Biological Agent - Severe Acute Respiratory Syndrome (SARS)

Severe acute respiratory syndrome (SARS) is an emerging, sometimes fatal, respiratory illness. The first identified cases occurred in China in late 2002, and the disease has now spread throughout the world. Although SARS is believed to be caused by a virus, the specific agent has not been identified, and there is not yet any laboratory or other test that can definitively identify cases. Suspected SARS cases in the United States have involved individuals returning from travel to Asia and health care workers and other contacts of those patients. SARS does not appear to be caused by casual contact; transmission appears to be primarily through close contact with a symptomatic patient.

The Centers for Disease Control and Prevention (CDC) has defined a suspect case of SARS as an illness of unknown cause that began in February 2003 or later and meets the following criteria:
 

• Fever of at least 100.5 degrees F;
  
   
• One or more clinical findings of respiratory illness, such as cough, shortness of breath, difficulty breathing, hypoxia, or x-ray evidence of either pneumonia or acute respiratory distress syndrome; and
  
   
• The onset of symptoms occurs within 10 days of either (1) travel to an area with documented or suspected community transmission of SARS; or (2) close contact with either a person with a respiratory illness who traveled to a SARS area or a known suspect SARS case. Close contact means having cared for, lived with, or had direct contact with respiratory secretions and/or body fluids. 

Suspect cases with radiographic evidence of pneumonia, respiratory distress syndrome, or evidence of unexplained respiratory distress syndrome by autopsy are designated "probable" cases by the World Health Organization (WHO) case definition.

In addition to fever, reports indicated that the majority of SARS patients experienced chills, and about half had muscle aches and dry cough. Fewer than half have also shown other symptoms such as dizziness. The incubation period is typically 2 to 7 days, although some reports suggest an incubation period as long as 10 to 12 days. Signs of the illness include a decreased white blood cell count in most patients as well as below normal blood platelet counts, liver enzyme increase, and electrolyte disturbances in a number of patients.

Most people with SARS are adults. Those age 40 and older and those with certain medical conditions appear to be at increased risk of more severe disease and of death. Treatment consists of antibiotics and steroids, with other options being explored. Between 10 and 20 percent of SARS patients have required ventilator support for a period of time. To date, about 4 percent of identified SARS cases have been fatal.

Standard Precautions and Personal Protective Equipment

Since the infectivity and route of transmission of SARS are unknown, healthcare workers treating patients known to be infected with SARS should use standard precautions, including good work and hygiene practices and the use of personal protective equipment (PPE) appropriate for bloodborne and airborne exposures. Appropriate PPE includes protective gowns, gloves, N95 respirators, in addition to and eye protection.

If workers providing care to a SARS patient have potential exposure to blood or other potentially infectious materials, they must use PPE in accordance with OSHA's Bloodborne Pathogens Standard, 29 CFR 1910.1030.

Engineering Controls
Acute care facilities already should have appropriate ventilation systems (including appropriate exhaust and filtration) to eliminate the potential for exposure to airborne infectious diseases. If appropriate ventilation systems are in place, any airborne SARS exposures should also be controlled. Individuals with suspected SARS should be placed in an isolation room with negative pressure. If air recirculation is unavoidable, infected individuals should be placed in an area that exhausts room air directly to the outdoors or through HEPA filters if recirculation is unavoidable.

Housekeeping
There are no disinfectant products currently registered by the U.S. Environmental Protection Agency (EPA) for the newly identified viruses associated with SARS. The CDC recommends the use of EPA-registered chemical germicides that provide low- or intermediate-level disinfection during general use because these products are known to inactivate related viruses with physical and biochemical properties similar to the suspected SARS agents.

Biosafety Precautions and PPE
Laboratory workers must wear appropriate PPE, including disposable gloves, gowns, eye protection, and respiratory protection. N95, N100 air-purifying respirators, or powered air-purifying respirators (PAPRs) equipped with high-efficiency particulate air (HEPA) filters are recommended. If there is potential exposure to blood or other potentially infectious materials, laboratory workers must use PPE in accordance with OSHA's bloodborne pathogens standard, 29 CFR 1910.1030.