polymerase chain reaction (RT-PCR)
assays for detecting SARS-CoV infection .
o Emery SL, Erdman DD, Meyer RF, Bowen MD, Newton BR, Winchell
JM, et al. Real-time reverse transcriptase–polymerase chain reaction assay for SARS-associated coronavirus. Emerg Infect
Dis 2004;10: 311–6.
o Zhai J, Briese T, Dai E, Wang X, Pang X, Du Z, et al. Real-time polymerase chain reaction
for detecting SARS coronavirus, Beijing, 2003. Emerg Infect Dis 2004;10: 300–3.
CHALLENGES
There are not
SARS-CoV laboratory assays which are sensitive early in the disease course to
support rapid clinical and infection-control decision-making.
SARS may reemerge from unidentified animal reservoirs or
from persistently infected humans.
Current planning efforts for response to a future SARS resurgence
rely upon vigilant application of clinical and epidemiologic criteria to evaluate cases of febrile illness.
o
Jernigan JA, Low DE, Helfand RF. Combining
clinical and epidemiologic features for early recognition of SARS. Emerg Infect Dis 2004;10: 327–33.
A bold and swift public health response to this disease must
be applied with fairness and in a manner that preserves dignity for all. Response to any future resurgence of SARS will be
aided by the body of knowledge about the infection that now exists and by the international experience in successfully containing
the first SARS outbreak.
|
Table. World Health Organization SARS case definitionsa |
|
|
|
Suspected case-patient: a person presenting after November 1, 2002,b
with a history of (ALL THREE): |
|
|
|
1. High fever (>38°C)
AND |
|
2. Cough or breathing
difficulty, AND |
|
3. One or more of
the following exposures during the 10 days before onset of symptoms: |
|
close contactc with a person who is a suspected or probable SARS case-patient |
|
history of travel to an area with recent local transmission of SARS |
|
residing in an area with recent local transmission of SARS |
|
Probable case-patient: a suspected case-patient with: |
|
|
|
1. Radiographic evidence
of infiltrates consistent with pneumonia or respiratory distress syndrome (RDS) on chest x-ray OR |
|
2. Consistent respiratory
illness that is positive for SARS coronavirus by one or more assays, OR |
|
3. Autopsy findings
consistent with the pathology of RDS without an identifiable cause |
|
|
|
aRevised
May 1, 2003 (6). SARS, severe acute respiratory syndrome. |
|
bThe surveillance
period begins on November 1, 2002, to capture cases of atypical pneumonia in China now recognized as SARS. International transmission
of SARS was first reported in March 2003 for cases with onset in February 2003. |
|
cA close
contact is someone who cared for, lived with, or had direct contact with respiratory secretions or body fluids of a suspected
or probable SARS case-patient.
Source: www.who.org
Disclaimer: The material edited in this website is intended for information purposes only. Please refer
to the references provided for updated information regarding to the topic. |
