How SARS Works

SARS Cases

Since SARS cases began popping up early this year, scientists from all over the world have been searching hurriedly for a cause. According to the CDC, scientists had found a "previously unrecognized coronavirus in patients with SARS." This coronavirus was believed to be the leading contender in the list of possibilities. On April 16, 2003, WHO confirmed that theory. Thirteen laboratories have been urgently participating in the SARS investigation. In a recent WHO SARS update, Dr. Klaus Stohr stated:

All the data have been put on the table, have been reviewed, and the colleagues have come to a consensus agreement. We can now say that the disease called SARS, which was first reported on 12 March, exactly five weeks ago, is being caused by the coronavirus. WHO will call this coronavirus SARS virus.

Named for its distinguishing crown-like appearance, coronaviruses are commonly associated with upper-respiratory disease and have, on occasion, been connected to pneumonia. What makes this unusual is that in the previous cases of related pneumonia, many of the patients had weakened immune systems. Most SARS cases have been found in adults who were healthy prior to infection. And, while coronaviruses have been a known culprit in acute sickness among animals (such as dogs, cats and pigs), this has not been common among humans. Researchers have been investigating the possibility that this coronavirus jumped between species.

This would not be the first time a disease has migrated from animal to man. All of these conditions were first evident in animals:

Clinical research has also detected a paramyxovirus in specimens from patients infected with SARS. Among humans, viruses in this family cause conditions such as the mumps and measles.

The presence of the paramyxovirus initially caused scientists to consider a double etiology. Perhaps SARS could be a result of the two viruses working together. Further research does not support this theory. However, it doesn't exclude the possibility that the presence of other viruses, like the paramyxovirus, could worsen a SARS patient's condition. According to Dr. Albert Osterhaus:

The conclusion today, the people in the network agreed, that the coronavirus alone is capable of causing the typical symptoms. We cannot formally exclude that other agents, such as the human metapneumovirus, and the chlamydia that has been found in China, or a number of other viruses after you have this primary infection with the coronavirus, would eventually aggravate the situation.

Now that the SARS virus has been identified, scientists can concentrate their research on developing tests to identify people infected with SARS and creating drugs to treat and cure the condition.

For now, since there is no specific antiviral treatment, the most effective combatant is control. To curtail the spread of SARS, healthcare workers are adhering to strict safety procedures. But as we've seen, the condition has already spread around the world.

Let's look at how SARS has managed to move from continent to continent.