What started off as a “mystery illness” in China has begun to spread around the globe and has gained worldwide recognition as severe acute respiratory syndrome (SARS). Fears of this epidemic have prompted Hong Kong officials to close schools, residents of Toronto to wear surgical masks on public transportation, and people around the world to think twice before boarding an airplane.

To a certain extent, the caution is justified. As of April 2, 2003, there have been more than 1,500 reported cases of SARS around the world including 806 cases in China, 685 cases in Hong Kong, 92 cases in Singapore, 69 cases in the United States, and 53 cases in Canada. Though there have not been any SARS-related deaths in the United States as yet, four Canadians have died from the disease, as have 34 people in China, 16 people in Hong Kong, and three in Singapore.

Perhaps the most unsettling thing about SARS is how little is known about it. In two articles released early by the New England Journal of Medicine ( NEJM ), scientists from Hong Kong and Canada detail their epidemiologic, diagnostic, and clinical findings from SARS patients in their respective countries. This information should help define the signs and symptoms of the condition, what can be done to diagnose and treat it, and how to help avoid transmission.

About the Study

In the first article, scientists reported on the signs, symptoms, and progression of disease in 10 patients who were diagnosed with SARS in Hong Kong between February 22, 2003 and March 22, 2003. Each of these patients had either direct or indirect contact with at least one of the other patients in the study. X-rays and microbiology tests were performed on each patient.

In the second article, scientists analyzed data they collected from the first ten cases of SARS to be diagnosed in Canada.

The Findings

Hong Kong Cases

The patients in Hong Kong comprised five men and five women aged 35 to 72. All of the cases stemmed from direct or indirect contact with the first case of SARS to be identified in Hong Kong, a physician who had worked in a hospital in southern China.

All patients were admitted to the hospital with a fever greater than 100.4 degrees Fahrenheit, nine of the ten with severe, shaking chills. All patients began to have labored breathing between three to seven days of the onset of fever. More than half of the patients also reported a dry cough, a general feeling of ill health, and headache when they entered the hospital.

On examination, doctors could hear evidence of fluid in the chest and all but one patient had an abnormal chest x-ray, showing evidence of fluid in the air spaces. Examination of respiratory secretions did not detect the presence of any common viruses or bacteria including influenzavirus A and B, adenovirus, C. pneumoniae , M. pneumoniae , or pneumococcus.

All patients were treated with corticosteroids and ribavirin, an antiviral agent.

At the time the NEJM paper was written, two of the SARS patients had died of progressive respiratory failure. One patient had made a complete recovery.

Canadian Cases

Of the first ten people diagnosed with SARS in Canada—six men and four women aged 24 to 78—all except one had close contact with at least one other patient.

The most common symptoms in these patients were:

  • Fever (10/10 patients)
  • Dry cough (10/10)
  • Labored breathing (8/10)
  • Malaise (7/10)
  • Diarrhea (5/10)

Upon investigation, physicians also found:

  • Abnormal chest x-rays indicative of fluid in the lungs (9/9)
  • Reduction in the number of lymphocytes (immune cells) (8/9)
  • Elevated levels of various enzymes that accumulate in the blood when the liver, kidneys, muscles heart and/or brain are diseased or injured (4/5)

Seven of the patients were treated with antiviral agents and broad-spectrum antibiotics; the other three were treated with broad-spectrum antibiotics alone. Five of the patients required a respirator.

Laboratory tests were negative for all bacteria and fungi. However, they were positive for two viruses—metapneumovirus and a new coronavirus—in five of six patients (both viruses were isolated in four of the patients).

Of the ten original patients, three have died, and five have had clinical improvement.

How Does This Affect You?

The fact that NEJM decided to release these case studies early indicates the concern SARS has raised among health professionals. From these descriptions it appears that SARS is a contagious, rapidly progressive, infectious disease that can infect even healthy adults within 10 days of even minimal contact. The cause of the disease is not yet known, although metapneumovirus and a new coronavirus may play a role.

The U.S. Centers for Disease Control (CDC) have defined SARS as the following (this definition will evolve as more is learned about the condition):

  • Fever greater than 100.5 degrees Fahrenheit


  • Clinical evidence of respiratory illness


  • Travel within 10 days of onset of symptoms to an area with documented or suspected community transmission of SARS


  • Close contact within 10 days of onset of symptoms with either a person with a respiratory illness who traveled to a SARS area or a person known to be a suspect SARS case

Although SARS is clearly a serious concern, caution rather than fear is in order. Many illnesses at this time of year share symptoms in common with SARS. The main distinguishing factor between SARS and the flu, for example, is whether there was contact with someone who is suspected or known to have SARS.

Not everyone who comes in contact with SARS will contract it. For example, the wife of one of the patients in the Hong Kong study who had shared a hotel room with her husband during the early part of his illness has not contracted SARS. In addition, SARS has resulted in death in a minority of patients; some SARS patients have made a full recovery.

In order to stem further spread of SARS, the World Health Organization (WHO) has recommended that people avoid all but essential trips to Hong Kong and the Guangdong Province of China. Check the CDC and WHO Web sites (see Resources, below) for current information and recommendations about SARS.