Infection Control May Minimize Spread of SARS. (Travel History Essential)

Article excerpt

Standard infection control precautions may have been key in minimizing the spread of severe acute respiratory syndrome in the United States, said Dr. Irwin M. Berlin, chief of pulmonary critical care at Elmhurst (N.Y) Hospital Center.

"In retrospect and after reviewing the data, I think that's why in China and Hong Kong things spread so quickly mini daily to health care workers. As I understand it, their infection control practices were lax," Dr. Berlin told this newspaper. His institution is one of two New York City hospitals designated to treat these cases.

In U.S. hospitals, patients are put in isolation once severe acute respiratory syndrome (SARS) is even suspected, he said. "Standard or routine precautions are instituted immediately."

The Centers for Disease Control and Prevention recommends handwashing and use of an N95 particulate respirator, gowns, gloves, and eye protection by health workers who care for patients suspected of having SARS.

"It's nothing different for a hospital that is giving smallpox vaccinations to first responders or giving out information about how to deal with radiation effects. ... It's all part of preparedness, and we're at a high level of that right now," Dr. Berlin commented.

The SARS outbreak may turn out to be a good test of the nation's reinvigorated public health warning and treatment system. "We've been on the lookout for [a bioterrorism event] for about a year and a half, so in a sense the handling of SAPS for us is like a dress rehearsal," he remarked.

Dr. Mark Metersky disagreed. "I think we got lucky."

The United States doesn't have the same population density and it does have better sanitation and ventilation than the hardest-hit areas of Asia, noted Dr. Metersky of the division of pulmonary and critical care at the University of Connecticut, Farmington. "We also had some warning, so that we knew to practice isolation with suspected cases."

In late February 2003, the World Health Organization (WHO) and CDC began investigating a multicountry outbreak of atypical pneumonia with an unknown etiology that apparently first appeared in the southern Chinese province of Guangdong as early as last November.

Patients with suspected SARS present with a fever or history of fever--low-grade initially but higher after 2-7 days--and dry coughing, Dr. Berlin said. Because these symptoms are very common, travel history is key.

Dr. Metersky agreed: "If you have a febrile patient with a respiratory illness, ask about travel history." Until a definitive test is developed, exposure and travel history are a vital part of the diagnosis.

Thirteen laboratories worked around the dock for 4.5 weeks to identify the cause of the outbreak. In mid-April WHO announced that a new coronavirus is the primary culprit. However, researchers have not ruled out that human metapneumovirus or chlamydia (both identified in some SARS patients) may also have a role.

Developing a diagnostic test has proved problematic. Three tests in development have limitations as tools to control the spread of SARS, the WHO said. Enzymelinked immunosorbent assay detects antibodies reliably but only after 20 days from the onset of symptoms. The second test--an immunofluorescence assay--can detect antibodies reliably at about day 10 of the infection but is slow because it requires the growth of the virus in cell culture. The polymerase chain reaction test for viral genetic material, although useful in early stages of infection, has a high false-negative rate. Work continues to improve tests, and at press time, a ready-to-use PCR test kit containing primers and positive and negative control had been developed. WHO network laboratories are testing the kit.

Patients who present with shortness of breath and an infiltrate on x-ray should first be treated according to CDC standards for community-acquired pneumonia, Dr. Berlin said. …