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SARS
Coronavirus
Biosafety recommendations for Belgian diagnostic
and research laboratories
(Author: P. Herman) (Last revised:
February 28, 2006
)
Introduction - Classification and Biosafety recommendations - Additional informations
Severe acute respiratory syndrome (SARS) is a respiratory illness, which has its origins in Guangdong Province, China. The earliest known cases were identified in mid-November 2002. The syndrome has spread in Asia, North America, Africa and Europe, with 8098 suspected and probable cases of SARS, including 774 deaths up to September 26th, 2003, reported to the World Health Organization (WHO). In response to the SARS outbreak, WHO coordinated an international collaboration that included clinical, epidemiologic, and laboratory investigations, and initiated efforts to control the spread of SARS.
The mechanisms of SARS transmission remain unclear. However, on the basis of the reported exposures for the majority of cases (i.e., household contacts and health care workers), the primary way that SARS appears to spread is by close person-to-person contact involving exposure to infectious droplets of respiratory secretions from an infected person, by the faecal-oral route and likely by mechanical transmission. Indirect transmission by aerosolized material or animal vector as roof rats is not excluded as suggested by the peculiar outbreak in the Amoy Gardens in Hong Kong.
According to the latest findings, the etiologic agent primarily responsible for the syndrome is a previously unrecognised virus belonging to the family of coronaviruses, currently called SARS coronavirus (SARS-CoV).
Around 30% of SARS
cases were reported to occur in health care workers in direct
contact with patients, however until now SARS-CoV laboratory-acquired infections were not demonstrated. A doctoral student
was reported positive for the virus in Singapore recently
(
(564
kb) report from Singapore authorities). This man was
working in a virology laboratory but not manipulating intentionally SARS-CoV.
If
this case represents a confirmed case of a laboratory accident
it raises the question of biosafety for laboratories involved
in SARS-CoV manipulation. An other case of suspected SARS laboratory-acquired infection was reported more recently in Taiwan.
Classification
and Biosafety recommendations
The
Section of Biosafety and biotechnology considers that the
under-mentioned containment measures are theoretically
sufficient to prevent risks to human health and the environment.
However
such assessment is only indicative and without prejudice
of the final provisions that could be decided by competent
authorities, regarding the realistic applicability and
predictability of the proposed containment measures and
the bound laboratory practices.
There is no case of SARS reported in Belgium up to now and there is so far no routine diagnostic. Anticipating future SARS-CoV manipulation in Belgian laboratories, a class of risk (or risk group) and the biosafety levels for SARS-CoV manipulation have to be determined based on a thorough risk assessment. Taking into account that there is so far no SARS case reported in Belgium and based on a scientific risk assessment related to the contained use of biological agents, the SARS-CoV was at least classified as an agent of class of biological risk 3.
The SARS-CoV should be handled in appropriate biosafety containment levels in order to avoid laboratory acquired infections and spread of the disease in the human population and the environment.
Diagnostics activities with inactivated clinical specimens from suspect cases and specimens originating from countries where SARS is documented but from not SARS suspect cases, should be performed under biosafety level 2 (L2) conditions. Diagnostic activities involving non-inactivated clinical specimens from SARS suspect cases should be carried out under biosafety containment level 2 with level 3 (L3) safety equipment and L3 work practices and waste disposal management. Special emphasis should be made on potential spread by droplets, air and/or contaminated surfaces and objects.
Viral cell cultures and manipulations of cultured SARS-CoV for diagnostic as well as for research or production purposes (e.g. preparation of diagnostic tests for SARS) require L3 facilities, equipment and work practices and waste disposal management.
All activities involving inoculated animals require A3 facilities, equipment and work practices and waste disposal management . When possible, a class II biological safety cabinet is used (e.g. inoculations to small animals).
(see Flow chart hereafter synthesizing the required containment measures for manipulating SARS related samples).
* without culture, amplification of SARS-CoV
or use of cultured, amplified SARS-CoV
** HEPA filtered mask and restricted
entrance
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