As the Centers for Disease Control and Prevention (CDC) continues to investigate the cause of severe acute respiratory syndrome (SARS), UCSF experts emphasize that most people with respiratory symptoms do not have SARS and that appropriate infection control measures can prevent transmission of the disease.
In addition, they recommend a consultation with a health care provider if individuals match the SARS case definition, which includes:
1) Temperature greater than 100.4 ° F (> 38° C)
2) One or more symptoms of respiratory illness (cough, shortness of breath, difficulty breathing) AND
3) Travel within 10 days of symptom onset to an area with suspected community transmission of SARS
4) OR close contact within 10 days of onset of symptoms with either a person with respiratory illness who traveled to a SARS area or a person known to be a suspect SARS case.
Areas of documented or suspected community transmission of SARS include the Peoples’ Republic of China (mainland China and Hong Kong special administrative region); Hanoi, Vietnam; and Singapore. Close contact is defined as having cared for, lived with or had direct contact with respiratory secretions and/or body fluids of a patient known to be a suspect SARS case.
While the cause of SARS is not yet known, scientists suspect it is a new and more dangerous form of coronavirus, a family of viruses that causes colds and diarrhea.
Two weeks ago, using a technology that he and colleagues developed, Joe DeRisi, PhD, UCSF assistant professor of biochemistry and biophysics, led a team that provided the CDC with important supporting evidence that coronavirus may be the cause of SARS. DeRisi’s work is sponsored by an award from the Sandler Program for Asthma Research.
The mechanism by which SARS is transmitted is unknown, but evidence suggests that the SARS infection is spread by close contact between people, said John Conte, MD, director of hospital epidemiology and infection control at UCSF Medical Center. He explained that it is most likely spread when a sick person coughs droplets into the air, which are then breathed in by someone else or come into contact with the lining of the eyes (conjunctivae).
It is also possible that SARS can be spread more broadly through the air or from touching objects that have been contaminated.
To prevent transmission of the disease, UCSF Medical Center experts recommend regular hand washing with soap and warm water.
In addition, household setting suspected SARS patients are advised to cover the mouth and nose with a facial tissue when coughing or sneezing and, if possible, wear a surgical mask. If the suspected SARS patient is unable to wear a surgical mask, household members should wear surgical masks when in close contact with the patient, said Conte. Masks should be worn securely enough to ensure breathing through—and not around—the mask, he said.
Patients who have SARS and are being cared for at home should avoid sharing silverware, towels or bedding with anyone in their home until these items have been washed with soap and hot water.
Surfaces such as counters, tabletops, doorknobs and bathroom fixtures that have been contaminated by body fluids (sweat, saliva, mucus, or even vomit or urine) should be cleaned with household disinfectant. Those who clean these surfaces should wear gloves and dispose of them after use. These instructions should be followed for 10 days after the patient’s fever and respiratory symptoms have gone away, said Conte.
In addition to fever, SARS symptoms may also include headache, an overall feeling of discomfort, body aches, and/or mild respiratory symptoms. After two to seven days, SARS patients may develop a dry cough and have trouble breathing. After exposure, the incubation period for SARS is typically 2-7 days. However, isolated reports have suggested an incubation period as long as 10 days. The majority of patients identified with the disease have been adults 25-70 years old who were previously healthy. Few cases have been reported among children aged 15 years or less.
Several healthcare workers have been reported to develop SARS after caring for infected patients. Transmission to healthcare workers appears to have occurred after close contact with symptomatic patients before recommended infection control precautions for SARS were implemented. The severity of the illness has proven to be highly variable among patients, according to Conte.
Because there is no simple test to diagnose SARS, health care providers at UCSF Medical Center are using targeted screening questions concerning fever, respiratory symptoms, and recent travel to evaluate patients. If a suspect SARS patient is admitted to UCSF Medical Center, infection control measures include: hand hygiene, eye protection, use of gown and gloves for contact with the patient or their environment and the implementation of airborne precautions.
Airborne precautions include the use of a negative pressure isolation room with adequate ventilation and use of high filtration N-95 masks for people entering the patient room. N-95 masks effectively remove 95 percent of particulates and are reusable as long as they remain dry and intact, according to Kathy Mathews, RN, nurse epidemiologist at UCSF Medical Center.
Mathews and Conte are part of a campus-wide group developing a set of guidelines regarding SARS for health care workers and employees at UCSF. UCSF clinical guidelines for SARS are largely based on CDC guidelines, which appear on the CDC web site at .
UCSF experts note that this illness can be severe and, due to global travel, has spread to several countries in a relatively short period of time. On April 2, 2003, the World Health Organization (WHO) revised its advice to international travelers recommending that persons traveling to Hong Kong and Guangdong Province of China consider postponing all but essential travel as a measure for preventing the further international spread of SARS. On April 4, 2003, President Bush issued an executive order allowing the Health and Human Services secretary to decide when forced quarantine of patients with SARS symptoms is necessary. More information on travel precautions can be found at CDC.
The CDC currently recommends that patients with SARS receive the same treatment that would be used for any patient with community acquired atypical pneumonia of unknown cause. Reported therapeutic regimens have included antibiotics, antiviral agents such as oseltamivir or ribavirin.
Steroids also have been administered in combination with ribavirin and other antimicrobials. However, there is insufficient information at this time to determine if they have had a beneficial effect, according to Julie Gerberding, MD, director of the CDC.
The CDC recommends that people with fever or respiratory symptoms that develop during the 10 days following an unprotected exposure to a SARS patient, should limit their activities outside the home (work, school, public areas) for 10 days after resolution of fever and respiratory symptoms.
People do not need to stay home if they have not developed fever or respiratory symptoms. However, those exposed to a SARS patient may be required to report the unprotected exposure to an appropriate workplace official, according to CDC officials.
As of April 8, 2003, the WHO has reported 2, 671 cases in 20 countries. The United States is reporting 148 suspect cases under investigation. There have been 103 deaths internationally and no deaths in the United States so far. Most of the United States patients are doing well and recovering, according to Gerberding.
NOTE TO THE MEDIA: Reporters wishing to contact UCSF experts in the fields of virology, epidemiology/infection control, or clinical management of SARS should contact Maureen McInaney at (415) 476-2557.