Medical Update

New SARS Diagnostic test

The Microbiology Team of the Faculty of Medicine, HKU has recently developed a new SARS diagnostic test. This test (LAMP assay) has provided an inexpensive and simple tool for early diagnosis of SARS patients. From the practical viewpoint, within the first week of illness, the highly sensitive PCR assays should be used. After the first week, the LAMP assay might be an inexpensive and accurate alternative for SARS diagnosis. It is expected that with this rapid diagnostic method, prompt identification of SARS pathogen will facilitate control of the disease and provision of prompt treatment.

Source: Clinical Chemistry 50, No. 6, 2004
4th June 2004
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Hong Kong stands down Alert Level

Hong Kong have stood down the Alert Level of SARS response system on 28th May 2004.
Since September 2003, a total of 15 cases of SARS have been reported outside Hong Kong: 1 in Singapore, 1 in Taiwan, 4 in Guangdong, 2 in Anhui and 7 in Beijing. One case had died, and all other cases were discharged from hospital. On 18 May 2004, more than 3 weeks after the last case in Beijing was placed in isolation, the WHO declared that the chain of human-to-human transmission appeared to have been broken.
Nevertheless, all are advised to maintain vigilance in infection control.

Source: Situation Report (Friday, 28th May 2004) Department of Health.
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SARS cases in China: since 22 April, China has reported that 8 persons have been clinically diagnosed as SARS cases or are under investigation for possible SARS infection. Six of these are in Beijing and 2, including the single fatality, are in Anhui Province.
2 of the recently reported cases were conducting laboratory research at the National Institute of Virology in Beijing. The dates of symptom onset in the two cases were widely separated, suggesting more than one opportunity for exposure may have occurred in the laboratory.
As of today, close to 1000 contacts of these cases are under medical observation, including 640 in Beijing and 353 in Anhui. To date, all diagnosed cases and cases under investigation have been linked to chains of transmission involving close personal contact with an identified case. There is no evidence of wider transmission in the community.
Source: WHO Update 26 April 2004

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Jumping of SARS from Wild Animals to Humans

Centres for Disease Control & Prevention of Guangdong, Shenzhen and Guangzhou and the University of Hong Kong found another jumping of SARS Coronavirus from Wild Animals to Human in the past month.
The research data shows that the viral genetic sequence obtained from the first suspected SARS case in human in the recent month is similar to that of the Civet cats. This is another sublineage of SARS-like Coronavirus, different from the SARS-like coronavirus found last year.
In order to stop another outbreak of SARS, there is need to control and manage the rearing, sale, transport, slaughter and the food processing of wild animals.

Source: Medical Faculty Press Release on 5th January, 2004.

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On 5th January, WHO announced that a case of SARS in a 32-year-old man in Gunagdong, China was confirmed. This is the first confirmed case not linked to a laboratory incident that has occurred since the initial outbreak of SARS was declared contained on 5th July 2003. Laboratory-related cases occurred after that date in Singapore, Taiwan, China in December of last year.
The source of infection for this newly confirmed case remains unclear. Epidemiological investigations in China have not yet been able to link the patient to exposure to wild animals or any other known or suspected source of the virus.
The patient has been treated in isolation since his hospitalisation on 20 December, four days after the onset of symptoms. All contacts have been traced and followed up. All are reported to be free of symptoms.

Source: World Health Organisation, 5 January 2004.

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A confirmed SARS case in Taiwan

ON 17th December, the health authorities in Taiwan confirmed a SARS case involving a 44 year old man who is a researcher participating in laboratory SARS study. It is suspected to be a laboratory-acquired infection. The patient is now isolated in a designated hospital for management and his close contacts have been required to remain at home.

Alert level (a) is activated in Hong Kong in accordance with the Checklist of Measures to Combat SARS at the following website: http://www.hwfb.gov.hk/ch/wnew/030922_combat_sars/combat_sars.htm

Please maintain due vigilance in infection control measures, especially in your laboratory, and report any suspected SARS case or acute respiratory outbreak to the UHS and the Department of Health.

Source: Department of Health, 17th December, 2003.

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Probable SARS case in Singapore:
In the afternoon on 9 September, the Ministry of Health, Singapore reported a probable SARS case involving a 27-year-old laboratory worker. The man had onset of fever on 26 August 2003 around midnight. On admission to hospital on 3 September, he had fever, muscle aches and joint pain, and he developed dry cough after admission. Three serial chest x-rays were all normal. Polymerase chain reaction (PCR) tests and serology test results were positive for SARS coronavirus on 8 September and on 9 September. Fever had subsided and the patient remains well. His close contacts have been put under home quarantine order. No other laboratory co-workers have fever or feel unwell.
The clinical picture does not meet the World Health Organization clinical case definition of SARS but there is laboratory evidence of SARS coronavirus infection. According to the Ministry of Health, Singapore, the patient has no history of travel to previously SARS-affected areas and no known contact with SARS patients, and this appears to be a single, isolated case. Investigation into the source of infection is underway.
(Source: Department of Health, 10th September, 2003)

Date: 10th September, 2003.

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Might SARS recur?
Considerable uncertainty surrounds the question of whether SARS might recur, when the weather turns cooler.
Currently, SARS has no vaccine, no effective treatment, and no reliable point-of-care diagnostic test. As the recurrence of SARS during the influenza season cannot be ruled out, some health authorities are concerned that cases of influenza and other respiratory diseases could raise suspicions of SARS.
Influenza vaccinationin given to high risk groups and health workers caring for them will reduce the number of pneumonia cases which could be confused with SARS.
(Source: WHO: Influenza vaccination for the 2003-04 season; 2 September 2003)

10th September 2003

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WHO revised the clinical case definition of SARS
The revised definition is :
A person with a history of fever (38 degrees C)
AND
one or more symptoms of lower respiratory tract illness (cough, difficulty breathing, shortness of breath)
AND
Radiographic evidence of lung infiltrates consistent with pneumonia or Respiratory Distress Syndrome (RDS) OR autopsy findings consistent with the pathology of pneumonia or RDS without an identifiable cause.
AND
No alternative diagnosis can fully explain the illness

(Source: Department of Health (7) in DH/CM/11/53/2)
22nd August 2003

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Outbreak in Canada:
There is an outbreak of acute respiratory illness in a nursing home in British Columbia. The outbreak started in early July 2003, and up to 14 August, affected 97 of 142 residents and 46 of 160 staff there. This illness has been relatively mild. Symptoms have been predominantly upper respiratory including rhinitis, cough, sorethroat, and muscle pain. Fever has not been a prominent symptom, only present in approximately 10% of staff and residents; a few residents have had diarrhoea or nausea. There have been a total of 7 deaths during the outbreak, all among frail elderly individuals and at least two of which were unrelated to the outsbreak. The outbreak is currently resolving. PCR and serologic tests in some patients were positive for a virus similar to the SARS coronovirus. Possible explanations include a newly identified less virulent variant of coronovirus or a mild form of SARS-CoV infection.
(Source: Department of Health Ref: (7) in DH/CM/11/53/2)

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SARS Overcomed ?:
On 5th July, WHO removed Taiwan from its list of areas with recent local transmission of SARS. This achievement means that all known chains of person-to-person transmission of the SARS virus have now been broken. Failure to detect new cases over the next two weeks will greatly increase confidence that the SARS coronavirus has indeed been pushed out of its new human host, although a return of the disease cannot be ruled out completely on the basis of current knowledge.
(Source: WHO Update 96)

8th July 2003.

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WHO guidelines for detecting SARS need to be reconsidered
The overall accuracy of the WHO guidelines for identifying suspected SARS was 83% with a sensitivity of 26% and a specificity of 96%.
In an observational study of 556 people screened for SARS in Hong Kong, Rainer and colleagues found that the best predictor of SARS was radiological evidence of pneumonic change, which often preceded the onset of fever. The main discriminatory symptoms in the early stages of the disease were fever, chills, malaise, myalgia, and rigor—not respiratory tract symptoms, as stated in the WHO guidelines.
(Source: Rainer et al; British Medical Journal 2003;326 (21 June))

20th June, 2003

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SARS-Continued vigilence required
During June, the global number of new cases has gradually dwindled to the present handful. This dramatic reduction is not attributable to a change in the virulence or infectivity of the SARS virus, but as the result of monumental efforts of the government and health care staff, supported by a well-informed and cooperative public.
WHO sees the need for continued vigilance and at least a full year of surveillance.
As long as a single case of SARS exists or is suspected anywhere in the world, and as long as fundamental questions about the origins of the virus remain unanswered, all countries need to remain on guard.

Source: WHO Update 83 http://www.who.int/csr/don/2003_06_18/en/

18th June 2003

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SARS in Wild Animals: Research Teams in Hong Kong and Shenzhen, China have detected SARS coronavirus in wild animals in southern China (masked palm civet and racoon-dog). The animals also seroconverted and their sera inhibited the growth of SARS coronavirus isolated from humans. Another species (Chinese ferret badger) also elicited antibodies against SARS coronavirus.
These and other wild animals are traditionally considered delicacies and are sold for human consumption in markets throughout southern China.
Persons who might come into contact with these species or their products should be aware of the possible health risks.
(Source: WHO Update 64)

23rd May 2003.
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SARS and Blood Safety: Although no probable SARS case has been ascribed to transmission by labile blood products or blood derivatives, there is a theoretical risk of transmission of the SARS virus through transfusion of labile blood products, since low viraemia has been detected up to approximately 10 days after the onset of symptoms from probable SARS patients. Probable SARS patients should defer blood transfusion till 3 months after full recovery and cessation of therapy. Asymptomatic close contacts of SARS patients should be advised to defer till 3 weeks after the last day of contact.
(Source: WHO Guidelines)

15th May, 2003.
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SARS can be contained.
In the absence of a vaccine, the most effective way to control SARS is to break the chain of transmission from infected to healthy persons. Three activities - case detection, patient isolation, and contact tracing - can reduce the number of people exposed to each infectious case and eventually break the chain of transmission.
The inital stages of containment are the most dangerous time to start lowering the level of control. Comprehensive procedures of contact tracing and isolation to reduce the "time to isolation" have proven to be effective.
(Source: WHO Update 54)

13 May 2003

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SARS: The mean incubation period of the disease is estimated to be
6 days. The estimated case fatality rate was 13% for patients younger
than 60 years and 43% for patients aged 60 years or older.
(Source: C A Donnelly et al; Lancet: May 7, 2003)

(May 7, 2003)

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Data on stability and resistance of SARS virus:
Survival time:
- at least 2 days on plastic surface in room temperature
- 4 days in diarrheal stool
- less than 30 minutes in culture medium at 56 degrees C.
- at least 21 days in culture medium at 4 degrees C
- 5 minutes in 10% Clorox, formaldehyde, 75% ethanol
(Source: members of WHO laboratory network, WHO)

(May 3, 2003)

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Clinical progression of SARS patient: The fever and pneumonia initially responded to treatment. However, patient developed recurrent fever on day 9 +/- 3, watery diarrhoea on day 7.5 +/- 2, radiological deterioration on day 7 +/- 2 and respiratory deterioration on day 8+/3. 20% progressed to acute respiratory distress syndrome (ARDS) during the third week. Peak viral load appeared at day 10. Deterioration during the second week is not related to viral replication but rather to immunopathological damage.
[Source: Peiris et al; WHO (accepted by Lancet pending publication next week)]

(May 1, 2003)
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SARS - a tri-phasic disease:

First week: viral replicative phase: symptoms of fever, myalgia and chills with minimal respiratory symptoms. Some may recover spontaneously in this phase.

Second week: immune hyperactive phase: 70% develops into this phase. Patients start to develop respiratory symptoms of shortness of breath, cough with pinkish sputum and bilateral chest X ray involvement.

Third week: pulmonary destruction phase: ground glass appearance in chest X ray, blood oxygen saturation decrease, patients require intensive care.
(Source: Prof. JJY Sung; Hong Kong Medical Diary)

(April 30, 2003)
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SARS seems to have a less aggressive clinical course in younger children.
(Source: Hon et al ; Lancet, April 29, 2003)

(April 29, 2003)
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