How SARS Works

SARS Symptoms and Treatment

Originally, the World Health Organization (WHO) defined severe acute respiratory syndrome (SARS) as an "atypical pneumonia of unknown etiology." In other words, we recognized it as a form of pneumonia, but we didn't know its cause. However, thanks to infectious disease experts, scientists, epidemiologists and other research specialists from all over the globe we now know that SARS is caused by a new coronavirus. According to Dr. David Heymann of the World Health Organization,

This network of laboratory directors has been meeting by telephone, sharing on a secure web site for the past four and a half weeks. It is very interesting because these laboratory directors have put aside profit, certainly prestige, and national pride to work together to help put into the public domain the information that is so necessary to learn about this disease. And it has been done in record time.

SARS Symptoms

Here are the major known facts and symptoms of SARS:

  • The incubation period ranges from 2 to 10 days. This means that once someone has been exposed, it can take anywhere from 2 to 10 days for symptoms to occur. Some authorities have reported incubation periods of as many as 14 days, but this is not currently considered the norm.
  • The initial indication of infection is a fever of 100.4 degrees Fahrenheit or more (38 degrees Celsius or more). Chills, headache, muscle soreness and a general feeling of discomfort are also common.
  • A dry, unproductive cough develops after 3 to 7 days. The cough can be accompanied by or eventually result in hypoxemia (a condition characterized by a reduced concentration of oxygen in the blood). Approximately 10 to 20% of infected patients require some type of assistance in breathing -- either through intubation or mechanical ventilation.

SARS Treatment

Although the causeative agent has now been identified, more research is needed to identify a cure. For now, the Centers for Disease Control (CDC) and the World Health Organization (WHO) recommend that healthcare workers treat the symptoms of SARS in the same way they would handle any other unknown form of atypical pneumonia.

Although the effectiveness is uncertain, reported regimens include the administration of:

  • antibiotics
  • antiviral agents like oseltamivir or ribavirin
  • a combination of steroids and antimicrobials

Let's take a look at what causes SARS and some of the other possibilities scientists initially considered.