In February-March of 2003, several atypical cases of pneumonia were identified in Vietnam, Hong Kong, Canada, and Singapore. The disease, severe acute respiratory syndrome (SARS), spread extensively from a single infected person and became a global threat as a result of air travel. The World Health Organization issued a global public health emergency; shortly after the global response, the etiological agent, SARS-associated coronavirus (SARS-CoV), was isolated.
Potential Health Hazards
SARS-CoV is an enveloped, positive-sense, single stranded RNA virus. Coronaviruses are typically associated with enteric and respiratory disease syndromes in a variety of animal species. While the pathogenesis of SARS is not completely understood, the virus has been isolated in human autopsy specimens from lung, intestinal, brain, and kidney tissue. Lymphopaenia, with a reduction in CD4+ lymphocyte counts and reduction in circulating CD8+ T lymphocytes, B lymphocytes and natural killer cells, is common among SARS patients. Mortality is associated with respiratory distress syndrome, multiorgan failure, secondary infections and septic shock.
Modes of Transmission
SARS-CoV is transmitted through aerosolization, mainly through respiratory droplets, and close personal contact. There is a possibility of fomite transmission due to the stability of the virus in the environment and possibly small-particle aerosols. Fecal-oral or fecal-respiratory transmission is also possible as the virus can be shed in the stool.
The greatest risk of transmission occurs during the second week of illness when the viral load reaches a maximum in respiratory secretions. The risk of transmission from an asymptomatic SARS-CoV infection is unknown.
Laboratory Acquired Infections
Laboratory acquired infections (LAIs) with SARS-CoV have been documented in Beijing, Singapore and Taiwan. Infection of Beijing laboratory staff may have resulted during research with presumed inactivated SARS-CoV; the effectiveness of inactivation had not been determined prior to release from the BSL3 facility. The LAI in Singapore resulted during active research in a BSL3 facility; in Taiwan a worker was infected during remediation of a spill.
In a study examining the host range of SARS-CoV, productive infection was restricted to mammalian cell lines; however, not all mammalian cells are permissive for infection. While functional receptors for SARS-CoV have been identified, including angiotensin-converting enzyme 2 (ACE2) and CD209L (L-SIGN), further species specificity exists at the receptor level as human ACE2 but not murine ACE2 allows for efficient SARS-CoV replication.
SARS-CoV remains viable for several days in the environment.
The appropriate biosafety level (BSL) practices and facilities will depend on the biological material that the laboratory is manipulating.
Biosafety level 2 practices and facilities, at a minimum, must be used for activities involving diagnostic procedures for clinical material.
- Biohazard signs and labels must be displayed in areas and on equipment where bacteria are used and stored. This includes, but is not limited to, laboratory entrance doors, biological safety cabinets, incubators, refrigerators, and freezers.
- Use a biological safety cabinet (BSC) (a.k.a. tissue culture hood) for manipulations that can generate aerosols, such as pipetting, harvesting, infecting cells, filling tubes/containers, and opening sealed centrifuge canisters.
- Use aerosol containment devices when centrifuging. These include sealed canisters that fit in the centrifuge bucket, covers for the centrifuge bucket, heat sealed tubes, or sealed centrifuge rotors. Rotors should be removed and opened inside a BSC. Centrifuge tubes should be filled and opened in a BSC.
- Vacuum lines must be protected with liquid disinfectant traps and/or micron filters.
- Policies for handling and disposing of sharps (needles, pipettes, broken glassware, etc.) must be implemented. Work practice controls and engineering devices should be implemented to reduce sharps injuries.
- Decontaminate work surfaces after completion of work and after any spill or splash of potentially infectious material with appropriate disinfectant.
- All cultures, stocks and other potentially infectious materials should be decontaminated prior to disposal with an effective method, such as autoclaving or treatment with a bleach solution.
- Potentially infectious materials must be placed in a durable, leak proof container during collection, handling, processing, storage, or transport within a facility.
- Personal protective equipment (PPE) requirements are outlined below.
Biosafety level 3 practices and facilities must be used when preparing or manipulating cultures, characterizing viral agents recovered in cultures of SARS specimens, and experimental animal studies.
- Directional airflow is provided, drawing air into the laboratory from “clean” areas and toward “contaminated” areas.
- A BSL3 specific biosafety manual and biosafety precautions are incorporated into standard operating procedures.
- Respiratory protection is required.
- Policies and procedures are developed such that only persons who have been advised of the potential biohazards, who meet any specific entry requirements, and who comply with all entry and exit procedures may enter the lab.
- BSL3 policies and standard operating procedures are outlined in manuals specific to the BSL3 laboratory.
Personal Protective Equipment
Personal protective equipment (PPE) for the BSL2 laboratory includes, but is not limited to:
- Disposable gloves (nitrile, latex, etc.).
- Lab coat when working in the area. Remove when leaving the laboratory.
- Face and eye protection must be used when potentially infectious material is handled outside of the biosafety cabinet or containment device.
- Protective laboratory clothing must be laundered by the University and not taken home for cleaning.
PPE requirements for the BSL3 laboratory are outlined in the BSL3 specific manuals.
Precautions When Using Animals
Animal use requests are made to the Institutional Animal Care and Use Committee (IACUC) by submitting an Animal Care and Use Form (ACURF)
When animals are infected with SARS-CoV, the animal biosafety level (ABSL) will be assigned to ABSL-3.
Recombinant SARS Research
Eye Exposure – Rinse eyes in an eyewash for at least 15 minutes.
Skin Exposure – Wash skin with soap and water.
Accidental Needlestick Injury – Scrub contaminated skin with soap and water.
Report Incidents and Seek Treatment – Report actual or suspected exposure incidents to your supervisor immediately and seek treatment at the Worker’s Health Clinic. It is located on the first floor of Boyd Tower – General Hospital. The clinic’s phone number is 353-8653. If the incident occurs after 4:30pm, during the weekend, or on a holiday, proceed to UIHC’s Emergency Treatment Center (ETC). The phone number is 356-2233.
- Incubation Period – The incubation period is approximately 2-7 days. Symptoms may appear between 2 to 10 days after exposure.
- Symptoms – Symptoms include fever, headache, myalgias, malaise, chills and rigor. Respiratory symptoms may not appear until 2-7 days after fever onset. Lower respiratory tract symptoms include non-productive cough with later onset of dyspnoea. Pneumonia generally develops by illness day 7-10; 10-25% of patients require mechanical ventilation. Diarrhea has been observed and is believed to result from fecal-oral/respiratory transmission. Children infected with SARS-CoV generally present milder symptoms. Asymptomatic SARS-CoV infections have been recorded.
- Immunizations – none available.
Spill and Disposal Procedures
For spills outside a biological safety cabinet
- Leave the area while holding your breath.
- Once outside the area, wash hands and face with soap and water.
- Do not allow anyone inside the area or room where the spill occurred.
- Allow 30 minutes for the aerosols to settle.
- Enter the room wearing required protective clothing, carefully cover the spill with paper towels, and apply disinfectant starting at the perimeter and working towards the center.
- Allow the disinfectant to remain on the spill for at least 20 minutes before initiating spill clean up.
- After initial clean up, disinfect the area a second time.
For spills inside a biological safety cabinet
- Cover the spill with paper towels or wipes.
- Carefully pour disinfectant over the spill area.
- Let the disinfectant soak for 20 minutes before cleaning up the spill.
- After initial clean up, disinfect the area a second time.
Contaminated materials must be disposed of as biohazardous waste.
Decontaminate adjacent surfaces with a bleach solution.
For spills in the BSL3 laboratory, follow the specific procedures outlined in the BSL3 biosafety and emergency manuals.
Disinfectants should be allowed a minimum of 20-30 minutes contact time. Use one of the following:
- Sodium hypochlorite (1-10% dilution of fresh bleach).
- Autoclave cultures and other laboratory waste for 60 minutes at 121oC or 250oF (15lbs per square inch of steam pressure).
- Infected animal carcasses must be autoclaved before disposing with the biohazardous waste.
- Disinfect work surfaces using an effective germicide (see above). This may be followed by an alcohol wipe to lessen the corrosive nature of the germicide.
Materials must be appropriately contained and labeled for transport within the University. Shipping infectious substances, diagnostic specimens, and/or shipping with dry ice off-campus require training and certification. See EHS’s fact sheet “Transporting and Shipping Infectious Substances” for additional information.
If you have questions contact EHS’s Biological Safety Section at 335-8501.
Information and References
- Centers for Disease Control and Prevention. 2004. Public Health Guidance for Community-Level Preparedness and Response to Severe Acute Respiratory Syndrome (SARS) Version 2. Supplement F: Laboratory Guidance. Retrieved July 2007.
- Centers for Disease control and Prevention. 2004. Severe Acute Respiratory Syndrome. Frequently Asked Questions about SARS. Retrieved July 2007.
- Jeffers, S.A., et. al. 2004. CD209L (L-SIGN) is a receptor for severe acute respiratory syndrome coronavirus. PNAS 44:15748-15753.
- Mossel, E.C., et. al. 2005. Exogenous ACE2 expression allows refractory cell lines to support severe acute respiratory syndrome coronavirus replication. Journal of Virology 79:3846-3850.
- Parashar, U.D. and L.J. Anderson. 2004. Severe acute respiratory syndrome: review and lessons of the 2003 outbreak. International Journal of Epidemiology 33:628-634.
- Perlman, S. and A.A. Dandekar. 2005. Immunopathogenesis of coronavirus infections: implications for SARS. Nature Reviews Immunology 5:917-927.
- U.S. Department of Health and Human Services Centers for Disease Control and Prevention and National Institutes of Health. (2007, February). Biosafety in microbiological and biomedical laboratories (BMBL) 5th edition. Retrieved February 2015.