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CDC pulls out all stops for mysterious new syndrome
Use isolation precautions and N-95 respirators
Infection control professionals should implement a combination of stringent barrier precautions and N-95 respirators if they suspect they have a case of the emerging severe acute respiratory syndrome (SARS), which had reached the United States as this issue of Hospital Infection Control went to press.
Eleven cases were under investigation at undisclosed locations in the United States, and the total worldwide was 264, according to the Centers for Disease Control and Prevention (CDC) and the World Health Organization. Seven of the original infected patients stayed at the same hotel in Hong Kong. The disease subsequently began appearing in several other countries in Asia, Europe, and North America via travelers. "The 11 [U.S.] cases that are currently being evaluated are individuals who have a travel history," says Julie Gerberding, MD, MPH, CDC director. "We have no individuals at the moment who are contacts of cases or in a suspicious category. We will obviously be on high alert for this."
Until the etiology and route of transmission are clearly established, the CDC recommends that in addition to standard precautions, infection control measures for inpatients should include:
When caring for patients with SARS, clinicians should wear eye protection for all patient contact. To minimize potential of transmission outside the hospital, case patients as described above should limit interactions outside the home until the epidemiology of illness transmission is better understood. Placing a surgical mask on case patients in ambulatory health care settings, during transport, and during contact with others at home is prudent, the CDC advises.
The recommendation for N-95 respirators, normally used by health care workers treating tuberculosis patients, underscores the severity of the situation in the eyes of public health officials.
"We are recommending precautions to prevent airborne spreads, droplet spread, and direct contact spread until we have further information," says Gerberding. "We’re erring on the side of caution until we can be more specific." Many of the initial cases occurred in family members and health care workers treating the infected. It appears, however, that the pathogen can be contained by infection control barrier precautions. "The fact that most cases are in household contacts or in health care personnel who have had very close and direct contact with infected people or their body fluids really does suggest to us that this is a probable droplet transmission infection," she says. "But it’s very difficult sometimes to distinguish a droplet, which means you have to be real close, from an aerosol, which can spread in a broader area. So we’re using airborne precautions, droplet precautions, and then, of course, the standard infection control precautions that we use for everyone."
The suspected etiologic agent is an emerging virus in the family of paramyxoviridae, which includes the viral agents for mumps, measles, and canine distemper. The virus, which appears to be a distinct new strain, was identified in two patients in Germany and one in Hong Kong. The CDC is reviewing numerous isolates to verify whether the initial suspicion of a new virus is correct. In the meantime, a full regalia of infection control measures is recommended for suspect cases.
While the CDC obviously is concerned about a possible newly emerging pathogen, Gerberding stresses that clinicians should not assume everyone with a travel history and fever has SARS. "They [should] evaluate patients with an open mind and treat them with the appropriate antimicrobial therapy that they would use for any case of serious community onset pneumonia until additional information is available to help guide them in one direction or another. This is something we want a high index of suspicion for, but we don’t want it to be the only thing on people’s minds because there are other important and very treatable medical conditions that can present in the identical manner." Early signs and symptoms include influenzalike symptoms such as fever, myalgias, headache, sore throat, dry cough, and shortness of breath. In some cases, symptoms are followed by hypoxia, pneumonia, and occasionally acute respiratory distress requiring mechanical ventilation, and death. Lab findings may include thrombocytopenia and leukopenia. In the absence of an identified etiologic agent, the CDC has established a nonspecific case definition of fever, symptoms, and travel history, Gerberding says. "We are not recommending prophylaxis at this point in time. Our treatment recommendations are basically utilizing the kinds of empiric treatment that would be appropriate for any patient with an unexplained pneumonia, including antimicrobials or antivirals depending on the clinical judgment of the treating physician."
The CDC has established the following case description for SARS:
Clinicians should be alert for people with onset of illness after Feb. 1, 2003, with these symptoms:
And with one or more of these symptoms:
Initial diagnostic testing should include chest radiograph, pulse oximetry, blood cultures, sputum Gram’s stain and culture, and testing for viral respiratory pathogens, notably influenza A and B and respiratory syncytial virus. Clinicians should save any available clinical specimens (respiratory, blood, and serum) for more testing until a specific diagnosis is made. They should evaluate people meeting those description and, if indicated, admit them to the hospital. Close contacts and health care workers should seek medical care for symptoms of respiratory illness.
(For an update on this developing story, go to: www.HIConline.com, your free subscribers’ web site.)